INTERPRETIVE CRITERIA AND QUALITY-CONTROL GUIDELINES FOR NEISSERIA-GONORRHOEAE SUSCEPTIBILITY TEST STANDARDIZATION FOR CEFOTETAN

Cefotetan was tested in a multilaboratory study to standardize susceptibility testing criteria and quality control guidelines for Neisseria gonorrhoeae. Cefotetan was most active against penicillinase-producing and penicillin-susceptible strains (MIC for 50% of strains tested, 0.5-mu-g/ml) and was least active against the chromosomally resistant isolates (MIC for 50% of strains tested, 2-mu-g/ml). The recommended 30-mu-g disk cefotetan interpretive criteria were as follows: susceptible at greater-than-or-equal-to 26 mm (less-than-or-equal-to 2-mu/gl), intermediate at 20 to 25 mm (4-mu-g/ml), and resistant at greater-than-or-equal-to 19 mm (greater-than-or-equal-to 8-mu-g/ml). Quality control guidelines for agar dilution and disk diffusion tests were established by using numerous GC agar lots, three cefotetan 30-um-g disk lots, two quantity control organisms, and a volume of tests consistent with National Committee for Clinical Laboratory Standards M23-T guidelines.