Profile and Outcome of Children Treated for Multi-drug Resistant Gram-negative Bacterial Infection with Colistin or Polymyxin B in a Tertiary Hospital in the Philippines

Background The rise of multidrug-resistant gram-negative bacteria (MDR-GNB) presents a critical challenge in pediatric care, necessitating the use of last-resort polymyxins. Data on the comparative safety and efficacy of Colistin versus Polymyxin B in children remain limited. This study describes the profile and outcomes of pediatric patients treated with these agents. Methods A retrospective cross-sectional study was conducted at a Philippine tertiary government hospital. Pediatric patients (0-18 years) with culture-proven MDR-GNB infections treated with Colistin or Polymyxin B from January 2019 to December 2023 were included. Data on demographic, clinical, microbiologic profiles, treatment outcomes, and adverse events were analyzed. Results Among 40 patients, 21 received Colistin and 19 received Polymyxin B. The median age was 1-5 years (37.5%), with a male predominance (77.5%). Most were underweight (77.5%) and admitted to the ICU (70%). Infections were predominantly hospital-acquired (90%). The most common isolates were Klebsiella pneumoniae (37.5%), Acinetobacter baumanii (25%), and E. coli (17.5%). Overall treatment success was high and comparable between Colistin (95.2%) and Polymyxin B (89.5%) groups (p=0.93). However, the mean duration of successful treatment was significantly longer in the Colistin group (49 days vs. 22.5 days, p<0.01). Clinical response time and rates of post-treatment infections were similar. Nephrotoxicity occurred in 7.5% of all patients, with no significant difference between groups (Colistin 4.76% vs. Polymyxin B 10.52%, p=0.65). No neurotoxicity was reported. Conclusion Both Colistin and Polymyxin B were effective and relatively safe for treating MDR-GNB infections in this pediatric cohort, demonstrating high treatment success and manageable toxicity profiles. The significantly longer treatment duration in the Colistin group warrants further investigation. These findings support the vigilant use of polymyxins in children while underscoring the need for continued monitoring and larger prospective studies to optimize therapy.