Blood Culture Positivity Rates among Babies Admitted to the Premature Baby Unit of a Secondary Care Hospital in Southern Sri Lanka: An Analysis of Microbial Isolates and Antimicrobial Susceptibility Patterns

Abstract

Bloodstream infections are a major cause of morbidity and mortality among babies in premature baby units (PBU). Periodic monitoring of the antimicrobial sensitivity of the causative organisms in a particular setting is important for the early management of infections in babies. The aim of this study was to determine the proportion of blood culture positivity and to assess the factors associated with bloodstream infections among the babies and the causative microorganisms and their antibiotic susceptibility pattern, isolated in blood cultures of babies with suspected sepsis admitted to PBU at District General Hospital Matara (DGHM). An institution based cross-sectional study was conducted in microbiology laboratory of DGHM to review blood culture reports received from PBU retrospectively. All the consecutive samples from the PBU from January 2021 to December 2022 were included in the study. Data on culture isolates, antibiotic susceptibility patterns and related variables were collected and analysed using SPSS version 25.0. Over the study period, 1612 blood cultures had been sent to the laboratory from the PBU. Overall blood culture positivity rate was 9%. The majority of isolates were gram-positive organisms (68%). Coagulase-negative staphylococci (51.6%) were the most common isolates, followed by lactose fermenting coliforms (16%) and Pseudomonas spp. (8%). Amikacin showed a higher sensitivity than gentamicin among gram-negative organisms. Carbapenem resistance was observed in 40.5% of the isolates. Among Staphylococcus aureus 55.6% were methicillin-resistant and 44.4% were methicillin-sensitive. Prematurity (p=0.017) and low birth weight (p=0.002) were significantly associated with culture positive sepsis. Preterm and low birth weight were significantly associated with bloodstream infections among babies admitted to PBU of DGHM. Coagulase-negative Staphylococci, lactose fermenting coliforms, and Pseudomonas spp. were the predominant causative organisms.