[Effect of methylrosanilinium chloride to MRSA nasal carriers]

Since the end of 1987, we have noticed an increasing incidence of Methicillin resistant Staphylococcus aureus (MRSA) among the inpatients of Yamanashi Medical College Hospital. MRSA strains were identified in 70-80 percent of the specimens obtained from patients with Staphylococcus aureus. From 1988 we performed yearly bacteriological examinations of the nares of medical personnel at Yamanashi Medical College Hospital. We treated nasal carriers with OFLX drop lotion or Povidone-iodine applied to the nares. In 1991 we treated eight nasal carriers, who had been unsuccessfully treated with Povidone-iodine, with 0.01% Methylrosanilinium Chloride ointment which was applied to the nares once a day for two weeks. A post-bacteriological examination again revealed that MRSA vanished from the nares of six nasal carriers. The minimum inhibitory concentration (MIC) of Methylrosanilinium Chloride was determined by the agar plate dilution method. The 100% MICs of MSSA were 1.0 microgram/ml and of MRSA were 1.0 microgram/ml by Methylrosanilinium Chloride. Moreover we examined the MICs of Methylrosanilinium Chloride against MRSA under the existing 5% Albumin, and consequently the 100% MICs were 4.0 micrograms/ml. Therefore a 0.01% Methylrosanilinium Chloride has sufficient efficacy against MRSA. The reaction of the skin and nasal mucosa to Methylrosanilinium Chloride was examined by using three groups of guinea pigs. 0.1% and 0.01% Methylrosanilinium Chloride ointment and hydrophylic poloid were applied to the nares and skin once a day for two weeks. Post-observation with an opticmicroscope revealed no significant findings. Methylrosanilinium Chloride shows good anti-Staphylococcus aureus ability. Further investigation is needed to determine if Methylrosanilinium Chloride has additional clinical application.