Empirical combination of a β-lactam to vancomycin may not improve outcomes of methicillin-susceptible Staphylococcus aureus bacteremia, compared to vancomycin monotherapy

Eur J Clin Microbiol Infect Dis. 2017 Jul;36(7):1091-1096. doi: 10.1007/s10096-016-2893-4. Epub 2017 Jan 11.

Abstract

To evaluate effect of empirical combination of a β-lactam to vancomycin and vancomycin monotherapy in Staphylococcus aureus bacteremia (MSSA-B), we conducted a retrospective cohort study. Electronic medical records of individuals who were diagnosed with MSSA-B between January 2005 and February 2015 at a tertiary care center were reviewed. Patients were classified into three groups according to empirical antibiotic regimen (BL group, β-lactam; VAN group, vancomycin; BV group, combination of β-lactam and vancomycin), and 30-day all-cause mortality of each group was compared. During the study period, 561 patients with MSSA-B were identified. After exclusion of 198 patients (36 with poly-microbial infection, 114 expired within 2 days, and 48 already received parenteral antibiotics) and a matching process, 46 patients for each group were included. Baseline characteristics were similar except for severity and comorbidity scores. The 30-day mortality for all three groups were not significantly different (BL 4.3%, VAN 6.5%, BV 8.7%; P = 0.909). In a multivariate analysis, type of empirical antibiotic regimen was not statistically associated with 30-day all-cause mortality. In comparison with the VAN group, the BV group yielded a HR of 0.579 (95% CI = 0.086-3.890, P = 0.574). Pitt bacteremia score was the only significant factor for mortality. The empirical combination of a β-lactam to vancomycin was not associated with lower mortality in treating MSSA-B, compared to vancomycin monotherapy.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / administration & dosage*
  • Bacteremia / drug therapy*
  • Bacteremia / mortality
  • Drug Therapy, Combination / methods
  • Female
  • Humans
  • Male
  • Middle Aged
  • Retrospective Studies
  • Staphylococcal Infections / drug therapy*
  • Staphylococcal Infections / mortality
  • Survival Analysis
  • Tertiary Care Centers
  • Treatment Outcome
  • Vancomycin / administration & dosage*
  • Young Adult
  • beta-Lactams / administration & dosage*

Substances

  • Anti-Bacterial Agents
  • beta-Lactams
  • Vancomycin