ANTIMICROBIAL SUSCEPTIBILITY OF RAPID GROWING MYCOBACTERIA INFECTED PATIENTS WITH NTM AT TERTIARY CARE CENTER

Rapidly growing mycobacteria (RGM) are ubiquitous organisms found in the environment and are the main cause of pulmonary NTM disease. Some species of RGM are recognized as human pathogens. Mycobacterium abscessus, Mycobacterium fortuitum and Mycobacterium chelonae are most common species in RGM. It is important to correctly distinguish RGM from other species of mycobacteria for the proper treatment of disease. The aim of this study was to perform the antibiotic susceptibility of RGM isolates using standard microbroth dilution test. The study was conducted in the department of microbiology at a tertiary care hospital. This study included 125 isolates of RGM obtained from clinical specimens of suspected cases of pulmonary tuberculosis. 125 isolates of RGM were speciated by Line probe assay and Antimicrobial susceptibility testing was performed as per the guidelines provided by CLSI using Sensititre® RAPMYCO panel test (TREK Diagnostic Systems Magellan Biosciences, West Sussex, and UK). Of the 125 RGM isolates from pulmonary specimens, the majority of RGM were M. abscessus consisting of 65 (52%) strains, followed by 43 (34.4%) strains of M. fortuitum and 17 (13.6%) of M. chelonae. Amikacin was active against nearly all RGM isolates. In patients with M. abscessus, the majority of isolates were susceptible to tigecycline and amikacin followed by linezolid and then clarithromycin. For M.fortuitum the majority of strains were sensitive to amikacin, tigecycline and TMP-SMZ followed by clarithromycin, moxifloxacin, doxycycline and imipenem. M.chelonae was found to be more sensitive for amikacin, clarithromycin, tigecycline, moxifloxacin followed by doxycycline, imipenem and linezolid. Public Health Problems in RGM pulmonary diseases are going to increase. The treatment of pulmonary infections due to RGM is clearly difficult. Due to the lack of facilities and expertise, many laboratories these types of infections are undiagnosed. Our study demonstrates the importance of accurate and correct identification of isolates to the species level and antibiotic susceptibility of RGM species for proper treatment and management of patients is important. Key words Nontuberculous mycobacteria, Rapid growing mycobacteria, Sensititre broth dilution