Detection of nuc, mecA, and tsst-1 Genes in Staphylococcus aureus Isolated from Clinical Specimens, Yemen

Background Staphylococcus aureus ( S. aureus ) is a life-threatening pathogen that threatens the lives of millions of people worldwide because of its resistance to multiple antibiotics. This study aimed to detect the nuc, mecA , and tsst -1 genes in S. aureus isolated from clinical specimens in Yemen and to evaluate their antibiotic susceptibility patterns and multidrug resistance. Methods A cross-sectional study was conducted among patients attending the National Center for Public Health Laboratory (NCPHL) between September 2023 and January 2024. Specimens and relevant data were collected from the participating patients. Isolation and identification of S. aureus were performed by phenotypic and genotypic methods using polymerase chain reaction (PCR) to detect the nuc, mecA , and tsst -1 genes. Additionally, the antimicrobial susceptibility profile and multidrug resistance were determined using the Kirby–Bauer method for disc diffusion. Results Of the 203 clinical specimens, 51 (25.1%) were identified as S. aureus based on phenotypic methods, and the genotyping revealed that 31/51 (60.8%) of S. aureus isolates were positive for the nuc gene, with the majority rate present in males (37.25%), the age group of 21–30 years (21.7%), and pus (37.25%) specimens. Moreover, of the 31 S. aureus isolates identified by genotyping, 8 (25.8%) and 3 (10.6%) harbored the mecA and tsst -1 genes, respectively. In addition, the mecA gene was more abundant in males (26.3%), in the age group of 16–20 years (100%), and in blood specimens (66.7%). Furthermore, tsst -1 was only detected in females (25%), those aged ≥ 31 years (18.2%), and in urine specimens (50%). Additionally, S. aureus isolates harbored mecA and tsst- 1 genes, exhibiting complete resistance to amoxicillin and ceftazidime, which are completely sensitive to vancomycin. Additionally, approximately 35.5%, 25%, and 66.7% of the S. aureus isolates with nuc, mecA , and tsst -1 genes, respectively, were resistant to four types of antimicrobials. Conclusions Even though the frequency of S. aureus carrying the mecA and tsst -1 genes was low in this study, its prevalence is considered very harmful because it can lead to further complications and is difficult to treat. Therefore, implementing an antibiotic management policy and incessantly monitoring antimicrobial susceptibility surveillance systems would help clinicians to select effective antibiotics to treat patients and combat the spread of antibiotic-resistant bacteria.