Phenotypic and molecular characterization of antimicrobial resistance in Staphylococcus epidermidis strains isolated from urinary tract infections and bovine mastitis

Abstract

Coagulase Negative Staphylococci (CoNS), especially Staphylococcus epidermidis, are skin commensal bacteria. The aim of this study was to compare cultivation, PCR, and LAMP-PCR methods in identifying the positive strains of S. epidermidis and to investigate the prevalence rate, distribution of virulence factors, and antimicrobial resistance properties of S. epidermidis strains isolated from different UTI and mastitis cow milk samples. 229 samples including 126 urine and 103 cow's milk were collected and S. epidermidis strains were identified using culture, biochemical tests and molecular methods. Out of 126 urine samples and 103 milk samples, 39(30.95%) and 26(25.24%) samples were positive for S. epidermidis, respectively. In the LAMP method, after extracting the genome, 44(34.92%) and 29(28.15%) samples, and without the extraction, 41(32.54) and 28(27.18) samples, were identified as S. epidermidis, respectively. S. epidermidis strains harbored the highest prevalence of resistance against penicillin (89.23%), tetracycline (64.61%), erythromycin (63.08%) and, cefazolin (50.77%). aacA-D (69.23%), tetK (67.69%), tetM (55.38%), ermA (55.38%), ermC (46.15%) and, msrA (43.08%) were most commonly detected antibiotic resistance genes. The prevalence of vatC (13.85%), vatA (15.38%), vatB (16.92%), msrB (27.69%) were lower than other detected antibiotic resistance genes. agrI (32.31%), ClfA (29.23%) and agrIII (27.69%) were the most commonly detected virulence factors. In this study, the prevalence of resistance to a wide range of antibiotic agents and the presence of virulence factors amongst S. epidermidis strains were observed. Failure to pay attention to the antibiotic-resistant strains of S. epidermidis can be a serious warning to the health of the community.