Differences in Drug-Susceptibility Patterns between Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium chimaera Clinical Isolates: Prospective 8.5-Year Analysis by Three Laboratories

Abstract

It has been suggested that Mycobacterium avium, Mycobacterium intracellulare, and M. chimaera have differential drug susceptibility patterns. We prospectively analyzed and compared the drug susceptibility patterns among these species over an 8.5-year period. Methods: A microdilution method (Slomyco®) was performed for drug susceptibility testing of 402 M. avium, 273 M. intracellulare, and 139 M. chimaera clinical isolates. Results: M. avium showed significantly higher resistance to moxifloxacin, ciprofloxacin, rifampicin, ethambutol, streptomycin, linezolid, cotrimoxazole, and clarithromycin. M. avium also showed higher minimum inhibitory concentrations (MIC) than M. intracellulare and M. chimaera against all drugs except ethionamide, to which M. intracellulare and M. chimaera showed greater resistance. Conclusions: Our series demonstrated differential drug resistance patterns among the most frequent M. avium complex species. M. avium was more resistant than M. intracellulare and M. chimaera versus eight antibiotics and showed greater MIC values to most of the antibiotics studied. These data suggest that knowledge of the local distribution and susceptibility profiles of these pathogens is essential for adequate clinical management.

In Vitro Effect of Three-Antibiotic Combinations plus Potential Antibiofilm Agents against Biofilm-Producing Mycobacterium avium and Mycobacterium intracellulare Clinical Isolates

“…The percentage of synergistic activity was higher in M. intracellulare than in M. avium . In our area, the susceptibility of M. intracellulare to antimycobacterial antibiotics has been reported to be higher than that of M. avium [ 35 ]. These results clearly demonstrate that MIC values showed a greater reduction in association with the three-antibiotic combinations compared to the use of antibiotics alone.…”

Drugs for treating infections caused by non-tubercular mycobacteria: a narrative review from the study group on mycobacteria of the Italian Society of Infectious Diseases and Tropical Medicine

“…In several studies, NTM showed high levels of resistance: 95.8% for Mabs (Mabs subsp. massiliense was reported to be between 0 and 97% susceptible) and 64.3% for M. kansasii [ 82 , 183 , 184 ]. No data from clinical trials are available, but case reports suggest the use for rare or difficult to treat NTM diseases [ 185 ].…”

Antibiotic Resistance in Bacterial Pathogens

“…Another important aspect of AMR is the study of the evolution of resistance. Thus, an increase in the percentage of vancomycin-resistant S. aureus [ 2 ], the prevalence of ESBL CTX-M-15 [ 3 ], and the different resistance patterns among species [ 4 , 5 , 6 ] support the idea that the knowledge of local distribution and susceptibility profiles of bacterial pathogens is essential for adequate clinical management.…”