Molecular characterization of a cephamycin-hydrolyzing and inhibitor-resistant class A β-lactamase, GES-4, possessing a single G170S substitution in the ω-loop

Jun Ichi Wachino, Yohei Doi, Kunikazu Yamane, Naohiro Shibata, Tetsuya Yagi, Takako Kubota, Yoshichika Arakawa

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

The nosocomial spread of six genetically related Klebsiella pneumoniae strains producing GES-type β-lactamases was found in a neonatal intensive care unit, and we previously reported that one of the six strains, strain KG525, produced a new β-lactamase, GES-3. In the present study, the molecular mechanism of cephamycin resistance observed in strain KG502, one of the six strains described above, was investigated. This strain was found to produce a variant of GES-3, namely, GES-4, which was responsible for resistance to both cephamycins (cefoxitin MIC, >128 μg/ml) and β-lactamase inhibitors (50% inhibitory concentration of clavulanic acid, 15.2 ± 1.7 μM). The GES-4 enzyme had a single G170S substitution in the Ω-loop region compared with the GES-3 sequence. This single amino acid substitution was closely involved with the augmented hydrolysis of cephamycins and carbapenems and the decreased affinities of β-lactamase inhibitors to GES-4. A cloning experiment and sequencing analysis revealed that strain KG502 possesses duplicate blaGES-4 genes mediated by two distinct class 1 integrons with similar gene cassette configurations. Moreover, the genetic environments of the blaGES-4 genes found in strain KG502 were almost identical to that of blaGES-3 in strain KG525. From these findings, these two phenotypically different strains were suggested to belong to a clonal lineage. The blaGES-4 gene found in strain KG502 might well emerge from a point mutation in the blaGES-3 gene harbored by its ancestor strains, such as strain KG525, under heavy antibiotic stress in order to acquire extended properties of resistance to cephamycins and carbapenems.

Original languageEnglish
Pages (from-to)2905-2910
Number of pages6
JournalAntimicrobial Agents and Chemotherapy
Volume48
Issue number8
DOIs
Publication statusPublished - 01-08-2004
Externally publishedYes

Fingerprint

Cephamycins
Carbapenems
Genes
Integrons
Cefoxitin
Clavulanic Acid
Neonatal Intensive Care Units
Klebsiella pneumoniae
Amino Acid Substitution
Point Mutation
Inhibitory Concentration 50
Organism Cloning
Hydrolysis
Anti-Bacterial Agents
Enzymes

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Pharmacology (medical)
  • Infectious Diseases

Cite this

Wachino, Jun Ichi ; Doi, Yohei ; Yamane, Kunikazu ; Shibata, Naohiro ; Yagi, Tetsuya ; Kubota, Takako ; Arakawa, Yoshichika. / Molecular characterization of a cephamycin-hydrolyzing and inhibitor-resistant class A β-lactamase, GES-4, possessing a single G170S substitution in the ω-loop. In: Antimicrobial Agents and Chemotherapy. 2004 ; Vol. 48, No. 8. pp. 2905-2910.
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abstract = "The nosocomial spread of six genetically related Klebsiella pneumoniae strains producing GES-type β-lactamases was found in a neonatal intensive care unit, and we previously reported that one of the six strains, strain KG525, produced a new β-lactamase, GES-3. In the present study, the molecular mechanism of cephamycin resistance observed in strain KG502, one of the six strains described above, was investigated. This strain was found to produce a variant of GES-3, namely, GES-4, which was responsible for resistance to both cephamycins (cefoxitin MIC, >128 μg/ml) and β-lactamase inhibitors (50{\%} inhibitory concentration of clavulanic acid, 15.2 ± 1.7 μM). The GES-4 enzyme had a single G170S substitution in the Ω-loop region compared with the GES-3 sequence. This single amino acid substitution was closely involved with the augmented hydrolysis of cephamycins and carbapenems and the decreased affinities of β-lactamase inhibitors to GES-4. A cloning experiment and sequencing analysis revealed that strain KG502 possesses duplicate blaGES-4 genes mediated by two distinct class 1 integrons with similar gene cassette configurations. Moreover, the genetic environments of the blaGES-4 genes found in strain KG502 were almost identical to that of blaGES-3 in strain KG525. From these findings, these two phenotypically different strains were suggested to belong to a clonal lineage. The blaGES-4 gene found in strain KG502 might well emerge from a point mutation in the blaGES-3 gene harbored by its ancestor strains, such as strain KG525, under heavy antibiotic stress in order to acquire extended properties of resistance to cephamycins and carbapenems.",
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Molecular characterization of a cephamycin-hydrolyzing and inhibitor-resistant class A β-lactamase, GES-4, possessing a single G170S substitution in the ω-loop. / Wachino, Jun Ichi; Doi, Yohei; Yamane, Kunikazu; Shibata, Naohiro; Yagi, Tetsuya; Kubota, Takako; Arakawa, Yoshichika.

In: Antimicrobial Agents and Chemotherapy, Vol. 48, No. 8, 01.08.2004, p. 2905-2910.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Molecular characterization of a cephamycin-hydrolyzing and inhibitor-resistant class A β-lactamase, GES-4, possessing a single G170S substitution in the ω-loop

AU - Wachino, Jun Ichi

AU - Doi, Yohei

AU - Yamane, Kunikazu

AU - Shibata, Naohiro

AU - Yagi, Tetsuya

AU - Kubota, Takako

AU - Arakawa, Yoshichika

PY - 2004/8/1

Y1 - 2004/8/1

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