Detection of drug resistant Mycobacterium tuberculosis by high-throughput sequencing of DNA isolated from acid fast bacilli smears.

BACKGROUND: Drug susceptibility testing for Mycobacterium tuberculosis (MTB) is difficult to perform in resource-limited settings where Acid Fast Bacilli (AFB) smears are commonly used for disease diagnosis and monitoring. We developed a simple method for extraction of MTB DNA from AFB smears for sequencing-based detection of mutations associated with resistance to all first and several second-line anti-tuberculosis drugs. METHODS: We isolated MTB DNA by boiling smear content in a Chelex solution, followed by column purification. We sequenced PCR-amplified segments of the rpoB, katG, embB, gyrA, gyrB, rpsL, and rrs genes, the inhA, eis, and pncA promoters and the entire pncA gene. RESULTS: We tested our assay on 1,208 clinically obtained AFB smears from Ghana (n = 379), Kenya (n = 517), Uganda (n = 262), and Zambia (n = 50). Coverage depth varied by target and slide smear grade, ranging from 300X to 12000X on average. Coverage of ≥20X was obtained for all targets in 870 (72%) slides overall. Mono-resistance (5.9%), multi-drug resistance (1.8%), and poly-resistance (2.4%) mutation profiles were detected in 10% of slides overall, and in over 32% of retreatment and follow-up cases. CONCLUSION: This rapid AFB smear DNA-based method for determining drug resistance may be useful for the diagnosis and surveillance of drug-resistant tuberculosis.

Improving performance of Zambia Defence Force antiretroviral therapy providers: evaluation of a standards-based approach.

BACKGROUND: The Zambia Defence Force (ZDF) has applied the Standards-Based Management and Recognition (SBM-R®) approach, which uses detailed performance standards, at some health facilities to improve HIV-related services offered to military personnel and surrounding civilian communities. This study examines the effectiveness of the SBM-R approach in improving facility readiness and provider performance at ZDF facilities. METHODS: We collected data on facility readiness and provider performance before and after the 2010-2012 intervention at 4 intervention sites selected for their relatively poor performance and 4 comparison sites. Assessors observed whether each facility met 16 readiness standards and whether providers met 9 performance standards during consultations with 354 returning antiretroviral therapy (ART) clients. We then calculated the percentages of criteria achieved for each readiness and performance standard and conducted bivariate and multivariate analyses of provider performance data. RESULTS: Facilities' ART readiness scores exceeded 80% before the intervention at both intervention and comparison sites. At endline, scores improved on 4 facility readiness standards in the intervention group but on only 1 standard in the comparison group. Multivariate analysis found that the overall provider performance score increased significantly in the intervention group (from 58% to 84%; P<.01) but not in the comparison group (from 62% to 70%). The before-and-after improvement in scores was significantly greater among intervention sites than among comparison sites for 2 standards-initial assessment of the client's condition and nutrition counseling. CONCLUSION: The standards-based approach, which involved intensive and mutually reinforcing intervention activities, showed modest improvements in some aspects of providers' performance during ART consultations. Further research is needed to determine whether improvements in provider performance affect client outcomes such as adherence to ART.