An alternative strategy for the storage and transport of sputum specimens for Mycobacterium Tuberculosis drug resistance surveys

Abstract

SETTING: A district level tuberculosis (TB) programme in Indonesia. OBJECTIVE: To evaluate whether a single sputum specimen could be stored by refrigeration for an extended period of time, then transported to a reference laboratory and successfully cultured for Mycobacterium tuberculosis. METHODS: Single sputum specimens were collected from newly diagnosed smear-positive pulmonary TB patients, refrigerated at the study site without addition of 1% cetylpyridinium chloride, batched and sent to the reference laboratory, where they were decontaminated and inoculated into BACTEC MGIT 960 liquid media. RESULTS: One hundred and seven patients were enrolled. The median specimen storage time was 12 days (range 1-38) and median transportation time was 4 days (2-12). The median time from specimen collection until processing was 18 days (4-42). Only 4 (3.7%) specimens failed to grow Mycobacterium species and M. tuberculosis was isolated from 101 (94.4%) specimens. Six specimens with breakthrough contamination successfully grew M. tuberculosis after a second decontamination procedure. CONCLUSIONS: Single sputum specimens collected at a remote setting, refrigerated for relatively long periods without preservatives and transported without refrigeration to a reference laboratory can yield a high positive culture rate. These findings offer potential logistic simplification and cost savings for drug resistance surveys in low-resource countries.