Prevalence of Clostridium difficle (C. diff) in Connecticut Swine farms

View the project final report

• 2010 annual report

Commodities

• Animals: swine

Practices

• Education and Training: on-farm/ranch research

There is a growing concern over the antibiotic-induced emergence of bacteria such as Clostridium difficle in livestock and its implication for public health. C. difficle (C. diff) is the main cause of antibiotic induced diarrhea acquired in hospital settings. Recently, infection has not only been seen in individuals with no hospital contact – referred to as Community acquired Clostridium difficle associated diarrhea (CA-CDAD) - but infections have also increased in severity. At the same time C. diff is the main cause of neonatal diarrhea in pigs with morality as high as 30%. Molecular studies have shown similarities between animal and human strains suggesting inter-specie transmission but mechanism is unknown. Furthermore, In 2006 CDC published a study using data collected from CT physicians showing that a quarter of patients presenting with gastroenteritis symptoms were otherwise healthy individuals with no known risk factors, thereby signifying infection sources within the community. Thus, this study proposes to determine if the farm environment is a potential source of infection by looking at colonization rates for C. diff in CT swine industry. This involves collecting and testing animal fecal materials on 20 breeding farms, and comparing strains isolated to human strains circulating in the region. As the epidemiology of this disease changes it is necessary to determine its threat to human and animal health. In addition, this study demonstrates the feasibility of farm screening as a surveillance tool in emerging infectious disease since 70% of these are zoonotic.

There are three main objectives of this study:

1.To determine the prevalence of C. difficle in CT swine breeding farms: Even though New England is not known for swine production, CT has the largest number of swine farms in the southern New England region. According to the CT state dept there are about 50 breeding farms in the state, though pigs are usually raised with other livestock. There is a vast difference in the rearing practices in this region compared to those in the better-known swine-producing ones, so it is of interest to see if these practices are associated with farm colonization rates with certain bacteria. Most CT farms are family owned, and pigs are usually housed in wooden barns with little restriction on movement, although there are rudimentary attempts to separate the farrowing flock from the rest of the herd. Most farms do not use antibiotics in feed, and the ones that do use them during the winter months. Farmers in the region usually get their replacement stock from known swine states, and some of them actually rent boars from these regions to service their gilts/sows, underscoring the possibility for geographic dispersion. Thus, in this study swine fecal samples will be collected in different holdings/pens on a farm, and tested for C. difficile toxins -- specifically Toxin A and B which have been associated with the increased pathogenesis of CDAD. Even though this will only give information on farm colonization rate it will inform the necessity of further studies in individuals pigs, and even humans working and living with pigs. Furthermore this study will educate participating farmers about CDAD, and its possible implication for both their health and their animals’ health. Songer et al 2004 reported farmers’ and even vets` ignorance (7) about disease even in diarrheic piglets, as was the case with doctors in the earlier stages of human CA-CDAD.

2.Using established molecular methods compare the strain of C. difficle in farms to existing strains circulating in the human population in the region and also porcine isolates in other regions of the country so as to give a broader picture on the disease burden. Antibiotic resistance patterns of strains isolated in this study will be conducted which may have implications for prophylaxis or therapy. According to Post et al 2001, tiamulin, virginamysin and tylosin in sow feed may be useful in limiting CD colonization (8) although generalization of this results to CT may be inappropriate due to clear differences in animal husbandry practices thus the premise of this study.

3. Conduct a Knowledge, Attitude and Belief (KAB) survey regarding bio-safety practices. This will aid the development of a concise information pamphlet for farmers regarding safety. Preliminary findings from MRSA study show that farmers are only vaguely aware of the published guidelines. Even though there are available guidelines for farmers in general, and some specific for swine workers due to swine flu, these guidelines are not easily assessable to farmers. They are housed at different website by different agencies (CDC, USDA, and National Pork Council).