Transformation of commensal to a pathogen: Blood stream infection due to coagulase negative staphylococci among patients attending tertiary care hospital in North India

Abstract

Aim of this study was to know the prevalence of Coagulase Negative Staphylococci (CoNS) in Blood Stream Infection (BSI) among patients attending a Superspeciality hospital in North India. Objective of this study was to compare incidence of CoNS in ICU and ward patients suffering from BSI and their antimicrobial susceptibility pattern. This retrospective hospital based study was conducted in the Microbiology Department, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow for a period of two years (January, 2017 -December, 2018). Blood samples from a total of 6498 patients from Out-Patient, In-Patient and Intensive care unit departments were subjected to aerobic and anaerobic bacterial culture. Culture positive broth was subcultured on Blood Agar and MacConkey Agar to isolate pathogens in pure culture. Pure cultured isolates were tested for antimicrobial susceptibility pattern by Kirby Bauer Disk Diffusion method as per CLSI 2018.During the study period, out of total 3284 samples in 2017 and 3214 in 2018, 663 and 595 were found to be culture positive respectively.Staphylococci were isolated from 636 (9.78%) patients (10.2% in 2017 and 9.2% in 2018). Staphylococcus aureus was isolated from 18.8% and CoNS from 81.2% of total Staphylococcal isolates. Among CoNS isolates 70.7% were found to be Methicillin Resistant CoNS (MRCoNS). This study observed CoNS as a major cause of BSI as compared to Staphylococcus aureusThe significance of CONS bacteremia should be evaluated better in light of clinical profile of the patient. Better screening and infection control practices in the future can decrease the rate of methicillin resistant CoNS in our centre.