Academic journal article Bulletin of the World Health Organization

Drug Resistance of Mycobacterium Tuberculosis in Malawi: A Cross-Sectional survey/Pharmacoresistance Du Mycobacterium Tuberculosis Au Malawi: Une Enquete transversal/Resistencia Medicamentosa a la Mycobacterium Tuberculosis En Malawi: Una Encuesta Transversal

Academic journal article Bulletin of the World Health Organization

Drug Resistance of Mycobacterium Tuberculosis in Malawi: A Cross-Sectional survey/Pharmacoresistance Du Mycobacterium Tuberculosis Au Malawi: Une Enquete transversal/Resistencia Medicamentosa a la Mycobacterium Tuberculosis En Malawi: Una Encuesta Transversal

Article excerpt

Introduction

Although the World Health Organization (WHO) has monitored the emergence of drug resistance of Mycobacterium tuberculosis since 1994, (1) there have been few national surveys of such resistance in sub-Saharan Africa. (2)

In 2012, it was estimated that about 1.9% of people newly diagnosed and 9.4% of those undergoing retreatment in Africa had multidrug-resistant (MDR) tuberculosis.' The prevalence of MDR tuberculosis in Africa varies between countries (1) and might be generally increasing. (3,5)

Over several years, attempts have been made--at the Central Reference Laboratory in Lilongwe--to isolate M. tuberculosis from all smear-positive patients undergoing retreatment in Malawi to investigate drug susceptibility. In 2008, about 8% of people investigated in this manner were found to have MDR tuberculosis (James Mpunga, Malawi National Tuberculosis Control Programme, personal communication, 2008)--although most of the samples came from urban centres and the laboratory's attempts to isolate M. tuberculosisM. tuberculosis often failed. (6) The only published data on MDR tuberculosis in Malawi indicated that just 0.5% of people newly diagnosed with tuberculosis and 0.9% of people being retreated in Karonga district had MDR tuberculosis in 1996-1998. (7)

In 2007, the nationally recommended treatment regimen for people newly diagnosed with tuberculosis in Malawi changed. The initial supervised treatment remained the same--i.e. daily isoniazid, rifampicin, pyrazinamide and ethambutol for 2 months--but the unsupervised continuation phase changed from 6 months of isoniazid and ethambutol to 4 months of isoniazid and rifampicin. (8,9) There are four problems since this change that need monitoring. The first is that poor adherence during this currently-recommended continuation phase could lead to the emergence of MDR tuberculosis. Another problem is that nothing is known about the resistance of Malawian isolates of M. tuberculosis to the second-line drugs that began to be used routinely in Malawi in 2007. A third problem is the high prevalence of human immunodeficiency virus (HIV) infection among people with tuberculosis. (10) In 2010, 63% of Malawian tuberculosis patients tested for HIV were found positive. (4) Finally, the national prevalence of drug-resistant tuberculosis may be affected by migration of people from neighbouring countries, where such outbreaks have occurred. (11) Given these issues, we conducted a national survey of resistance to anti-tuberculosis drugs in Malawi.

Methods

Study setting and design

We engaged all of Malawi's 48 tuberculosis registration centres to conduct a prospective, cross-sectional survey. The centres were grouped into three zones --northern, central and southern--for phased sample collection.

Data collection and management

Health workers in each registration centre formed a recruitment team and attended a three-day training course about the survey protocol. They subsequently collected data on each consenting smear-positive tuberculosis patient, including the patient's age, sex, level of education, occupation, marital status and HIV status--if known--and details of any previous tuberculosis treatment. After each patient was asked if they had received tuberculosis treatment, the patient's medical records at the health facility of recruitment were checked for evidence of such treatment.

Following national policy in Malawi, (8) each participant in the survey was offered HIV testing and counselling. At the time of the survey, two rapid blood tests--Uni-Gold Recombigen HIV-1/2 (Trinity Biotech, Bray, Ireland) and Determine HIV-1/2 (Alere, Waltham, United States of America) were used in the registration centres. Any samples giving inconclusive results were sent to the Central Reference Laboratory for retesting.

Data were collected on piloted forms and double-entered into an Epi Info (Centers for Disease Control and Prevention, Atlanta, United States of America) spreadsheet. …

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