Isolation of mycobacteria from clinical samples collected in the United States from 2004 to 2011

BACKGROUND: Mycobacteria other than M. bovis may interfere with current bovine tuberculosis diagnostic tests resulting in false positive test results. As the prevalence of M. bovis decreases in the United States, interference from other mycobacteria play an increasingly important role in preventing the eradication of M. bovis. To identify mycobacteria other than M. bovis that may be interfering with current diagnostic tests, a retrospective study was performed to identify mycobacteria isolated from clinical tissues at the National Veterinary Services Laboratories between 1 January 2004 and 9 October 2011. RESULTS: During the study period, 2,366 mycobacteria other than M. bovis were isolated from samples submitted for clinical diagnosis of M. bovis. Fifty-five mycobacterial species were isolated during this time period. In cattle, M. avium complex, M. fortuitum/fortuitum complex, M. smegmatis, M. kansasii, and M. terrae complex were the predominate species other than M. bovis isolated from tissues submitted for culture. Mycobacteria other than M. bovis isolated from deer were predominantly M. avium complex, M. terrae/terrae complex, and M. fortuitum/fortuitum complex. CONCLUSIONS: These data provide information characterizing the species and relative prevalence of mycobacteria other than M. bovis that may interfere with current diagnostic tests.