Effect of the incubation time on blood culture results and bacterial pathogens causing bloodstream infections among children attending Sekou Toure Regional Referral Hospital in Mwanza, Tanzania

Background: One-hour delay in initiating appropriate antimicrobial treatment increases the mortality rate of patients with bloodstream infections by 2%. This highlights the risk associated with manual blood culture methods, as they tend to have long turn-around time with initial incubation period of 18-24 hours leads to delays in obtaining diagnostic results. This study examined the impact of incubation time on blood culture results and analyzed the patterns of the pathogens causing bloodstream infections (BSIs) among children attending Sekou Toure Regional Referral Hospital, Mwanza, Tanzania Methodology: A hospital-based, descriptive cross-sectional study was conducted at Sekou Toure Regional Referral Hospital from May to July 2024. The conventional blood culture method, using in-house prepared brain heart infusion broth with slight modifications on the initial time of the blind subculture (at 8 hours, 24 hours and 120 hours) was done to isolate the pathogens causing BSIs. Descriptive data analysis was performed using STATA software version 15. Results: The study enrolled 302 children with clinical diagnosis of BSI. Of these, 160 (53%) were male, with a median age of 6 years (IQR: 1-7 years). Fever was the predominant clinical sign reported in 259 (85.8%) children. Microbiologically confirmed bloodstream infections were detected in 90 (29.8%) children. Among them, 51.1% (46/90) were detected through blind subculture after 8 hours of initial incubation. An additional 31 (34.4%) were detected after 24 hours, and 13 (14.4%) were identified after 120 hours of incubation. The most frequently isolated pathogens were Klebsiella pneumoniae (25.6%, 23/90) and Staphylococcus aureus (24.4%, 22/90). Gram-negative bacteria formed the majority, (71.1% 64/90) of the isolated pathogens, with 62.5% (40/64) showing resistance to third-generation cephalosporins. Additionally, 45.5% (10/22) of the Staphylococcus aureus strains were methicillin-resistant (MRSA). Conclusion: Blind subculture after 8 hours of initial incubation correctly detected more than half of the children with microbiological confirmed bloodstream infections. Incorporating blind subculture on MacConkey agar supplemented with cefotaxime 2µg/ml (MCA-C) after 8 hours of incubation resulted in the correct treatment of half of the children with bloodstream infections caused by Gram-negative bacteria within 24 hours. In areas with high prevalence of third-generation cephalosporin resistance, blind subculture within 8 hours should include MacConkey agar supplemented with cefotaxime 2µg/ml for appropriate treatment within 24 hours.