Clostridium difficile – an Emerging Zoonosis?Posted on by
The media has recently given attention to studies [G. Songer; Rodriguez-Palacios A, et al] that isolated a bacterium called Clostridium difficile from meats sold in grocery stores. C. difficile causes a severe colon infection and is generally acquired in hospitals and long-term care facilities. Although most of the cases of C. difficile infection are healthcare associated (80%), the other twenty percent of cases are acquired in the community – outside of healthcare settings. The cause(s) of these infections are still poorly understood. The recent studies question whether C. difficile in meats is a source of human infection.
Clostridium difficile causes several hundred thousand human infections and several thousand deaths each year in the United States. In recent years, the number and severity of these infections has been on the rise. Certain antibiotics can actually improve the growth environment for the bacteria in our gut by decreasing the natural flora that normally protects us. For this reason, previous use of antibiotics to treat other illnesses is a major risk factor for C. difficile infection. The elderly and individuals with weakened immune systems are also at great risk of becoming infected. This occurs mainly by the “so called” fecal-oral route, which I refuse to discuss in a blog. Careful hand washing and disinfection of contaminated surfaces helps to reduce the spread of infection and are the best preventive measures.
Persons in the community who acquire C. difficile infections generally use antibiotics less frequently, and the causes of their infections are not as straight forward. They could be getting C. difficile from infected but otherwise healthy persons, food, or visits to healthcare settings. C. difficile lives in the gut of infected persons or animals, and may be found in healthy pets like cats, dogs or horses. Healthy adult food producing animals like beef and dairy cattle may also carry the bacteria. In the studies of retail meat, the rate of C. difficile reported varied from 20-40%. At this time, we do not know how these bacteria got into the meat. We also don’t know of any people getting sick from eating food that contains C. difficile.
So, is C. difficile an emerging zoonosis? The answer is: we don’t know yet. CDC will continue to collaborate with various experts in food safety and veterinary medicine to identify research needs and learn more about C. difficile infection in foods. Our scientists are also working closely with USDA – the government agency responsible for regulating the safety of meat – and sharing emerging information as it becomes available.