Molecular characterisation of &lt;i&gt;Mycobacterium bovis&lt;/i&gt; isolated from African buffaloes (&lt;i&gt;Syncerus caffer&lt;/i&gt;) in Hluhluwe-iMfolozi Park in KwaZulu-Natal, South Africa

Tiny M Hlokwe,Jacques Godfroid,Anita L Michel,Estelle H Venter,Dave Cooper,Akinbowale O Jenkins,Elizabeth M Streicher

doi:10.4102/ojvr.v78i1.232

Abstract

Bovine tuberculosis (BTB), a chronic disease of mammals caused by Mycobacterium bovis, is a threat to South African wildlife. It has been reported that African buffaloes (Syncerus caffer) are reservoir hosts of BTB in South African wildlife populations. This study reports on the molecular identification and typing of 31 M. bovis isolates collected between 1993 and 2008, mainly from buffaloes but also from two lions and a bush pig, in the Hluhluwe-iMfolozi Park (HiP) in KwaZulu-Natal. To study the dynamics of BTB in the buffalo populations, 28 M. bovis isolates from the HiP and epidemiologically related parks were characterised using regions of difference deletion analysis for species identification and spoligotyping, variable number of tandem repeats (VNTR), polymorphic G-C-rich sequences and IS6110 restriction fragment length polymorphism (RFLP) genotyping methods. At least three distinct M. bovis genotypes were found amongst HiP samples. The combination of VNTR typing (using a 16-loci panel) and IS6110 RFLP revealed the presence of three additional genetic profiles in individual buffaloes, demonstrating that the highest level of discrimination was achieved by these typing methods. One of the observed spoligotypes (SB0130) was dominant and represented 75% of isolates from buffaloes. A novel M. bovis spoligotype (SB1474), which is reported for the first time in this study, was observed in 14.3% of isolates from buffaloes. Based on the observed genetic relationships, the findings suggest independent introductions from at least three unrelated sources. These findings improve the knowledge regarding the diversity of circulating M. bovis strains in the HiP.

Highlights

Bovine tuberculosis (BTB) is a chronic, contagious disease caused by Mycobacterium bovis, a Grampositive acid-fast bacterium
Molecular characterisation of M. bovis isolated from wildlife in the Hluhluwe-iMfolozi Park (HiP) was performed using a combination of three genetic tools, namely spoligotyping and restriction fragment length polymorphism (RFLP), including IS6110 and polymorphic G–C-rich sequence (PGRS) typing (Michel et al 2009)
Isolates were classified as members of the M. tuberculosis complex following detection of a 372-bp fragment by polymerase chain reaction (PCR) using primers targeting the sequence that codes for the MPB 70 antigen of the M. tuberculosis complex

Summary

Introduction

Bovine tuberculosis (BTB) is a chronic, contagious disease caused by Mycobacterium bovis, a Grampositive acid-fast bacterium. This pathogen is noted for its diverse host tropism, which includes humans, livestock and several wildlife species. The HiP is situated in KwaZulu-Natal, South Africa and the area of 100 000 ha is almost entirely surrounded by communal farmland and livestock It is the fourth largest game reserve in South Africa and has a buffalo population of approximately 3500 heads. Molecular characterisation of M. bovis isolated from wildlife in the HiP was performed using a combination of three genetic tools, namely spoligotyping and restriction fragment length polymorphism (RFLP), including IS6110 and polymorphic G–C-rich sequence (PGRS) typing (Michel et al 2009). This report showed that epidemiologically unrelated strains are in circulation in the HiP and in the greater Kruger National Park (Michel et al 2009)

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