[Analysis of extended-spectrum CTX-M-14 beta-lactamase (ESBLs) producing Escherichia coli isolates in the same ward over the long term].

We bacteriologically and genetically analysed 30 cephalosporin-resistant Escherichia coli strains isolated from specimens from 19 neurology-ward inpatients at our hospital over the 3 years from April 2006 to March 2009, surveying and comparing subjects' backgrounds. Of the 30, 19 (63%) were urine, 6 (20%) sputum, and 3 (10%) blood. We tested extended-spectrum beta-lactamase (ESBLs) production, found in all samples. PCR and gene sequencing showed that 25 strains (83%) were CTX-M-14 and 5 (17%) CTX-M-2. Among CTX-M-14 strains, two cluster groups I and II, were obtained using pulsed-field gel electrophoresis (PFGE). Cluster group I in particular, continued to be detected for 18 months in the same hospital room. The detection rate was high at 13 (68%) in subjects with urinary catheters and morbidity was high in those with a history of cerebrovascular disease, diabetes, and hypertension. Our findings suggest that genetically identical strains may become established and spread in hospitals possibly due to inadequate contact prevention, subjects' immune status, and risk factor existence.