Evaluation of OMNIgene®â€¢SPUTUM reagent for mycobacterial culture.

SETTING: National Mycobacterium Reference Laboratory, Borstel, Germany. OBJECTIVE: To evaluate the effectiveness of OMNIgene®â€¢SPUTUM (OM-S) reagent in comparison with a method using N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) with regard to mycobacterial recovery and contamination of broth and solid cultures. DESIGN: Sputum samples from patients with tuberculosis and other respiratory diseases underwent decontamination with NALC-NaOH-based (MycoDDR™) or OM-S reagent. The decontamination procedure was assigned by block randomisation. Samples were inoculated on Löwenstein-Jensen, Stonebrink and MGIT™ (Mycobacterial Growth Indicator Tubes). Mycobacterial recovery from samples spiked with Mycobacterium tuberculosis following decontamination was determined. RESULTS: Eighty-five samples were randomised to NALC-NaOH and 84 to OM-S reagent. Mycobacterial recovery was significantly lower for samples processed with OM-S reagent compared with the NALC-NaOH method across all media types. Culture contamination was lower with NALC-NaOH reagent on solid media (9.4-12.9% vs. 28.6-29.8%). Growth was not observed in MGIT among samples spiked with 10 600-16 800 colony-forming units of M. tuberculosis following decontamination with OM-S reagent. CONCLUSION: Low mycobacterial recovery, especially in MGIT, observed in the present study suggests that OM-S reagent might not be compatible with the MGIT system. More extensive field evaluations of the OM-S reagent are warranted to demonstrate a significant benefit over currently used methods.

Impact of quality improvement in tuberculosis laboratories in low- and lower-middle-income countries: a systematic review.

BACKGROUND: The effect of quality improvement measures on the performance of diagnostic tuberculosis (TB) laboratories in low- and lower-middle-income countries is not known, and is the subject of this review. METHODS: Three databases were searched for quality improvement studies presenting data on performance parameters before and after the implementation of quality improvement interventions. RESULTS: Twenty-one studies were included in this review. Quality improvement measures were most frequently implemented by an external organization; settings targeted ranged from microscopy centers, hospitals, districts, regional and national reference laboratories. Quality improvement interventions and outcome measurements were highly heterogeneous. Most studies investigated interventions aimed at improving smear microscopy (n = 17). Two studies evaluated comprehensive quality improvement measures (n = 2) and another three studies focused on mycobacterial culture and drug susceptibility testing. Most studies showed an improvement in outcomes measured on before-after or time trend analysis. CONCLUSION: Quality improvement measures implemented in TB laboratories showed a positive impact on various outcomes. Due to the high heterogeneity of outcome reporting and interventions and the low quality of the studies, the effect size was not clear. Identification of standardized quality indicators and their link to the quality of patient care would improve knowledge in this field.

Direct DNA Extraction from Mycobacterium tuberculosis Frozen Stocks as a Reculture-Independent Approach to Whole-Genome Sequencing.

Culturing before DNA extraction represents a major time-consuming step in whole-genome sequencing of slow-growing bacteria, such as Mycobacterium tuberculosis. We report a workflow to extract DNA from frozen isolates without reculturing. Prepared libraries and sequence data were comparable with results from recultured aliquots of the same stocks.