Survey of Mycobacterium spp. in Eurasian Badgers (Meles meles) in Central Italy

A survey to determine the presence of Mycobacterium spp. in the Abruzzo and Molise regions was conducted by testing samples from 124 badgers found dead or road-killed during the 2013-2021 period. Head lymph nodes were collected from all carcasses, as well as mediastinal lymph nodes from 20 of them, for bacteriological and molecular tests; tissues were inoculated onto a set of solid egg-based Lowenstein-Jensen media and in a liquid culture system (BACTEC) and were analyzed by polymerase chain reactions (PCRs). Organs and lymph nodes from 31 carcasses were collected for histological tests. During post-mortem examinations, macroscopic lesions consistent with a Mycobacterium tuberculosis complex (MTBC) and with nontuberculous mycobacteria (NTM) infections were not detected. Mycobacteria were isolated from four animals (3.22%). M. avium subsp. avium was isolated by head lymph nodes from two badgers (1.61%), M. avium subsp. paratuberculosis (0.80%) from one, and Mycobacterium spp. from another (0.80%). The significance of nontuberculous mycobacteria (NTM) in wildlife hosts in the absence of clinical signs and gross pathology has yet to be assessed. The most critical aspect came from isolates belonging to the Mycobacterium avium complex infection in wildlife due to the possible interference with tuberculin skin tests in cattle.