Mycobacteria in the environment of pig farms in the Czech Republic between 2003 and 2007

Abstract

In the Czech Republic, most mycobacterial infections in pigs are caused by the Mycobacterium avium complex (MAC) and potentially pathogenic mycobacteria (PPM) derived from the environment. This study was undertaken after the isolation of PPM from various components of the environment of pig herds between 1996 and 2002 (Matlova et al., Veterinarni Medicina, 48, 2003, 343-357). Between 2003 and 2007, a total of 1114 environmentally-derived samples from 24 farms were examined. After staining according to Ziehl-Neelsen, acid-fast rods were found in 42 (3.8%) samples by direct microscopy, and PPM were isolated from 223 (20.0%) samples by culture. PPM occurred primarily in soil from the paddocks (53.8%), peat (53.2%), bedding (28.4%) and biofilm from the pipeline (21.0%). From MAC, M. avium subsp. hominissuis (MAH) genotype IS901-and IS1245+ was most frequent; M. avium subsp. avium (MAA) genotype IS901+ and IS1245+ and M. intracellulare genotype IS901-and IS1245-were isolated from one (0.4%) and three (1.3%) samples, respectively. The remaining isolates were identified as 19 other mycobacterial species: M. gordonae (n = 8), M. triviale (n = 6), M. flavescens (n = 3), M. nonchromogenicum (n = 3), M. terrae (n = 3), M. xenopi (n = 3), M. fortuitum (n = 2), M. chelonae (n = 2), M. chitae (n = 2), M. abscessus (n = 1), M. gastri (n = 1), M. kumamotonense (n = 1), M. marinum (n = 1), M. parafortuitum (n = 1), M. peregrinum (n = 1), M. porcinum (n = 1), M. scrofulaceum (n = 1), M. smegmatis (n = 1) and M. simiae (n = 1). The remaining 41 isolates of unidentified mycobacterial species did not contain the sequences IS901 and/or IS1245, specific for medically important members of MAC (MAA and MAH); a further 44 isolates were not tested due to their contamination or loss of ability to grow in vitro. A farm where MAH was often detected in the lymph nodes of pigs and in the environment between 1996 and 2002 (Period I), was selected for further investigation between 2003 and 2007 (Period II). A comparison of the findings of mycobacteria on the investigated farm in Period I and in the following Period II showed a significant increase (P < 0.01) in the occurrence of mycobacteria other than MAH, especially in peat samples.