Antimicrobial Susceptibility Distributions of Clinical Isolates of Nontuberculous Mycobacteria in Israel

Abstract

There is a scarcity of data regarding the antimicrobial susceptibility testing profiles of nontuberculous mycobacterial (NTM) in Israel and other Middle Eastern countries. We aimed to describe the antimicrobial susceptibility profiles of NTM in Israel. A total of 410 clinical isolates of NTM, identified to the species level using matrix-assisted laser desorption ionization-time of flight mass spectrometry or hsp65 gene sequencing, were included. Minimum inhibitory concentrations for slowly growing mycobacteria (SGM) and rapidly growing mycobacteria (RGM) for 12 and 11 drugs were determined using the Sensititre SLOMYCOI and RAPMYCOI broth microdilution plates, respectively. Mycobacterium avium complex (MAC) was the most frequently isolated species (n = 148; 36%), followed by Mycobacterium simiae (n = 93; 23%), Mycobacterium abscessus group (n = 62; 15%), Mycobacterium kansasii (n = 27; 7%), and Mycobacterium fortuitum (n = 22; 5%) accounting together for 86% of isolates. The most active agents against SGM were amikacin (98%/85%/100%) and clarithromycin (97%/99%/100%), followed by moxifloxacin (25%/10%/100%) and linezolid (3%/6%/100%) for MAC, M. simiae, and M. kansasii, respectively. For RGM, the most active agents were amikacin (98%/100%/88%) followed by linezolid (48%/80%/100%) and clarithromycin (39%/28%/94%) for M. abscessus group, M. fortuitum, and M. chelonae, respectively. These findings can assist in guiding the treatment of NTM infections.