Identification of a Chromosome-Borne Expanded-Spectrum Class A β-Lactamase from Erwinia persicina

Abstract

From whole-cell DNA of an enterobacterial Erwinia persicina reference strain that displayed a penicillinase-related antibiotic-resistant phenotype, a β-lactamase gene was cloned and expressed in Escherichia coli. It encoded a clavulanic-acid-inhibited Ambler class A β-lactamase, ERP-1, with a pI value of 8.1 and a relative molecular mass of ca. 28 kDa. ERP-1 shared 45 to 50% amino acid identity with the most closely related enzymes, the chromosomally encoded enzymes from Citrobacter koseri , Kluyvera ascorbata , Kluyvera cryocrescens , Klebsiella oxytoca , Proteus vulgaris , Proteus penneri , Rahnella aquatilis , Serratia fonticola , Yersinia enterocolitica , and the plasmid-mediated enzymes CTX-M-8 and CTX-M-9. The substrate profile of the noninducible ERP-1 was similar to that of these β-lactamases. ERP-1 is the first extended-spectrum β-lactamase from an enterobacterial species that is plant associated and plant pathogenic.