title: Comparative efficacy of ceftriaxone in experimental infections involving Bacteroides fragilis and Escherichia coli.
abstract: The in vivo activity of ceftriaxone was examined in an experimentally induced subcutaneous infection involving Bacteroides fragilis and Escherichia coli. Mice were challenged with 1 of 10 strains of B. fragilis or E. coli, or a dual combination of the two species. The efficacy was measured by a reduction in the count of viable organisms when antimicrobial treatment was initiated 1 h after challenge and continued for 5 days. Ceftriaxone exhibited impressive activity against E. coli but showed poor in vivo activity versus B. fragilis. The antimicrobial activity of ceftriaxone was influenced by the microbial interaction in our dual-isolate model. Pharmacokinetic studies showed that ceftriaxone penetrated into abscesses and achieved peak levels of about 40% of the peak serum levels. However, in abscesses infected with B. fragilis nearly all biological activity of ceftriaxone was lost.
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Md.
authors.forename: M
authors.initials: M
authors.lastname: Dezfulian
authors.forename: R A
authors.initials: RA
authors.lastname: Bitar
authors.forename: J G
authors.initials: JG
authors.lastname: Bartlett
mesh_terms: D000818:Animals; D001442:Bacteroides Infections / Q000382:microbiology*; D001441:Bacteroides fragilis / Q000187:drug effects; D002443:Ceftriaxone / Q000097:blood / Q000627:therapeutic use*; D004926:Escherichia coli / Q000187:drug effects; D004927:Escherichia coli Infections / Q000382:microbiology*; D051379:Mice; D008826:Microbial Sensitivity Tests; D017192:Skin Diseases, Bacterial / Q000382:microbiology*
chemical_list: D002443:Ceftriaxone