title: Ofloxacin susceptibility testing quality control parameters for microdilution and disk diffusion, and confirmation of disk diffusion interpretive criteria.
abstract: The susceptibilities of 221 clinical isolates to ofloxacin were tested simultaneously by broth microdilution and disk diffusion methods with commercially prepared 5-micrograms ofloxacin disks. The acceptability of the following previously proposed zone diameter breakpoints was confirmed: greater than or equal to 16 mm, susceptible; 13 to 15 mm, intermediate; less than or equal to 12 mm, resistant. On the basis of a multilaboratory collaborative study, the following are proposed as acceptable ofloxacin MIC ranges for quality control organisms: Escherichia coli ATCC 25922, 0.03 to 0.06 micrograms/ml; Staphylococcus aureus ATCC 29213, 0.12 to 0.5 micrograms/ml; Pseudomonas aeruginosa ATCC 27853 and Enterococcus faecalis ATCC 29212, 1.0 to 4.0 micrograms/ml. Ofloxacin quality control zone diameter ranges for the disk diffusion test are tentatively proposed, but variations in the performance of different lots of Mueller-Hinton agar may prove to be a serious problem for users.
authors.affiliation: St. Vincent Hospital and Medical Center, Portland, Oregon 97225.
authors.forename: P C
authors.initials: PC
authors.lastname: Fuchs
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
authors.forename: A L
authors.initials: AL
authors.lastname: Barry
authors.forename: T L
authors.initials: TL
authors.lastname: Gavan
mesh_terms: D001419:Bacteria / Q000187:drug effects*; D013293:Enterococcus faecalis / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D008826:Microbial Sensitivity Tests / Q000592:standards*; D015337:Multicenter Studies as Topic; D015242:Ofloxacin / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D011786:Quality Control; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D015242:Ofloxacin