Clinical outcomes of children with carbapenem-resistant Acinetobacter baumannii bacteremia

A relentless increase in the rate of carbapenem-resistant among Acinetobacter baumannii has substantially reduced the access to effective antimicrobial regimens. Currently limited information is available regarding the prognosis or outcomes of children with blood stream infection caused by carbapenem resistant A. baumanii.

To determine the clinical outcomes and predictors for fatality among children with carbapenem-resistant A. baumannii (CRAB) bloodstream infection (BSI).

A retrospective descriptive study was conducted among children hospitalized at the Queen Sirikit National Institute of Child Health (Children's Hospital), Bangkok, Thailand. Those who had CRAB isolated from blood cultures during theperiod between October 2005 and September 2010 were included in the study.

A total of 89 cases of BSI caused by CRAB were identified. The incidence was 1.2 cases per 1,000 hospitalized patients. The median age at onset of bacteremia was 62 days and 88% had at least one underlying comorbidity. The 2-week and 30-day case fatality rates were 39% and 42%, respectively. A large proportion of deaths (63%) occurred before blood culture results became available. Extended spectrum resistance, defined as resistance to all other first line antibiotics at the hospital, i.e., all cephalosporins, aminoglycoside, quinolone and carbapenems, was significantly associated with a higher 2-week case fatality rate (CFR) (48% compared with 23% among their counterpart, p = 0.028) and death at an earlier stage of the bacteremia (Kaplan-Meierp = 0.016). In univariate analysis, factors associated with 2-week case fatality include malignancy-associated febrile neutropenia, fever ≥2 days before the initiation of appropriate antibiotic, presence of septic shock, organ dysfunction, and being infected by extended spectrum resistant strains. Correspondingly, CFR of cases who received ≥1 appropriate empiric antibiotics within 24 hours of clinical suspicion appears to be lower albeit not reaching statistical significance, than their counterpart, i.e., the CFRs between the two groups were 10% vs. 23%, respectively (p = 0.675). Colistin susceptibility based on disc diffusion test remained high (100%) in this sample. Nevertheless, those who received colistin treatment had a 2-week CFR of 20%. On the other hand, none of the cases infected with sulbactam susceptible strain, who received sulbactam containing regimen (n = 15), died. No significant renal toxicity was observed among children receiving colistin treatment in our sample.

Carbapenem resistant A. baumannii bacteremia exhibited a high fatality rate, which mainly occurred before the pathogen was known to the clinicians. Extended spectrum resistance was associated with high fatality rate. Early administration of effective empirical antibiotics such as colistin and sulbactam in this sample was associated with lower fatality rate among children affected by this condition.