Purpose: Carbapenem-resistant Klebsiella pneumoniae  (CRKP) infections have been increasingly reported worldwide. We aimed to identify the risk factors for nosocomial CRKP infections and assess the clinical outcomes.
Patients and Methods: We conducted a case-control study with data collected from January 2016 to December 2018 in China. Controls were selected at a ratio of 1:1 from patients with nosocomial carbapenem-susceptible Klebsiella pneumonia  (CSKP) infections. Risk factors for nosocomial CRKP infections and clinical outcomes were assessed with univariate and multivariate analyses.
Results: A total of one hundred forty-two patients with CRKP infections and one hundred forty-two patients with CSKP infections were enrolled in this study. Multivariate analysis showed that exposure to antibiotics within 3 months prior to admission (odds ratio OR, 2.585; 95% confidence interval [CI], 1.425– 4.691; P=0.002), exposure to carbapenems (OR, 2.532; 95% CI, 1.376– 4.660; P=0.003), exposure to fluoroquinolones (OR, 3.309; 95% CI, 1.326– 8.257; P=0.010), and the presence of a nasogastric tube (OR, 2.796; 95% CI, 1.369– 5.712; P=0.005) were independent risk factors for CRKP infections. The 30-day mortality rate in the CRKP group was 19.7%, while the in-hospital mortality rate was 28.9%. In the CRKP group, a higher creatinine level (OR, 1.009; 95% CI, 1.002– 1.016; P = 0.013), being in shock at the time of a positive culture (OR, 4.454; 95% CI, 1.374– 14.443; P = 0.013), and co-infection with other resistant bacteria (OR, 4.799; 95% CI, 1.229– 18.740; P = 0.024) were independent predictors of in-hospital mortality in patients with CRKP infections. Kaplan–Meier curves showed that the CRKP group had a shorter survival time than the CSKP group.
Conclusion: Nosocomial CRKP infection was associated with exposure to carbapenems and fluoroquinolones within 3 months prior to hospitalization and the presence of a nasogastric tube. Patients infected with CRKP had higher 30-day and in-hospital mortality rates. A higher creatinine level, shock and co-infection with other resistant bacteria were independent predictors of in-hospital mortality in patients with CRKP infections.
Keywords: carbapenem-resistant Klebsiella pneumoniae , risk factors, clinical outcomes, nosocomial infection