Nasal Staphylococcus Colonization in Nursing Home Residents and Antibiotic Resistance Profiles

• Published in: Mediterranean journal of infection, microbes & antimicrobials microbes & antimicrobials, 2022-01, Vol.11 (1)
• Main Authors: Cansu ÖNLEN GÜNERİ, Pınar DÖNER GÜNER, Özkan ASLANTAŞ
• Format: Article
• Language: eng ; tur
• Subjects: nasal flora; nursing home; pcr; staphylococcus epidermidis
• ISSN: 2147-673X
• DOI: 10.4274/mjima.galenos.2022.2022.44

Introduction: Staphylococci are microorganisms that are resistant to many antibiotics. Staphylococcus epidermidis is a normal flora bacterium that has recently emerged as a nosocomial pathogen and has become a worldwide issue. The aim of the study was to determine the prevalence of coagulase negative staphylococci, Staphylococcus aureus nasal carriage, and antibiotic resistance of these bacteria in nursing home residents. Materials and Methods: This study was conducted in July 2017. Forty-six samples obtained from the nasal mucosa of the participants were cultured. The species identification was done by MALDI-TOF-MS. Disk diffusion was applied to determine the antibiotic susceptibility of isolates, and polymerase chain reaction assay was employed to identify the known antimicrobial resistance genes. Results: Staphylococci were isolated from 28 (61%) of the 46 residents. The isolates (n=29) were S. epidermidis (n=22), Staphylococcus succinus (n=4), and S. aureus (n=3). Two different strains of S. epidermidis were isolated from one participant. While methicillin-resistant S. aureus was not identified in isolates; Methicillin-resistant S. epidermidis (MRSE) was found in 43% (n=12). In addition, 68% of S. epidermidis strains were multidrug resistant (MDR) (to at least one agent in three or more antimicrobial groups other than β-lactams). All methicillin-resistant S. epidermidis (MRSE) isolates were mecA positive. Among the MRSE isolates (n=12), the following resistance genes were found: blaZ (n=5), lnuA (n=1),tetK (n=1), ermA (n=1), aac(6’)/aph(2’’) (n=1), and ant(4’)-Ia (n=1). Conclusion: To our knowledge, multi-drug resistant MRSE was detected in nursing home residents for the first time in Turkey with this study. This result suggests that S. epidermidis could serve as a reservoir of drug resistance by persistent colonization in the nasal mucosa. Observation and molecular surveillance could be applied to limit the spread of such resistant nosocomial pathogens.