Percentages of Drug Resistance Detected in Nontuberculous Mycobacteria Isolated From Pulmonary Samples

Abstract

Introduction: Nontuberculous Mycobacteria (NTM) infections have recently increased significantly in the world. Especially, lung diseases caused by various NTM are noteworthy. Susceptibility to antimicrobials can vary greatly by species, geographic region and timefor NTMs. In this study, it was aimed to determine the resistance percentages of antimicrobials by performing drug susceptibility tests(DST) for NTM isolated from lower respiratory tract samples.Materials and Methods: Sputum and other lower respiratory tract samples sent to the National Tuberculosis Reference Laboratoriesfrom various provinces in Turkey between January 2014 and December 2015 were studied. Among them, 121 NTM were considered asinfectious agent, and identification at species level was performed using GenoType Mycobacterium CM/AS kit (Ver 1.0) (HAIN Lifescience,Germany). For rapid growing mycobacterium (RGM), RAPMYCO- and for slow growing mycobacterium (SGM), SLOMYCO-SENSITITRE BrothMicrodilution (MIC) (Trek Diagnostic Systems Limited, UK) were used to study DSTs according to the recommendations of the manufacturer.Results: In the study, RGM (n= 81) were identified as Mycobacterium abscessus (n= 36), Mycobacterium chelonae (n= 26),Mycobacterium fortuitum (n= 19), while SGM (n= 40) were Mycobacterium avium (n= 16), Mycobacterium kansasii (n= 14),Mycobacterium intracellulare (n= 10). The highest susceptibility percentages for M. abscessus were found as amikacin 97%, clarithromycin 94%, tigecycline 97%; for M. chelonae, clarithromycin 92%, tigecycline 89%; and for M. fortuitum, amikacin, moxifloxacin,tigecycline 100%. Clarithromycin susceptibility was the highest for M. avium 94%, M. intracellulare 90% and M. kansasii 100%, whilefor M. fortuitum 58%. M. kansasii was detected susceptible to rifabutin 100%, linezolid 100% and etioniamid 86%.Conclusion: The drugs to be selected in treatment should show differences specific to our country based on these susceptibilitypercentages, as following: for empirical treatment, clarithromycin would be better to be added to combined therapy until speciesidentification. Amikacin, moxifloxacin or tigecycline could be used instead of clarithromycin for M. fortuitum.