Origin of Catheter-Related Bloodstream Infections Caused by Staphylococcus epidermidis in Critical Neonates

Abstract

Bloodstream infection (BSI) remains the most frequent adverse event among premature infants worldwide, associated with increased hospital stay length and costs, poor outcomes, and even death. The aim of this study was to investigate the origin of catheter-related bloodstream infections (CR-BSIs) by Staphylococcus epidermidis in critical neonates, using molecular biology techniques. This was an observational study comprising neonates presenting BSI using central venous catheters (CVCs) for over 24 hours. Skin cultures obtained from the catheter insertion site, CVC hub, and neonate nasal and intestinal mucosa, were performed weekly from 48 hours from the beginning of the invasive procedure, as well as from the tip of the CVC after its withdrawal. Quantitative cultures were also performed of the tip with modifications and the “roll-plate” technique. Isolates identification were obtained using a VITEK II automated system. Molecular subtyping by pulsed-field gel electrophoresis (PFGE) was used to determine the origin of all BSIs. Among 19 primary BSI caused by S. epidermidis, BSI origin was defined in only 21.1% of the cases, where one was characterized as definite intraluminal, two as definite extraluminal, and one as translocation. Origin was indeterminate in 78.9% of the cases analyzed by PFGE. A total of 27 different genotype profiles were obtained. The spread of a prevalent clone in the unit (clone A) was detected in 28.6% of the samples. Most BSIs related to catheter caused by S. epidermidis were not able to prove the origin of most microorganisms present in neonate blood, demonstrating the difficulty in determining it in this population of patients. The lack of a better explanation of the origin of CR-BSI in neonates limits the direction of specific intervention measures.