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

• Published in: European journal of clinical microbiology & infectious diseases 2017-07, Vol.36 (7), p.1091-1096
• Main Authors: Park, G. E., Ko, J.-H., Cho, S. Y., Ha, Y. E., Lee, N. Y., Kang, C.-I., Chung, D. R., Song, J.-H., Peck, K. R.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents - administration & dosage; Bacteremia - drug therapy; Bacteremia - mortality; beta-Lactams - administration & dosage; Biomedical and Life Sciences; Biomedicine; Drug Therapy, Combination - methods; Female; Humans; Internal Medicine; Male; Medical Microbiology; Middle Aged; Original Article; Retrospective Studies; Staphylococcal Infections - drug therapy; Staphylococcal Infections - mortality; Survival Analysis; Tertiary Care Centers; Treatment Outcome; Vancomycin - administration & dosage; Young Adult
• ISSN: 0934-9723; 1435-4373
• DOI: 10.1007/s10096-016-2893-4

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.