The antimicrobial susceptibility of non-tuberculous mycobacteria

• Published in: The Journal of infection Vol. 72; no. 3; pp. 324 - 331
• Main Authors: Cowman, S., Burns, K., Benson, S., Wilson, R., Loebinger, M.R.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.03.2016
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents - pharmacology; Anti-mycobacterial agents; Antimicrobial drug resistance; Child; Child, Preschool; Drug Resistance, Bacterial; Female; Humans; Infant; Infant, Newborn; Infectious Disease; Male; Microbial Sensitivity Tests; Middle Aged; Mycobacteriaceae; Mycobacterium abscessus; Mycobacterium avium; Mycobacterium Infections - microbiology; Mycobacterium simiae; Non-tuberculous mycobacteria; Nontuberculous Mycobacteria - drug effects; Nontuberculous Mycobacteria - isolation & purification; Pneumonia, Bacterial - microbiology; Retrospective Studies; Young Adult; Mycobacteriaceae; Non-tuberculous mycobacteria; Anti-mycobacterial agents; Antimicrobial drug resistance
• ISSN: 0163-4453; 1532-2742; 1532-2742
• DOI: 10.1016/j.jinf.2015.12.007

Pulmonary non-tuberculous mycobacterial infection (NTM) is a challenging and increasingly prevalent infection. Antimicrobial resistance is common and may be associated with poor outcomes. This retrospective study aimed to report longitudinal trends in mycobacterial isolation and NTM drug susceptibility. Mycobacterial culture and drug sensitivity testing results were obtained over a 13 year period. Drug sensitivity testing was performed by broth macrodilution for slow-growing mycobacteria and disc diffusion for rapidly growing mycobacteria. Culture results were obtained from 109,311 samples (31,758 subjects) of which 5960 samples (1209 subjects) isolated NTM over 13 years. Drug susceptibility results were obtained for 2637 NTM isolates (898 subjects). NTM isolation increased over time, driven by the Mycobacterium avium complex and Mycobacterium abscessus. Amongst most species, resistance to the key agents clarithromycin and amikacin was rare. The highest rate of resistance was found in M. abscessus and Mycobacterium simiae. Most M. abscessus isolates were sensitive to macrolides, aminoglycosides and tigecycline; M. simiae isolates were only consistently sensitive to clofazimine, amikacin and cycloserine. NTM isolation is increasingly common in our centre. Reassuringly, resistance to clarithromycin and amikacin is rare in most species. Tigecycline, cycloserine and clofazimine may be useful in the treatment of the most resistant species, M. abscessus and M. simiae. •Isolation of NTM increased over time, primarily driven by Mycobacterium avium complex and Mycobacterium abscessus.•Just over half of subjects isolating NTM met ATS 2007 microbiological criteria.•More than one different NTM species was isolated in 20.6% of subjects.•Resistance to the key agents clarithromycin and amikacin was rare.•The highest rates of drug resistance were found in M. abscessus and Mycobacterium simiae.