Risk Factors for Mortality in Patients with Elizabethkingia Infection and the Clinical Impact of the Antimicrobial Susceptibility Patterns of Elizabethkingia Species

Abstract

Elizabethkingia species (spp.), which can colonize hospital environments, are emerging nosocomial pathogens presenting high mortality. Due to their intrinsic resistance to a broad range of antibiotics, optimal antibiotic dosage has yet to be determined against infections caused by Elizabethkingia spp. This study aimed to investigate the risk factors for the mortality of infections caused by Elizabethkingia spp. and assess the clinical implications of their antimicrobial susceptibility patterns. Data from 210 patients affected by Elizabethkingia-induced pneumonia and bacteremia between 1 November 2005 and 31 May 2016, were analyzed. Further antimicrobial susceptibility tests for moxifloxacin, rifampin, and vancomycin using Elizabethkingia isolates were performed to compensate for the Elizabethkingia spp. susceptibility panel in patients affected after 2013. The mean age of the patients was 66.5 ± 18 years and the 28-day mortality rate was 25.2% (53/210). In the univariate analysis, history of prior stay in an intensive care unit, central venous catheter use, presented thrombocytopenia, immunocompetent status, a high simplified acute physiology score II (SAPS II score), a high C-reactive protein (CRP)/albumin ratio on the day of isolation and seven days later, and a high minimum inhibitory concentration (MIC) value of rifampin were significantly associated with a higher mortality rate. In the multivariate logistic regression analysis, the MIC values of rifampin (odds ratio (OR): 1.045; 95% confidence interval (CI): 1.006-1.085; p = 0.023), SAPS II score (OR: 1.053; 95% CI: 1.022-1.084; p = 0.001), and initial CRP/albumin ratio (OR: 1.030; 95% CI: 1.009-1.051; p = 0.004) were significantly associated with 28-day mortality. To reduce the mortality associated with Elizabethkingia infections, prediction of the clinical course using initial CRP/albumin ratio and SAPS II and early intervention are essential. Rifampin is a promising candidate as the drug of choice in treating Elizabethkingia infections.

Keywords: Elizabethkingia; anti-bacterial agent; microbial sensitivity tests; mortality; risk factors.

Figure 1

The proportion of isolated Elizabethkingia species and in vitro antibiotic susceptibility rate of three Elizabethkingia species. The proportions of three Elizabethkingia species are presented in a pie chart, and the percentage of each species is shown in parentheses. The susceptibilities of each Elizabethkingia species to three antibiotics (moxifloxacin, rifampin, and vancomycin) are also presented in bar charts. (A), E. anopheles, (B), E. miricola, and (C), E. meningoseptica, respectively.