Detection of some virulence factors in Staphylococcus epidermidis isolated from clinical specimens in Iraq

Abstract

 120 samples were collected from different clinical samples including swabs from wounds, noses, and pimples, blood, CSF, and medical equipment (catheters for dialysis and heart valves), among different age groups and sexes, from Gazzi Al-Hariri Hospital and Baghdad Teaching Hospital, during the period from Dec. 2022 to Aug. 2023. The ages from 10 to 65 years old were the range of the study. According to the results, 73 (60.83%) of the samples tested positive for Staphylococcus epidermidis, and the 47 females (64.38%) were more infected than the 26 males (35.61%). The age group of (36–50 years) showed a considerable increase in the infection ratio, followed by (25-35 years), then the age group of (51-65 years) and (10-24 years). The current study was performed in Baghdad Teaching Hospital/Department of Bacteriology. Differential and specific culture media were used to confirm the isolated clinical specimens.  Virulence factors and biochemical tests were performed. The diagnosis was verified with the Vitek 2 system. Antibiotic sensitivity testing was achieved by applying the disk diffusion method. Ten S. epidermidis isolates were chosen, and their DNA was extracted and amplified using PCR to detect and validate the presence of the (mecAand ermA) genes. The current study used male mice as a model to perform the lethal dose (LD50). The mice weighed between 22 and 30 g and were between the ages of 2 and 3 months. And in the College of Veterinary Medicine, the mice were sheltered in the animal house. The mice were treated with the bacterial suspension that was adjusted to 0.5 McFerland standard, while, the control group was treated with phosphate buffer saline (PBS), and the mice were daily monitored. The mice exhibited transient behavioral abnormalities, decreased movement, and lethargy when compared with the control group. The skin showed pictures of severe dermatitis. When the mice died, their affected skin, liver, intestine, and heart were taken and preserved in the formalin to send them to the laboratory of histopathology. The histopathology techniques were performed in the histopathology laboratory-College of Veterinary Medicine. Normal cytoarchitecture and appearance were seen in the histopathology figures of the control group. While, the figures of the histopathology of the injury group showed severe hepatitis, severe myocardial infarction, severe enteritis, and the skin appeared with severe dermatitis.