Coagulase-negative Staphylococci – A True Pathogen in Bloodstream Infections and their Resistance Patterns in a Tertiary Care Hospital

Abstract

Coagulase-negative staphylococci (CoNS) are primary skin commensals that have long been considered contaminants even when grown in blood cultures. This group of organisms has been recently recognized as a potential causative pathogen of septicemia. This increase has been attributed to the increased use of intravascular and prosthetic devices. Hence, we aimed to estimate the prevalence of CoNS as a true pathogen in adult and pediatric blood cultures along with their antibiotic susceptibility patterns. A total of 1076 adult and 611 pediatric blood cultures were subjected to an automated BacT/ALERT continuous monitoring system. Isolated CoNS were considered true pathogens if they met the diagnostic, clinical, and laboratory criteria. Antimicrobial susceptibility testing for pathogenic CoNS was carried out using the Kirby-Bauer disk diffusion method and interpreted as per CLSI 2021. CoNS were considered true pathogens in 23 (42.5%) of 54 adults and 12 (41.3%) of 29 pediatric CoNS isolated from blood cultures. Methicillin-resistant CoNS was detected in 66% and 70% of adult and pediatric cultures, respectively. All the CoNS isolates were sensitive to vancomycin and linezolid. Coagulase-negative staphylococci (CoNS) can either be a contaminant or a true pathogen, whose discrimination based on clinical and laboratory indices plays a pivotal role in the management of patients with sepsis.

Keywords

• coagulase-negative staphylococci (cons)
• blood culture
• true pathogen