title: Molecular epidemiology of Escherichia coli producing extended-spectrum beta-lactamases isolated in Rome, Italy.
abstract: Escherichia coli strains producing extended-spectrum beta-lactamases (ESBLs) are a major problem in many different hospitals worldwide, causing outbreaks as well as sporadic infections. The prevalence of Escherichia coli ESBL producers was analyzed in a surveillance study performed on the population attending the Policlinico Umberto I, the largest university hospital in Rome, Italy. We also investigated genotypes, pathogenicity islands, and plasmids in the ESBL-positive E. coli isolates as further markers that are useful in describing the epidemiology of the infections. In this survey, 163 nonreplicate isolates of Escherichia coli were isolated from patients from 86 different wards, and 28 were confirmed as ESBL producers. A high prevalence (26/28) of CTX-M-15 producers was observed within the bacterial population circulating in this hospital, and the dissemination of this genetic trait was associated with the spread of related strains; however, these do not have the characteristics of a single epidemic clone spreading. The dissemination was also linked to horizontal transfer among the prevalent E. coli genotypes of multireplicon plasmids showing FIA, FIB, and FII replicons in various combinations, which are well adapted to the E. coli species. The analysis of related bacteria suggests a probable interpatient transmission occurring in several wards, causing small outbreaks.
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy. alecara@iss.it
authors.forename: Alessandra
authors.initials: A
authors.lastname: Carattoli
authors.forename: Aurora
authors.initials: A
authors.lastname: García-Fernández
authors.forename: Paola
authors.initials: P
authors.lastname: Varesi
authors.forename: Daniela
authors.initials: D
authors.lastname: Fortini
authors.forename: Serena
authors.initials: S
authors.lastname: Gerardi
authors.forename: Adriano
authors.initials: A
authors.lastname: Penni
authors.forename: Carlo
authors.initials: C
authors.lastname: Mancini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Giordano
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016000:Cluster Analysis; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology* / Q000635:transmission; D022761:Gene Transfer, Horizontal; D044404:Genomic Islands; D005838:Genotype; D006785:Hospitals, University; D006801:Humans; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D010957:Plasmids; D012384:Rome / Q000453:epidemiology; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D001618:beta-Lactamases