Comparative Evaluation of VITEK-2 Compact System and Conventional Methods from BacT/ALERT Flagged Blood Culture Bottles in Neonatal Septicaemia

Abstract

Introduction: Blood culture is a proven gold standard method for the identification of causative agents of bloodstream infections. Prompt identification (ID) and antimicrobial susceptibility testing (AST) of organisms causing blood stream infections has a significant impact on the morbidity and mortality associated with these infections. The need to circumvent the slow turnaround time of conventional gold standard methods has paved way for the rapid automated systems. In this regard automated identification aid in rapid diagnosis/treatment of bacterial pathogens. Aims: Evaluation of automated system Vitek-2 compact system with conventional blood culture method for the identification of organisms causing neonatal septicaemia. Materials and Methods: In this hospital-based retrospective study conducted in the Department of Microbiology in a tertiary care hospital, New Delhi. A total of 170 non duplicate isolates of both Gram Positive and Gram-Negative organisms recovered from blood samples were included. Organisms were processed on the Vitek-2 compact system and simultaneously from conventional method (ID) for comparison. Descriptive statistics was used for the presentation and comparison of data and appropriate statistical charts were used to present the data. Results: Concordant identification (ID) results of Vitek-2 compact system were seen with all the isolates of S. aureus, S. epidermidis, S. pneumonia, E. faecalis and E. faecium. Discordant results of Vitek-2 were noticed with S. hominis (5 isolates of the organism misidentified as S. epidermidis). Conclusion: The organisms having slow metabolic rates and late lactose fermenters (S. hominis) are prone to errors by the Vitek-2 compact system; hence need to be reconfirmed with other possible method.

Keywords

• vitek-2 compact system
• bac t/alert
• blood culture
• neonatal septicaemia