Phenotypic detection of virulence determinants and antibiotics resistance in Staphylococcus aureus from different clinical isolates in Kirkuk city

Abstract

Background: Staphylococcus aureus is responsible for hospital and community- acquired infections worldwide. It is capable of causing conditions ranging from minor skin infections to systemic serious diseases such as urinary tract infections (UTIs), pneumonia, osteomyelitis, and endocarditis. Objective: The aim of this study is to isolate and identify S. aureus from different clinical samples and to detect their production of some virulence factors and their correlation with antibiotics resistance. Materials and Methods: A 202 clinical samples were collected from patients of different ages and genders admitted to various hospitals in Kirkuk city (Azadi Teaching Hospital, Kirkuk General Hospital and Public Health Laboratory in Kirkuk city) during the period from November 2021 to June 2022. Staphylococcus aureus were diagnosed based on standard laboratory procedures such cultural characteristics, Gram staining, biochemical tests and VITEK compact 2 system. Virulence factors were also determined using colorimetric agar plates. Antibiotic susceptibility testing was performed by using Kirby-Bauer disc diffusion technique. Methicillin- resistant S. aureus isolates were also identified by oxacillin disc. Result: Out of 202 clinical samples, 65 (32.18%) were positive for S. aureus. These isolates were more predominant among males and in the age group ranges between 21-30 years. S. aureus isolates showed resistance towards benzylpenicillin (92%), oxacillin (68%), (52%) clindamycin, (48%) tetracycline and (48%) cefoxitin. The most effective antibiotics were linezolid, gentamicin and trimethoprim-sulfamethoxazole with a susceptibility rate higher than 84%. Fifty six percent of S. aureus isolates was protease producers, (72%) lipase producer, (76%) and (64%) were lecithinase and capsule producers.