title: Prevalence of Extensively Drug Resistant Tuberculosis among Archived Multidrug Resistant Tuberculosis Isolates in Zimbabwe.
abstract: We conducted a cross-sectional study of second line drug resistance patterns and genetic diversity of MDR-TB isolates archived at the BRTI-TB Laboratory, Harare, between January 2007 and December 2011. DSTs were performed for second line antituberculosis drugs. XDR-TB strains were defined as MDR-TB strains with resistance to either kanamycin and ofloxacin or capreomycin and ofloxacin. Strain types were identified by spoligotyping. No resistance to any second line drugs was shown in 73% of the isolates, with 23% resistant to one or two drugs but not meeting the definition of XDR-TB. A total of 26 shared types were identified, and 18 (69%) matched preexisting shared types in the current published spoligotype databases. Of the 11 out of 18 clustered SITs, 4 predominant (>6 isolates per shared type) were identified. The most and least abundant types were SIT 1468 (LAM 11-ZWE) with 12 (18%) isolates and SIT 53 (T1) with 6 (9%) isolates, respectively. XDR-TB strains are rare in Zimbabwe, but the high proportion of "pre-XDR-TB" strains and treatment failure cases is of concern. The genetic diversity of the MDR-TB strains showed no significant association between SITs and drug resistance.
authors: Biomedical Research and Training Institute, Harare, Zimbabwe ; Department of Medical Laboratory Sciences, University of Zimbabwe, Harare, Zimbabwe.
authors: Tichaona
authors: T
authors: Sagonda
authors: Biomedical Research and Training Institute, Harare, Zimbabwe.
authors: Lucy
authors: L
authors: Mupfumi
authors: Biomedical Research and Training Institute, Harare, Zimbabwe.
authors: Rumbidzai
authors: R
authors: Manzou
authors: Biomedical Research and Training Institute, Harare, Zimbabwe.
authors: Beauty
authors: B
authors: Makamure
authors: Immunology Department, College of Health Sciences, University of Zimbabwe, P.O. Box A178, Avondale, Harare, Zimbabwe.
authors: Mqondisi
authors: M
authors: Tshabalala
authors: Biomedical Research and Training Institute, Harare, Zimbabwe ; Department of Medical Laboratory Sciences, University of Zimbabwe, Harare, Zimbabwe.
authors: Lovemore
authors: L
authors: Gwanzura
authors: Biomedical Research and Training Institute, Harare, Zimbabwe ; Department of Medical Laboratory Sciences, University of Zimbabwe, Harare, Zimbabwe.
authors: Peter
authors: P
authors: Mason
authors: Biomedical Research and Training Institute, Harare, Zimbabwe.
authors: Reggie
authors: R
authors: Mutetwa