Incidence of Virulent factors in Staphylococci isolated from clinical and foods specimens in Egypt

Abstract

ONE HUNDRED Gram positive staphylococci isolates were isolated from 80 clinical specimens and 20 food samples using Baird Parker and mannitol salt agar media. Sixty isolates out of 80 (75%) isolated from clinical specimens were found to be coagulase positive staphylococci while the other 20 isolates (25%) were proved to be coagulase negative staphylococci. Meanwhile, all staphylococci isolated from food samples (20 isolates) were found to be coagulase negative isolates. The antibiotic susceptibility profile of all isolated staphylococci against 11 antibiotics indicated that 8 isolates were found to be resistant to more than 4 antibiotics which means that they are multi-drug resistant (MDR). Following the key of Bergey’s Manual of Determinative Bacteriology, the 2 coagulase positive clinical isolates (41 and 66) were preliminary identified as S. aureus and the other 6 coagulase negative staphylococci isolates were found to be related to different species of Staphylococcus genus. Using specific designed primers, some toxin target genes namely: entA, entC, entD1 and hlg were screened in the 8 selected MDR isolates. The isolates encoded 7 and 11, preliminary identified as S. saprophyticus 7 and S. xylosus 11, showed obvious significant amplicons of toxins genes entA, entD1 and hlg while the clinical isolates 41 and 66 which were preliminary identified as S. aureus, possessed entA and hlg genes only. Identification of coagulase negative S. xylosus 11 containing more than 3 toxin genes was confirmed by amplification of 16S rRNA gene which showed 99% similarity with S. xylosus strain. This sequence was deposited in Genbank under accession number MH118574.