title: Susceptibility of coagulase-negative staphylococci to a kanamycin and cefalexin combination.
abstract: A combination of kanamycin and cefalexin was licensed in Europe in 2008 to treat bovine clinical mastitis. Preliminary broth and disk clinical breakpoints for this antibiotic combination have been proposed for Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus uberis, and Escherichia coli. This study indicates that these proposed breakpoints also hold for coagulase-negative staphylococci (CNS), a group of bacteria frequently isolated in milk samples from cows with clinical mastitis. The data show that clinical bovine mastitis isolates of CNS from Europe have a high degree of susceptibility to the kanamycin/cefalexin combination, with minimal resistance to either agent alone. The use of the available kanamycin and cefalexin combination disk for testing the susceptibility of bovine mastitis isolates of Staph. aureus, Strep. uberis, Strep. dysgalactiae, and E. coli is also reliable for use in the testing of CNS, as disk results correlated with broth minimum inhibitory concentrations. The study reports, for the first time, the approved Clinical Laboratory Standards Institute quality control ranges for the kanamycin/cefalexin combination and wild-type cutoff values for major bacterial pathogens implicated in bovine mastitis.
authors.affiliation: MB Consult Limited, Southampton, SO14 3XB, United Kingdom; University of Bradford, Bradford BD7 1DP, United Kingdom. p-s@mbconsult.co.uk
authors.forename: P
authors.initials: P
authors.lastname: Silley
authors.forename: L
authors.initials: L
authors.lastname: Goby
authors.forename: C M
authors.initials: CM
authors.lastname: Pillar
mesh_terms: D000818:Animals; D002417:Cattle; D002506:Cephalexin / Q000008:administration & dosage / Q000627:therapeutic use*; D052978:Disk Diffusion Antimicrobial Tests / Q000662:veterinary; D004338:Drug Combinations; D004926:Escherichia coli / Q000187:drug effects; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary; D005260:Female; D007612:Kanamycin / Q000008:administration & dosage / Q000627:therapeutic use*; D008414:Mastitis, Bovine / Q000188:drug therapy* / Q000382:microbiology; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000187:drug effects*; D013296:Streptococcus pneumoniae / Q000187:drug effects
chemical_list: D004338:Drug Combinations; D007612:Kanamycin; D002506:Cephalexin