Exploring drug-resistant tuberculosis profiles within the West Coast, South Africa

[摘要] ENGLISH ABSTRACT : Tuberculosis is still to this day the most widespread infectious disease globally. The spread of drug-resistant strains which has been reported to be attributed to primary transmission threatens TB control and prevention programmes. Previous molecular epidemiological studies have reported that the dynamics of tuberculosis transmission varies geographically.The aim of the present study was to describe the drug-resistant tuberculosis epidemic and identify transmission hotspots and possible outbreaks of drug-resistant tuberculosis within the West Coast region of the Western Cape, South Africa. We used the internationally standardised spoligotyping method to classify Mycobacterium tuberculosis into different lineages and strain family and DNA sequencing of drug resistance conferring genes to genotypically characterise drug-resistant tuberculosis isolates collected from the West Coast region over a 5 year period (2008-2012).Spoligotyping data revealed the X-family as the most dominant M. tuberculosis strain family, followed by the Beijing family. Our findings are contradicting to what has been reported in the rest of the Western Cape Province that identified the Beijing family to be the predominant family responsible for drug-resistant tuberculosis within the province.We identified a cluster of multidrug-resistant isolates mainly located in the Northern parts of the region, harbouring similar spoligotyping patterns and identical mutations conferring resistance to the 4 first-line drugs used in tuberculosis treatment. This is indicative of transmission. Isolates belonging to this outbreak, but with different additional mutations conferring to resistance to second-line drugs were also identified, indicating that Pre-XDR and XDR-TB are primarily acquired on an existing MDR strain genotype.Even though spoligotyping is considered to have a low discriminatory power and could overestimate the extent of transmission, this study described an epidemic spread of multi-drug resistant strains in the West Coast region of the Western Cape. Our study highlighted the regional variation of outbreaks and the need for molecular epidemiology studies in various regions to tailor interventions to curb TB and drug-resistant TB spread.

[发布机构] Stellenbosch University