Prevalence of, and risk factors for, carriage of carbapenem-resistant Enterobacteriaceae among hospitalized patients in Japan

Background The prevalence of carbapenem-resistant Enterobacteriaceae (CRE) has been reported to be lower in Japan than in many other countries. However, extensive surveillance for CRE carriage has not been performed in Japan. Aim To investigate the prevalence of CRE carriage in Japan among convalescent patients considered to be at high risk of being CRE carriers using an improved selective culture medium. Methods A cross-sectional survey was conducted in 22 acute care hospitals (ACHs) and 21 long-term care hospitals (LTCHs) in northern Osaka from December 2015 to January 2016. Patients who used incontinence aids, an enteral feeding tube or a urinary catheter were enrolled. Faecal specimens were examined using the newly developed M-ECC for imipenemase (IMP)-producing CRE, which is the most prevalent form of CRE in Japan. The positive isolates were analysed by polymerase chain reaction and sequencing. Risk factors associated with carriage were analysed by logistic regression. Findings Among 1507 patients, 184 (12.2%) carried CRE. The percentage of positive patients was significantly higher in LTCHs (14.9%) than in ACHs (3.6%) (P<0.001). Risk factors for CRE carriage were longer hospital stay [odds ratio (OR) 2.59; 95% confidence interval (CI) 1.87–3.60], enteral feeding (OR 3.03, 95% CI 2.08–4.42) and antibiotic exposure (OR 2.00, 95% CI 1.40–2.87). Among the 233 CRE isolates identified, 223 were IMP producers; the remaining isolates did not produce carbapenemase. Conclusions This is the first Japanese report to demonstrate the significant spread of CRE in both ACHs and LTCHs using an improved selective medium. A coordinated regional approach may help to prevent further spread.