Study on drug susceptibility of Staphylococcus aureus and its correlation with virulence genes

Abstract Aim Staphylococcus aureus has become a common pathogen that causes hospital-acquired infections. This study aimed to investigate the drug resistance and virulence genes (mupA, fnbA, arcA, PVL, TSST, mecA, ermC, ermA) of Staphylococcus aureus from infectious patients in a tertiary hospital in China. Moreover, the levels of these genes in erythromycin-resistant Staphylococcus aureus isolates were performed. Methods From 2020 to 2022, 58 strains of Staphylococcus aureus isolated from patients with clinical Staphylococcus aureus infection in the hospital were collected, and strain identification and susceptibility tests were performed by using VITEK 2 and supporting gram-negative bacteria identification cards. DNA was extracted using a DNA extraction kit and all genes were magnified using the polymerase chain reaction. Results A total of 58 Staphylococcus aureus isolates were detected in 58 wound and secretion specimens. MRSA isolates accounted for 48.3% and MSSA isolates accounted for 51.7%. The percentage of multidrug resistance (MDR) in Staphylococcus aureus isolates was 60.3%. Staphylococcus aureus was highly susceptible to ceftaroline, tigecycline, teicoplanin, vancomycin, daptomycin, and linezolid, while it was highly resistant to benzylpenicillin, clindamycin, erythromycin, and oxacillin. fnbA was the gene with the highest detection rate (100%), and arcA also had a higher detection rate (98.3%), followed by mecA (56%), TSST (46.6%), ermA (33.3%), mupA (27.6%), ermC (17.5%), and PVL (13.8%). There were significant differences in the distribution of mecA, ermC, and ermA in erythromycin-resistant and erythromycin-sensitive isolates (P < 0.05), and there were also statistically significant differences in resistance to oxacillin, sulfamethoxazole, levofloxacin, cefoxitin, and clindamycin (P < 0.05). Conclusion The incidence of infection caused by multidrug-resistant Staphylococcus aureus increases significantly with the prevalence of MRSA. The genes mecA, ermC, and ermA are virulence factors in antibiotic-resistant strains and are significantly associated with erythromycin. Erythromycin-resistant staphylococcus aureus is more susceptible to resistance to oxacillin, sulfamethoxazole, levofloxacin, cefoxitin, and clindamycin.