Species distribution and clinical profiles of coagulase-negative staphylococci (CoNS) isolated from blood cultures among paediatric patients in Hospital Kuala Lumpur

INTRODUCTION: Coagulase-negative staphylococci (CoNS) is often considered as a culture contaminants but it can potentially be pathogenic to patients with risk factors. A combination of species identification and clinical criteria has been suggested in determining true CoNS bacteraemia.

OBJECTIVES: To identify the species distribution, antibiotic susceptibility patterns and clinical profiles of CoNS isolated from blood cultures among paediatric patients in Hospital Kuala Lumpur (HKL).

METHODS: This study involved CoNS isolation from blood cultures of paediatric in-patients of the Paediatric Institute HKL. Isolates were identified to species level using Analytical Profile Index Staph identification strips and antimicrobial susceptibility pattern following Kirby-Bauer Disc Diffusion method. The clinical profiles of patients were obtained from their medical records.

RESULTS: Eleven CoNS species were identified from 148 isolates. Staphylococcus epidermidis was the most frequent species isolated (67.6%). The majority of the isolates showed resistance to penicillin (85.8%); while 70.3% were methicillin-resistant (MR) CoNS, which demonstrated a significant association with true infection (p=0.021). Predictors for significant CoNS infection included thrombocytopaenia, presence of predisposing factors, nosocomial infection, blood collected from peripheral vein, and CoNS isolated from two consecutive blood cultures. The most common predisposing factors for the isolation of CoNS were the presence of peripheral (54.1%) and central venous catheters (35.1%).

CONCLUSION: CoNS can cause significant bloodstream infections. The isolation of CoNS from blood cultures should be carefully interpreted by considering the predictive factors. Local data regarding predictive factors of patients with culture-positive CoNS, species distribution and antimicrobial susceptibility pattern are useful to determine the significance of blood culture results and care management of patients.