Background: Staphylococcus aureus has a great ability to form biofilms on implant-related biomaterials. This study aimed to investigate the resistance, biofilm and molecular characteristics of S. aureus strains isolated from patients with postoperative infections after arthroplasty in two Chinese tertiary care hospitals during 2017 to 2018.
Methods: Antimicrobial susceptibility was determined by the agar dilution method. Bacterial biofilm formation was determined by crystal violet staining. The genes related to biofilm formation and molecular typing were analyzed by PCR amplification.
Results: A total of 33 isolates were collected, 21 of which were from Henan. The strains were completely sensitive to vancomycin, linezolid, and nitrofurantoin. All the isolates had adhesion ability and could produce biofilms. Of the isolates, 75.0% from Chongqing and 85.7% from Henan had stronger biofilm formation abilities. The strains from Henan had slightly higher resistance, adhesion and biofilm-forming abilities than those from Chongqing. The strains in both hospitals carried at least two genes related to biofilm formation, and the ica and fnb genes were the most frequently detected genes. Three SCCmec types and seven sequence types (STs) were found in Henan, and two SCCmec types and six STs were found in Chongqing. ST239-SCCmec III was the main epidemic clone in the two hospitals.
Conclusion: The resistance phenotype and molecular characteristics of S. aureus strains varied in different hospitals. The results reflect the potential risks of S. aureus infection in postoperative arthroplasty patients. Our study provides a powerful basis for the clinical treatment, infection control and monitoring of outbreaks of epidemic strains.
Keywords: Staphylococcus aureus; adhesion; arthroplasty infection; biofilm; resistance.