Clinical Outcomes of Mycobacterium abscessus Infections in Miami, Florida
Infections caused by Mycobacterium abscessus (MA) are usually resistant to multiple antimicrobials and challenging to treat worldwide. The prevalence of MA infections in Florida is unknown. We describe the risk factors, treatment and clinical outcomes of patients in 2 large academic hospitals.
Retrospective cohort study of hospitalized adults with a positive culture for MA at Jackson Memorial Hospital (1,550-beds) and the University of Miami Hospital (550-beds) Miami, FL (January 1, 2011 to January 31, 2014). Demographics, comorbidities, source of infection, antimicrobial susceptibilities and clinical outcomes were analyzed. Treatment failure was defined as death and/or infection relapse within 4 weeks of treatment. Mortality was defined as death related to MA during hospital stay. Data were analyzed using SPSS version 16.
68 patients were analyzed. Mean age 51.16±19.46 years, 35 (51.5%) males, 28 (41.2%) Hispanics, 7 (10.3%) end-stage renal disease, 16(21.9%) were on immunosuppressive therapy (IT). Organisms were isolated: 40 (58.8%) respiratory sources, 14 (20.6%) blood, 11 (16.2%) skin and wound cultures, 5 (7.4%) peritoneal catheter associated infections, 2 (2.9%) bone. Antimicrobial susceptibility reports were available for 26 (35.4%) of the patients. Of those: 26 (100%) were susceptible (S) to amikacin, 19 (73.1%) clarithromycin, 10 (38.5%) tigecycline, 8 (30.7%) linezolid, 4(15.4%) cefoxitin. Only 2 (7.7%) were S to imipenem, fluoroquinolones (FQs) and tobramycin, 14 (53.8%) were intermediate to imipenem and 17 (65.4%) to cefoxitin. Few organisms were tested for susceptibilities to clofazimine 5 (100%) and azithromycin 4 (80%). 24 (35.3%) patients failed treatment; of those, 12 (14.7%) died. Risk factors significantly associated with treatment failure were acute kidney injury (p =0.001), dialysis (p=0.002), solid organ transplant (p=0.03), second site of infection (p=0.04), IT (p=0.02) and presence of prosthetic device (p=0.04).
There is a high prevalence of MA in Miami with an in-hospital mortality rate of 14.7%. The most frequent source of infections was respiratory (57.4%). We found a high proportion of FQs resistance. Clarithromycin and amikacin were the most likely to be susceptible in-vitro. Immunosuppression and renal disease were significantly associated with treatment failure.
R. Rosa, None
L. Kaming, None
L. Abbo, None