title: In vitro combined effects of cefozopran/teicoplanin and cefozopran/vancomycin on methicillin-resistant Staphylococcus aureus.
abstract: We determined the in vitro effects of teicoplanin (TEIC) or vancomycin (VCM) added to cefozopran (CZOP) on 50 methicillin-resistant Staphylococcus aureus (MRSA) strains, using a modified checkerboard method with serial 1.25-fold dilutions, and assessed the time-kill curve. CZOP + TEIC was synergistic (fractional inhibitory concentration index < or = 0.5) against 98% and CZOP + VCM against 20% of strains. Both drug combinations were additive against the remaining strains. A comparison of the fractional bactericidal concentration indices for 32 strains showed synergistic bactericidal effects for CZOP + TEIC in 88%, and in 48% for CZOP +VCM, confirming that CZOP + TEIC is superior to CZOP + VCM. The time-kill curve confirms that the bactericidal potency of these drugs is increased through combined use with CZOP. These results suggest that treatment using TEIC or VCM with CZOP may be useful in treating MRSA infections, including polymicrobial infections and those involving Gram-negative rods.
authors.affiliation: Laboratory for Clinical Investigation, Osaka University Hospital, Osaka University, Suita City, Osaka, Japan. toyokawa@hp-lab.med.osaka-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Toyokawa
authors.forename: S
authors.initials: S
authors.lastname: Asari
authors.forename: I
authors.initials: I
authors.lastname: Nishi
authors.forename: M
authors.initials: M
authors.lastname: Horikawa
authors.forename: H
authors.initials: H
authors.lastname: Tsukamoto
authors.forename: A
authors.initials: A
authors.lastname: Sunada
authors.forename: A
authors.initials: A
authors.lastname: Ueda
authors.forename: Y
authors.initials: Y
authors.lastname: Iwatani
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002511:Cephalosporins / Q000008:administration & dosage / Q000494:pharmacology*; D004359:Drug Therapy, Combination; D066298:In Vitro Techniques; D008712:Methicillin / Q000008:administration & dosage / Q000494:pharmacology*; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D010406:Penicillins / Q000008:administration & dosage / Q000494:pharmacology*; D013203:Staphylococcal Infections / Q000188:drug therapy; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000472:pathogenicity; D017334:Teicoplanin / Q000008:administration & dosage / Q000494:pharmacology*; D014640:Vancomycin / Q000008:administration & dosage / Q000494:pharmacology*; D000097586:Cefozopran
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D008712:Methicillin; D010406:Penicillins; D017334:Teicoplanin; D014640:Vancomycin; D000097586:Cefozopran