A retrospective study on the effects of colistin therapy in children with multidrug-resistant Gram-negative bacterial pathogens: impact of HIV status on outcome.

BACKGROUND: Nosocomially acquired multidrug-resistant (MDR) Gram-negative bacteria are important contributors to paediatric intensive care unit (PICU) mortality and morbidity, with limited treatment options. AIM: To investigate the outcomes of all children treated with colistin for infection with MDR Gram-negative bacteria while admitted to PICU.
METHODS: Retrospective observational study of 19 months. Primary endpoints were all-cause intensive care unit mortality and safety. Secondary endpoints evaluated clinical and microbiological outcomes. Cases were stratified according to HIV status.
RESULTS: Twenty-seven children received 30 colistin courses during the study period. Eight patients (29.6%) were HIV infected, six (22.2%) were HIV uninfected but exposed, and 11 (40.7%) were HIV uninfected and unexposed. Common MDR Gram-negative bacteria cultured were: Acinetobacter species (n=22, 81.5%), Pseudomonas aeruginosa (n=11, 40.7%) and Klebsiella pneumoniae (n=7, 25.9%). Mortality was 37%, with no significant difference between HIV strata. No adverse drug reactions were noted. A composite clinical improvement was noted in 16 courses (53.3%) of colistin. Only 30% of colistin courses used in HIV-infected children resulted in an improved clinical assessment as compared with 83.3% of courses in HIV-uninfected/unexposed children (p=0.04). In HIV-infected children, five of 10 (50%) courses of colistin showed bacteriological clearance compared to the HIV uninfected/unexposed group where all cases showed bacterial eradication (p=0.02).
CONCLUSIONS: HIV-infected children had poorer clinical and bacteriological responses to colistin treatment than HIV uninfected/unexposed. These results require confirmation with prospective studies to determine whether findings are due to poor microbial response, immunodeficiency or repeated reinfections.