Molecular detection of Mycobacterium tuberculosis from bovine milk samples

V Bhanurekha,L Gunaseelan,Reza Nassiri,Ganesh Pawar,Sukumar Bharathy

doi:10.5455/javar.2015.b44

V Bhanurekha, L Gunaseelan + Show 3 more

Open Access

https://doi.org/10.5455/javar.2015.b44

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Abstract

Mycobacterium tuberculosis and Mycobacterium bovis are the major causes of tuberculosis. These may infect many animal species, and are likely to be the main source of infection in humans. A total of 181 bovine raw milk samples and 123 pre-scapular lymph node biopsy samples were collected and subjected to acid fast staining, fluorescent staining, isolation and identification. Genus specific PCR to identify the Mycobacterium tuberculosis complex (MTBC) organism, and multiplex PCR (mPCR) were done to differentiate M. tuberculosis and M. bovis. Among the milk samples tested, only one sample was culture-positive for M. tuberculosis. Four samples were positive by MTBC-PCR and mPCR; all these four were proved to be M. tuberculosis. It is quite likely that animals can be infected with human-originated M. tuberculosis, which in turn may act as a source of infection in humans, becoming a reverse zoonosis. Hence, control strategies for human tuberculosis caused by M. tuberculosis should necessarily include the control strategies in animals too.

Highlights

Tuberculosis (TB) is an important zoonotic disease, and its causal agent belongs to Mycobacterium tuberculosis complex comprising Mycobacterium tuberculosis, Mycobacterium bovis, Mycobacterium africanum, Mycobacterium microti and Mycobacterium canetti (Van Soolingen et al, 1997)
All these samples were subjected to multiplex PCR (mPCR) for differentiation between M. tuberculosis and M. bovis using CSB1, CSB2 and CSB3 primers (Table 1)
Of the 181 milk samples and 123 pre-scapular lymph node (PSLN) biopsy samples, four samples were positive by both IS6110 and mPCR

Summary

INTRODUCTION

Tuberculosis (TB) is an important zoonotic disease, and its causal agent belongs to Mycobacterium tuberculosis complex (tubercle bacillus) comprising Mycobacterium tuberculosis, Mycobacterium bovis, Mycobacterium africanum, Mycobacterium microti and Mycobacterium canetti (Van Soolingen et al, 1997). M. tuberculosis and M. bovis are the major causes of tuberculosis, which are highly pathogenic that may infect many animal species and are likely to be the source of tuberculus infection in humans. The first contamination of these animals with M. tuberculosis is caused by humans, and infection may occur between animals, which in turn become the source of infection in humans (Unea and Mori, 2007). Bovis from animal to human and back to animal was documented where tuberculosis was developed in cattle after being exposed to a patient infected with M. bovis; the person was reported to have been exposed and infected during childhood. M. tuberculosis infection has been reported in a wide range of domestic or wildlife animal species, most frequently those living in close contact with humans for a long time. It is imperative to see that the source of the pathogen is the cattle as there is a possibility of cross contamination of the samples (Cadmus et al, 2006)

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSION