Review Genetic support and diversity of acquired extended-spectrum b-lactamases in Gram-negative rods Laurent Poirel, Rémy A. Bonnin, Patrice Nordmann ⇑ Service de Bactériologie-Virologie, INSERM U914 «Emerging Resistance to Antibiotics», Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine et Université Paris-Sud, K. Bicêtre, France article info Article history: Received 24 November 2011 Received in revised form 14 February 2012 Accepted 15 February 2012 Available online 3 March 2012 Keywords: b-Lactamases Integron Transposon Insertion sequence ESBL abstract Genes encoding extended-spectrum b-lactamases (ESBLs) have been reported in a variety of Gram-neg- ative species, mostly in Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii. They are either TEM- or SHV-derivatives, CTX-M-like enzymes and less frequently of the GES, PER, or VEB types. The mechanisms at the origin of their acquisition are diverse, and mostly are related to insertion sequences, transposons and class 1 integrons. This diversity of genetic vehicles at the origin of these mobilization/acquisition processes may explain spread of ESBLs worldwide. Ó 2012 Elsevier B.V. All rights reserved. Contents 1. Introduction ......................................................................................................... 884 1.1. Extended-spectrum b-lactamase definition ........................................................................... 884 1.2. Insertion sequences .............................................................................................. 884 1.3. Transposons .................................................................................................... 884 1.4. Integrons and multidrug resistance integrons ......................................................................... 884 2. TEM- and SHV-like enzyme ............................................................................................. 884 2.1. Diversity of TEM-like ESBLs ....................................................................................... 884 2.2. Genetic support and expression of bla TEM -like ESBL genes ............................................................... 885 2.3. Diversity of SHV-like ESBLs ....................................................................................... 886 2.4. Genetic support of SHV-like ESBLs .................................................................................. 886 3. CTX-M-like enzymes .................................................................................................. 887 3.1. Diversity....................................................................................................... 887 3.2. Genetic support and expression of bla CTX-M genes ..................................................................... 887 4. GES-, PER- and VEB-like enzyme......................................................................................... 888 4.1. GES-type ESBLs ................................................................................................. 888 4.1.1. Diversity ............................................................................................... 888 4.1.2. Genetic support and expression ............................................................................ 888 4.2. PER-type ESBLs ................................................................................................. 889 4.2.1. Diversity ............................................................................................... 889 4.2.2. Genetic support and expression ............................................................................ 889 4.3. VEB-type ESBL .................................................................................................. 889 4.3.1. Diversity ............................................................................................... 889 4.3.2. Genetic support and expression ............................................................................ 889 1567-1348/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.meegid.2012.02.008 ⇑ Corresponding author. Address: Service de Bactériologie-Virologie, Hôpital de Bicêtre, 78 rue du Général Leclerc, 94275 Le Kremlin-Bicêtre, France. E-mail address: nordmann.patrice@bct.aphp.fr (P. Nordmann). Infection, Genetics and Evolution 12 (2012) 883–893 Contents lists available at SciVerse ScienceDirect Infection, Genetics and Evolution journal homepage: www.elsevier.com/locate/meegid