Clinical characteristics and risk factors of enterococcal infections in Nagasaki, Japan: a retrospective study

Background: Enterococcus spp. are particularly important etiological agents of nosocomial infections. However, the clinical characteristics of and risk factors for enterococcal infections in clinical settings are poorly understood. Methods: The sample included patients with Enterococcus spp. infections detected from clinical samples at Nagasaki University Hospital between 2010 and 2011 and patients with enterococcal colonization (control patients). In this retrospective study, the risk factors for enterococcal infections were analyzed by comparing infected and control patients via multivariate logistic regression. Results: A total of 182 infected (mean age, 64.6±18.2years; 114 men) and 358 control patients (patients with enterococcal colonization) (mean age, 61.6±22.4years; 183 men) were included. Enterococcal infections were classified as intraperitoneal (n=87), urinary tract (n=28), or bloodstream (n=20) infections. Cancer and hematological malignancies were the most common comorbidities in enterococcal infections. Carbapenem and vancomycin were administered to 43.8% and 57.9% of patients infected with Enterococcus faecalis and Enterococcus faecium, respectively. No vancomycin-resistant enterococci were isolated. Multivariate analysis identified abdominal surgery (odds ratio [OR], 2.233; 95% confidence interval [CI], 1.529-3.261; p≤0.001), structural abnormalities of the urinary tract (OR, 2.086; 95% CI, 1.088-4.000; p=0.027), male sex (OR, 1.504; 95% CI, 1.032-2.190; p=0.033), and hypoalbuminemia (OR, 0.731; 95% CI, 0.555-0.963; p=0.026) as independent risk factors for enterococcal infections. Multivariate analysis showed abdominal surgery (OR, 2.263; 95% CI, 1.464-3.498; p≤0.001), structural abnormalities of the urinary tract (OR, 2.634; 95% CI, 1.194-5.362; p=0.008), and hypoalbuminemia (OR, 0.668; 95% CI, 0.490-0.911; p=0.011) were independent risk factors for E. faecalis infection. Finally, immunosuppressive agent use (OR, 3.837; 95% CI, 1.397-10.541; p=0.009) and in situ device use (OR, 3.807; 95% CI, 1.180-12.276; p=0.025) were independent risk factors for E. faecium infection. Conclusions: These findings might inform early initiation of antimicrobial agents to improve clinical success