Giuseppe
Emeritus
[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]
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Genetic and biochemical characterization an acquired subgroup B3 metallo-β-lactamase gene, bla<SUB>AIM-1</SUB>, and its unique genetic context in Pseudomonas aeruginosa from Australia
Dongeun Yong 1,4, Mark A. Toleman 4, Jan Bell 2, Brett Ritchie 3, Rachael Pratt 3, Henry Ryley 4 and Timothy R. Walsh 4,5
Author Affiliations: <SUP>1</SUP>Yonsei University College of Medicine, Seoul, Korea; <SUP>2</SUP>Womens and Childrens Hospital, Adelaide, Australia; <SUP>3</SUP>Institute of Medical and Veterinary Science, Adelaide, Australia; <SUP>4</SUP>Department of Medical Microbiology and Infectious Diseases, Cardiff University, Cardiff, CF14 4XN, UK; <SUP>5</SUP>University of Queensland, Centre for Clinical Research, Herston 4169, Queensland, Australia
ABSTRACT
Three clinical Pseudomonas aeruginosa isolates (WCH2677, WCH2813 and WCH2837) isolated from the Womens and Childrens Hospital, Adelaide, Australia produced an MBL positive Etest result. All isolates were PCR negative for known MBL genes. A gene bank was created and the MBL gene, designated bla<SUB>AIM-1</SUB> was cloned and fully characterised. The encoded enzyme, AIM-1, is a group B3 MBL that has most identity to THIN-B and L1. It is chromosomally encoded and flanked by two copies (one intact and one truncated) of an ISCR element, ISCR15. Southern hybridisation studies indicate movement of both ISCR15 and bla<SUB>AIM-1</SUB> within the three different clinical isolates. AIM-1 hydrolyses most β-lactams with the exception of aztreonam and to a lesser extent ceftazidime; however, it is possesses significantly higher k<SUB>cat</SUB> values for cefepime and carbapenems than most other MBLs. AIM-1 was the first detected mobile group B3 enzyme and signals further problems for already beleaguered antimicrobial regimes to treat serious P. aeruginosa and other Gram-negative infections.
Copyright ? 2012, American Society for Microbiology. All Rights Reserved.
-Author Affiliations: <SUP>1</SUP>Yonsei University College of Medicine, Seoul, Korea; <SUP>2</SUP>Womens and Childrens Hospital, Adelaide, Australia; <SUP>3</SUP>Institute of Medical and Veterinary Science, Adelaide, Australia; <SUP>4</SUP>Department of Medical Microbiology and Infectious Diseases, Cardiff University, Cardiff, CF14 4XN, UK; <SUP>5</SUP>University of Queensland, Centre for Clinical Research, Herston 4169, Queensland, Australia
ABSTRACT
Three clinical Pseudomonas aeruginosa isolates (WCH2677, WCH2813 and WCH2837) isolated from the Womens and Childrens Hospital, Adelaide, Australia produced an MBL positive Etest result. All isolates were PCR negative for known MBL genes. A gene bank was created and the MBL gene, designated bla<SUB>AIM-1</SUB> was cloned and fully characterised. The encoded enzyme, AIM-1, is a group B3 MBL that has most identity to THIN-B and L1. It is chromosomally encoded and flanked by two copies (one intact and one truncated) of an ISCR element, ISCR15. Southern hybridisation studies indicate movement of both ISCR15 and bla<SUB>AIM-1</SUB> within the three different clinical isolates. AIM-1 hydrolyses most β-lactams with the exception of aztreonam and to a lesser extent ceftazidime; however, it is possesses significantly higher k<SUB>cat</SUB> values for cefepime and carbapenems than most other MBLs. AIM-1 was the first detected mobile group B3 enzyme and signals further problems for already beleaguered antimicrobial regimes to treat serious P. aeruginosa and other Gram-negative infections.
Copyright ? 2012, American Society for Microbiology. All Rights Reserved.
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