Diverse Molecular Genotypes of Mycobacterium tuberculosis Complex Isolates Circulating in the Free State, South Africa

Published ArticleTuberculosis is a serious public health concern especially in Africa and Asia. Studies describing strain diversity are lacking in the Free State region of South Africa. The aim of the study was to describe the diversity of Mycobacterium tuberculosis (M. tuberculosis) strain families in the Free State province of South Africa. A total of 86 M. tuberculosis isolates were genotyped using spoligotyping. A 12-locusmycobacterial interspersed repetitive units-variable-number tandem repeats (MIRU-VNTRs) typing was used to further characterize the resulting spoligotyping clusters. SITVITWEB identified 49 different patterns with allocation to six lineages including Latin-American-Mediterranean (LAM) (18 isolates), T (14 isolates), Beijing (five isolates), S (six isolates), Haarlem (one isolate), and X (five isolates), while 37 (43.0%) orphans were identified. Eight clusters included 37 isolates with identical spoligotypes (2 to 13/cluster). MIRU-VNTR typing further differentiated three spoligotyping clusters: SIT1/Beijing/MIT17, SIT33/LAM3/MIT213, and confirmed one SIT34/S/MIT311. In addition, SpolDB3/RIM assignment of the orphan strains resulted in a further 10 LAM and 13 T families. In total, LAM (28 isolates) and T (27 isolates) cause 63% of the individual cases of MTB in our study. The Free State has a highly diverse TB population with LAM being predominant. Further studies with inclusion of multidrug-resistant strains with larger sample size are warranted

High strain diversity among isoniazid-resistant M tuberculosis isolates from the Free State and Northern Cape provinces

This study set out to determine the diversity of the isoniazid-resistant M tuberculosis isolates causing pulmonary tuberculosis in the Free State and Northern Cape provinces of South Africa. Thirty-seven isoniazid-resistant isolates from a nation-wide survey could be fingerprinted by IS6110-based RFLP. Spoligotyping and MIRU-VNTR typing were performed to confirm inconclusive results. The number of IS6110 copies per isolate varied from 2 to 18, with nine (24.3%) isolates harbouring five insertions or fewer. Nine (24.3%) of 37 cases grouped into four RFLP-clusters. The clustered isolates with fewer than five IS6110 copies were all shown to be different when   subjected to spoligotyping and MIRU-VNTR typing, whereas the clustering of the high-copy isolates was confirmed. The high degree of diversity among H-resistant isolates in the Free State suggests a low recent transmission rate, but this should be investigated by long-term analyses. For the Northern Cape province, representative sampling is needed before proper conclusions can be drawn

Diverse Molecular Genotypes of Mycobacterium tuberculosis

Tuberculosis is a serious public health concern especially in Africa and Asia. Studies describing strain diversity are lacking in the Free State region of South Africa. The aim of the study was to describe the diversity of Mycobacterium tuberculosis (M. tuberculosis) strain families in the Free State province of South Africa. A total of 86 M. tuberculosis isolates were genotyped using spoligotyping. A 12-locus mycobacterial interspersed repetitive units-variable-number tandem repeats (MIRU-VNTRs) typing was used to further characterize the resulting spoligotyping clusters. SITVITWEB identified 49 different patterns with allocation to six lineages including Latin-American-Mediterranean (LAM) (18 isolates), T (14 isolates), Beijing (five isolates), S (six isolates), Haarlem (one isolate), and X (five isolates), while 37 (43.0%) orphans were identified. Eight clusters included 37 isolates with identical spoligotypes (2 to 13/cluster). MIRU-VNTR typing further differentiated three spoligotyping clusters: SIT1/Beijing/MIT17, SIT33/LAM3/MIT213, and confirmed one SIT34/S/MIT311. In addition, SpolDB3/RIM assignment of the orphan strains resulted in a further 10 LAM and 13 T families. In total, LAM (28 isolates) and T (27 isolates) cause 63% of the individual cases of MTB in our study. The Free State has a highly diverse TB population with LAM being predominant. Further studies with inclusion of multidrug-resistant strains with larger sample size are warranted

DNA fingerprinting analyses of M tuberculosis-complex isolates from the Free State, South Africa, as part of a multidisciplinary study

The objective of this study was to serve as a complement to socio-economic analyses of TB patients in a DOTS system, providing microbiological data and documenting the TB population dynamics. Sputum samples were collected from smear-positive TB patients in the Goldfields, Thaba Nchu and Qwaqwa areas. Laboratory analyses comprised the culturing of Mycobacterium tuberculosis isolates and DNA fingerprinting. The primary aim was hampered by problems encountered during specimen sampling, inadequate resources, and a low culture-positivity rate. Nevertheless, the fingerprinting data of a random sample showed a heterogenous TB population,   suggesting that reactivation might be an important factor in the area studied. Clustering was the highest in the mining area. Preliminary data from serial isolates also detected possible re-infection during treatment or initial mixed infections in five of the eleven patients

High strain diversity among isoniazid-resistant M tuberculosis isolates from the Free State and Northern Cape provinces

This study set out to determine the diversity of the isoniazid-resistant M tuberculosis isolates causing pulmonary tuberculosis in the Free State and Northern Cape provinces of South Africa. Thirty-seven isoniazid-resistant isolates from a nation-wide survey could be fingerprinted by IS6110-based RFLP. Spoligotyping and MIRU-VNTR typing were performed to confirm inconclusive results. The number of IS6110 copies per isolate varied from 2 to 18, with nine (24.3%) isolates harbouring five insertions or fewer. Nine (24.3%) of 37 cases grouped into four RFLP-clusters. The clustered isolates with fewer than five IS6110 copies were all shown to be different when   subjected to spoligotyping and MIRU-VNTR typing, whereas the clustering of the high-copy isolates was confirmed. The high degree of diversity among H-resistant isolates in the Free State suggests a low recent transmission rate, but this should be investigated by long-term analyses. For the Northern Cape province, representative sampling is needed before proper conclusions can be drawn

DNA fingerprinting analyses of M tuberculosis-complex isolates from the Free State, South Africa, as part of a multidisciplinary study

The objective of this study was to serve as a complement to socio-economic analyses of TB patients in a DOTS system, providing microbiological data and documenting the TB population dynamics. Sputum samples were collected from smear-positive TB patients in the Goldfields, Thaba Nchu and Qwaqwa areas. Laboratory analyses comprised the culturing of Mycobacterium tuberculosis isolates and DNA fingerprinting. The primary aim was hampered by problems encountered during specimen sampling, inadequate resources, and a low culture-positivity rate. Nevertheless, the fingerprinting data of a random sample showed a heterogenous TB population,   suggesting that reactivation might be an important factor in the area studied. Clustering was the highest in the mining area. Preliminary data from serial isolates also detected possible re-infection during treatment or initial mixed infections in five of the eleven patients