Abstract: | The effect of mercury salts on 200 hospital strains of Staph. pyogenes was investigated. Two methods of performing the mercury inhibition test were compared, and the agar plate technique was found to be the more practical. An attempt was made to correlate the results of the test with antibiotic sensitivity tests, phage patterns and virulence tests. Resistance to mercury was found to be associated with antibiotic resistance, and the majority of the resistant strains were found in the lytic group III. No difference in virulence between mercury-resistant and mercury-sensitive strains could be demonstrated by intracerebral inoculation of mice. The mercury inhibition test may be useful as a screening test for “hospital staphylococci”. |