Evaluation of bacteriologic culture of pooled fecal samples for detection of Mycobacterium paratuberculosis.
OBJECTIVE
To compare sensitivity of several methods of bacteriologic culture of pooled bovine fecal samples for detection of Mycobacterium paratuberculosis and evaluate homogeneity in number of M paratuberculosis in pooled fecal samples.


METHODS
Feces from 10 dairy cows that shed M paratuberculosis at various concentrations and 1 dairy cow known to be free of infection with M paratuberculosis.


METHODS
5 fecal pooling methods, 2 culture methods, and 2 pool sizes were evaluated. Each pooled sample contained 1 infected sample and 4 or 9 uninfected samples.


RESULTS
Sensitivity of detection of M paratuberculosis was greater with smaller pool size (5 vs 10 samples/pool). Detection sensitivity was also associated with concentration of bacteria in the infected sample. Results indicated that, compared with concurrent bacterial culture of individual infected samples, 37 to 44% of pooled samples with low bacterial concentrations yielded positive culture results and 94% of pooled samples with high bacterial concentrations yielded positive results.


CONCLUSIONS
Bacteriologic culture of pooled fecal samples may provide a valid and cost-effective method of detecting M paratuberculosis infection in cattle herds.
Wells
Scott J
SJ
College of Veterinary Medicine, Department of Clinical and Population Sciences, University of Minnesota, St Paul 55108-1004, USA.
Whitlock
Robert H
RH
Lindeman
Cynthia J
CJ
Fyock
Terry
T
D000818:Animals; D001431:Bacteriological Techniques / Q000379:methods / Q000592:standards / Q000662:veterinary*; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000382:microbiology; D005243:Feces / Q000382:microbiology; D005260:Female; D016015:Logistic Models; D015999:Multivariate Analysis; D016927:Mycobacterium avium subsp. paratuberculosis / Q000302:isolation & purification*; D010283:Paratuberculosis / Q000175:diagnosis* / Q000382:microbiology; D015995:Prevalence