Detection of Virulence, Antibiotic Susceptibility and Molecular Characterization of Antibiotic Resistance (blaZ) Gene in Staphylococcus Aureus by PCR Assay

Abstract—This study was aimed to examined 59 isolates of Staphylococcus aureus (isolated previously from milk of ewes with mastitis, diagnosed by bacteriological methods and PCR confirmation by using 23SrRNA) for detection of slime producing (as virulence factor) by culturing on modified Congo red agar, antimicrobial susceptibility test to 11 antibiotics and Molecular assay with phylogenetic analysis of antibiotic resistance gene (blaZ) by Conventional PCR technique. The results revealed that all S. aureus isolates were slime producers and showed varying degrees of susceptibility patterns to antibiotic, high resistance to methicillin 100% and penicillin 74.5%, while resistance to Oxacillin, Cefotaxime and Ampicillin showed 50.8%, 47.4% and 42.3% respectively, mild resistance to other antibiotic (Erythromycin, Tetracyclin and Amikacin), while Ciprofloxacin showed Susceptibility 100%. Antibiotic resistance profiles showed multidrug-resistant to two, three and more than three antibiotics. The PCR assay on 59 extracted DNA showed amplification of the blaZ, in 6 isolates only, PCR-product of 6 blaZ gene samples were sequenced, analyzed, and deposited and published on the Genbank (NCBI) under the accession number MZ359750.1, MZ359751.1, MZ359752.1, MZ359753.1, MZ359754.1, MZ359755.1 and it is available for download. Five samples match the global results by 100%, and one sample possess a mutation at the site 1866418, the second at the site 1866425. In conclusion, this study revealed the importance of detection of slime as a virulence factor in all isolates suggests that these isolates were virulent and pathogenic for humans and animals, the widespread use of antibiotics lead to the emergence of multiresistant pathogen, which phenotypically presented as double, triple, and multiple drug resistance. Some isolates were possess the gene blaZ which responsible for resistance to Penicillin.