BACKGROUND: South Africa has a high burden of drug-resistant tuberculosis (TB). METHODS: Routine drug susceptibility testing was performed prospectively over a 2-year period on Mycobacterium tuberculosis isolates in two health districts of the Western Province, South Africa. A cluster of drug-resistant strains that shared a rare mutation in katG315 was found in 64 of the 450 cases identified as having been infected with drug-resistant TB. Isolates belonging to this cluster were phenotypically and genotypically characterised. Epidemiological and clinical characteristics were used to identify mechanisms leading to the acquisition and spread of this drug-resistant strain. RESULTS: An outbreak of an emerging non-Beijing drug-resistant strain infecting 64 pulmonary tuberculosis (PTB) cases was identified. This previously undetected genotype (now designated DRF150) is characterised by five IS6110 insertions, specific spoligotypes and high levels of resistance to the first-line TB medications isoniazid, streptomycin and rifampicin. In 45% of the cases it is also resistant to ethambutol and pyrazinamide. Key factors leading to the development and spread of this drug-resistant genotype were inappropriate chemotherapy, poor adherence to treatment and prolonged periods of infectiousness due to delays in susceptibility testing. CONCLUSIONS: Molecular markers allowed early identification of an emerging non-Beijing drug-resistant strain.
BACKGROUND: South Africa has a high burden of drug-resistant tuberculosis (TB). METHODS: Routine drug susceptibility testing was performed prospectively over a 2-year period on Mycobacterium tuberculosis isolates in two health districts of the Western Province, South Africa. A cluster of drug-resistant strains that shared a rare mutation in katG315 was found in 64 of the 450 cases identified as having been infected with drug-resistant TB. Isolates belonging to this cluster were phenotypically and genotypically characterised. Epidemiological and clinical characteristics were used to identify mechanisms leading to the acquisition and spread of this drug-resistant strain. RESULTS: An outbreak of an emerging non-Beijing drug-resistant strain infecting 64 pulmonary tuberculosis (PTB) cases was identified. This previously undetected genotype (now designated DRF150) is characterised by five IS6110 insertions, specific spoligotypes and high levels of resistance to the first-line TB medications isoniazid, streptomycin and rifampicin. In 45% of the cases it is also resistant to ethambutol and pyrazinamide. Key factors leading to the development and spread of this drug-resistant genotype were inappropriate chemotherapy, poor adherence to treatment and prolonged periods of infectiousness due to delays in susceptibility testing. CONCLUSIONS: Molecular markers allowed early identification of an emerging non-Beijing drug-resistant strain.
Authors: Gail E Louw; Robin M Warren; Nicolaas C Gey van Pittius; Rosalba Leon; Adelina Jimenez; Rogelio Hernandez-Pando; Christopher R E McEvoy; Melanie Grobbelaar; Megan Murray; Paul D van Helden; Thomas C Victor Journal: Am J Respir Crit Care Med Date: 2011-04-21 Impact factor: 21.405
Authors: Neel R Gandhi; Darren Weissman; Prashini Moodley; Melissa Ramathal; Inga Elson; Barry N Kreiswirth; Barun Mathema; Elena Shashkina; Richard Rothenberg; Anthony P Moll; Gerald Friedland; A Willem Sturm; N Sarita Shah Journal: J Infect Dis Date: 2012-11-19 Impact factor: 5.226
Authors: E M Streicher; I Bergval; K Dheda; E C Böttger; N C Gey van Pittius; M Bosman; G Coetzee; R M Anthony; P D van Helden; T C Victor; R M Warren Journal: Antimicrob Agents Chemother Date: 2012-02-13 Impact factor: 5.191
Authors: Alistair D Calver; Alecia A Falmer; Megan Murray; Odelia J Strauss; Elizabeth M Streicher; Madelene Hanekom; Thelma Liversage; Mothusi Masibi; Paul D van Helden; Robin M Warren; Thomas C Victor Journal: Emerg Infect Dis Date: 2010-02 Impact factor: 6.883
Authors: Kimberly E Beatty; Monique Williams; Brian L Carlson; Benjamin M Swarts; Robin M Warren; Paul D van Helden; Carolyn R Bertozzi Journal: Proc Natl Acad Sci U S A Date: 2013-07-22 Impact factor: 11.205