title: A proposal of interpretive criteria for cefoperazone applicable to bovine mastitis pathogens.
abstract: The correct assessment of mastitis pathogens for their susceptibility/resistance to cefoperazone is currently hampered by the lack of harmonized test conditions and interpretive criteria. The aim of this study was to provide a proposal for clinical breakpoints of cefoperazone which are applicable to Staphylococcus aureus, coagulase-negative staphylococci, Escherichia coli, Streptococcus agalactiae, Streptococcus dysgalactiae and Streptococcus uberis from cases of bovine mastitis and better reflect the situation in the bovine udder than breakpoints adopted from human medicine. For this, pharmacological data and clinical efficacy data of the documents submitted for approval of cefoperazone have been revisited. In addition, 1086 bacterial pathogens of the aforementioned six species/groups collected in Germany and in the USA during recent years were tested in parallel for their cefoperazone MICs and the zone diameters using a 75 μg disk. Subsequently, MICs were plotted against zone diameters. Based on the pharmacological data, the clinical efficacy and the microbiological data, a proposal was made for veterinary-specific breakpoints which classify members of the aforementioned species/groups as (a) susceptible to cefoperazone when their MIC is ≤ 2 μg/ml and their zone diameters are ≥ 27 mm (staphylococci or E. coli) or ≥ 21 mm (streptococci), (b) intermediate when their MIC is 4 μg/ml and their zone diameters are 22-26 mm (staphylococci or E. coli) or 16-20mm (streptococci), and (c) resistant when their MIC is ≥ 8 μg/ml and their zone diameters are ≤ 21 mm (staphylococci or E. coli) or ≤ 15 mm (streptococci).
authors.affiliation: Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut (FLI), Neustadt-Mariensee, Germany.
authors.forename: Andrea T
authors.initials: AT
authors.lastname: Fessler
authors.forename: Heike
authors.initials: H
authors.lastname: Kaspar
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Lindeman
authors.forename: Michael R
authors.initials: MR
authors.lastname: Stegemann
authors.forename: Thomas
authors.initials: T
authors.lastname: Peters
authors.forename: Joachim
authors.initials: J
authors.lastname: Mankertz
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Watts
authors.forename: Stefan
authors.initials: S
authors.lastname: Schwarz
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle; D002438:Cefoperazone / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary; D005260:Female; D005858:Germany; D008414:Mastitis, Bovine / Q000188:drug therapy* / Q000382:microbiology; D008826:Microbial Sensitivity Tests / Q000592:standards*; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary; D013211:Staphylococcus aureus / Q000187:drug effects; D013290:Streptococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary; D013291:Streptococcus / Q000187:drug effects; D014481:United States
chemical_list: D000900:Anti-Bacterial Agents; D002438:Cefoperazone