Insights into bloodstream infections in South African paediatric burn patients: implications for antimicrobial stewardship.

Abstract

Introduction: Bloodstream infections (BSIs) significantly contribute to the morbidity and mortality in paediatric burn patients from low- and middle-income countries; with common pathogens like Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa frequently being multidrug resistant (MDR). Due to the growing prevalence of MDR BSIs, antimicrobial stewardship needs to be improved with perhaps more targeted initial antimicrobial use. The study describes the aetiology, and timing of burn-associated BSIs and MDR infections in paediatric burn patients admitted to two paediatric surgery units in Tshwane District, South Africa.

Methods: This multi-centre retrospective review analysed paediatric burn patients (ages 0-12 years) admitted between January 2020 and December 2022 to two public hospitals in Tshwane District, South Africa. Collected data was from patient records and the National Health Laboratory System TrakCare database. BSIs were defined according to the CDC criteria.

Results: Of 245 burn patients admitted, 18.8% (n = 46) developed BSIs. From 63 positive blood cultures, the most common isolates were S. aureus (n = 19; 30%), Acinetobacter baumannii (n = 18; 29%), and P. aeruginosa (n = 10; 16%). Collectively, gram negative bacteria were responsible for most BSIs (n = 41; 65%). Candida spp accounted for 9% (n = 5). Thirty-five pathogens (56%) were MDR; this included methicillin-resistant S. aureus (MRSA) (n = 7; 11%), carbapenem-resistant A. baumannii (n = 16; 25%), and P. aeruginosa (n = 6; 10%). The median time to the first positive blood culture was 5 days (IQR: 3-12) (gram positive organisms: median: 5 days [IQR: 3-15}); gram negative organisms: median: 8 days [IQR: 4-20]; Fungal: median: 9 days [IQR: 8-27]; p-value 0.37). In the first week, S. aureus caused 32% of infections, including five MRSA cases. Gram negative bacteria dominated weeks two and three, with fungal and polymicrobial infections mainly in weeks two and four.

Conclusion: Our findings show that as gram positive and gram negative infections predominantly occurred early in the admission period, while polymicrobial infections are more frequently observed later. Consequently, initial targeted narrow-spectrum antimicrobial use is not possible. Instead, antimicrobial de-escalation should be prioritized once culture results are available. Efforts should shift from a focus on treating BSIs to preventing them through wound care and infection control measures. Broad-spectrum antibiotics should be used judiciously and quickly de-escalated to minimise antimicrobial resistance development.