Antibiotic susceptibility of Kingella kingae isolates from respiratory carriers and patients with invasive infections.

The antimicrobial drug susceptibilities of 145 isolates of Kingella kingae to eight antibiotics were determined by the disc diffusion method. In addition, penicillin MICs were determined by the Etest. Study isolates included 37 from blood, 34 from the skeletal system and 74 from respiratory carriers. All isolates were beta-lactamase negative and susceptible to erythromycin, gentamicin, chloramphenicol, tetracycline and ciprofloxacin. A single isolate exhibited resistance to trimethoprim-sulphamethoxazole, and 56 (38.6%) were resistant to clindamycin. The penicillin MIC(50) was 0.023 mg/L and the MIC(90) was 0.047 mg/L. The distribution of MIC values did not differ according to the site of isolation.