Effect of transport enrichment media, transport time, and growth media on the detection of Campylobacter fetus subsp. venerealis
Advisor:Spike, Peter W.
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Publisher:The Ohio State University
Series/Report no.:The Ohio State University. College of Food, Agricultural, and Environmental Sciences Honors Theses; 2000
Bovine genital campylobacteriosis is a contagious venereal disease of cattle caused by Campylobacter fetus subsp. venerealis. Semen collected from a bull infected with C. fetus subsp. venerealis can be contaminated and the bacteria transmitted to thousands of cows by artificial insemination. Reliable diagnostic procedures are required to accurately test semen donor bulls and to prevent seminal transmission of disease. The purpose of this study was to determine a combination of microbiological growth conditions such as transport enrichment media (TEM), transport time, TEM incubation, and growth media that best yields C. fetus subsp. venerealis while inhibiting contaminants. Transport enrichment medias evaluated include Weybridge, Cary and Blair, and 0.85% saline solution. Each TEM was inoculated with preputial smegma spiked with C. fetus subsp. venerealis and transported for 4 or 24 hours before being inoculated onto growth media with and without overnight incubation at 37 C. C. fetus subsp. venerealis and contamination growths were evaluated on a scale of 0-4. Median scores of C. fetus subsp. venerealis and microbial contamination were compared within TEM, transport time, overnight incubation, and growth media groups using the Mann-Whitney U test and Kruskal-Wallis test. The proportion of samples with any C. fetus subsp. venerealis growth or microbial contamination within each group was compared using the chi square test. The results suggest that C. fetus subsp. venerealis growth was significantly influenced by three of the four criteria. Weybridge TEM more effectively promoted growth than either Cary and Blair TEM or 0.85% saline solution (P<0.0001 ). Transport time of 4 hours rather than 24 hours was superior (P<0.000l). Benefits were associated with avoiding overnight TEM incubation at 37 C (P=0.0002). Significant differences were not identified for growth media; however, Skirrow's Campylobacter Agar yielded slightly better growth than either blood agar or Greenbriar Plus Agar. Contaminant growth was also significantly influenced by three of the four variables. Differences associated with TEM indicated Weybridge TEM inhibited contaminant growth more effectively than either Cary and Blair TEM or 0.85% saline solution (P<0.0001). Transport times of 4 and 24 hours did not significantly influence contaminant growth. Abstaining from overnight incubation of TEM was preferred for reduction of contaminant growth (P=0.0032). Skirrow's Agar was preferred to both blood agar and Greenbriar Plus Agar (P<0.0001). These results suggest that the detection of C. fetus subsp. venerealis is enhanced when preputial smegma samples arrive at the diagnostic laboratory within 4 hours of collection using Weybridge TEM followed by direct inoculation onto Skirrow's Agar the day samples arrive. Adherence to these guidelines will facilitate accurate diagnosis of bovine genital campylobacteriosis in bulls, thereby reducing the potential for seminal transmission of C. fetus subsp. venerealis and subsequent occurrence of infertility, early embryonic death, and abortion.