Glycopeptide use is associated with increased mortality in Enterococcus faecalis bacteraemia.

OBJECTIVES: Enterococci are an important cause of nosocomial and community-acquired infections, with bacteraemia being one of the most common presentations. Although inappropriate antimicrobial therapy has been associated with poorer outcomes in Enterococcus faecalis (EF) bacteraemia, the impact of antimicrobial choice, namely ß-lactam versus glycopeptide therapy, has not been well described. We sought to determine whether choice of antibiotic affects patient outcomes in EF bacteraemia. PATIENTS AND METHODS: This retrospective cohort study was conducted at Liverpool and Bankstown Lidcombe Hospitals, Sydney, Australia between 2006 and 2013. Medical records and laboratory data for consecutive EF bacteraemias were reviewed. Clinical and microbiological data were obtained for all patients who received appropriate antimicrobial therapy with either a ß-lactam or a glycopeptide antibiotic. Outcomes and predictors of mortality were determined and treatment groups were compared. RESULTS: One hundred and seventy-two episodes of clinically significant EF bacteraemias received appropriate antimicrobial therapy with a ß-lactam (n = 126) or a glycopeptide (n = 46). All-cause 30 day mortality was 15.1%, with mortality significantly higher in patients receiving glycopeptide therapy compared with ß-lactam therapy (26.1% versus 11.1%, P = 0.015). Glycopeptide therapy remained an independent predictor of 30 day mortality [OR 2.46 (95% CI 1.01-6.02), P = 0.048]. APACHE II score [OR 1.10 (95% CI 1.02-1.18), P = 0.011] and malignancy [OR 2.58 (95% CI 1.03-6.49), P = 0.044] were also independent predictors of 30 day mortality. CONCLUSIONS: Glycopeptide use is associated with increased mortality in patients with EF bacteraemia. In the treatment of ß-lactam-susceptible EF bacteraemia, ß-lactams should be considered first-line therapy.

Utility of matrix-assisted laser desorption ionization-time of flight mass spectrometry following introduction for routine laboratory bacterial identification.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was evaluated prospectively in a diagnostic laboratory. Nine hundred twenty-seven organisms were tested in triplicate; 2,351/2,781 (85%) species and 2,681/2,781 (96%) genus identifications were correct. Known issues such as the misidentification of alpha-hemolytic streptococci as Streptococcus pneumoniae were easily corrected. Identifications cost AUD$0.45 per isolate and were available in minutes. MALDI-TOF MS is rapid, accurate, and inexpensive.