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Exogenous Re-infection with Multidrug- and Extensively Drug-resistant TB among TB/HIV Co-infected Patients in Rural South Africa
J Andrews1, Neel Gandhi*2, P Moodley3, S Shah2, L Bohlken3, T Moll4, M Pillay3, G Friedland1, W Sturm3, and Tugela Ferry Care and Research Collaboration
1Yale Univ Sch of Med, New Haven, CT, US; 2Albert Einstein Coll of Med, Bronx, NY, US; 3Nelson R Mandela Sch of Med, Durban, South Africa; and 4Philanjalo and Church of Scotland Hosp, Tugela Ferry, South Africa
Background: Multidrug-resistant (MDR) and extensively
drug-resistant (XDR) TB have emerged as major health threats in high HIV
prevalence settings in South Africa; however, the role of primary drug
resistance has not been determined.
Methods: We used data derived from a
case-control study of patients with sputum culture-positive TB at Church of
Scotland Hospital, KwaZulu-Natal, South Africa from 2005 to 2006. We performed
spoligotyping on isolates from patients who had cultures showing resistance to
an increasing number of drugs over the study period.
Results: Of 170 patients in the case-control study,
43 had baseline and follow-up sputum cultures obtained at least one month after
the initial culture; 23 of these develop MDR or XDR TB. Paired spoligotypes
were available for 17 of the 23 patients; all had differing spoligotypes between
initial and follow-up isolates, suggesting exogenous re-infection. All 17
patients had been hospitalized. HIV status was known for 15 patients; all were
HIV infected.
Conclusions: Exogenous re-infection with
drug-resistant strains was responsible for all new drug resistance among
patients in the first year after TB diagnosis. In addition to supporting
medication adherence, TB control programs must urgently address infection
control to reduce transmission of resistant TB and curtail the rise of MDR and XDR
TB in HIV-infected patients.
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