The bactericidal effect of four kinds of disinfectant-benzethonium chloride, benzalkonium chloride, chlorhexidine gluconate and alkyl diaminoethyl glycine-was evaluated against 30 strains of Staphylococcus aureus which comprised of 24 strains of Methcillin-resistant Staphylococcus aureus (MRSA) and six of Methicillin-sensitive Staphylococcus aureus (MSSA). The effect was measured by the phenol coefficient method and the MRSA strains were classified by typecombination of coagulase and enterotoxin as IIA, IIB, IIC and IINT (non-typable)
The results were as follows: 1) All strains except for three strains of MRSA and MSSA became growth-inhibited within 15 seconds due to each disinfectant at a rate of 0.1% which was the ordinary dose in clinical use. 2) There were differences in inhibition time by 0.02% of the disinfectants among the MRSA type-combinations.
So far as our materials were concerned, we concluded that there was no necessity to distinguish MRSA from MSSA when “disinfection” is considered.
