When it comes to public health concerns about staphylococcal bacteria from pets, most of the attention gets paid to methicillin-resistant strains like MRSA. That's not surprising considering how important MRSA is in human medicine. However, staph that aren't methicillin-resistant can also be a problem, since they can cause the same types of infections that resistant types can (they are just easier to treat). Another issue that often gets overlooked is staphylococcal food poisoning.
Staphylococcal food poisoning is one of the most common foodborne illnesses and results from growth of certain strains of staphylococci in poorly handled or stored foods. If staph get into food and the food is kept at improper temperatures, the bacteria can grow. If the strain of staph that's in the food is one that can produce enterotoxins, these toxins can accumulate in the food at high enough levels to cause food poisoning when eaten. In most cases, people are probably the origin of enterotoxin-producing staph that contaminate food, but pets are another possible source.
A recent study in Vector-borne and Zoonotic Diseases (Abdel-moein et al 2011) looked at enterotoxigenic staph in 70 dogs and 47 cats. Swabs were collected from the mouth, nose and wounds. Nasal swabs were also collected from 26 people. The researchers isolated enterotoxigenic Staphylococcus aureus (strains of S. aureus that possessed genes for enterotoxin production) from 10% of dogs and 2.1% of cats, as well as 7.7% of people. Most of the positive samples from pets were oral samples.
This study shows that dogs and cats can be potential sources of strains of S. aureus that cause food poisoning. Since the staph are often in the animals' mouths (and therefore presumably shed in saliva), animals can potentially contaminate food with these enterotoxigenic staph fairly easily, but it's unknown how often this occurs.
Prevention measures are pretty basic but should be considered, including:
- Keeping pets off kitchen counters.
- Discarding foods that pets have licked.
- Washing hands after pet contact, before handling food.
- Properly storing food, so that even if it gets contaminated with staph, the bacteria don't get the opportunity to grow and produce toxins.
- Photo from http://www.wagreflex.com/2009/06/taking-cat-ownership-to-the-next-level.html