Effect of silver ion resistance in Staphylococcus aureus on production of extracellular enzymes & toxins
Kaur, P.; Saxena, M.; Sareen, M.; Vadehra, D.V.
Indian Journal of Medical Research 86: 716-721
1987
ISSN/ISBN: 0019-5340 PMID: 3450595 Document Number: 304732
The development of resistance to silver nitrate in Staphylococcus aureus concurrently altered the production of hemolysins, deoxyribonuclease and thermonuclease. Hemolysin production was enhanced up to a resistance level of 20 .mu.g/ml (Agr20 strain) beyond which a decline was observed and at 70 .mu.g/ml (Agr70) the levels of beta and delta hemolysin were only 0.8 and 20 per cent respectively of the levels in the wild type organism (Ags). Thermonuclease and deoxyribonuclease synthesis was also decreased in the resistant strain and was only 50 percent of the Ags strain. In the Agr70 strain, a two-fold increase was observed in the production of coagulase, however, the titre of protein A was only one half of the that in the Ags strain. Minor, but insignificant changes, were also observed in the amounts of protease, elastase and phospholipase. Curing of the metal ion resistance property by acriflavin (15 .mu.g/ml) did not restore the original status of beta hemolysin production. In both the resistant and the cured strains, extra as well as intra-cellular .beta.-hemolysin levels were inhibited indicating a decreased synthesis and not decreased release of the toxin by the strains.