oa Southern African Journal of Epidemiology and Infection - Molecular characterisation of resistant isolates from Dr George Mukhari Hospital, Pretoria, South Africa : original research

Volume 23, Issue 3
  • ISSN : 1015-8782
  • E-ISSN: 2220-1084



Drug-resistant tuberculosis is a serious problem throughout the world. Resistance to rifampicin (RIF) and isoniazid (INH) is due to mutations in the B and G genes, respectively. The distribution of B and G gene mutations in RIF- and INH-resistant clinical (MTB) isolates from Dr George Mukhari Hospital, Garankuwa, South Africa was determined. The B and G genes were amplified using PCR and sequenced. Among the 240 resistant MTB isolates obtained, 143/240 (59.6%) were multidrug-resistant (MDR), defined as resistance to INH and RIF, 44/240 (18.3%) were resistant to INH and 4.6% (11/240) to RIF while 17.5% (42/240) isolates were resistant to a combination of drugs. A total of 67.1% (161/240) isolates had mutations in the B region. The most frequent mutations encountered were at codon 516 GAC to GTC 42.2% (68/161), codon 526 CAC to GAC 37.3% (60/161), and the least, at codon 531 TCG to TTG 0.6% (1/161). Codon 315 in the G gene showed mutations in 70% (168/240) isolates resistant to INH. Of these, 58.3% (98/168) isolates showed a mutational change from AGC to ACC, 23.8% (40/168) from AGC to AAC, AGC to ATC in 10.1% (17/168), AGC to CGC in 4.8% (8/168) and AGC to ACA 3% (5/168) while mutations in codon 314 contributed 9.6% (20/209) with the change from ACC to CCC. This study provided information on the genetic diversity of multidrug-resistant MTB strains as well as the effects it can take on the clinical management of patients.

Loading full text...

Full text loading...


Article metrics loading...


This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error