Chronic infection sustained by a Pseudomonas aeruginosa High-Risk clone producing the VIM-1 metallo-β-lactamase in a cystic fibrosis patient after lung transplantation.

Background: The significance of chronic lung infection by multidrug-resistant (MDR) pathogens in Cystic Fibrosis (CF) transplanted patients remains controversial, and the available information is overall limited. Here we describe the case of a chronic infection, sustained by a metallo-β-lactamase (MBL)-producing P. aeruginosa strain, in a CF patient following lung transplantation.

Persistence of TEM-52/TEM-92 and SHV-12 extended-spectrum β-lactamases in clinical isolates of Enterobacteriaceae in Italy.

Extended-spectrum β-lactamases (ESBLs) belonging to the TEM and SHV families were investigated in 583 ESBL-producing Enterobacteriaceae collected at the clinical microbiology laboratories of 11 teaching Italian hospitals. By molecular analysis TEM-type and SHV-type ESBLs were confirmed on 154 and 74 isolates, respectively. High variability was found among TEM-types β-lactamases with the following variants: TEM-5, TEM-6, TEM-12, TEM-15, TEM-24, TEM-26, TEM-29, TEM-52, TEM-92, TEM-134, and TEM-149.

First countrywide survey of acquired metallo-beta-lactamases in gram-negative pathogens in Italy.

Metallo-beta-lactamases (MBLs) can confer resistance to most beta-lactams, including carbapenems. Their emergence in gram-negative pathogens is a matter of major concern. Italy was the first European country to report the presence of acquired MBLs in gram-negative pathogens and is one of the countries where MBL producers have been detected repeatedly.

CTX-M-type extended-spectrum beta-lactamases in Italy: molecular epidemiology of an emerging countrywide problem.

A nationwide survey of extended-spectrum beta-lactamase (ESBL) production among Enterobacteriaceae, carried out in 2003, showed that CTX-M-type enzymes have achieved a sizeable prevalence among ESBL producers in Italy, mostly in Escherichia coli and, to a lesser extent, in Klebsiella pneumoniae. In this work, we report on the molecular epidemiology of the CTX-M-producing isolates from that survey and on the mechanisms of dissemination of these emerging resistance determinants. The CTX-M-producing isolates were detected in 10 of the 11 participating centers distributed across the Italian national territory, although at remarkably variable rates in different centers (1.

Trends in production of extended-spectrum beta-lactamases among enterobacteria of medical interest: report of the second Italian nationwide survey.

Results of a 2003 survey carried out in Italy to evaluate the prevalence of extended-spectrum beta-lactamase (ESBL)-producing enterobacteria are presented. Eleven Italian Microbiology Laboratories investigated 9,076 consecutive nonreplicate isolates (inpatients, 6,850; outpatients, 2,226). ESBL screening was performed by MIC data analysis.

Dissemination of CTX-M-type extended-spectrum beta-lactamase genes to unusual hosts.

A Citrobacter amalonaticus and a Morganella morganii producing the CTX-M-1 extended-spectrum beta-lactamase (ESBL) were isolated from an area where this enzyme is now widespread in Escherichia coli. This is the first report of CTX-M-1 in the former species. In both cases the ESBL determinant was possibly acquired by these unusual hosts in vivo, after coinfection with E.

Novel TEM-type extended-spectrum beta-lactamase, TEM-134, in a Citrobacter koseri clinical isolate.

A new natural TEM derivative with extended-spectrum beta-lactamase activity, TEM-134, was identified in a ceftazidime-resistant clinical isolate of Citrobacter koseri. Compared to TEM-1, TEM-134 contains the following mutations: Q39K, E104K, R164H, and G238S. The bla(TEM-134) gene was not transferable by conjugation and, apparently, was chromosomally encoded.

Prevalence and characterization of metallo-beta-lactamases in clinical isolates of pseudomonas aeruginosa.

The prevalence and the type(s) of metallo-beta-lactamases (MBLs) produced by isolates of Pseudomonas aeruginosa were investigated. During 2001, 506 nonduplicate isolates were obtained from hospitalized patients. Eighty-two strains were selected because of resistance to carbapenems and/or ceftazidime.

IMP-12, a new plasmid-encoded metallo-beta-lactamase from a Pseudomonas putida clinical isolate.

A Pseudomonas putida strain showing broad-spectrum resistance to beta-lactams, including expanded-spectrum cephalosporins and carbapenems, was isolated from a patient with a urinary tract infection at the University Hospital of Varese in northern Italy. The isolate was found to produce metallo-beta-lactamase activity and to harbor a 50-kb plasmid, named pVA758, carrying a new bla(IMP) determinant, named bla(IMP-12). Plasmid pVA758 was not self-transferable by conjugation to either Escherichia coli or Pseudomonas aeruginosa but could be introduced by electroporation and maintained in the latter host, where it conferred resistance or decreased susceptibility to various beta-lactams.

Simple microdilution test for detection of metallo-beta-lactamase production in Pseudomonas aeruginosa.

A microdilution test measuring imipenem MICs in the presence or absence of a mixture of EDTA plus 1,10-phenanthroline was developed and tested on 190 Pseudomonas aeruginosa isolates, including 18 VIM- and 4 IMP-type metallo-beta-lactamase (MBL) producers. The chelator mixture reduced by fourfold or more the imipenem MICs for MBL producers, while a lower effect or no effect was usually observed with MBL nonproducers.