Alternative technique for culturing sputum for mycobacteria isolation: Feasibility, performance and effect on laboratory quality assessment - A technical note

Mycobacteria culture remains the cornerstone of tuberculosis diagnosis. Naturally contaminated samples need pre-inoculation processing but some economically challenged medical facilities may benefit from a simpler and cheaper sputum decontamination procedure. The aim of this study was to test a simple decontamination method lacking a centrifugation step to be used in conjunction with the culture on Löwenstein-Jensen medium. A total of 7446 sputum samples collected from 3229 patients were microscopically examined and then cultured on Löwestein-Jensen medium using a simplified Petroff method. All positive cultures were confirmed by direct microscopic examination and biochemical identification. Culture and microscopic status and time to positivity were recorded. Mean and median times to culture and contamination rate were similar as compared to classical Löwenstein-Jensen culture method. Overall results suggest that the described modified of Petroff method may be used with adequate results in resource poor settings as the method does not require an aerosol safe centrifuge and relies on cheap, stable and readily available reagents.