Characterization of CSP-1, a novel extended-spectrum beta-lactamase produced by a clinical isolate of Capnocytophaga sputigena

Abstract

The Capnocytophaga sputigena isolate NOR, responsible for septicemia, was resistant to amoxicillin and narrow-spectrum cephalosporins. In a cloning experiment, a new gene, bla(CSP-1), was identified; this gene encodes a novel extended-spectrum beta-lactamase (ESBL) that shares only 52% and 49% identities with the CME-1 and VEB-1 beta-lactamases, respectively. The G+C content of this gene, its genetic environment, the absence of conjugation transfer, and its detection in two reference strains suggested that it was an intrinsic resistance gene located on the chromosome.

FIG. 1.

Multiple alignment of the amino acid sequences of the closely related class A β-lactamases with that of CSP-1. Boxes I through VI correspond to those described by Joris et al. (9). TLA-1, E. coli (GenBank accession no. AF148067); CME-1, Chryseobacterium meningosepticum (EMBL accession no. AJ006275); VEB-1, E. coli (EMBL accession no. O87489); PER-1, Pseudomonas aeruginosa (SwissProt accession no. P37321); PER-2, Salmonella enterica serovar Typhimurium (EMBL accession no. X93314); CblA, Bacteroides uniformis (SwissProt accession no. P30898); CepA, Bacteroides fragilis (GenBank accession no. L13472); CfxA, Bacteroides vulgatis (SwissProt accession no. P30899); TEM-1 (GenBank accession no. AAR25033); SHV-1 (GenBank accession no. AAK69828); CTX-M-1 (GenBank accession no. CAJ01342); IMI-1 (GenBank accession no. AAA93461); GES-1 (GenBank accession no. AAO32356); BRO-1 (GenBank accession no. AAA92126); CARB-1 (GenBank accession no. P16897).