Detection of some virulence factors of staphylococcus aureus isolated from urinary tract patients in Kirkuk city, Iraq

Abstract

Background: Staphylococcus aureus is an important uropathogen that is a known cause of urinary tract infections (UTIs) and the virulence factors contribute to the pathogenicity and persistence of S. aureus.

Objective: To isolate and identify S. aureus from patients with UTI and to characterize some of the virulence factors present among the isolates.

Methods: The number of urine samples collected from patients with UTI was 200 of which 100 were male and 100 were female. The isolates were identified by biochemical tests and phenotypic and microscopic features and confirmed by API 20 Staph system. Confirmed S. aureus isolates were then tested for some of the virulence factors such as DNase production, biofilm formation, hemolysin production, production of broad spectrum beta-lactamase and adherence ability.

Results: 23 S. aureus isolates were confirmed from 200 urine specimens (11.0%) by female patients and 15 (7.5%) by male patients. Virulence factor analysis showed that 76.31% of the isolates produced DNase and all the isolates (100%) were biofilm producers. As far as hemolytic activity is concerned, 65.78% of the isolates showed complete (full) hemolysis. The rate of beta-lactamase production by the isolates was 55.26% (broad spectrum) and 81.57% of the isolates showed adherence ability.

Conclusion: S. aureus from UTI patients were highly virulent with 100% of the isolates producing biofilm and significant proportions of the isolates had DNase, hemolysin, beta-lactamase production, and adherence ability. The higher level of isolation in female patients and the broad spectrum of virulence factors and resistance determinants expressed indicates the pathogenicity of S. aureus in UTIs and the continued need to monitor virulence and resistance factors of uropathogenic isolates.