Virulence Factors of Staphylococcus Aureus Hemolysin HLA and HLB Isolated from Catheters of Dialysis Patients Referred to Nikan Hospital in Tehran During the Spring and Summer of 2021

Staphylococcus aureus (S. aureus) is one of the most frequent causes of infection around the world. Insertion of intravascular catheter and formation of biofilms by methicillinresistant Staphylococcus aureus (MRSA) have contributed to the increased risk of infection, and morbidity and mortality rates. Biofilms formation on intravascular catheters and other medical devices are of major postoperative concerns because biofilms are often the source of persistent and difficult-to-treat bacterial infections. This study aimed to evaluate different genetic patterns of this bacterium in samples collected from dialysis patients of Nikan hospital.

In this descriptive cross-sectional study 30 samples from the removed catheters of patients suspected to have S. aureus infection and admitted to the dialysis ward of Nikan hospital were collected and phenotypic evaluations were done to confirm the type of the infectious species. Evaluation of antibiotic resistance of bacterial samples using Kirby-Bauer method was done. Biofilm production of the samples was assessed by the 96-plate microtiter method. The existence of two genes hla and hlb were evaluated using Multiplex PCR.

The biofilm production test showed that 60% of the samples were able to produce strong biofilms. Multiplex PCR results revealed that both hla and hlb genes were expressed in 93% of the samples, while, hlb gene alone was expressed in 53% of cases.

The results of this study provide significant insight into the virulence gene makeup of catheter-colonizing S. aureus strains, and will assist in developing a more targeted treatment approach for persistent S. aureus biofilm contamination of medical devices.