title: FIM-1, a new acquired metallo-β-lactamase from a Pseudomonas aeruginosa clinical isolate from Italy.
abstract: Acquired metallo-β-lactamases (MBLs) are resistance determinants of increasing clinical importance in Gram-negative bacterial pathogens, which confer a broad-spectrum β-lactam resistance, including carbapenems. Several such enzymes have been described since the 1990s. In the present study, a novel acquired MBL, named FIM-1, was identified and characterized. The bla(FIM-1) gene was cloned from a multidrug-resistant Pseudomonas aeruginosa clinical isolate (FI-14/157) cultured from a patient with a vascular graft infection in Florence, Italy. The isolate belonged in the sequence type 235 epidemic clonal lineage. The FIM-1 enzyme is a member of subclass B1 and, among acquired MBLs, exhibited the highest similarity (ca. 40% amino acid identity) with NDM-type enzymes. In P. aeruginosa FI-14/157, the bla(FIM-1) gene was apparently inserted into the chromosome and associated with ISCR19-like elements that were likely involved in the capture and mobilization of this MBL gene. Transfer experiments of the bla(FIM-1) gene to an Escherichia coli strain or another P. aeruginosa strain by conjugation or electrotransformation were not successful. The FIM-1 protein was produced in E. coli and purified by two chromatography steps. Analysis of the kinetic parameters, carried out with the purified enzyme, revealed that FIM-1 has a broad substrate specificity, with a preference for penicillins (except the 6α-methoxy derivative temocillin) and carbapenems. Aztreonam was not hydrolyzed. Detection of this novel type of acquired MBL in a P. aeruginosa clinical isolate underscores the increasing diversity of such enzymes that can be encountered in the clinical setting.
authors.affiliation: Department of Biotechnologies, Section of Microbiology, University of Siena.
authors.forename: Simona
authors.initials: S
authors.lastname: Pollini
authors.forename: Simona
authors.initials: S
authors.lastname: Maradei
authors.forename: Patrizia
authors.initials: P
authors.lastname: Pecile
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Olivo
authors.forename: Francesco
authors.initials: F
authors.lastname: Luzzaro
authors.forename: Jean-Denis
authors.initials: JD
authors.lastname: Docquier
authors.forename: Gian Maria
authors.initials: GM
authors.lastname: Rossolini
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000494:pharmacology; D001398:Aztreonam / Q000494:pharmacology; D015780:Carbapenems / Q000378:metabolism* / Q000494:pharmacology; D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D057075:Enzyme Assays; D004926:Escherichia coli / Q000235:genetics; D018014:Gene Transfer Techniques; D006801:Humans; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D010406:Penicillins / Q000378:metabolism* / Q000494:pharmacology; D010802:Phylogeny; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity; D001618:beta-Lactamases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D010406:Penicillins; D011994:Recombinant Proteins; D001618:beta-Lactamases; D001398:Aztreonam