title: The antimicrobial susceptibility of non-tuberculous mycobacteria.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Host Defence Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP United Kingdom; National Heart and Lung Institute, Imperial College London, Guy Scadding Building, Dovehouse Street, London, SW6 6LY, United Kingdom. Electronic address: s.cowman12@imperial.ac.uk.
authors.forename: S
authors.initials: S
authors.lastname: Cowman
authors.affiliation: Microbiology Department, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, United Kingdom. Electronic address: k.burns@rbht.nhs.uk.
authors.forename: K
authors.initials: K
authors.lastname: Burns
authors.affiliation: Microbiology Department, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, United Kingdom. Electronic address: s.benson@rbht.nhs.uk.
authors.forename: S
authors.initials: S
authors.lastname: Benson
authors.affiliation: Host Defence Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP United Kingdom; National Heart and Lung Institute, Imperial College London, Guy Scadding Building, Dovehouse Street, London, SW6 6LY, United Kingdom. Electronic address: r.wilson@rbht.nhs.uk.
authors.forename: R
authors.initials: R
authors.lastname: Wilson
authors.affiliation: Host Defence Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP United Kingdom; National Heart and Lung Institute, Imperial College London, Guy Scadding Building, Dovehouse Street, London, SW6 6LY, United Kingdom. Electronic address: m.loebinger@rbht.nhs.uk.
authors.forename: M R
authors.initials: MR
authors.lastname: Loebinger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009164:Mycobacterium Infections / Q000382:microbiology*; D009170:Nontuberculous Mycobacteria / Q000187:drug effects* / Q000302:isolation & purification; D018410:Pneumonia, Bacterial / Q000382:microbiology*; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents
keywords: Anti-mycobacterial agents; Antimicrobial drug resistance; Mycobacteriaceae; Non-tuberculous mycobacteria