Extended-spectrum betalactamases producing Escherichia coli:: a new health-care associated infection threat?

Objectives. - Study the health-care associated infection risk due to Extended-Spectrum Betalactamases Producing Escherichia coli (ESBL Esc) isolated from diagnostic samples. Methods. - Descriptive, longitudinal and prospective study of 104 diagnostic isolates of ESBL Esc, one per patient, identified in Amiens university hospital between February 1999 and December 2005. Patients (sex, age, contamination risk factor, antecedent hospitalization) and microbiological data were progressively collected, entered into EPI INFO 6.04dFr software (ENSP, France) database, and compared using the chi-square test and Wilcoxon rank sum test, as appropriate. A p value of less than 0.05 was considered significant. Results. - Diagnostic ESBL Esc isolates raised, per 1000 isolates of Esc, from 1.2 in 1999 to 6 in 2005. Global and acquired isolates number of ESBL Esc varied from 7 and 3 in 2002 to 25 and 19 in 2003 (P = 0.22). ESBL Esc global and acquired incidence per 105 patient-days were, 0.8 and 0.6 in 1999 and 4.99 and 3.4 in 2005 (P < 10(-6)), but rose from 0.6 acquired isolate in 2002 to 3.9 in 2003 (P = 0.002). ESBL Esc, isolated from urines, stools, pulmonary, blood and surgical site samples of patients of > 65 years aged (68.3%), were imipenem and latamoxef sensitive. Their acquisition risk factors found were hospitalization during the last 6 month period (40/104) and transfer from other institutions (20/104). Conclusion. - ESBL Esc isolates, among ESBL-producing Enterobacteriaceae, constitute an escalating health-care associated risk in our institution. The research at admission time of ESBL-producing Enterobacteriaceae, mainly in acute geriatric wards, strict isolation precaution and hand hygiene observance, rational antibiotic usage, are the key actions to control their cross transmission. Nonetheless, other studies are needed to determine whether we are in front of an ESBL Esc new clone emergence. (c) 2006 Elsevier Masson SAS. Tons droits reserves.