Mupirocin is an antibiotic for topical application developed by Smith Kline Beecham in the United Kingdom. We studied the effect and optimal dosage of mupirocin nasal ointment for eliminating nasal carriage of Staphylococcus aureus including MRSA. Twice a day and three times a day application methods were compared by prospective randomization method in a multi-centered study. Sixty (60) mg of mupirocin nasal ointment was applied to both sides of the anterior nares (30mg each) twice a day (morning and evening) or three times a day (morning, evening and at bedtime) for three days. The elimination effect, safety and usefulness of mupirocin nasal ointment were evaluated on the day after and one week after the last application. Forty-one subjects (hospital staff and inpatients) with nasal carriage of S. aureus were enrolled. By the day after the last application, nasal carriage of S. aureus was eliminated in 78.4% (29) of 37 assessable cases, and by one week after the last application, it was eliminated in all the cases. Twenty-eight of the 41 enrolled subjects (hospital staff and inpatients) were found to have nasal carriage of MRSA. By the day after the last application, nasal carriage of MRSA was eliminated in 80.0% (20) of 25 assessable cases, and by one week after the last application, it was eliminated in all the cases. In comparison between two application methods, by the day after the last application, nasal carriage of S. aureus was eliminated in 73.7% (14 out of 19) of the twice a day group and 83.3% (15 out of 18) of the three times a day group. By one week after the last application, it was eliminated in all the cases in both groups. In the cases with nasal carriage of MRSA, by the day after the last application, nasal carriage of MRSA was eliminated in 75.0% (9 out of 12) of the twice a day group and 84.6% (11 out of 13) of the three times a day group. By one week after the last application, it was eliminated in all the cases in both groups. No adverse reactions were reported by any subject. In conclusion, application of 60 mg of mupirocin nasal ointment three times a day for three days is efective in elimination of nasal carriage of S. aureus (including MRSA).
The disinfective effect of hot water against methicillin-resistant Staphylococcus aureus (MRSA) was examined. A reduction in the count of MRSA on a silicone disc to less than 0.001% was achieved within 15 seconds by exposure to 75°C water, within 30 seconds by exposure to 70°C water and 2 minutes by exposure to 65°C water. 70-75°C water exerted a more rapid bactericidal action against MRSA than did 0.1% benzalkonium chloride, 0.01% sodium hypochlorite or 0.1% alkyldiaminoethyl glycine at 22±2°C. These results indicate that hot water is a useful means of disinfecting instruments and devices contaminated with MRSA.
Microbial contamination of tracheal suction catheters, which were re-used after disinfection over 24 hours, was investigated. Of the 12 catheters examined, nine were contaminated with 103-107 colony forming units per catheters. Pseudomonas cepacia and P. fluorescens were the primary contaminants. This contamination was caused by contaminated 0.02% benzalkonium chloride or 0.05% chlorhexidine in which the catheters were soaked. The contaminants that have grown to high concentrations over 24 hours in these disinfectants allowed gross contamination of the catheters. Substitution of 0.1% benzalkonium chloride containing 8v/v% ethanol or 0.05% chlorhexidine containing 8v/v% ethanol eliminated the bacterial contamination of the catheters.