The University of Georgia College of Veterinary Medicine

Georgia Veterinary Scholar Program

2003 Scholars

Georgia Veterinary Scholar	Faculty Mentor	Faculty Mentor

Nicole Giusto University of Georgia Class of 2005	Dr. Amelia Woolums	Dr. Susan Sanchez

Preliminary Prevalence Study of Mycoplasma bovis and Mycoplasma spp. in Selected Dairy and Beef Herds in Georgia

In cattle mycoplasmas are well-known agents of antibiotic resistant mastitis, arthritis and pneumonia. Mycoplasma bovis appears to be the most important cause of bovine mycoplasmosis in areas free of the agent of contagious bovine pleuropneumonia, Mycoplasma mycoides. Epidemiologic studies of these organisms have been undertaken in many regions of the world and in some areas of the United States . These have shown infection due to M. bovis to be an emerging disease. However, the prevalence has never been studied in the state of Georgia , a state with both dairy and beef cattle production. The objective of this study was to compare polymerase chain reaction assays and culture methods for M. bovis and other relevant mycoplasmas on nasal swabs to determine if either is a sensitive and specific method for use in an epidemiologic study. We hypothesized that PCR is an effective method for recovering mycoplasmas from nasal swabs for an epidemiologic study. We further hypothesized that PCR would be a more sensitive method of detection than culture. Nasal swabs were collected from ninety-nine calves ranging in age from 2-8 months of age. Four farms (two beef and two dairy) were sampled. Three of the farms were UGA owned operations and one was a separately owned operation. The calves were observed for signs of respiratory disease (cough, nasal discharge) and rectal temperatures were taken from all subjects. The swabs were subjected to PCR using mycoplasma genus specific primers. The mycoplasma positive samples were then subjected to PCR with M. bovis specific primers. Culture was performed on samples from one farm to compare the sensitivity of culture to that of PCR. The results indicated that mycoplasma and specifically M. bovis could be recovered from nasal swabs of calves. Approximately 50% of the samples tested positive for the genus mycoplasma. Two samples from the non-UGA owned farm tested positive for M. bovis. Three out of thirty culture samples revealed by light microscopy growth that appeared to be Mycoplasma spp. However, over 50% of the cultures were too highly contaminated with bacterial overgrowth to be of use. Future research will be directed at further characterization of the non-M. bovis Mycoplasma that were identified by using PCR primers for M. agalactiae, M. dispar, M. bovirhinis, and M. bovigenitalia. The culture samples showing mycoplasmal growth will be cryogenically preserved and later subjected to florescent antibody testing to attempt to identify the species of mycoplasma. We conclude that nasal swabs are an appropriate and feasible sampling method for the detection of mycoplasma species and M. bovis and that PCR is more sensitive than culture in our hands for the detection of mycoplasma species.