Transportation of sputum samples in cetylpyridinium chloride for drug resistance studies from remote areas of Odisha, India

Abstract

Introduction: Antimicrobial susceptibility testing of Mycobacterium tuberculosis is required for successful treatment of patients, mainly in retreatment cases which necessitate isolation of mycobacteria from sputum samples within 24-48 hours. In situations where transportation of sputum is required, the use of cetylpyridinium chloride (CPC) effectively sustains the viability of mycobacteria up to two weeks.

Methodology: Sputum samples were collected from pulmonary TB patients attending designated microscopy centres (DMC), stored in CPC solution and transported to a culture drug susceptibility testing laboratory using overnight bus transport facilities. For culture, the sputum specimens were processed and inoculated in Lowenstein- Jensen (LJ) medium. Growth on LJ was identified by colony morphology, growth rate and biochemical tests, and transit time was calculated as the time taken from the date of sample collection to the inoculation date.

Results: Out of the 816 sputum samples collected in CPC, 691 (84.7%) yielded M. tuberculosis, 97 (11.9%) yielded no growth, 21(2.6%) grew contaminants and 7 (0.8%) were nontuberculous mycobacteria. CPC containing sputum samples processed within two weeks showed 88.6% culture positivity, while positivity was significantly affected beyond two weeks.

Conclusions: CPC is cheap, easy to use, inhibits the growth of other organisms and can effectively be used to transport sputum specimens within two weeks from hard to reach areas to central locations without compromising culture positivity. Bus transport services can also help in reducing delay and the cost of transportation from remote areas.