Abstract

Introduction: Staphylococci are clinically-important bacteria notable for catalase production when grown in-vitro and during host infections. However, comparative activities of the enzyme in the presence and absence of different chemical components in body fluids is apparently unknown. Aim: This study investigated the qualitative influence of blood plasma on in-vitro activity of staphylococcal enzyme and virulence potentials of the organism. Materials and methods: Twenty-seven (27) clinical staphylococcal isolates, comprising 33% coagulase positive strains were screened for catalase production using swabbed colonies and thick cell suspensions exposed to 6% w/v H2O2. Thereafter, separate 25 µL and 50 µL of any of ten (10) blood plasma samples with little or no catalase activities were added to different cell suspensions of 25 µL on Petri dishes and 50 µL contained in tubes respectively. Individual cell suspensions and test plasma samples of same volumes served as controls. Equal volumes (25 µL / 50 µL) of H2O2 were added to all preparations and observed for characteristic bubble formation. Results: All the bacterial suspensions without plasma showed immediate vigorous bursting bubbling reaction for a few seconds but those with plasma took about 15 seconds before producing tiny bubbles and progressed to forming profuse foams, rising high in narrow tubes or extending beyond the droplet spots. The foams persisted for several minutes or till dryness. The plasma control produced very little or no foams. Conclusion: This study shows blood plasma has the potential of slowing down the characteristic intense rapid in-vitro activity of staphylococcal catalase activity and if applicable in-vivo, it may be tissue protective but the observed suboptimal enzyme performance may reduce oxidative stress survival of the bacteria during invasive infections. , , , ,, , .

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