Phenotypic and Genotypic Characterization of Staphylococcus epidermidis Isolated from Clinical Samples in Gaza Strip

Abstract

Characterization of disease-causing bacteria helps in understanding the infection map it follow and make its dissemination criteria clearer, what make it easier to combat and prevent infection. This study was conducted to characterize S. epidermidis isolates recovered from various biological samples phenotypically and genotypically and investigate the genetic relatedness between the isolates as well as investigating factors that may be related to its ability to cause disease. Also, the study aimed to compere between the clinical isolates recovered from various locations. In this study a total of 256 S. epidermidis isolates were studied, where the 256 isolates are grouped into two main groups, the clinical isolates which recovered from clinical samples and the nasal isolates collected from right nasal nares of healthy volunteers (128 isolates in each group). Antibiogram, methicillin resistance, biofilm producing ability, hemolysins production and ACME were investigated among the isolates where all except antibiogram were investigated phenotypically and genotypically, antibiogram was studied by disc diffusion method and the genetic relatedness was investigated by RAPD-PCR. Results reflect clear significant differences in several parameters. Clinical isolates were significantly resistant for 8 out of the 12 tested antibiotic including the cefoxitin and significantly more in the number of antibiotics they resist as well as for the frequency of MDR. No differences in the distribution of mecA gene between the two groups, but significance seen in the ability to resist methicillin despite the presence of the mecA gene. Between isolates from different locations, ASH isolates were significantly resistant to clindamycin and in the relatedness between methicillin resistance and the presence of the mecA gene.