[Susceptibility of clinical isolates from primary care clinics to oral antibacterial agents].

The antimicrobial susceptibility of clinical isolates from specimens of patients in primary care clinics in 2005 was investigated by determining the minimum inhibitory concentrations of oral antibacterial agents. The numbers of test strains were 550 for Gram-positive aerobes, 700 for Gram-negative aerobes, and 150 for anaerobes. Cefcapene (CFPN), cefditoren (CDTR), and cefteram (CFTM) showed the most potent activities against Staphylococcus spp. and Streptococcus spp. among the cephems tested and moxifloxacin (MFLX) and tosufloxacin among the new quinolones. Although the new quinolones generally showed potent activities against these species, resistant strains were frequently detected in methicillin-resistant Staphylococcus aureus. In addition, 70% or more of Streptococcus pneumoniae isolates were intermediate or resistant to macrolides. Cephems showed good activities against aerobic Gram-negative bacteria except for Proteus spp. Specifically, CFPN, CDTR, and CFTM showed the most potent activity against Haemophilus influenzae among the cephems tested. The new quinolones showed potent activities against Gram-negative bacteria, especially H. influenzae and Moraxella catarrhalis, but not against Proteus mirabilis and Providencia spp. When compared with the susceptibilities of clinical isolates from tertiary care hospitals, found in other research, differences were noted, for example, there was a lower frequency of quinolone-resistant strains of methicillin-susceptible S. aureus but a higher frequency of macrolide-resistant strains of Streptococcus pyogenes. Therefore, to accurately grasp susceptibility trends, well-focused surveillance studies are necessary.