TABLE 1.

Antimicrobial test ranges, MIC quality control ranges, and MIC breakpoints used for antimicrobial susceptibility testing

Antimicrobial agentAgar dilution test range (μg/ml)MIC quality control range of C. jejuni ATCC 33560 (μg/ml)bMIC breakpoint (μg/ml)a
SIR
Ampicillin0.06-128N/Ac≤816≥32
Tetracycline0.06-1281-4≤48≥16
Gentamicin0.06-1280.5-4≤48≥16
Kanamycin0.25-128N/A≤1632≥64
Clindamycin0.06-128N/A≤0.51-2≥4
Erythromycin0.06-1281-8≤0.51-4≥8
Ciprofloxacin0.008-1280.06-0.5≤12≥4
Norfloxacin0.06-128N/A≤48≥16
Nalidixic acid0.25-1288-32≤16≥32
  • a MIC breakpoints for enteric bacteria for all agents except norfloxacin were used by the NARMS. MIC breakpoints for Enterobacteriaceae for norfloxacin were recommended by the CLSI (formerly NCCLS). S, susceptible strains; I, intermediate strains; R, resistant strains.

  • b Tentative agar dilution quality control ranges of C. jejuni ATCC 33560 were approved by the CLSI.

  • c N/A, no data available.