Enterobacter Sakazakii Blog

Enterobacter sakazakii found rarely in infant formula

Bill Marler — Wed, 23 Dec 2009 05:33:37 -0800

The Centre for Food Safety (CFS) recently conducted a targeted food surveillance to assess the situation of Enterobacter sakazakii in powdered infant formula. "Enterobacter sakazakii can be found in the environment, but it generally causes disease only in people with weakened immune systems. Enterobacter sakazakii can cause invasive infection such as bacteria in blood or brain infection.

Pre-term infants, neonates (28 days old or below), infants less than 2 months of age, low-birth-weight infants (below 2.5 kg) and infants with weakened immunity, are at greater risk," a CFS spokesman said today (December 21). The centre collected 100 samples of powdered infant formula from the local market for testing of Enterobacter sakazakii. The samples, which involve 17 different brands, are from different countries.

All results were satisfactory. "The World Health Organisation recommends that infants should be exclusively breastfed for the first six months of life to achieve optimal growth, development and health. For those who are not breastfed, risk of infection can be greatly reduced by correctly preparing and storing the powdered infant formula.

Reconstitution of powdered infant formula with water that is no less than 70 degrees Celsius can significantly inactivate Enterobacter sakazakii. Feeds prepared in advance should be cooled immediately after preparation, stored in a refrigerator and used within 24 hours of preparation. Reconstituted feed should be re-warmed, no more than 15 minutes, immediately before feeding," the spokesman said.

"For high-risk infants who cannot be breastfed, caregivers should use commercially sterile liquid formula," he added. The spokesman also urged the trade to implement preventive measures (such as good manufacturing practice) as well as monitoring and environmental management programmes to reduce the risk of product contamination.

Cronobacter sakazakii Isolated in Two Infants in New Mexico, 2008

E. Sakazakii Lawyer — Tue, 03 Nov 2009 13:10:14 -0800

In the October 30, 2009, edition of its weekly MMWR publication, the Centers for Disease Control and Prevention (CDC) reported on an investigation in November, 2008, when the Cronobacter sakazakii bacteria was isolated in two different infants. As recognized by the CDC, isolation of this organism from human specimens is rare and makes these cases notable. Cronobacter sakazakii (formerly Enterobacter sakazakii) are rare causes of infant septicemia and meningitis, resulting in death in approximately 40% of cases. Since 1958, 120 cases of Cronobacter sakazakii infection in infants have been reported, an average of fewer than three cases per year worldwide. Powdered infant formula (PIF), which is not sterile, has been implicated repeatedly as a vehicle of Cronobacter infection. This report provides important additional information regarding this elusive pathogen, and updates the CDC’s recommendations regarding safer PIF preparation, storage, and handling.

The Cronobacter sakazakii bacteria were isolated from two non-hospitalized, unrelated infants in November, 2008, in New Mexico. The CDC and FDA investigators determined that the female infant had been infected with Cronobacter sakazakii, and that the male infant had been colonized with Cronobacter sakazakii, without clear evidence of infection. Ingestion of PIF was the only identified risk factor for Cronobacter sakazakii exposure for the two infants. The two infants had consumed the same brand of PIF but had no other common exposures. The female infant had documented Cronobacter sakazakii infection that led to severe brain injury and hydrocephalus. Although a Cronobacter sakazakii organism was isolated from the male infant at autopsy, the role of that organism in the infant's apparent death from SIDS is unknown.

The two infants had consumed the same brand of formula, but their clinical Cronobacter sakazakii isolates had different Pulsed Field Gel Electrophoresis (PFGE) patterns. None of the samples obtained from the home of the female infant yielded Cronobacter sakazakii. Samples taken from the home of the male infant, however, provided positive results for Cronobacter sakazakii. An opened can of PIF yielded a Cronobacter sakazakii isolate with a PFGE pattern that was indistinguishable from the clinical Cronobacter sakazakii isolate from the male infant. Additionally, the vacuum cleaner filter from the home of the male infant also yielded Cronobacter sakazakii, but with a different PFGE pattern than the PFGE pattern isolated in both the male infant and the open PIF can.

The CDC reaffirmed in this report that prior investigations have found Cronobacter sakazakii cultured from prepared formula, unopened PIF containers, and the environment where PIF was reconstituted, clearly implicating PIF as the source of outbreaks. Other than an improperly prepared intravenous nutrition solution implicated in one outbreak, no other clear source of Cronobacter sakazakii infection has been identified to date. Accordingly, the report recommended that preparers should be aware that PIF is not sterile and can contain pathogenic organisms, such as Cronobacter sakazakii. The report also recommended that WHO guidelines for preparation of PIF, including reconstitution with water hot enough to inactivate Cronobacter sakazakii, be adopted, for safer PIF preparation, storage, and handling. In the United States and elsewhere, present recommendations are: to breastfeed infants when possible; to use sterile liquid infant formula in high-risk settings (e.g., neonatal intensive-care units and hospital nurseries); and to adhere to the safest available PIF preparation procedures. Interestingly, the CDC report noted that the manufacture of sterile powdered infant formula, perhaps by using irradiation in combination with other techniques, could prevent infant disease. Finally, the CDC stated that further precautions to prevent extrinsic contamination of PIF are needed, including the engineering of PIF packaging to prevent introduction of contaminated hands, scoops, or other items.

The complete report is accessible at MMWR. 2009:58;1179-1183.

The Naming Of Cronobacter Sakazakii

E. Sakazakii Attorney — Mon, 28 Sep 2009 06:10:02 -0800

"Classifications are theories about the basis of natural order, not dull catalogues compiled only to avoid chaos." Stephen Jay Gould, Wonderful Life (1989), 98.

Enterobacter sakazakii, a gram-negative bacillus, is a rare cause of bloodstream and central nervous system infections. In 2007, following extensive study, it was proposed that the original taxonomy of Enterobacter sakazakii be revised, to consist of five new species moved to a new genus, identified as "Cronobacter". (1) A review of the what, the how, and the why the change was first proposed, and why it was eventually approved, provides an insight into the related scientific process of taxonomy at work, involving this notorious neonatal pathogen.

Initially, taxonomy is the science of classifying organisms, identifying and naming species, and organizing them into systems of classification. At least 1.7 million species of living organisms have been discovered, and the list grows longer every year. Ideally, classification should be based on homology, i.e., the shared characteristics that have been inherited from a common ancestor. Until recent decades, the study of homologies was limited to anatomical structures and pattern of embryonic development. However, since the birth of molecular biology, homologies can now also be studied at the level of proteins and DNA. (2)

More specifically, E. sakazakii is a rare, but life-threatening cause of neonatal meningitis, sepsis, and necrotizing enterocolitis. In general, E. sakazaii kills 40-80 % of infected newborns diagnosed with this type of severe infection. (5) E. sakazakii meningitis may lead to cerebral abscess or infarction with cyst formation and severe neurologic impairment. E. sakazakii can cause a variety of infections, though central nervous system infection has been most commonly described. (6) For infants, infection typically manifests through signs of sepsis in the first week of life: irritability or lethargy, temperature instability, and feeding intolerance. Meningitis often produces overwhelming infection that rapidly moves through cerebral hemorrhage, infarct, necrosis, liquefaction, and eventually, cyst formation. (7)

E. sakazakii invasive infections occur more frequently in infants than in older children. (9) The neonate's immature immune system may increase the risk of acquiring an E. sakazakii infection. (10) In a study of E. sakazakii cases over a 47 year period, investigators found that the median age at infection onset was two days and 94% of cases were less than 28 days old. (11)

While the reservoir for E. sakazakii is unknown in many cases, a growing number of reports have established powdered infant formula as the source and vehicle of infection. In several investigations of outbreaks of E. sakazakii infection that occurred among neonates in neonatal intensive care units, investigators were able to show both statistical and microbiological association between infection and powdered infant formula consumption. These investigations included cohort studies which implicated infant formula consumed by the infected infants. In addition, there was no evidence of infant-to-infant or environmental transmission; all cases had consumed the implicated formula. The stomach of newborns, especially of premature babies, is less acidic than that of adults: a possible important factor contributing to the survival of an infection with E. sakazakii in infants. (13)

The first cases attributed to this organism occurred in 1958 in England (Urmenyi and Franklin, 1961). Since then, up to July 2008, around 120 documented cases of E. sakazakii infection, and at least 27 deaths, have been identified from all parts of the world in the published literature and in reports submitted by public health organizations and laboratories. (12)

E. sakazakii used to be previously known as a "yellow pigmented Enterobacter cloacae", until 1980. E. sakazakii was first defined as a novel species in 1980, when it was introduced as a new species based on differences in DNA-DNA hybridization, biochemical reactions, and antibiotic susceptibility. The bacteria was named sakazakii in honour of the Japanese microbiologist, Riichi Sakazaki, when the species was first designated in 1980. (15) Enterobacter sakazakii (E. sakazakii) then became identified as one of sixteen distinct species in the genus Enterobacter, within the Enterobacteriaceae family. (14)

From the beginning, however, many different biogroups were defined as E. sakazakii, with the existence of these divergent geno- and biogroups suggesting that E. sakazakii could in fact represent multiple species. (14) Accordingly, in 2007, a research group clarified the taxonomic relationship among the various E. sakazakii strains, by using sophisticated new means of viewing and analyzing the bacteria. Iverson et al were thus able to distinguish numerous separate species. Their work resulted in the proposal of an alternative classification of E. sakazakii into a new genus, Cronobacter. (16)

The new techniques used by the research group provide clear proof of the substantial advances made in molecular biology, and included f-AFLP, automated ribotyping, full-length 16S rRNA gene sequencing and DNA-DNA hybridization. (14) F-AFLP (fluorescent amplified fragment length polymorphism) is a means to genotype bacteria, by selecting pre-adapted fragments of DNA and amplifying them to easily detectable and accurately sizeable concentrations. Automated ribotyping is a genotyping method that can be used to generate genetic fingerprints of bacterial isolates. Full-length 16S rRNA gene sequencing provides a means to compare a stable part of the genetic code (the 16S rRNA gene) amongst different bacteria. The technique of DNA-DNA hybridization provides genetic comparisons amongst the total genome of two species.

E. sakazakii has thus now been reclassified as 6 separate species in the new genus, Cronobacter, gen. nov., within the Enterobacteriaceae family. The new species are presently Cronobacter sakazakii; C. turicensis; C. malonaticus; C. muytjensii and C. dublinensis; the sixth species is identified simply as genomospecies I, as currently it includes only two representative strains. (19)

The name Cronobacter was appropriately derived from Greek mythology. E. sakazakii constitutes a microbiological hazard in the infant food chain, with historic high mortality in neonates. Accordingly, it was named after the Greek mythological god, Cronos. (17). Cronos was the son of Uranus (Heaven) and Gaea (Earth), being the youngest of the 12 Titans. He eventually became the king of the Titans, and took for his consort his sister Rhea. Rhea bore him a number of children, including Hestia, Demeter, Hera, Hades, and Poseidon. Cronos, however, had been previously warned by his parents that he would be overthrown by his own child. Accordingly, he swallowed all those children. When Zeus was born, however, Rhea hid him in Crete, and tricked Cronus into swallowing a stone instead. Zeus grew up, forced Cronus to disgorge his brothers and sisters, waged war on Cronus, and was victorious. (18)

It was proposed that these species be moved to the new genus, "Cronobacter", in order to facilitate their identification for the diagnosis of infection and the microbiological monitoring of food products. (20) All these species have been linked retrospectively to clinical cases of infection in either infants or adults, and therefore all these species should be considered pathogenic. (21) The correct and more detailed identification of these organisms will improve the understanding of the broader epidemiology of the members of the new genus.  

It is also important, however, that this reclassification of species not be detrimental to health protection measures already in place, and that all these risk organisms continue to be recognized. (22) As the genus Cronobacter is synonymous with Enterobacter sakazakii, current identification schemes developed for E. sakazakii remain applicable for the Cronobacter genus. The reclassification of E. sakazakii to the new genus Cronobacter will not require the modification of dedicated culture-based laboratory isolation and detection protocols. All currently valid laboratory methods will continue to facilitate the recognition of all of the organisms defined within the new taxonomy. (23) Furthermore, the reclassification does not require any change to the regulatory framework currently in place. (24)

REFERENCES:

(1) Iversen, C., Lehner, A., Mullane, N., Marugg, J., Fanning, S., Stephan, R., and Joosten, H., "Identification of 'Cronobacter' spp. (Enterobacter sakazakii)", Journal of Clinical Microbiology, Nov. 2007, Vol. 45, No. 11, p. 3814-3816.

(2) Kimball's Biology Pages, http://www.ultranet.com/~jkimball/BiologyPages/ (9/25/2009)

(3) Dauga, C and Breeuwer, P Taxonomy and Physiology of Enterobacter sakazakii, in ENTEROBACTER SAKAZAKII. Washington D.C.: ASM Press; 2008:1 (Farber, JM and Forsythe, SJ editors).

(4) Bowen AB, Braden CR. Invasive Enterobacter sakazakii disease in infants. Emerg Infect Dis [serial on the Internet]. 2006 Aug publication. Available from http://www.cdc.gov/ncidod/EID/vol12no08/05-1509.htm.

(5) Bowen, AB and Braden, CR Enterobacter sakazakii Disease and Epidemiology. Farber, JM and Forsythe, SJ ed. ENTEROBACTER SAKAZAKII. Washington D.C.: ASM Press; 2008:104.

(6) Id.

(7) Id.

(8) Id.

(9) "Enterobacter sakazakii and other microorganisms in powdered infant formula" Microbiological Risk Assessment Series 6, World Health Organization (2004).

(10) "Enterobacter sakazakii (Cronobacter spp.) in follow-up formula", Microbiological Risk Assessment Series 15- FAO/WHO (2008).

(11) Iversen, C., A. Lehner, N. Mullane, E. Bidlas, I. Cleenwerck, J. Marugg, S. Fanning, R. Stephan, and H. Joosten. 2007. "The taxonomy of Enterobacter sakazakii: proposal of a new genus Cronobacter", 1. BMC Evol. Biol. 7:64

(12) "Enterobacter sakazakii (Cronobacter spp.) in follow-up formula", Microbiological Risk Assessment Series 15- FAO/WHO (2008).

(13) Id.

(14) Iversen, C., A. Lehner, N. Mullane, E. Bidlas, I. Cleenwerck, J. Marugg, S. Fanning, R. Stephan, and H. Joosten. 2007. "The taxonomy of Enterobacter sakazakii: proposal of a new genus Cronobacter", 1. BMC Evol. Biol. 7:64.

(15) "Enterobacter sakazakii (Cronobacter spp.) in follow-up formula", Microbiological Risk Assessment Series 15- FAO/WHO (2008).

(16) Id.

(17) Iversen, C., A. Lehner, N. Mullane, E. Bidlas, I. Cleenwerck, J. Marugg, S. Fanning, R. Stephan, and H. Joosten. 2007. "The taxonomy of Enterobacter sakazakii: proposal of a new genus Cronobacter", 1. BMC Evol. Biol. 7:64.

(18) "Cronus." Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 21 Sep. 2009.

(19) Iversen, C., Lehner, A., Mullane, N., Marugg, J., Fanning, S., Stephan, R., and Joosten, H., "Identification of 'Cronobacter' spp. (Enterobacter sakazakii)", Journal of Clinical Microbiology, Nov. 2007, Vol. 45, No. 11, p. 3814-3816.

(20) "Enterobacter sakazakii (Cronobacter spp.) in follow-up formula", Microbiological Risk Assessment Series 15- FAO/WHO (2008).

(21) Iversen, C., Lehner, A., Mullane, N., Marugg, J., Fanning, S., Stephan, R., and Joosten, H., "Identification of 'Cronobacter' spp. (Enterobacter sakazakii)", Journal of Clinical Microbiology, Nov. 2007, Vol. 45, No. 11, p. 3814-3816.

(22) "Enterobacter sakazakii (Cronobacter spp.) in follow-up formula", Microbiological Risk Assessment Series 15- FAO/WHO (2008).

(23) Id.

Cronobacter sakazakii advice, policy and research in Canada

E. Sakazakii Attorney — Wed, 26 Aug 2009 09:11:13 -0800

Editor's Note: We return to one of the presentations made at last January's Dublin conference on Cronobacter sakazakii. This one by Dr. Jeff Farber of Health Canada.

Biography: Dr Jeffrey M. Farber gained an MSc and PhD from McGill University, Montreal, Canada, in Medical Microbiology & Immunology and Food Microbiology respectively. He worked as a research scientist and as Division Chief in the Microbiology Research Division before becoming Associate-Director of the Bureau of Microbial Hazards Food Directorate, Health Products and Food Branch, Health Canada where he is currently the Director. Dr Farber`s major interests are Listeria monocytogenes, Enterobacter sakazakii in foods, produce safety, molecular typing, food safety risk assessment and policy. He is a member of the Editorial Board of the International Journal of Food Microbiology; a reviewer for a number of other Journals; and Content Editor for IAFP Report. He is also an Adjunct Professor, at the University of Ottawa where he co-supervise undergraduate and graduate students; sits on a number of graduate student advisory committees; and is a member of thesis committees. Dr Farber is the treasurer of the International Commission on the Microbiological Specifications for Foods (ICMSF), and is a Past-President of the International Association for Food Protection.

Cronobacter sakazakii advice, policy and research in Canada

Although Canada has not had many reported cases of Cronobacter sakazakii, Health Canada has been actively studying this organism since 1998. In 2002, as a result of an outbreak in Tennessee in the USA, Health Canada issued an advisory to inform Health Professionals in Canada what measures they could take to reduce the risk to infants, of consuming powdered-infant formula (PIF).

After reviewing the situation at the national level and due to health concerns with powdered formulae and its international trade, in 2003, Health Canada raised this issue at the international level by proposing to revise the Code of Practice for Powdered Formulae for Infants and Young Children at the Codex Alimentarius Committee of Food Hygiene.

Canada volunteered to chair the Working Group that would be developing the Code. Because of the high level of interest in this issue, the Code was completed in four years, which is a relatively short time considering the complexity and politics behind this issue. The Code has contributed to a big improvement in the hygienic conditions in plants manufacturing PIF, resulting in a lower level of product contamination with C. sakazakii. Canada has produced a document detailing Good Manufacturing Practices (GMPs) for Infant Formula in Canada.

The purpose of this text is to establish and document the current GMPs for the production and quality control of infant formula products made for distribution in Canada. Health Canada uses the GMPs as a basis on which to assess the manufacturing information received in pre-market notifications for new or changed infant formulas.

Health Canada does have microbiological criteria for C. sakazakii in PIF; however, they are currently being revised to be more in line with recent Codex thinking. At present, unfortunately, there are no active or passive surveillance systems for C. sakazakii, in Canada, although this has been discussed.

Health Canada has recently adapted and condensed FAO/WHO guidelines to develop a draft guidance document on the preparation and handling of PIF in home and hospitals/care settings, which outline requirements for parents, caregivers, and staff in hospitals and day-care centers. The guidance document can be used to educate parents, caregivers and staff in hospitals and day-care centres, on the potential hazards associated with PIF.

Health Canada’s Bureau of Microbial Hazards conducts research focussed at examining the ecology, biology and pathogenesis of the organism. Some of the research projects include specific aspects of molecular typing, virulence studies involving animal models, as well as in-vitro tissue culture work to examine adhesion and invasion. Collaborative research is also being done with the National Research Council, using NMR and mass spectroscopy to reveal the structure of the O- polysaccharide of the various Cronobacter species. For more, see his Powerpoint.

South Korea's Maeil Dairy Baby Formula Contaminated With Enterobacter Sakazakii

E. Sakazakii Attorney — Mon, 13 Jul 2009 17:53:28 -0800

From news services in Seoul comes world that a South Korean baby formula is contaminated with Enterobacter sakazakii, the baceria that can cause meningitis in infants.

South Korea's National Veterinary Research and Quarantine Service (NVRQS) said Enterobacter sakazakii bacteria was found in 695kg of powdered milk made by Maeil Dairies Co. June 17. The discovery was made during regular sample testing by the agency under the food and agriculture ministry.

The government agency said the 53,460 individual 13g packages were contaminated overall, although none had reached the retail market.

Enterobacter sakazakii or Cronobacter poses particular risks to babies under six months old or weighing under five and half pounds. However, it poses no threat if mixed with boiling water exceeding 158 decrees.

"Investigators are trying to find the cause of the contamination that may have been related to the manufacturing process or the ingredients used," an NVRQS official said.

He said all products suspected of being tainted with the bacteria are currently in a holding area and will be destroyed, with Maeil ordered to take steps to prevent a recurrence.

The products contaminated were all disposable packages of the company's Premium Goong 1 baby formula. Larger cans containing the formula were not tainted with the bacteria.

According to financial websites: Maeil Dairy Industry Co., Ltd. with annual sales in the $1 billion range produces baby foods, beverages, yogurts, and soybean milk products. It also offers milk, fermented milk, cheese, nutritional meals for the pregnant, and oil products. In addition, the company imports and supplies chocolates, olive oil, and grape seed oil. Its products are used in hotels, restaurants, bakeries, and coffee franchises. Maeil Dairy Industry Co., Ltd. offers its products through contracted distributors. The company exports its products to Saudi Arabia, Jordan, Syria, Sudan, Egypt, the United Arab Emirates, China, Japan, Hong Kong, Macao, Singapore, Vietnam, Bangladesh, Afghanistan, the United States, Guam, Canada, Mexico, and the Russian Federation.

Codex Addresses Powdered Formula For Infants Out Of Concern About E. Sakazakii

E. Sakazakii Attorney — Mon, 06 Jul 2009 11:54:48 -0800

The Codex Alimentarius Commission (CAC) adopted 30 new international standards and guidelines to improve food safety and protect consumers, including some that impact powdered infant formula. The Codex changes came during a just ended week-long meeting.

The Commission adopted criteria for salmonella and other bacteria in powdered follow-up formulae for children six months of age or older and for special medical purposes for young children.

A bacterium of special concern is E. sakazakii, for which Codex adopted specific criteria for powdered formula for infants (0 to 6 months) in 2008. The Commission decided that in countries with particular risk for E. sakazakii from consumption of follow-up formulae (i.e. countries with substantial populations of immunocompromised babies) similar criteria for E. sakazakii could be introduced for follow-up formula as for powdered formula for infants.

Follow-up formulae should only be used for the intended target population. Unfortunately, they are often consumed by babies younger than six months of age. The standard stresses the need to address such product misuse issues through education campaigns and training.

Codex, established in 1963, has 181 member states plus the European Community. It is an offshoot of the United Nations.

Nestle Role In Alberta Conference Called Into Question

E. Sakazakii Attorney — Sun, 05 Jul 2009 13:23:29 -0800

1st Annual Canadian Perinatal & Pediatric Nutrition Conference

Date & Time: September 25 - 26, 2009, 8:15 a.m. - 4:30 p.m.

Location: Bernard Snell Hall, University of Alberta Hospital

City/Town: Edmonton, AB

Description: This conference features two full days on obesity, allergies and other nutritional "hot topics" with expert faculty from across North America. It will be of interest to all those working with infants, children and nutrition including physicians, nurses, dietitians and pharmacists.

Early Bird Registration: $350
After August 15th: $400
One-day and student rates are also available

More Information: Call 780-735-1359 or e-mail RNFSEduc@cha.ab.ca

OUR COMMENT: This is the conference that the Infant Feeding Action Coalition (INFACT Canada) is out with an alert on, saying that organizers are allowing "unethical marketing" by Nestle.

Here is what INFACT Canada says:

INFACT Canada has learned that a pediatric nutrition conference slated for September has listed Nestlé Nutrition as a major sponsor. The Alberta Health Services First Annual Canadian Perinatal and Pediatric Nutrition Conference being held in Edmonton on September 25-26 is not only being sponsored by Nestlé, but one of its speakers will be a Nestlé employee.

It is a serious conflict of interest for a public health agency such as Alberta Health Services (AHS) to stage a pediatric nutrition conference in partnership with an infant formula manufacturer like Nestlé. Nestlé is notorious for its aggressive marketing of infant formula and obstinate rejection of the WHO International Code of Marketing of Breastmilk Substitutes. The company recently launched a deceptive marketing campaign claiming that probiotics added to its formula will mimic the bifidus factor of human milk. It is no coincidence that one of the conference’s themes will be probiotics in infant nutrition.

As reported in a previous INFACT email, Nestlé’s new formula contains so-called “natural cultures” of bifidus bacteria, which are found in breastmilk. The company is marketing the new brand as equivalent to breastmilk. “There are only two places your baby can get natural cultures,” reads the advertising tagline, “The first is you. The other is from Nestlé Good Start Natural Cultures.” No scientific study is cited as proof that the bacterial cultures in this formula have the same effect on infants as breast milk.

We've seen no response to this from Alberta Health Services, the conference organizer.

Dr. Keith Lampel From U.S. Food & Drug Administration (FDA) Addresses Standard Method Of Detection

E. Sakazakii Attorney — Wed, 10 Jun 2009 08:35:02 -0800

Editor's Note: We continue presentations from the international Cronobacter conference held earlier this year in Ireland. In this segment, we hear from the USA's Dr. Keith Lampel from FDA.

Biography: Dr. Keith Lampel is director of the Division of Microbiology at the U.S. Food & Drug Administration (FDA). He joined the FDA as a research microbiologist in 1987 after five years as a senior staff fellow at the National Institutes of Health, National Institute of Neurological Disorders and Stroke.
Dr. Lampel received his PhD in Microbiology from the University of Miami and was a postdoctoral fellow at the State University of New York at Stony Brook.
At FDA today, he is responsible for developing bacteriological and molecular-based methods to isolate, detect, and subtype foodborne pathogens. Dr Lampel is also the Editor of FDA’s Bacteriological Analytical Manual and serves as the FDA’s expert on the detection and isolation of the foodborne bacterial pathogen Shigella.
Other professional activities include serving on several editorial boards; NIH and USDA study panels, and ad’hoc review panels for several journals and extramural grant programs. He also serves as an adjunct professor at the University of Maryland and Uniformed Services University of the Health Sciences, and is a member of several PhD dissertation committees.

Summary - Development of an FDA/AOAC standard method for detection of Cronobacter

Although the number of incidences of illnesses caused by the ingestion of the bacterial pathogen Cronobacter (Enterobacter sakazakii) has not been as dramatic as other foodborne pathogens, a need remains for a robust isolation method to recover this microbe from powdered infant formula (PIF).
The current method described on the FDA website was developed in response to one such incident. Although C. sakazakii was a rather novel pathogen in an unusual food matrix, a method was devised quickly and applied to PIF samples. Unfortunately, this method requires multiple steps and at least 3-4 days for complete analysis of PIF for isolation and confirmation of C. sakazakii from the formula sample.
The revised method, however, includes a bacteriological enrichment and isolation protocol as well as the integration of a PCR-based assay. As for the bacteriological application, plating follows one-step enrichment on chromogenic agar(s) for presumptive identification of C. sakazakii. Suspected colonies are confirmed by either biochemical analysis or a real-time PCR-based assay. Therefore, isolation and identification of E. sakazakii from PIF is markedly improved and can be accomplished in 24-28 hrs.

Dr. Lampel's POWERPOINT can be found here

Development of a CEN-ISO horizontal standard method

E. Sakazakii Lawyer — Tue, 02 Jun 2009 08:09:15 -0800

Editor's Note: Another of the presentations follows from last January's 1st International Conference on Cronobacter (Enterobacter Sakazakii) held at University College Dublin. Dr. Han Joosten from the Nestle Research Center in Switzerland addresses the standard method for detection of Cronobacter.

Biography: Dr. Han Joosten is a Senior Scientist at the Nestle Research Center in Lausanne, Switzerland. At Nestle since 1996, he is responsible for providing scientific guidance on various research projects and early identification of emerging microbiological safety issues. He also provides advice to the business and quality management on analytical methods, hurdle technology, safety assessments and HACCP.
After finishing his studies at the University of Nijmegen in the Netherlands in 1983 Joosten worked five years at NIZO Food Research on the formation of biogenic amines in cheese, obtaining his PhD degree from the University of Wageningen on this subject.
From 1989 to 1991 he worked as a postdoc at the Autonomous University of Madrid on molecular characterization of African Swine Fever Virus. After this he headed the microbiological laboratory of Coberco Research in Deventer, the Netherlands and moved back to Spain in 1994 where he worked for two years at the National Instititute for Agricultural and Food Research (CIT-INIA) in Madrid on a bacteriocin-producing Enterococcus strain.

Summary - Development of a CEN-ISO horizontal standard method for detection of Cronobacter
The availability of a reliable and internationally accepted reference method for detection of Cronobacter in powdered infant formula is an essential tool to verify compliance with regulatory requirements by public health authorities and manufacturers. ISO-TS 22964:2006 was developed as a temporary solution for this purpose, but shortly after being issued it was decided to prepare a full-fledged horizontal CEN-ISO standard.
A summary will be given of the work done thus far, in particular with respect to the modifications that are envisaged to address the main shortcomings of TS 22964:

The scope will be extended to all types of powdered infant formula (incl. soy- based) and infant formula ingredients.
It will take into account the latest taxonomical revisions (e.g. definition of the genus Cronobacter and phenotypically related species)
It will no longer use yellow pigment production as a confirmation criterion
The enrichment broth (mLST) and chromogenic isolation agar (ESIATM) are too selective and need to be replaced by media that will also allow the detection of strains that are very susceptible to commonly used inhibitors of gram positive microorganisms.
The main performance characteristics of the new standard will be determined

Based on the results obtained during an extensive comparative/collaborative trial a method based on the utilization of Cronobacter Screening Broth (CSB) in combination with modified DFI agar appears to be the most suitable procedure to be adopted in the new standard.

His POWERPOINT can be found here.

Oxoid Thermofisher Scientist Patrick Duggan Address Culture Media For Isolation and Detection of Cronobacter Species

E. Sakazakii Attorney — Tue, 26 May 2009 07:37:44 -0800

Editor's Note: This is another report on the presentations that were made in Dublin earlier this year at the 1st International Meeting on Cronobacter (Enterobacter Sakazakii). In this segment, we hear from Dr. Patrick Druggan, Oxoid Ltd., Thermo Fisher Scientific, Basingstoke, Hampshire RG24 8PW, United Kingdom.

Biography: Patrick Druggan is Principle Scientist, Oxoid Thermofisher, Basingstoke, UK.

He received an Honours BSc in Food Science from the University of Strathclyde, Glasgow, UK. He has worked in the diagnostics industry for 22 years. He designed his first chromogenic medium in 1989 while working at Gibco.

Patrick studied part-time for his Ph.D. at the Pharmacy Department of University of Brighton, UK. His thesis was on improvements in the resuscitation of heat-injured Salmonella species from processed food samples.

He synthesized a number of autocytotoxic compounds that could be used during pre-enrichment to inhibit competitive microflora while allowing injured Salmonella spp. to resuscitate and grow.

This invention lead to the development of Inhibigens.™ His skills in chemistry and microbiology have allowed him to design a number of successful rapid biochemical tests and chromogenic culture media, including Druggan-Forsythe-Iversen Agar for the isolation of Cronobacter spp.

Summary – - Culture media for isolation and detection of Cronobacter species

In 2001 a pre-term infant died of meningitis caused by Enterobacter sakazakii (Cronobacter spp.). Infant formula milk (IFM) was implicated as a potential source of the infection.

The Food and Drug Administration (FDA) independently develop a method for enumeration of this emerging pathogen in IFM using culture collections from national bodies that have later been shown to be poorly defined.

This method was introduced in 2002 and has regulatory standing for the import of IFM and skimmed milk powder in to the USA and a number of other countries. The FDA method is a modification of the procedure for the detection of Enterobacteriaceae, with the addition of yellow pigmentation of colonies for presumptive identification of Cronobacter spp.

It should be remembered that the FDA method was developed in a short time due to a public health concern, and this would have put a time constraint and significant pressure on those working on Enterobacter sakazakii (Cronobacter) to get a working method in the field as soon as possible. The FDA method has been shown to have a sensitivity of around 50 percent and a specificity of around 70 percent. Only 75 percent of Cronobacter strains phenotypically express yellow pigmentation, and the low specificity of the method coupled with the recommendation that only five presumptive Enterobacteriaceae colonies are tested from Violet Red Bile Glucose Agar (VRBGA) may explain the poor sensitivity of the method.

Assuming the prevalence of Cronobacter spp. in IFM is around 2 percent, the FDA method will fail to detect around 50 percent of batches contaminated with Cronobacter, while around 95 percent of rejected batches will not contain this organism.

This high rate of failure has lead many stakeholders to question the usefulness of the FDA method. This presentation reviews developments in culture media since the release of the FDA method in 2002, with specific emphasis on media that have improved the specificity of methods for Cronobacter spp. The unique phenotypic trait of this emerging pathogen that aid and hinder design of methods is discussed.

POWERPOINT is here.

Dublin's Professor Fanning Speaks About Molecular Identification Methods for Cronobacter spp.

E. Sakazakii Attorney — Tue, 19 May 2009 09:54:01 -0800

Editor’s Note: We next are going to hear from Professor Seamus Fanning of University College Dublin, addressing Molecular identification methods for Cronobacter. He also spoke at the Dublin conference on Cronobacter.

Biography: Seamus Fanning is the Professor of Food Safety & Zoonoses and the Director of the Centre for Food Safety, University College Dublin. Professor Fanning is an editor of Research in Microbiology and a member of the editorial board of the Journal of Food Protection.

Professor Fanning received an Honours BSc in Biochemistry from NUI, Cork, where he also completed his PhD in Microbiology and Molecular Genetics. Current research interests include the application of molecular methods to Food Safety to control zoonotic microorganisms associated with human disease. A significant part of this work relates to the characterization of the genetic mechanisms contributing to the emergence of multiple drug resistance (MDR); the role of membrane bound efflux pumps in MDR and virulence and how these phenotypes are regulated at a local and global level.
Also, in the past few years the UCD Centre for Food Safety has published several papers describing the detection and characterization of Cronobacter. Professor Fanning is a member of the Microbiology Sub-Committee of the Food Safety Authority of Ireland (FSAI), the Scientific Advisory Committee of safe food and was recently appointed by the European Food Safety Authority (ESFA) to a working group to provide expert opinion on the emergence of antibiotic resistance in food. He also served as a member on the FAO/WHO expert panel on Enterobacter sakazakii in follow-up formula.

Summary: Molecular identification methods for Cronobacter spp.

Historically the ancestry of the genus Enterobacter can best be described as nebulus and confusing. In the 1970’s and 1980’s considerable movement of species, originally assigned to this genus occurred, and these re-designations arose because of initial misplacements, based on older phenotypic and morphological approaches to describing taxonomy.
Currently the genus Enterobacter comprises a large and heterogenous group of organisms within the Enterobacteriaceae family being accounted for by 16 distinct species. Enterobacter sakazakii (E. sakazakii) is one of these species and the only member of the genus recognised as a food-borne pathogen. Following a revision of Enterobacter taxonomy, a new genus Cronobacter was devised which is synonymous with E. sakazakii. Cronobacter consists of a least five distinct species and an additional genomospecies, Cronobacter sakazakii (C. sakazakii), C. dublinensis, C. malonaticus, C. muytjensii, C. turicensis and C. genomospecies I. A further three sub-species of C. dublinensis are also recognised. Correct identification of these organisms is important in order to improve our understanding of the broader epidemiology of the members of this new genus.
In recent years there have been rapid improvements in the provision of microbiologically-based culture approaches to isolate and identify these organisms. A number of molecular identification methods have also been proposed, however the recent recognition of multiple species that share less than 70 percent DNA-DNA similarity has important implications for the sensitivity and specificity of these methods. In this paper, three examples of the application of molecular-based detection strategies for the identification of Cronobacter will be presented.
These will include strategies to identify the genus, specific targets that are thought to be related to pathogenicity and the development of a molecular-based approach to begin to define the O-serotypes of C. sakazakii. Although by no means complete, these examples will illustrate some of the current and future challenges to enable a more refined and reliable molecular-based approach to the identification of all Cronobacter spp.
The development of appropriate molecular methods will facilitate not only a rapid identification of an isolate, but in addition complement the more traditional microbiological-based methods.

POWERPOINT is here.

It's All In The Enterobacteriaceae Family For University of Bern's Dr. Kuhnert

E. Sakazakii Lawyer — Tue, 12 May 2009 10:04:08 -0800

Editor's Note: This is another report on the presentations that were made in Dublin earlier this year at the 1st International Meeting on Cronobacter (Enterobacter Sakazakii). Below we hear from Professor Peter Kuhnert of the Institute of Veterinary Bacteriology, University of Bern, Switzerland.

Biography: Peter Kuhnert is working at the University of Bern, Switzerland as an associate professor in bacteriology. He completed a PhD in molecular biology studying gene regulation of the porcine TNF-locus.
As a postdoc at the Weizmann Institute of Science in Israel he focused on the regulation of the human TNF-receptor genes and its role in the immune response. After his return 1994 he switched topics and is since then working at the Institute of Veterinary Bacteriology where he focuses on bacterial virulence, phylogeny and taxonomy. His work includes pathotyping of E. coli, genotyping of foodborne pathogens with an emphasis on Campylobacter, pathogenesis and virulence mechanisms of Pasteurellaceae as well as work on Mycoplasma hyopneumoniae.

Summary - Multilocus sequence analysis (MLSA) of Cronobacter and related taxa Genetic similarity as determined by DNA-DNA hybridization is still considered the ‘gold standard’ method to determine relatedness between bacterial species. Nevertheless, it is very time consuming and cumbersome to perform and requires cross-hybridization between representatives of a species and related taxa. Moreover, variation between experiments, techniques and laboratories make exchange and comparison of data difficult. Whole genome sequence comparisons could be an alternative to DNA-DNA hybridization however, data handling and the
open question as to what genes should be used for defining genome similarity cannot be neglected. Therefore, for taxonomic purposes investigating as many isolates of a species as possible in order to respect the biodiversity of taxa, a few representative genes indicative for genetic similarity between isolates is the optimal way to go. Recently, we showed that the three genes recN, rpoA, and thdF can be used to estimate whole genome similarity of representatives of the family Pasteurellaceae [Kuhnert & Korczak (2006) Int.J.Syst.Evol.Microbiol 152: 2537-2548]
In the presented work multilocus sequence analysis (MLSA) based on recN, rpoA and thdF genes was done on more than 30 species of the family Enterobacteriaceae with a focus on Cronobacter and the related genus Enterobacter. The sequences provided valuable data for phylogenetic, taxonomic and diagnostic purposes. Phylogenetic analysis showed that the genus Cronobacter forms a homogenous cluster related to recently described species of Enterobacter, but distant to
other species of this genus. Combining sequence information on all three genes is highly representative for the species’ percentage of GC-content used as taxonomic marker. Sequence similarity of the three genes and even of recN alone can also be used to extrapolate genetic similarities between species of Enterobacteriaceae, being an alternative to DNA-DNA hybridization. Finally, the rpoA gene sequence, which is the easiest one to determine, provides a powerful diagnostic tool to identify and differentiate pathogens of this family. The comparative analysis gives important
insights into the phylogeny and genetic relatedness of the family Enterobacteriaceae and will serve as a basis for further studies and clarifications on the taxonomy of this large and heterogeneous family.

Powerpoint: Find it here.

Dr. Iversen Introduces The Updated Version Of E. Sakazakii; Now Call It Cronobacter

E. Sakazakii Attorney — Fri, 17 Apr 2009 13:59:41 -0800

Editor's Note: In January, the 1st International Meeting on Cronobacter (Enterobacter sakazakii) was held in Dublin. As we can get to it, we are featuring summaries from some of the main speakers along with links to their power point presentations.

We begin with Ireland's own Dr. Carol Iversen.

Biography: After completing a PhD at Nottingham Trent University, Carol Iversen worked for Nestlé Research Centre, Switzerland, where she led an international collaboration to define the taxonomy of Enterobacter sakazakii and propose a new genus, Cronobacter.
Dr. Iversen then joined the research team at the Institute for Food Safety and Hygiene, University of Zürich, to continue work on isolation methods and virulence characterisation of these organisms before moving to Ireland under an IRCSET postdoctoral fellowship in 2008.
Dr. Iversen is currently engaged in research on foodborne pathogens at the Centre for Food Safety, UCD. She is also a representative for the National Standards Authority of
Ireland on the ISO and CEN committees for Microbiology and Microbial Contamination, and is co-project leader of the ad’hoc group for development of a horizontal EN ISO
standard for the detection of Cronobacter (E. sakazakii).

Summary: What is (and isn’t) Cronobacter?

Enterobacter sakazakii is an opportunistic pathogen that can cause meningitis, necrotising enterocolitis, and bacteraemia infants. It was first designated as a species in 1980 by Farmer et al. and several outbreaks in NICUs have been linked to contaminated powdered infant formula.
The organism is therefore of concern to infant food manufacturers as well as clinical microbiologists and food safety regulators. In 2008 the taxonomy of E. sakazakii was updated using a polyphasic approach based on extensive geno- and phenotypic evaluations. This resulted in the description of five novel species and the proposal that these be incorporated into a new genus, Cronobacter, which is contaxic with E. sakazakii. The isolation of Cronobacter is complicated by the existence of closely related species, Enterobacter pulveris, E. helveticus and E. turicensis. These species share
similar characteristics to Cronobacter and occur in the same ecological niches including infant foods. However, no health risk has been attributed to these organisms.

Her Powerpoint is Here.

Bad Whey Not the Route Into China's Infant Market.

E. Sakazakii Attorney — Tue, 17 Mar 2009 13:11:00 -0800

Whey protein being exported from the United States and New Zealand has been stopped at the borders of the People's Republic of China, the Shanghai Daily reports.

The whey protein was, according to China, contaminated by enterobacter sakazakii, a potentially fatal bacteria for infants that can cause bacteraemia, meningitis and necrotising enterocolitis.

The whey protein was being shipped to the infant products manufacturer Beingmate Group Co Ltd and Hangzhou-based Wahaha Health Food Co Ltd.

A total of 37 tons of whey protein imported by Beingmate from the United States and 5.2 tons Wahaha imported from New Zealand were tainted with the bacteria.

All the whey protein was " rejected or destroyed." The Shanghai Daily did not name the companies importing the bad whey. For more, go here.

50 Year Old Species Gets New Name: Cronobacter

E. Sakazakii Attorney — Sun, 01 Mar 2009 15:25:23 -0800

In January some of the world's most distinguished health scientists gathered in Dublin for what they called "1st International Conference on Cronobacter (Enterobacter sakazakii)"

We've been reviewing the conference proceedings. It seems that one of the things they did was change the name of Enterobacter sakazakii to Cronobacter.

Being diplomatic about it, they also recognized both the memory of Dr. Riichi Sakazaki (August 21, 1920 - January 11, 2002) for whom the organism is named (see picture) and Dr. Don J. Brenner, Frances Brenner, Richard Fanning, Arnold J. Steigerwalt, and the late Mary Alyce Fife-Asbury who were all involved in the original Centers on Disease Control(CDC) studies that led to it being recognized as a separate species. They also gave a salute to Dr. Harry Muytjens for "his pioneering work in uncovering its ecology and epidemiology in cases of neonatal meningitis and the important role of powdered infant formula."

It's been 50 years since the first case of neonatal meningitis due to the organism now known as Cronobacter (Enterobacter sakazakii) was documented. That case occurred in 1958, and was reported in 1961 by Urmenyi and White-Franklin.

Obviously, this name-changing is going to eventually be recognized in the name of this blog. In the meantime, and probably for a long time, we will do what every scientist in Dublin did, which is to use the old and new names interchangeably.

Iowa Family Sues Maker Of Enfamil In Federal Court: Seeks Damages, Requests Jury Trial

E. Sakazakii Lawyer — Wed, 18 Feb 2009 10:52:36 -0800

Daniel Korte was one of the twin boys born prematurely on April 23, 2007 at Mercy Medical Center in Des Moines, Iowa. Because of the pre-mature birth, Daniel remained in Mercy’s NICU unit where he was fed Enfamil Powdered Human Milk Fortifier for the first time on May 5, 2007.

This week, Patrick and Michelle L. Korte, Daniel’s parents, sued Mead Johnson Nutritionals, the spin-off of Bristol Myers Squibb Co. that makes the Enfamil Powdered Human Milk Fortifier.

The family alleges that within hours of consuming the Enfamil product, Daniel was in tachycardia and blood cultures taken revealed the presence of the Enterobacter Sakazakii bacteria.

“The E. Sakazakii bacteria that infected Daniel Korte came from the powdered human milk fortifier he received out of the Enfamil container,” says the lawsuit filed in U.S. District Court in Iowa.

The two year old continues to suffer from severe brain and other physical damages caused by the E. Sakazakii, which the Korte family blames the manufacturing defect in the Enfamil product, which they says was produced in a defective and unreasonably dangerous condition of contamination.

Evansville, IN-based Mead Johnson just raised $724 million in its initial public offering. Symbol for its now publicly traded stock is MJN. Its IPO was priced at $24 a share.

The Korte family is represented by attorneys William R. King of the Davis, Brown, Koehn, Shors & Roberts law firm in Des Moines, and Andrew Weisbecker and Bruce Clark of Marler Clark in Seattle. In seeking damages for the Korte family, the lawyers have asked for a jury trial.

E Sakazakii Discussion From A Settlement Demand Letter

Bill Marler — Tue, 03 Feb 2009 18:20:53 -0800

Editor's Note: A Settlement Demand Letter (SDL) is a communication that is sent to defense attorneys on behalf of the plaintiff. In food-borne illness litigation, an SDL usually requires some academic discussion like the one that follows on Enterobacter Sakazakii. Our hat-tip goes to Andy Weisbecker, one of the talented attorneys at Marler Clark, for sharing his work with us.

THE ENTEROBACTER SAKAZAKII BACTERIA

Characteristics, Epidemiology, and Virulence

Enterobacter sakazakii is a gram-negative , non-spore-forming bacterium belonging to the Enterobacteriaceae family.

Enterobacteriaceae have increasingly been identified as pathogens in the past 30 years. E. sakazakii is a relatively newly identified pathogenic bacteria and used to be known as a "yellow pigmented Enterobacter cloacae" until 1980, when it was introduced as a new species based on differences in DNA-DNA hybridization, biochemical reactions, and antibiotic susceptibility.

E. sakazakii is a rare, but life-threatening cause of neonatal meningitis, sepsis, and necrotizing enterocolitis. In general, E. sakazaii kills 40-80 percent of infected newborns diagnosed with this type of severe infection. E. sakazakii meningitis may lead to cerebral abscess or infarction with cyst formation and severe neurologic impairment.

E. sakazakii can cause a variety of infections, though central nervous system infection has been most commonly described. For infants, infection typically manifests through signs of sepsis in the first week of life: irritability or lethargy, temperature instability, and feeding intolerance. Meningitis often produces overwhelming infection that rapidly moves through cerebral hemorrhage, infarct, necrosis, liquefaction, and eventually, cyst formation.

With a single reported exception, E. sakazakii meningitis has been reported exclusively among infants. In a study of E. sakazakii cases over a 47 year period, investigators found that the median age at infection onset was two days and 94 percent of cases were less than 28 days old. Premature infants are thought to be at greater risk for E. sakazakii infections than term babies, older children and adults.

Enterobacter species are opportunistic and generally infect those with underlying illness or are immunosuppressed. E. sakazakii invasive infections occur more frequently in infants than in older children. The neonate’s immature immune system may increase the risk of acquiring an E. sakazakii infection. Among adults E. sakazakii infection appears uncommon.

E. sakazakii is recognized as a life-threatening hazard for high risk populations including newborns. The virulence mechanisms of E. sakazakii are still poorly understood, but are believed to involve the production of enterotoxins.

Once E. sakazakii travels from the intestinal tract to the blood, it likely attaches to endothelial cells, crosses the blood-brain barrier to infect the meninges and brain.

Neonates are inherently vulnerable to E. sakazakii infections given the practical immunodeficiency experienced by babies less than twelve months that is further complicated in cases of premature birth. Premature infants suffered an increased susceptibility to disease due to various factors, including reduced natural epidermal and epithelial barrier cells, and reduced secreted products that are part of the immune system.

Further, phagocytic and bactericidal activities are diminished. In addition, the stomach of newborns, especially of premature babies, is less acidic than that of adults and another factor that may contribute to the risk of infection with E. sakazakii in neonates. Finally, infants delivered by Caesarean section fail to acquire the normal bacterial flora found in vaginally delivered neonates.

The incubation period for E. sakazakii is unknown. The infectious dose of E. sakazakii has yet to be determined in part due to the practical difficulty of isolating the bacteria in powdered formula. It has been advanced that based on reported levels of contamination in powdered infant formula, a single feeding could multiply sufficiently to induce infection in seven hours at human body temperature. It has also been asserted that low levels of E. sakazakii in infant formula (<3 cfu/100g) can lead to infections.

E. sakazakii and Powdered Infant Formula

Many possible sources and modes of transmission for E. sakazakii infections have been debated. However, the only vehicle that has been epidemiologically and microbiologically associated with infection is powdered infant formula or the equipment used to prepare it.

Epidemiological and microbiological evidence has convincingly shown powdered infant formula to be the vehicle and source of E. sakazakii infection in infants. While E. sakazakii is difficult to detect in powdered infant formula due to low levels of contamination, it has been identified as an intrinsic rare contaminant of powdered formula from multiple manufacturers.

One reason for E. sakazakii’s affinity for powdered infant formula may be its unusual ability to survive when exposed to dry conditions. Since neonates are most often the victims of E. sakazakii infections, vertical transmission (mother to child) has been one source of suggested infection. There is, however, only a single report of vaginal infection or colonization, and that was a 26 year-old non-pregnant woman with vaginitis. Further, there are multiple documented cases of E. sakazakii infection among neonates delivered via Cesarean section. Likewise, nosocomial sources of infection have been postulated, but no hospital sources other than equipment used to prepare formula have been implicated.

In several investigations of outbreaks of E. sakazakii infection that occurred among neonates in neonatal intensive care units, investigators were able to show both statistical and microbiological association between infection and powdered infant formula consumption.

These investigations included cohort studies which implicated infant formula consumed by the infected infants. In addition, there was no evidence of infant-to-infant or environmental transmission; in all cases the infant had consumed the implicated formula.

In a review of E. sakazakii cases in infants where feeding practices were described, 92 percent of cases received powdered infant product and E. sakazakii was cultured from formula associated with 68 percent of cases investigated.

While the reservoir for E. sakazakii remains unknown, several environmental sources have been reported, including factories where milk powder, chocolate, cereal, potato flour, spices, and pasta are produced.Formula preparation equipment contaminated by E. sakazakii has been demonstrated to have caused two outbreaks, but the original source of E. sakazakii was not determined in either case. Environmental swabbing of formula preparation areas in the course of outbreak investigations has not demonstrated E. sakazakii in the general environment.

Furthermore, outbreaks have occurred in which the investigators have failed to identify lapses in formula preparation procedures. E. sakazakii has been identified in the environments of milk powder production facilities and other food production facilities, as well as in households.
Production of powdered infant formula occurs by either “wet” or “dry” processing, or a combination of the two.

Wet-mix processes, during which all unprocessed raw materials as well as separately processed ingredients are handled as a liquid intermediate product that is heat treated, dried, and then further handled up to the filling stage. In this process, no further additions are done after the heat treatment and, in particular, after the drying step.

Dry-mix processes, during which all separately processed ingredients are dry blended to obtain the final product, which is then further handled up to the filling stage. The process may include and combine difference mixing steps to obtain the final formulation.

Whether wet or dry processing holds a higher risk for E. sakazakii contamination is probably unknowable because the contamination most likely occurs between the spray drying and the packaging steps. One of the most extensive surveys of E. sakazakii contamination suggested that contamination must occur post-processing and following thermal treatment.

Thus, it seems that neither high levels of contamination nor lapses in preparation-hygiene are necessary to cause infection from E. sakazakii in powdered infant formula.
In recent years, a number of recommendations have been made to reduce the risk of E. sakazakii infections secondary to contaminated powdered infant formula.

These range from thermal treatment of rehydrated infant formula to limiting hang time once formula is removed from a refrigerated environment to controlling the initial populations of E. sakazakii in raw materials on receipt.

In its “Health Professionals Letter on Enterobacter sakazakii Infections Associated With Use of Powdered (Dry) Infant Formulas in Neonatal Intensive Care Units,” April 11, 2002, Revised October 10, 2002, the US Food and Drug Administration in part recommended “…that powdered infant formulas not be used in neonatal intensive care settings unless there is no alternative available”.
The World Health Organization and Food and Agriculture Organization of the United Nations have made these recommendations:

1) encourage industry to develop a range of affordable sterile infant formula options;
2) consider setting an industry standard for E. sakazakii in infant formula;
3) inform infant caregivers of the risks associated with non-sterile, powdered formula; and
4) consider feeding high-risk infants sterile formula if they cannot breast-feed.

Notably, it has also been strongly suggested that all neonates and premature infants be included in the high-risk infant category.

Most recently, the Codex Alimentarius Commission, composed of both the Food and Agriculture Organization of the United Nations and the World Health Organization, in its May 2008 “Proposed Draft Code of Hygienic Practice for Powdered Formulae for Infants and Young Children”, stated as follows: “For infants at greatest risk, when feasible, commercially available sterilized liquid products or other equivalent infant feeding options which have undergone an effective point of use decontamination procedure should be used instead of PF”.

FOOTNOTES:

[1] It is named after Riichi Sakazaki, a Japanese microbiologist.

[1] So called because it does not retain crystal violet dye in the Gram staining protocol. Many gram-negative bacteria cause disease.

[1] Dauga, C and Breeuwer, P Taxonomy and Physiology of Enterobacter sakazakii, in ENTEROBACTER SAKAZAKII. Washington D.C.: ASM Press; 2008:1 (Farber, JM and Forsythe, SJ editors).

[1] Id.

[1] Bowen AB, Braden CR. Invasive Enterobacter sakazakii disease in infants. Emerg Infect Dis [serial on the Internet]. 2006 Aug publication. Available from http://www.cdc.gov/ncidod/EID/vol12no08/05-1509.htm.

[1] Bowen, AB and Braden, CR Enterobacter sakazakii Disease and Epidemiology. Farber, JM and Forsythe, SJ ed. ENTEROBACTER SAKAZAKII. Washington D.C.: ASM Press; 2008:104.

[1]Id.

[1] Bowen, supra note 7, at 102.

[1] Bowen , supra note 6. These studied infants had a median birth weight of 2454 g. Id. Daniel Korte was 1380 g at birth.

[1] Id.

[1] Pagotto, F, et. al., Pathogenicity of Enterobacter sakazakii, in. ENTEROBACTER SAKAZAKII. Washington D.C.: ASM Press; 2008:128 (Farber, JM and Forsythe, SJ editors).

[1] Id.

[1] Pagotto, supra note 12, at 127.

[1] Id. at 129. Enterotoxins are protein toxins produced by microorganisms in the intestines.

[1] Id. at 132.

[1] Townsend, S and Forsythe, SJ. The Neonatal Intestinal Microbial Flora, Immunity, and Infections. In ENTEROBACTER SAKAZAKII. Washington D.C.: ASM Press; 2008:62 (Farber, JM and Forsythe, SJ editors). “The incidence of sepsis in this group [premature and very-low-birth-weight infants] is 20%, compared to 0.1% in term infants.” See also, Townsend, S, Hurrell E, and Forsythe, SJ. Virulence studies of Enterobacter sakazakii isolates associated with a neonatal intensive care unit outbreak. BMC MICROBIOL 2008, 8:64.

[1] Townsend, supra note 19, at 64-65.

[1] Id. at 76.

[1] Early studies have documented illnesses starting within 3 to 4 days after exposure to the implicated infant formula. Simmons, B., Gelfand M, Haas M, Metts L, and Ferguson J., Enterobacter sakazakii infections in neonates associated with intrinsic contamination of a powdered milk formula. INFECT CONTROL HOSP EPIDEMIOL. 1989;10:398-401; Van Acker J, De Smet F, Muyldermand A, Bougatef A, Naessens A, and Lauwres S. Outbreak of necrotizing enterocolitis associated with Enterobacter sakazakii in powdered milk formula. J CLIN MICROBIOL 2001;39:293-297. Other pathogenic bacteria have highly variable incubation periods, e.g., E. coli O157:H7 and Listeria monocytogenes.

[1] In addition to the heterogeneous contamination of a particular container of powdered formula, E. sakazakii is notoriously difficult to isolate and a relatively large amount of powdered formula is needed for such testing. The CDC has indicated that a minimum amount of 100 grams of powdered formula is required for isolation. Only 26 grams was available from the lot of Enfamil HMF implicated in Daniel Korte’s case. Thus, tracing contamination to a specific container, especially in the context of serial feedings is generally a practical impossibility.

[1] Pagotto, supra note 12, at 138. See also Iversen, C and Forsythe, S. Risk Profile of Enterobacter sakazakii, an emergent pathogen associated with infact milk formula. TRENDS FOOD SCI TECHNOL. 2003;14:443-454. While the infectious dose of E. sakazakii has been speculated to be comparable to E. coli O157:H7 by one published study, the estimate of 1,000 CFU is much higher than is now generally accepted. See, e.g. Paton, J.C. and Paton, A.W. 1998. Pathogenesis and diagnosis of shiga toxin-producing Escherichia coli infections. Clin. Microbiol. Reviews. 11(3):450-479.

[1] CFU is an acronym for colony forming units—a measure of the viable bacterial cells which will form into colonies through binary fission.

[1] Enterobacter sakazakii and other microorganisms in powdered infant formula: meeting report. In: Microbiological risk assessment series, no. 6 Geneva:6; World Health Organization; 2004. ISBN: 92 4 156262 5 (WHO).

[1] Bowen, supra note 7, at 106.

[1] Id.

[1] Id. See also Simmons, supra note 22, 98-401.

[1] aubilla-Barron C, Forsythe SJ. The desiccation survival of Enterobacter sakazakii and related Enterobacteriaceae. ABSTRACT P-003, 104^TH GEN MTG AM SOC MICROBIOL 23-27 May, New Orleans, LA USA 2004.

[1] Bowen, supra, note 7, at 107.

[1] Id.

[1] Simmons, supra note 22, at 398-401; 1989; Van Acker J, De Smet F, Muyldermand A, Bougatef A, Naessens A, and Lauwres S. Outbreak of necrotizing enterocolitis associated with Enterobacter sakazakii in powdered milk formula. J CLIN MICROBIOL 2001;39:293-297; Centers for Disease Control: Enterobacter sakazakii infections associated with the use of powdered infant formula—Tennessee, 2001. MORBID MORTAL WEEKLY REP 51:297-300; 2002.

[1] Id.

[1] Bowen, supra, note 5.

[1] Id.

[1] Noriega FR, Kotloff KL, Martin MA, and Schwalbe RS. Nosocomial bacteremia caused by Enterobacter sakazakii and Leucoostoc mesenteroides resulting from extrinsic contamination of infant formula. PEDIATR INFECT DIS 9:447-449; 1990; Block C, Peleg O, Minster N, Bar-Oz B, Simhom A, Arad I, and Shapiro M. Cluster of Neonatal infections in Jerusalem due to unusual biochemical variant of Enterobacter sakazakii. EUR J CLIN MOCROBIOL INFECT DIS 21:613-616; 2002.

[1] Van Acker , supra note 33, at 293-297. See also CDC, Enterobacter sakazakii infections associated with the use of powdered infant formula—Tennessee, 2001. MORBID MORTAL WEEKLY REP 51:297-300; 2002.

[1] Kandhai MC, Reij MW, Gorris LGM, and Zwietering MH. The effect of pre-culturing conditions on the lag time and growth rate of Enterobacter sakazakii. Book of Abstracts, 19^th Int. Symp., Int. Com. Food Microbiol. Hyg., FoodMicro 335; 12-16 September 2004, Portoroz, Slovenia.

[1] Cordier J, Production of Powdered Infant Formulae and Mirobiolgical Control Measures, in ENTEROBACTER SAKAZAKII. Washington D.C.: ASM Press; 2008:148 (Farber, JM and Forsythe, SJ editors).

[1] Id.

[1] Gurtler JB, Kornacki JL, and Beuchat LR. Enterobacter sakazakii: A coliform of increased concern to infant health. INTERN J FOOD MICROBIOL. 104:1-34,28; 2005.

[1] Muytjens HL, Roelofs WH, and Jaspar GHJ. Quality of powdered substitutes for breast milk with regard to members of the family Enterobacteriaceae. J CLIN MICROBIOL. 26:743-746;1988. In this study, E. sakazakii was detected in 14.9% of 141 samples of powdered infant formulae from 35 countries.

[1] Enterobacter sakazakii and other microorganisms in powdered infant formula: meeting report. In: Microbiological risk assessment series, no. 6 Geneva: World Health Organization; 2004.

The Food and Drink Innovation Network Nottingham Trent University Award for Research

E. Sakazakii Lawyer — Mon, 05 Jan 2009 11:41:33 -0800

The Food and Drink iNet Innovation Awards were recently announced at the UK's National Space Centre in Leicester.

This one caught our eye:

Nottingham Trent University School of Science & Technology for creating an easy-to-use, colour-changing agar that detects a specific bacterium which can be dangerous in food.

The Enterobacter sakazakii bacterium detected by the chromogenic agar is particularly risky for newborn babies.

The agar can be used right across the food industry, by virtually anyone in a workforce…making it a simple but effective food safety tool.

Recent E. Sakazakii Death and Near-Death Prompts Commentary

E. Sakazakii Lawyer — Mon, 29 Dec 2008 19:03:13 -0800

The Star-Gazette in Elmira, NY carries a timely commentary by Norma Ritter (right) on behalf of the La Leche League on the danger of Enterobacter Sakazakii in a first world country like the United States. Her comments come in response to these two terrible incidents:

On Dec. 2, the New Mexico Health Department reported that one baby died and another was hospitalized because of infections caused by different strains of the bacteria Enterobacter sakazakii. (We reported on the death here.) Both babies had been fed powdered formula, which the Centers for Disease Prevention and Control says has been associated with contaminated powdered formula products.
On Nov. 25, a 5-month-old baby, weighing only 8 pounds, 6 ounces, almost died from water intoxication and malnourishment. His mother had been using water to dilute the formula she got each month through the Women, Infants and Children program. She could not afford the $16 to $18 for each of the additional five to seven cans the baby needed.

She also ties in some pointed comment on the melamine scandal and our government's response to it. Check out what she has to say here.

New Mexican Baby Death Blamed On E. Sakazakii

E. Sakazakii Lawyer — Mon, 01 Dec 2008 10:48:27 -0800

One baby is dead and another is in the hospital as a result of baby formula contaminated with Enterobacter sakazakii. Both infants are from New Mexico border counties.

Enterobacter sakazakii causes an infection to the bloodstream and central nervous system.

The illnes has killed a male baby from Otero County and has left a female baby from Lea County hospitalized.

The U.S. Centers for Disease Control and Prevention says the illness is associated with powdered baby formula.

Both New Mexico babies, who were unidentified, had been fed powdered formula and other foods. They had different strains of the bacteria.

The Health Department says it's working to determine what caused the babies to develop the infection.