Extensively drug-resistant tuberculosis: epidemiology and management challenges.
ABSTRACT Widespread global use of rifampin for 2 decades preceded the emergence of clinically significant multidrug-resistant tuberculosis (MDR-TB) in the early 1990s. The prevalence of MDR-TB has gradually increased such that it accounts for approximately 5% of the global case burden of disease (approximately half a million cases in 2007). Eclipsing this worrying trend is the widespread emergence of extensively drug-resistant TB (XDR-TB). This article reviews the insights provided by clinical and molecular epidemiology regarding global trends and transmission dynamics of XDR-TB, and the challenges clinicians have to face in diagnosing and managing cases of XDR-TB. The ethical and management dilemmas posed by recurrent defaulters, XDR-TB treatment failures, and isolation of incurable patients are also discussed. Given the past global trends in MDR-TB, if aggressive preventive and management strategies are not implemented, XDR-TB has the potential to severely cripple global control efforts of TB.
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ABSTRACT: Singh and colleagues discuss the threat to regional and global public health posed by XDR-TB in KwaZulu-Natal, and propose new measures to control the outbreak.PLoS Medicine 02/2007; 4(1):e50. · 15.25 Impact Factor
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ABSTRACT: Kangaroo mother care (KMC) has become the standard of care for low-risk preterm babies born in developing countries. However, the potential risk of nosocomial transmission of Mycobacterium tuberculosis within KMC units, particularly in tuberculosis-endemic areas, has not been explored. We report an infant (sentinel case) who was admitted to our paediatric intensive care unit (PICU) with extensive pulmonary tuberculosis. When interviewed, the mother reported no household contact with a tuberculosis source case, but mentioned that she shared a KMC room with someone who had symptoms suspicious of tuberculosis. We found molecular evidence that nosocomial transmission of M. tuberculosis occurred within the KMC unit and conducted a contact investigation of all infants exposed to this infectious source case during her stay in the KMC unit. We present the findings of the contact investigation and discuss the implications of these findings for KMC units, particularly in tuberculosis-endemic areas.Acta Paediatrica 06/2006; 95(5):535-9. · 1.97 Impact Factor
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ABSTRACT: Multidrug-resistant (MDR) Mycobacterium tuberculosis poses a serious threat to the control of tuberculosis (TB) and constitutes an increasing public health problem. The availability of rapid in vitro susceptibility tests is a prerequisite for optimal patient treatment. Rifampicin resistance caused by diverse mutations in the rpoB gene is an established and widely used surrogate marker for MDR-TB. We used a high-resolution melting (HRM) curve analysis approach to scan for mutations in the rpoB gene. A total of 49 MDR-TB and 19 fully susceptible non-MDR-TB isolates, as determined by conventional drug susceptibility testing using the BACTEC-MGIT960 system, were used to evaluate the suitability of HRM curve analysis as a rapid and accurate screening system for rifampicin resistance. HRM analysis of the rpoB cluster I site allowed the correct allocation of 44 of the 49 MDR-TB isolates and all non-MDR-TB isolates. Three of the five MDR-TB isolates (60%) falsely identified as non-MDR-TB harboured the V176F mutation that could be specifically detected by an additional HRM assay. The combined HRM analysis of all strains and isolates exhibited 95.9% sensitivity and 100% specificity. With a positive predictive value of 100% and a negative predictive value of at least 99.9%, this combined HRM curve analysis is an ideal screening method for the TB laboratory, with minimal requirements of cost and time. The method is a closed-tube assay that can be performed in an interchangeable 96- or 384-well microplate format enabling a rapid, reliable, simple and cost-effective handling of even large sample numbers.Journal of Antimicrobial Chemotherapy 05/2009; 63(6):1121-7. · 5.34 Impact Factor