Diversity of Clavulanic Acid-Inhibited Extended-Spectrum β-Lactamases in Aeromonas spp. from the Seine River, Paris, France

Abstract

ABSTRACT Environmental Aeromonas sp. isolates resistant to ceftazidime were recovered during an environmental survey performed with water samples from the Seine River, in Paris, France, in November 2009. Selected isolates were identified by sequencing of the 16S rRNA and rpoB genes. PCR and cloning experiments were used to identify broad-spectrum-β-lactamase-encoding genes and their genetic context. Clavulanic acid-inhibited extended-spectrum-β-lactamase (ESBL) genes were identified in 71% of the Aeromonas sp. isolates. A variety of ESBL genes were detected, including bla VEB-1a , bla SHV-12 , bla PER-1 , bla PER-6 , bla TLA-2 , and bla GES-7 , suggesting an aquatic reservoir of those ESBL genes. Moreover, the repeated elements and different insertion sequences were identified in association with the bla PER-6 and the bla VEB-1a genes, respectively, indicating a wide diversity of mobilization events, making Aeromonas spp. a vehicle for ESBL dissemination.