If you’re a regular reader, you’ll note the recurring theme of "every animal (and person) is carrying multiple microbes that can harm you, given the right circumstances. Fortunately, the right circumstances don’t usually occur."

There are situations in which those risks increase, and understanding cost-benefit is a key aspect of disease prevention. Sometimes pet factors increase the risk, such as being of a certain species (e.g. most reptiles), young in age, or having an illness (e.g. diarrhea). Sometimes it’s human factors that increase the risk, such as immune status, poor animal handling practices, behavioural issues, or the impacts of diseases or medical treatments.

An example of the last one was published in a recent edition of the Canadian Journal of Infectious Diseases and Medical Microbiology (Poliquin et al 2015). It’s a review of peritoneal dialysis-associated infections caused by Pasteurella, a bacterium commonly associated with pets (especially cats). It doesn’t really tell us anything new, but it’s a reminder of the risks that are present in certain situations.

Peritoneal dialysis is a procedure used in some people with kidney failure. It involves placing a catheter into the abdomen through the body wall. Fluid is then put into the abdominal cavity through the catheter, and removed a short time later, taking with it various substances that would normally be removed by working kidneys. As opposed to hemodialysis, which removes these same substances directly from the blood, peritoneal dialysis can be done at home; however, the catheter has to be left in place and managed properly to prevent infection. Here’s where the pet risk comes in.

The Poliquin paper reviewed records of Pasteurella isolates from peritoneal fluid from patients in the the Manitoba (Canada) Renal Program from 1997-2013. They also looked at published reports of Pasteurella peritoneal dialysis-associated infections.

In total, they identified 37 cases: 33 caused by Pasteurella multocida and four caused by other Pasteurella species.

• Affected patients had varying degrees of illness, with abdominal pain, nausea and vomiting being most common.
• Two individuals also had bloodstream infections with P. multocida. One was very sick with a "shock-like syndrome."
• Contact with a cat was implicated in 83% of cases.
• Direct contact between a cat and peritoneal dialysis equipment was reported in 25 cases. Ten of these involved the cat puncturing (teeth or claws, presumably) the line or fluid bags.
• Infections linked to a known bite or puncture of the tubing had a much quicker onset (15 hours vs 44 hours following other contacts).
• Two people required an ICU stay.
• The peritoneal catheter had to be removed in 11% of patients.
• No one died.

As I said, nothing too surprising but more data to support some basic concepts:

• There are lots of people on peritoneal dialysis living at home with cats. The incidence of this problem seems to be low. However, low incidence doesn’t help much if you’re the one with the infection. So, preventive measures are still worthwhile.
• Pasteurella can be found in the mouth, nose and feces of most (or all) cats, so testing cats for the bacterium makes no sense. Trying to eliminate Pasteurella from its natural host would also be futile, so instead focus on keeping it out of the person’s abdomen.
• Since direct contact was documented in most cases (and probably occurred in at least some of the other cases), keeping cats away from peritoneal dialysis catheters and all associated items is important. That should be easy to do, and is probably a key control measure.
• Since Pasteurella is present in most or all cats, patients should practice good hygiene around their pets, especially hand hygiene. That’s particularly true before handling the peritoneal catheter site or any equipment.
• Punctures of the tubing or other equipment should be considered a high-risk situation. Part one is keeping the cat away. Part 2 is getting medical advice when a puncture does happen, since prophylactic antibiotics might be indicated.

Image from www.mayoclinic.org (click for source)