[Antibiotic sensitivity of bacteria isolated from patients at 6 hospitals in Osaka]

We examined MICs of 6 oral new quinolones and 4 oral cephems against bacteria isolated from patients at 6 hospitals in Osaka during the period from January to June in 1990, and the following results were obtained. 1. All species excluding Streptococcus pyogenes were more sensitive with less frequencies of resistance to new quinolones than to cephems. In new quinolones, tosufloxacin (TFLX) was the most active against Gram-positive cocci and ciprofloxacin (CPFX) and TFLX had the highest activities against Gram-negative rods. 2. Resistant (MIC of CPFX greater than or equal to 3.13 micrograms/ml) strains to new quinolones were observed at higher frequencies than 10% among Staphylococcus spp., Enterococcus faecalis, Citrobacter freundii, Morganella morganii, Providencia rettgeri, Serratia spp., Pseudomonas aeruginosa, Pseudomonas cepacia and Xanthomonas maltophilia. 3. The frequency of Staphylococcus aureus resistant to new quinolones isolated from in-patients or urine was significantly higher than that from out-patients or other sources. On the other hand, there was no significant difference in resistance frequencies of P. aeruginosa due to types of patients or sources. But, there were significant differences in frequencies of resistant organisms of either species to new quinolones among hospitals. 4. Twenty-seven strains (19.7%) of 137 S. aureus strains examined were methicillin-resistant, and they were similarly resistant to new quinolones also. Methicillin susceptible S. aureus were also similarly sensitive to new quinolones.