Molecular Characterization and Second-Line Antituberculosis Drug Resistance Patterns of Multidrug-Resistant Mycobacterium tuberculosis Isolates from the Northern Region of South Africa

Abstract

c Despite South Africa being one of the high-burden multidrug-resistant tuberculosis (MDR-TB) countries, information regarding the population structure of drug-resistant Mycobacterium tuberculosis strains is limited from many regions of South Africa. This study investigated the population structure and transmission patterns of drug-resistant M. tuberculosis isolates in a highburden setting of South Africa as well as the possible association of genotypes with drug resistance and demographic characteristics. A total of 336 consecutive MDR-TB isolates from four provinces of South Africa were genotyped using spoligotyping and mycobacterial interspersed repetitive-unit-variable number tandem repeat (MIRU-VNTR) typing. Drug susceptibility testing for ofloxacin, kanamycin, and capreomycin was performed using the agar proportion method. The results showed that 4.8% of MDR-TB isolates were resistant to ofloxacin, 2.7% were resistant to kanamycin, and 4.5% were resistant to capreomycin, while 7.1% were extensively drug resistant (XDR), and the remaining 83.6% were susceptible to all of the second-line drugs tested. Spoligotyping grouped 90.8% of the isolates into 25 clusters, while 9.2% isolates were unclustered. Ninety-one percent of the 336 isolates were assigned to 21 previously described shared types, with the Beijing family being the predominant genotype in the North-West and Limpopo Provinces, while the EAI1_SOM family was the predominant genotype in the Gauteng and Mpumalanga Provinces. No association was found between genotypes and specific drug resistance patterns or demographic information. The high level of diversity and the geographical distribution of the drug-resistant M. tuberculosis isolates in this study suggest that the transmission of TB in the study settings is not caused by the clonal spread of a specific M. tuberculosis strain.

Clonality and genetic profiles of drug‐resistant Mycobacterium tuberculosis in the Eastern Cape Province, South Africa

“…Said et al. () did not find any Beijing family in their study. The difference in the clonal spread of Beijing family in our study could be due to the difference in sampling size, time, and locations.…”

“…Previous studies (Marais et al., ; Said et al., ) described the clonal spread of genotypes of M. tuberculosis from different provinces of South Africa. However, an updated thorough analysis of the population structure of resistant M. tuberculosis isolates from the Eastern Cape Province, South Africa, was not available.…”

Transmission of Extensively Drug-Resistant Tuberculosis in South Africa

“…17,28–33 Moreover, our study design, which captured isolates from a large number of cases of XDR tuberculosis over a 4-year period, overcame limitations of previous studies that were not able to show the role of transmission. 34 …”

Multidrug-Resistant Tuberculosis in Panama Is Driven by Clonal Expansion of a Multidrug-Resistant Mycobacterium tuberculosis Strain Related to the KZN Extensively Drug-Resistant M. tuberculosis Strain from South Africa

“…Thus, it appears that the occurrence of the two strains is mostly region specific, with LAM9-c1 in Panama and the KZN strain in KwaZulu-Natal (despite the fact that isolated cases of transmission to other countries have been reported [50]). However, it should be noted that some LAM9 MDR strains have been identified in other provinces near KZN, including Gauteng and Mpumalanga (51).…”