Open AccessResistance to Cefepime and Cefpirome Due to a 4-Amino-Acid Deletion in the Chromosome-Encoded AmpC β-Lactamase of a Serratia marcescens Clinical Isolate
Author(s) -
Hedi Mammeri,
Laurent Poirel,
Pascal Bemer,
H Drugeon,
Patrice Nordmann
Publication year - 2004
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.48.3.716-720.2004
Subject(s) - cefepime , cefpirome , serratia marcescens , ceftazidime , microbiology and biotechnology , cephalosporin , cefotaxime , biology , ceftriaxone , escherichia coli , antibiotics , gene , bacteria , antibiotic resistance , imipenem , genetics , pseudomonas aeruginosa
A multiresistant Serratia marcescens strain, HD, isolated from a patient with a urinary tract infection, was resistant to amino-, carboxy-, and ureidopenicillins, ceftazidime, and cefepime and was susceptible to cefotaxime and ceftriaxone, according to the guidelines of the NCCLS. No synergy was found between expanded-spectrum cephalosporins and clavulanic acid, according to the double-disk synergy test. The bla(AmpC) gene of the strain was amplified by PCR and cloned into Escherichia coli DH10B, giving rise to high-level resistance to ceftazidime, cefepime, and cefpirome. Sequencing analysis revealed that the bla(AmpC) gene from S. marcescens HD had a 12-nucleotide deletion compared to the bla(AmpC) gene from reference strain S. marcescens S3, leading to a 4-amino-acid deletion located in the H-10 helix of the beta-lactamase. Kinetic analysis showed that this enzyme significantly hydrolyzed ceftazidime, cefepime, and cefpirome. This work underlined that resistance to the latest expanded-spectrum cephalosporins may be mediated by structurally modified AmpC-type beta-lactamases.