Abstract

Staphylococcus aureus, a common bacterium of seminal fluid, is also potentially pathogenic, with virulence factors contributed by virulence genes. Bacteria have been shown to agglutinate and immobilize spermatozoa, affecting male fertility. Methicillin resistance in S. aureus has been a major concern in the treatment of diseases caused by S. aureus. This study aimed to detect methicillin resistance and its co-occurrence in the presence of virulence genes for clumping factors (clfA gene and clfB gene) and for toxic shock syndrome toxin (tst gene) in S. aureus isolates obtained from the semen of suspected infertile men of Nepal. This study included 21 isolates of S. aureus obtained from 217 semen samples of male partners among infertile couples visiting a fertility centre for consultation. A cefoxitin disc diffusion test following CLSI guidelines (2021) was conducted to screen for phenotypic methicillin resistance in the bacteria. DNA was extracted from the isolates to detect the mecA, clfA, clfB, and tst genes via PCR amplification using specific primer sets. The data obtained were analysed via Fisher’s exact test at 95% confidence interval, with a p-value of <0.05 considered to be significant. Cefoxitin resistance was shown by 12 (57.14%) isolates, while the mecA gene was detected in 14 (66.67%) isolates. The odds of cefoxitin resistance were 6.25-fold higher among mecA- positive isolates than among mecA-negative isolates, although the association was not statistically significant (OR = 6.25, 95% CI: 0.68–57.2). The virulence genes clfA, clfB, and tst were present in 12 (57.14%), 12 (57.14%), and 2 (9.5%) of the isolates, respectively. There was no statistically significant correlation between the mecA gene and the virulence genes analysed in this study (p > 0.05). However, the detection of methicillin resistance in 66.67% of the isolates and at least one of the virulence genes of interest in 76.19% isolates reflects the antimicrobial resistance and virulence status of S. aureus in semen. Our study could not find significant association of methicillin resistance and virulence genes under study with semen quality (all p > 0.05). The study findings exhibit the presence of methicillin-resistant and virulence-associated S. aureus isolates in semen samples from suspected infertile men, which signifies the importance of microbiological investigation of semen during infertility evaluation. However, further studies are recommended to demonstrate the clinical significance of these isolates.