Abstract:
The Gram-positive bacterium Staphylococcus aureus is
well known for its ability to develop resistance to various
antimicrobial substances. Methicillin-resistant S. aureus
(MRSA), a cause of nosocomial infections worldwide,
is becoming increasingly resistant to the glycopeptide
antibiotic vancomycin, one of few antibiotics used to
treat serious multiple-antibiotic-resistant staphylococcal
infections. With the increase in the number of MRSA
strains showing reduced sensitivity to vancomycin,
it has become important to investigate alternative
treatment options. In this study, we examined the
effects of five metals: silver, copper, arsenate, zinc, and
cadmium on the growth of a clinical MRSA strain
MM66 demonstrating heterogeneous intermediatelevel
resistance to vancomycin. Disc diffusion and
gradient plate experiments were used to compare the
metal susceptibility levels of strain MM66 to that of the
methicillin-resistant S. aureus laboratory control strain.
MM66 grew less successfully when exposed to metals,
and showed an overall increased level of susceptibility to
metals compared to the laboratory control strain. Of the
metals tested, silver exerted the highest inhibitory effect
on the growth of MM66.
