Epidemiology of Rapidly Growing Mycobacteria Bloodstream Infections.
BACKGROUND
Rapidly growing mycobacteria (RGM) bloodstream infections (BSI) are an emerging problem often associated with therapeutic challenges. We review the epidemiology, treatment and outcomes over a 5-year period of a heterogeneous group presenting to our institution with RGM BSI.


MATERIALS AND METHODS
A retrospective cohort study of patients with primary RGM BSI from January 2006-December 2011 was conducted. Patient characteristics (age, race, sex and comorbidities), infection characteristics (catheter associated, hospital acquired, microbiology and antimicrobial susceptibilities), therapy and outcomes were recorded and compared by species.


RESULTS
Among 32 patients, 33 RGM BSI occurred. Patients had an average of 3-4 comorbidities, most commonly malignancy (45.5%). Most isolates (30.3%) were Mycobacterium fortuitum or Mycobacterium mucogenicum (27.2%), followed by Mycobacterium abscessus/chelonae (18.2%) and Mycobacterium immunogenum (12.2%). In all, 85% were catheter associated and 27.3% were hospital acquired. Empiric therapy was started in 19 (57.6%) patients and among these, it was adequate (at least 2 active agents based on susceptibilities) in 12 (63.2%). Among 21 patients with outcome data, cure was assumed for 14 (66.7%). One death was attributable to RGM BSI. Cure rates were higher among those who received adequate empiric therapy compared to those who did not (83.3% versus 42.9%). In general, antibiotic susceptibility was favorable across species for clarithromycin, amikacin and imipenem.


CONCLUSIONS
RGM BSI occurred in a population with multiple comorbidities, most commonly malignancy, and most were catheter associated. Higher cures were seen among those who received adequate empiric therapy and based on susceptibility data, a broad empiric regimen of clarithromycin, amikacin and imipenem would be expected to be adequate.
['Rodriguez-Coste|Michelle A|MA|', 'Chirca|Ioana|I|', 'Steed|Lisa L|LL|', 'Salgado|Cassandra D|CD|']
D000328:Adult D000900:Anti-Bacterial Agents D016470:Bacteremia D015331:Cohort Studies D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D009164:Mycobacterium Infections D016926:Mycobacterium chelonae D019907:Mycobacterium fortuitum D012189:Retrospective Studies
Rapidly growing mycobacteria Bloodstream infection Antimicrobial susceptibilities Empiric therapy Clinical outcomes