Molecular characterization and second-line antituberculosis drug resistance patterns of multidrug-resistant Mycobacterium tuberculosis isolates from the northern region of South Africa.
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 high-burden 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.
Department of Medical Microbiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa. ahlammdd@yahoo.com
Halima M
HM
Said
Marleen M
MM
Kock
Nazir A
NA
Ismail
Matsie
M
Mphahlele
Kamaldeen
K
Baba
Shaheed V
SV
Omar
Ayman G
AG
Osman
Anwar A
AA
Hoosen
Marthie M
MM
Ehlers
D000293:Adolescent; D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000494:pharmacology*; D002207:Capreomycin / Q000494:pharmacology; D002648:Child; D016000:Cluster Analysis; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D005838:Genotype; D006801:Humans; D007612:Kanamycin / Q000494:pharmacology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D058889:Molecular Typing; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D015242:Ofloxacin / Q000494:pharmacology; D013019:South Africa / Q000453:epidemiology; D018088:Tuberculosis, Multidrug-Resistant / Q000453:epidemiology* / Q000382:microbiology*; D055815:Young Adult
D000995:Antitubercular Agents; D002207:Capreomycin; D007612:Kanamycin; D015242:Ofloxacin