Antimicrobials Resistance Profiling and Clonal Lineages of Staphylococcus aureus Isolated from Cockroaches in University-Affiliated Hospitals, 2023.

BACKGROUND

Cockroaches, recognized as mechanical vectors, play a crucial role in transmitting microbial pathogens. Staphylococcus aureus (S. aureus), particularly antibiotic-resistant strains, poses a significant threat as a nosocomial pathogen. This study aimed to investigate the resistance profiles to gentamicin, vancomycin, and antiseptics in S. aureus strains isolated from cockroaches in hospitals affiliated with Babol University of Medical Sciences.

METHODS

In this cross-sectional study, 60 S. aureus strains were isolated from 376 cockroaches in three university-affiliated hospitals. Antibiotic susceptibility to gentamicin and vancomycin was tested by disk diffusion and agar dilution. PCR was used to detect resistance and antiseptic genes, and MLVA typing determined the genetic relatedness of resistant isolates.

RESULTS

Among the 60 bacterial isolates, 46.7% (28) displayed resistance to gentamicin. The frequencies of aminoglycoside resistance coding genes (AMEs) for the aac(6')-Ie+aph(2″), ant(4')-Ia, aph(3')-IIIa and ant(6)-Ia genes were 64.3%, 42.8%, 17.8%, and 46.4%, respectively. Only 3.3% (2 isolates) exhibited vancomycin resistance, with one isolate (1.7%) carrying the vanA gene. The frequencies of genes encoding the antiseptic resistance genes qacA/B, qacC, qacD, psmA, sasX, and smr were 5%, 20%, 18.3%, 26.4%, 1.2%, and 31.7%, respectively. Analysis of agr gene types showed that agr type I was the most prevalent. In addition, the multiple-locus variable number tandem-repeat analysis (MLVA) identified 29 unique type sequences among the identified antibiotic-resistant isolates.

CONCLUSION

The high genetic diversity among antibiotic-resistant S. aureus isolates, as revealed by MLVA, underscores the importance of controlling hospital cockroach populations to curb the spread of antibiotic resistance.