Patterns of Antibiotic Resistance in Staphylococcus aureus Isolates and Detection the Heteroresistance to Vancomycin by Population analysis Method

Staphylococcus aureus is a major cause of bacterial poisoning and spread widely in Iraq. In this study vancomycin resistant S. aureus (VRSA) were isolated from wounds, skin, and nose of human . The isolates were identified by using biochemical tests.Sixty one (72.6%) isolates were identified as S.aureus, followed by CoNS 23 (27.3%) from 250 sample collected. Antibiotic susceptibility was determined by disk diffusion ,the results of the susceptibility test indicated that 59 S. aureus isolates have different levels of resistance to antibiotics.In this study tow methods were used to identify resistant and intermediate resistance to vancomycin: which were Kirby-Bauer disk diffusion and automated system Vitek2 method. Results of Disk diffusion method indicated that (19.6%) isolates were resistant to vancomycin.The results of Vitek2 resistant test for 20 isolates indicated that 9(45%) isolates were resistant to vancomycin, with MIC value of (32 μg / ml); 3(15%) isolates showed intermediate resistant to vancomycin, with MIC value of (4 μg / ml),8(40%) isolates showed sensitive to vancomycin with MIC value of (≤0.5-2 μg / ml).Population analysis profile (PAP) method was uesd to detect Heteroresistant Vancomycin-Intermediate Staphylococcus aureus for the 10 isolates. The results showed that 9 (90%) isolates of S.aureus were resistant to vancomycin , while 1(10%) isolate was sensitive.