Majallah-i Dānishgāh-i ̒Ulūm-i Pizishkī-i Bābul (Apr 2000)
The study of correlations between B-Lactamase and protein A in Staphylococcus aureus
Abstract
Objective: Staphylococcus aureus is the type species and pathogen of human. There is some factors that determines the virulence of bacteria, but protein A and B-Lactamase are the most important factors. We studied the correlations between two factors of virulence (B-Lactamase and protein A) in this microorganism. Methods: We studied the resistance to B-Lactamase sensible to B-Lactamase as penicillin G (Pen G), Cefazolin (CeZ), Cefalotine (Cfn), resistant to B-Lactamase as methicillin (Met) and Oxacilin (Oxa) with disk diffusion method. MICS and B-Lactamase production detected by broth dilution and acidometric methods. Purification of SPA performed on these samples with ion exchange chromatography method (DEAE-Cellulose). Cell wall lysis was performed with heat extraction method. Findings: These results showed that resistance to drugs was 96% (Pen G), 83% (CeZ), 86% (Cfn) and 73% (Oxa). Purification performed on these samples with method (DEAE-Cellulose) have a sharp dense band in electrophoresis (SDS-PAGE) with a molecular weight of about 42 kd. Conclusion: After studying relationship between existence of SPA and B-Lactamase, we determined that 93.7% of strains with B-Lactamase had SPA but the strains without B-Lactamase only 50% had SPA. The result with methicillin resistant strains is most representative because in these kinds of strains there are not any strains with SPA.
