Incidence, clinical characteristics, risk factors and outcomes of patients with mixed Candida/bacterial bloodstream infections: a retrospective study

Purpose The mixed Candida/bacterial bloodstream infections (mixed C/B-BSIs) is worthy of particular attention recently, and we analyzed the incidence, co-pathogens, clinical characteristics, risk factors, and outcomes of mixed C/B-BSIs compared with monomicrobial candidemia (mono-candidemia) in adult patients in China. Methods All hospitalized adults with candidemia were recruited for this retrospective observational study from January 1, 2013, to December 31, 2019. Results Of the 296 patients with candidemia, 78 cases (26.3%) were mixed C/B-BSIs. Candida albicans (C. albicans) was the most common Candida species among all candidemia, and Klebsiella pneumoniae (K. pneumoniae) was the most concomitant bacteria (30.6%), followed by Acinetobacter baumannii (A. baumannii) (12.9%) and Enterococcus faecium (E. faecium) (11.8%) in mixed C/B-BSIs. In the multivariable analysis, prior beta-lactams exposure [adjusted odds ratio (aOR), 1.97; 95% confidence interval (CI), 1.01-3.87], burn injury (aOR, 6.35; 95% CI 1.82-22.21) and continuous renal replacement therapy (CRRT) (aOR, 3.00; 95% CI 1.46-6.17) were independent risk factors for mixed C/B-BSIs. Compared with mono-candidemia, patients with mixed C/B-BSIs developed with more proportion of septic shock (55.1% vs. 39.9%, P < 0.05), prolonged stay in ICU [22.0(12.0-57.0) vs. 9.5(0.0-37.0) days, P < 0.001] and longer mechanical ventilation time [19.0(4.5-40.8) vs. 6.0(0.0-24.8) days, P < 0.001]. The in-hospital mortality in patients with mixed C/B-BSIs was higher than those with mono-candidemia (59.0% vs. 34.9%, P < 0.001). Survival analysis revealed that 28-day and 60-day mortality were significantly higher in patients with mixed C/B-BSI than in those with mono-candidemia (57.7% vs. 31.7%, P < 0.001; 59.0% vs. 34.9%, P < 0.001; respectively). Conclusions There is a high rate of mixed C/B-BSIs cases among candidemia, and K. pneumoniae is the predominant coexisting species. Prior beta-lactams exposure, burn injury, and CRRT are independent risk factors for mixed C/B-BSIs. The mortality of patients with mixed C/B-BSIs is significantly higher than those with mono-candidemia, this deserves further attention for clinicians.

Automated summary

The incidence of mixed Candida/bacterial bloodstream infections (mixed C/B-BSIs) is high in adult patients in China. Compared with monomicrobial candidemia, patients with mixed C/B-BSIs are more likely to develop septic shock, have prolonged ICU stay, longer mechanical ventilation time, and higher mortality.