title: Nosocomial infections caused by multidrug-resistant isolates of pseudomonas putida producing VIM-1 metallo-beta-lactamase.
abstract: Successful carbapenem-based chemotherapy for the treatment of Pseudomonas infections has been seriously hindered by the recent appearance of IMP- and VIM-type metallo-beta-lactamases, which confer high-level resistance to carbapenems and most other beta-lactams. Recently, multidrug-resistant Pseudomonas putida isolates for which carbapenem MICs were >/=32 micro g/ml were recovered from cultures of urine from three inpatients in the general intensive care unit of the Ospedale di Circolo, Varese, Italy. Enzyme assays revealed production of a metallo-beta-lactamase activity, while molecular analysis detected in each isolate a bla(VIM-1) determinant carried by an apparently identical medium-sized plasmid. Conjugation experiments were unsuccessful in transferring the beta-lactamase determinant to Escherichia coli or Pseudomonas aeruginosa. Macrorestriction analysis by pulsed-field gel electrophoresis demonstrated that the isolates were of clonal origin. PCR mapping and sequencing of the variable region of the plasmid-borne class 1 integron carrying the bla(VIM-1) determinant (named In110) showed that the bla(VIM-1)-containing cassette was identical to that previously found in strains of different species from other Italian hospitals and that the cassette array of In110 was not identical but clearly related to that of In70 (a bla(VIM-1)-containing plasmid-borne integron from an Achromobacter xylosoxidans isolate), pointing to a common origin of this cassette and to a related evolutionary history of their cognate integrons.
authors.affiliation: Laboratorio di Microbiologia, Ospedale di Circolo, and Università dell'Insubria, I-21100 Varese, Italy.
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Lombardi
authors.forename: Francesco
authors.initials: F
authors.lastname: Luzzaro
authors.forename: Jean-Denis
authors.initials: JD
authors.lastname: Docquier
authors.forename: Maria Letizia
authors.initials: ML
authors.lastname: Riccio
authors.forename: Mariagrazia
authors.initials: M
authors.lastname: Perilli
authors.forename: Alessandra
authors.initials: A
authors.lastname: Colì
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Amicosante
authors.forename: Gian Maria
authors.initials: GM
authors.lastname: Rossolini
authors.forename: Antonio
authors.initials: A
authors.lastname: Toniolo
mesh_terms: D000368:Aged; D015780:Carbapenems / Q000494:pharmacology; D003428:Cross Infection / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D032023:Integrons / Q000235:genetics; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D008969:Molecular Sequence Data; D011552:Pseudomonas Infections / Q000382:microbiology; D016958:Pseudomonas putida / Q000187:drug effects / Q000201:enzymology*; D014552:Urinary Tract Infections / Q000382:microbiology*; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D015780:Carbapenems; D047090:beta-Lactams; C417264:VIM-1 metallo-beta-lactamase; D001618:beta-Lactamases