title: Genetic and biochemical characterization of an acquired subgroup B3 metallo-β-lactamase gene, blaAIM-1, and its unique genetic context in Pseudomonas aeruginosa from Australia.
abstract: Three clinical Pseudomonas aeruginosa isolates (WCH2677, WCH2813, and WCH2837) isolated from the Women's and Children's Hospital, Adelaide, Australia, produced a metallo-β-lactamase (MBL)-positive Etest result. All isolates were PCR negative for known MBL genes. A gene bank was created, and an MBL gene, designated bla(AIM-1), was cloned and fully characterized. The encoded enzyme, AIM-1, is a group B3 MBL that has the highest level of identity to THIN-B and L1. It is chromosomal and flanked by two copies (one intact and one truncated) of an ISCR element, ISCR15. Southern hybridization studies indicated the movement of both ISCR15 and bla(AIM-1) within the three different clinical isolates. AIM-1 hydrolyzes most β-lactams, with the exception of aztreonam and, to a lesser extent, ceftazidime; however, it possesses significantly higher k(cat) values for cefepime and carbapenems than most other MBLs. AIM-1 was the first mobile group B3 enzyme detected and signals further problems for already beleaguered antimicrobial regimes to treat serious P. aeruginosa and other Gram-negative infections.
authors.affiliation: Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Dongeun
authors.initials: D
authors.lastname: Yong
authors.forename: Mark A
authors.initials: MA
authors.lastname: Toleman
authors.forename: Jan
authors.initials: J
authors.lastname: Bell
authors.forename: Brett
authors.initials: B
authors.lastname: Ritchie
authors.forename: Rachael
authors.initials: R
authors.lastname: Pratt
authors.forename: Henry
authors.initials: H
authors.lastname: Ryley
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Walsh
mesh_terms: D000293:Adolescent; D000595:Amino Acid Sequence; D001315:Australia; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D016521:Electrophoresis, Gel, Pulsed-Field; D004697:Endocarditis, Bacterial / Q000150:complications / Q000382:microbiology; D005260:Female; D005798:Genes, Bacterial; D006801:Humans; D006824:Hybridization, Genetic; D007676:Kidney Failure, Chronic / Q000150:complications; D007700:Kinetics; D007951:Leukemia, Myeloid / Q000150:complications; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D011552:Pseudomonas Infections / Q000150:complications / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D013203:Staphylococcal Infections / Q000150:complications / Q000382:microbiology; D016985:Streptococcus bovis; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D001618:beta-Lactamases; C578527:beta-lactamase AIM-1, Pseudomonas aeruginosa