Drug susceptibility of rapid growing non-tuberculous mycobacteria

Abstract

Background: Non tuberculous mycobacteria are increasingly recognized as causative agents of opportunistic and device associated infections in humans. In india data on them is scarce as species identification and drug susceptibility are not performed in most laboratories. Objective of our study is to analyse the susceptibility pattern of rapidly growing mycobacteria which can guide the clinicians to fashion the empiric regimen when susceptibility testing is not available. Methods and materials: The present study endeavours to generate drug susceptibility data on NTM (rapid growers) isolated from various sample sent to tertiary care centre Mumbai from may 2018 to may 2019. Antibiotic susceptibility was performed using micro-broth dilution technique as per standard clinical and laboratory standard institute guidelines. Results: A total of 84 NTM (rapid growers) were identified. Sensitivity to amikacin and linezolid for rapidly growing mycobacteria was 99% (83 out of 84),followed by clarithromycin 95% (80 out of 84), imipenem 42% (35 out of 84), moxifloxacin 37% (31 out of 84), ciprofloxacin 31% (26 out of 84), tobramycin 22% (18 out of 84), cefoxitin 21% (18 out of 84), minocycline and doxycline 15% (13 out of 84), TMP SMX 1%(1out of 84). Conclusion: Linezolid and amikacin remain most susceptible (99%) followed by clarithromycin (95%). Inclusion of these three drugs in empiric regimen for rapidly growing NTM may helpful to improve patient outcome when DST is awaited or not available.