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 β-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 MIC50 was 0.023 mg/L and the MIC90 was 0.047 mg/L. The distribution of MIC values did not differ according to the site of isolation.