Investigation of Virulence Factors of Staphylococcus.Aureus That Isolated from Different Clinical Infections in Baladroz City (Iraq)

Abstract

One hundred Staphylococcus isolates were isolated form different clinical samples which were collected from hospital at Baladruz city (Diyala-Iraq). The specimens included wound, burn, ear and nasal swabs . The highest rate for the isolation of these bacteria from burn swabs 35% , wound swabs was 30%, ear was 25% ,nasal swabs 10% . All isolates produce DNase ,and lipase ,while 70% of them produce protease . An antibiotic sensitivity test was done for the bacterial isolates. All isolates resist to penicillin and Ampicillin with the ratio of 100% , 95% ,and the results showed that there was multiple resistant antibiotics. The pattern of minimum inhibitory concentration of S. aureus isolates to vancomycin , erythromycin was determined using MIC method, the MIC of them between (4-256 μgml). The results showed that 17 isolate of S.aureus with ratio (85%) were vancomycin resistant while in this study found that 3 isolates (15%) have intermediate resistance ,So (75%) of isolates that be found resistance to erythromycin antibiotic. Biofilm detection was tested by Tube method (TM), the method of Congo Red Agar (CRA), and the method Tissue culture plate (TCP) .Out of 20 isolates, method of tube detected 80% of isolates showed strong biofilm ,while by CRA method detected 77.8% as high biofilm producer. In the same time 30% of isolates gave the OD values ranged from 0.430 to 0.542. This isolates were detected for their bacteriocin production that found 35% were as bacteriocin Producers by well diffusion method, (15%) by the stab-over lay.