Control of (Multi)Drug Resistance and Tuberculosis Incidence over 23 Years in the Context of a Well-Supported Tuberculosis Programme in Rural Malawi

Sebastian M Mboma,Neil French,Amelia C Crampin,Lifted Sichali,Paul E M Fine,Francis Drobniewski,James Mpunga,Rein M G J Houben,Judith R Glynn,John Z Metcalfe

doi:10.1371/journal.pone.0058192

Abstract

BackgroundThe rise in tuberculosis (TB) incidence following generalized HIV epidemics can overwhelm TB control programmes in resource-limited settings, sometimes accompanied by rising rates of drug resistance. This has led to claims that DOTS-based TB control has failed in such settings. However, few studies have described the effect of a sustained and well-supported DOTS programme on TB incidence and drug resistance over a long period. We present long-term trends in incidence and drug resistance in rural Malawi.MethodsKaronga District in northern Malawi has an adult HIV prevalence of ∼10%. A research group, the Karonga Prevention Study, collaborates with the National Tuberculosis Programme to support core TB control activities. Bacteriological, demographic and clinical (including HIV status) information from all patients starting TB treatment in the District have been recorded since 1988. During that period isolates from each culture-positive TB patient were exported for drug sensitivity testing. Antiretroviral therapy (ART) has been widely available since 2005.ResultsIncidence of new smear-positive adult TB peaked at 124/100,000/year in the mid-90s, but has since fallen to 87/100,000/year. Drug sensitivity information was available for 95% (3132/3307) of all culture-positive cases. Initial resistance to isoniazid was around 6% with no evidence of an increase. Fewer than 1% of episodes involved a multi-drug resistant strain.DiscussionIn this setting with a generalised HIV epidemic and medium TB burden, a well-supported DOTS programme enhanced by routine culture and drug sensitivity testing may well have reduced TB incidence and maintained drug resistance at low levels.

Highlights

Introduction[1] In South Africa the HIV-driven rise in TB incidence was accompanied by escalating rates of TB drug resistance
We report long-term trends in TB incidence and drug resistance in the context of a well-supported TB programme in Karonga District, a rural district in northern Malawi [15], where an effective Antiretroviral therapy (ART) programme is in place
Patients are started on treatment if a culture growth suggests M.tuberculosis

Summary

Introduction

[1] In South Africa the HIV-driven rise in TB incidence was accompanied by escalating rates of TB drug resistance. WHO’s 2010 global report showed signs that overall TB incidence rates are beginning to fall in the African region outside South Africa [14], and that, despite their limited resources, the standard DOTS, smear-microscopy based programmes in the area are starting to control TB. The rise in tuberculosis (TB) incidence following generalized HIV epidemics can overwhelm TB control programmes in resource-limited settings, sometimes accompanied by rising rates of drug resistance. This has led to claims that DOTS-based TB control has failed in such settings. Sex Female Male Age ,15 15–24 25–34 35–44 $45 TB Type Pulmonaryb Extra-pulmonary only Sputum Status smear-negative smear-positive HIV-negative HIV-positive HIV-pos – not on ARTc HIV-pos – on ARTc Clustered with other case in the pastd Unique RFLP fingerprint Clustered RFLP fingerprint

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