title: Comparison of cefazolin versus oxacillin for treatment of complicated bacteremia caused by methicillin-susceptible Staphylococcus aureus.
abstract: Contrary to prior case reports that described occasional clinical failures with cefazolin for methicillin-susceptible Staphylococcus aureus (MSSA) infections, recent studies have demonstrated no difference in outcomes between cefazolin and antistaphylococcal penicillins for the treatment of MSSA bacteremia. While promising, these studies described low frequencies of high-inoculum infections, such as endocarditis. This retrospective study compares clinical outcomes of cefazolin versus oxacillin for complicated MSSA bacteremia at two tertiary care hospitals between January 2008 and June 2012. Fifty-nine patients treated with cefazolin and 34 patients treated with oxacillin were included. Osteoarticular (41%) and endovascular (20%) sources were the predominant sites of infection. The rates of clinical cure at the end of therapy were similar between cefazolin and oxacillin (95% versus 88%; P=0.25), but overall failure at 90 days was higher in the oxacillin arm (47% versus 24%; P=0.04). Failures were more likely to have received surgical interventions (63% versus 40%; P=0.05) and to have an osteoarticular source (57% versus 33%; P=0.04). Failures also had a longer duration of bacteremia (7 versus 3 days; P=0.0002), which was the only predictor of failure. Antibiotic selection was not predictive of failure. Rates of adverse drug events were higher in the oxacillin arm (30% versus 3%; P=0.0006), and oxacillin was more frequently discontinued due to adverse drug events (21% versus 3%; P=0.01). Cefazolin appears similar to oxacillin for the treatment of complicated MSSA bacteremia but with significantly improved safety. The higher rates of failure with oxacillin may have been confounded by other patient factors and warrant further investigation.
authors.affiliation: South Texas Veterans Health Care System, San Antonio, Texas, USA The University of Texas at Austin College of Pharmacy, Austin, Texas, USA Pharmacotherapy Education and Research Center, University of Texas Health Sciences Center San Antonio, San Antonio, Texas, USA juli@ochsner.org.
authors.forename: Julius
authors.initials: J
authors.lastname: Li
authors.affiliation: South Texas Veterans Health Care System, San Antonio, Texas, USA The University of Texas at Austin College of Pharmacy, Austin, Texas, USA Pharmacotherapy Education and Research Center, University of Texas Health Sciences Center San Antonio, San Antonio, Texas, USA Department of Medicine, Division of Infectious Diseases, University of Texas Health Sciences Center San Antonio, San Antonio, Texas, USA.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Echevarria
authors.affiliation: The University of Texas at Austin College of Pharmacy, Austin, Texas, USA Pharmacotherapy Education and Research Center, University of Texas Health Sciences Center San Antonio, San Antonio, Texas, USA Department of Pharmacy, University Health System, San Antonio, Texas, USA.
authors.forename: Darrel W
authors.initials: DW
authors.lastname: Hughes
authors.affiliation: South Texas Veterans Health Care System, San Antonio, Texas, USA Department of Medicine, Division of Infectious Diseases, University of Texas Health Sciences Center San Antonio, San Antonio, Texas, USA.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Cadena
authors.affiliation: Department of Medicine, Division of Infectious Diseases, University of Texas Health Sciences Center San Antonio, San Antonio, Texas, USA.
authors.forename: Jason E
authors.initials: JE
authors.lastname: Bowling
authors.affiliation: The University of Texas at Austin College of Pharmacy, Austin, Texas, USA Pharmacotherapy Education and Research Center, University of Texas Health Sciences Center San Antonio, San Antonio, Texas, USA Department of Medicine, Division of Infectious Diseases, University of Texas Health Sciences Center San Antonio, San Antonio, Texas, USA Department of Pharmacy, University Health System, San Antonio, Texas, USA.
authors.forename: James S
authors.initials: JS
authors.lastname: Lewis
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D016470:Bacteremia / Q000188:drug therapy*; D002437:Cefazolin / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008712:Methicillin / Q000627:therapeutic use*; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010068:Oxacillin / Q000627:therapeutic use*; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000188:drug therapy; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D002437:Cefazolin; D008712:Methicillin; D010068:Oxacillin