Role of vancomycin in the treatment of bacteraemia and meningitis caused by Elizabethkingia meningoseptica.

Elizabethkingia meningoseptica, a Gram-negative pathogen once deemed clinically insignificant, tends to cause infections among low-birth-weight infants and immunocompromised patients. Previously, vancomycin was reported to cure several patients with bacteraemia caused by E. meningoseptica. Nevertheless, some laboratory investigations also showed considerable discordance between in vitro vancomycin susceptibility results obtained by the disk diffusion and broth microdilution methods against clinical E. meningoseptica isolates as determined using the criteria for staphylococci recommended by the Clinical and Laboratory Standards Institute (CLSI). In this review, the PubMed database (1960-2017) was searched for studies that reported mainly cases with E. meningoseptica bacteraemia or meningitis treated with vancomycin alone or with regimens that included vancomycin. In addition, the in vitro synergy between vancomycin and other agents against isolates of E. meningoseptica was reviewed. Elizabethkingia meningoseptica bacteraemia appears not to universally respond to intravenous (i.v.) vancomycin-only therapy, especially in patients who require haemodialysis. If i.v. vancomycin is the favoured therapy against E. meningoseptica meningitis, the addition of ciprofloxacin, linezolid or rifampicin might be an option to effectively treat this difficult-to-treat infection. Further clinical studies are needed to determine the clinical efficacy of these combination regimens for the treatment of E. meningoseptica meningitis.

Comparison of the clinical efficacy between tigecycline plus extended-infusion imipenem and sulbactam plus imipenem against ventilator-associated pneumonia with pneumonic extensively drug-resistant Acinetobacter baumannii bacteremia, and correlation of clinical efficacy with in vitro synergy tests.

BACKGROUND/PURPOSE: To compare the clinical efficacy between salvage antimicrobial regimen consisting of tigecycline plus extended-infusion imipenem/cilastatin (TIC) and regimen of sulbactam plus imipenem/cilastatin (SIC) for patients with ventilator-associated pneumonia and pneumonic bacteremia due to extensively drug-resistant (XDR) Acinetobacter baumannii (Ab) isolates, and determine the correlation of results of in vitro tigecycline-imipenem synergy test with clinical efficacy. METHODS: The comparative survey was conducted at a medical center in Taiwan in 2013. Patients comprising the TIC group (n = 28) received tigecycline plus extended-infusion imipenem/cilastatin following unresponsiveness to 3-day sulbactam-imipenem/cilastatin therapy, and those in the SIC group (n = 56) received sulbactam-imipenem/cilastatin throughout the course. Univariate and multivariate analyses were applied to explore 30-day case-fatality independent predictors. Additionally, the checkerboard test and time-kill analysis were performed for the bloodstream XDR-Ab isolates from patients in the TIC group, and molecular characterization was done for the bloodstream XDR-Ab strains of all patients. RESULTS: We found that the TIC scheme has a significant benefit on improving patients' survival status (the mortality rate of TIC and SIC group patients was 14.3% and 64.3%, respectively), corresponding well with in vitro synergy or additivity results by the checkerboard test. Twenty TIC group cases had monomicrobial XDR-Ab cultured from tracheal aspirates after 10 days of tigecycline-imipenem/cilastatin therapy, but none developed subsequent pneumonia. However, breakthrough primary Burkholderia cepacia (n = 3) and Pseudomonas aeruginosa (n = 1) bacteremias were attributed to four TIC case fatalities. Shock, SIC regimen usage, and development of breakthrough bacteremia were independent predictors of 30-day in-hospital mortality. CONCLUSION: Although the TIC regimen showed good efficacy, its value regarding managing XDR-Ab ventilator-associated pneumonia bacteremia needs further evaluation.