Prevalence, Species Distribution, and Antimicrobial Susceptibility Patterns of Clinically Significant Methicillin-Resistant Coagulase-Negative Staphylococci Isolates From Patients in a Tertiary Care Hospital in Eastern India: A Retrospective Study

Background Coagulase-negative Staphylococci (CoNS), also referred to as Staphylococci other than Staphylococcus aureus (SOSA), have emerged as important nosocomial pathogens and are frequently resistant to methicillin, leading to the emergence of methicillin-resistant CoNS (MRCoNS). The present study aimed to evaluate the prevalence, species distribution, and antimicrobial susceptibility patterns of clinically significant MRCoNS isolates from patients in a tertiary care hospital in Eastern India. Methods This retrospective, laboratory-based observational study was conducted in the Department of Microbiology at a tertiary care hospital in Eastern India, after getting IEC approval (KIIT/KIMS/IEC/2441/2026). Laboratory and clinical data were collected from records from January 2021 to December 2025 for MRCoNS-positive cultures. Data on species distribution, antimicrobial susceptibility patterns of MRCoNS isolates, and corresponding clinical findings were retrieved from medical records and analyzed. Clinically significant CoNS isolates from patients aged >18 years, all sexes, from various clinical specimens were included in the study. Identification and antimicrobial susceptibility testing were performed using the VITEK 2 compact automated system (bioMérieux, Marcy‑l'Étoile, France). Methicillin resistance was determined using both Oxacillin/cefoxitin disc diffusion and the VITEK 2 system (bioMérieux, Marcy‑l'Étoile, France). Demographic, clinical, and laboratory data were collected and analyzed using R software Version 4.4.3 (R Foundation for Statistical Computing, Vienna, Austria). Descriptive statistics were used to determine the prevalence. Categorical data were presented as frequencies and percentages. The differences between the prevalence of MRCoNS and MSCoNS were evaluated using the Chi-square test. A p-value of <0.05 was considered statistically significant. Results Out of 10,984 clinical isolates of CoNS, 6,326 (57.6%) were confirmed to be MRCoNS. During the five-year period (2021-2025), a steady rise in MRCoNS prevalence was found from 17% to 23%. S. hemolyticus (37.9%, n = 2,397), S. hominis (21.0%, n = 1,330), and S. epidermidis (19.7%, n = 1,244) were the most common MRCoNS species. MRCoNS isolation was higher in ICU patients (60.5%) with male predominance. Specimen-wise, the highest proportions of MRCoNS were seen in blood (37%) and urine (35%), with 5% and 22% in sterile body fluids and others, respectively. Reduced susceptibility was found to oxacillin, erythromycin, ciprofloxacin, levofloxacin, clindamycin, and cotrimoxazole, whereas all MRCoNS isolates remained susceptible to vancomycin, teicoplanin, and linezolid. Conclusion This study shows a steady upsurge in the prevalence of MRCoNS during the stipulated time period, with S. hemolyticus as the predominant type. Even though MRCoNS remained susceptible to last-resort drugs like vancomycin, linezolid, and teicoplanin, stringent antimicrobial stewardship practices and improved infection control measures are recommended to reduce the spread of MRCoNS in hospitals as well as to prevent further development of resistance.