Molecular Epidemiology of Escherichia coli Producing Extended-Spectrum β-Lactamases Isolated in Rome, Italy

Abstract

Escherichia coli strains producing extended-spectrum ␤-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.A rapid dissemination of isolates producing CTX-M-type extended-spectrum ␤-lactamases (ESBLs) has recently been reported in some European countries, including Italy, and is a matter of major concern. The bla CTX-M genes have been captured on transferable plasmids from the chromosomes of Kluyvera spp., and their products are becoming the most prevalent ESBLs encountered in Enterobacteriaceae (19). The prevalent bla CTX-M -type genes in Europe have been identified as bla CTX-M-1 , bla CTX-M-3 , bla CTX-M-9 , bla CTX-M-14 , and bla CTX-M-15 (2, 19). Infections caused by enterobacteria producing ESBLs are associated with increased morbidity, mortality, and health care-associated costs (9, 16).In Italy, the presence of CTX-M-type ESBLs in clinical isolates of Enterobacteriaceae examined in a Italian nationwide survey (23,27), as well as in isolates from companion animals (7), was previously reported, and the results showed that CTX-M-type enzymes were common overall (around 20%) among ESBL producers (20). However, the local epidemiology of Escherichia coli producing ESBLs may differ from the national picture, with dominance of different strains. We therefore studied the prevalence and the clonality of the Escherichia coli ESBL producers in the population attending the Policlinico Umberto I, the largest university hospital in Rome, Italy, which had not been included in the nationwide survey. We also investigated virulence factors encoded on pathogenicity islands (PAIs) and plasmids carried by the E. coli ESBL producers as further markers that are useful in describing the epidemiology of nosocomially acquired infections. MATERIALS AND METHODS Clinical i...

International Clones of Klebsiella pneumoniae and Escherichia coli with Extended-Spectrum β-Lactamases in a Czech Hospital

“…The FII-type plasmids were probably specific for each of these PFGE types as shown by differences in their mating ability and transferable resistance markers. A number of reports demonstrated the strong link between bla CTX-M-15 and FII-type plasmids (7,11,23,24,33). These molecules often carry also bla OXA-1 , bla TEM-1 , and aac(6Ј)-Ib-cr genes, which was confirmed in this work by specific PCRs (11) and sequencing ( Table 1).…”

Extended-Spectrum-β-Lactamase-Producing Escherichia coli Isolate Possessing the Shiga Toxin Gene ( stx 1 ) Belonging to the O64 Serogroup Associated with Human Disease in India

“…which is also in corroboration with reports by others worldwide (17)(18)(19)(20). As in the present study, a higher prevalence of the bla CTX-M-1 gene than of the bla SHV gene has been reported, which may be due to the wide use of extended-spectrum cephalosporins in India, especially ceftriaxone and cefotaxime, or it may be associated with the high mobilization of the encoding genes (21,22,23,24).…”

Efficacy of current guidelines for the treatment of spontaneous bacterial peritonitis in the clinical practice

“…If this small subgroup is to be considered representative of the organisms currently involved in the development of SBP, our study supports the possibility that, in recent years, the microbial etiology of SBP is changing, as it seems to have more generally occurred for bacterial infections of these kinds of patients [14] . In our hospital, a recent survey [36] on 4769 samples collected for bacterial isolation from April to September 2006, showed a high prevalence of ESBL-producing enterobacteriacae as an emergent cause of infections. In particular, among the ESBL-positive E. coli, strains with CTX-M -lactamases, specifically able to hydrolyze cefotaxime, were the most diffused.…”