title: Cefmetazole and trospectomycin in vitro susceptibility testing interpretive criteria and quality control guidelines for Neisseria gonorrheae.
abstract: Cefmetazole and trospectomycin were tested in a multilaboratory trial to establish Neisseria gonorrhoeae susceptibility testing criteria and quality control (QC) guidelines. Cefmetazole was active against the penicillinase-producing isolates and has an MIC90 of 16 micrograms/ml, the breakpoint MIC previously used for nonfastidious species. However, a single-dose gonorrhea regimen (1 g i.m.) would require a lower less than or equal to 2 micrograms/ml breakpoint with a correlate zone (greater than or equal to 33 mm) consistent with similarly used cephamycins (cefoxitin and cefotetan). An intermediate category was proposed for MICs greater than 2-4 micrograms/m (28-32 mm) pending more clinical experience with higher and/or prolonged cefmetazole dosing regimens. Trospectomycin was active (MIC90, 8 micrograms/ml) against all spectinomycin-susceptible gonococci. A susceptible breakpoint MIC of less than or equal to 16 micrograms trospectomycin per milliliter was proposed with a correlate zone diameter of greater than or equal to 17 mm. An intermediate category was also suggested for trospectomycin at 32 micrograms/ml (14-16 mm). QC guidelines were established for 30-micrograms cefmetazole and 30-micrograms trospectomycin disk diffusion tests and the GC agar base MICs using a multilaboratory study design consistent with National Committee for Clinical Laboratory Standards (NCCLS) M23-T guidelines. Both drugs were stable in GC agar plates for 21 days stored at 2 degrees-5 degrees C.
authors.affiliation: University of Iowa Hospitals and Clinics, College of Medicine, Iowa City.
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
authors.forename: M E
authors.initials: ME
authors.lastname: Erwin
authors.forename: J A
authors.initials: JA
authors.lastname: Washington
authors.forename: F P
authors.initials: FP
authors.lastname: Koontz
authors.forename: P R
authors.initials: PR
authors.lastname: Murray
authors.forename: E H
authors.initials: EH
authors.lastname: Gerlach
mesh_terms: D015311:Cefmetazole / Q000494:pharmacology*; D004355:Drug Stability; D008826:Microbial Sensitivity Tests / Q000379:methods; D009344:Neisseria gonorrhoeae / Q000187:drug effects*; D011786:Quality Control; D000198:Spectinomycin / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D015311:Cefmetazole; C043267:trospectomycin; D000198:Spectinomycin