The Analysis of Virulence Factors and Β-LACTAMASE Production In Clinical Isolates of Staphylococcus Aureus

Staphylococcus aureus is associate with variety of clinical infections in various communities and healthcare institutions both in developed and developing countries. It produces extracellular enzymes like lipase, protease and lecithinase that degrade lipid, proteins present in the skin environment. Study was conducted to associated virulence factors in clinical isolates of S. aureus and to evaluate the incidence of β lactamase production. It comprised 271 clinical samples (pus from surgical, burn, ulcer, abscess and sputum from hospitals of Allahabad. S. aureus was isolated and identified by conventional culture followed by biochemical tests including coagulase test. β-lactamase test and antibiotic susceptibility tests were performed for all isolates. Among 59 isolates of S. aureus, coagulase, carotenoid pigment, haemolysis, lipase, lecithinase and protease activity was examined to be in 59 (100%), 55(93.22%), 51 (86.44%), 23 (39.98%), 25 (42.37%) and 19 (32.2%) respectively. Secretion of lipase, protease and lecithinase were insignificantly related to each other as well as bacterial isolates from different sample type.  Regarding 43 (72.89%) penicillin resistant isolates, 31(72.09%) were β-lactamase producers and of 20 (33.89%) methicillin resistant S. aureus (MRSA), 14 (70%) were β-lactamase producer. β-lactamase production was analyzed to be statistically significant for penicillin but not quite significant for methicillin resistant S. aureus (χ2=24.30, P>0.05 for penicillin and χ2=3.7, P=0.054 for methicillin). Positive correlation occurs between β-lactamase production and resistance to other antibiotics included in the study (R=0.97).It seems no variation in the liberation of virulence detecting enzymes among S. aureus. Even if penicillin resistance majorly results due to β-lactamase, methicillin resistance shares some other mechanism of resistance.