Dataset Information

CARB-17 family of ?-lactamases mediates intrinsic resistance to penicillins in Vibrio parahaemolyticus.

ABSTRACT: Vibrio parahaemolyticus is commonly resistant to ampicillin, yet the mechanisms underlying this phenomenon are not clear. In this study, a novel class A carbenicillin-hydrolyzing ?-lactamase (CARB) family of ?-lactamases, bla(CARB-17), was identified and found to be responsible for the intrinsic penicillin resistance in V. parahaemolyticus. Importantly, bla(CARB-17)-like genes were present in all 293 V. parahaemolyticus genome sequences available in GenBank and detectable in all 91 V. parahaemolyticus food isolates, further confirming the intrinsic nature of this gene.

SUBMITTER: Chiou J

PROVIDER: S-EPMC4432138 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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CARB-17 family of β-lactamases mediates intrinsic resistance to penicillins in Vibrio parahaemolyticus.

Chiou Jiachi J Li Ruichao R Chen Sheng S

Antimicrobial agents and chemotherapy 20150323 6

Vibrio parahaemolyticus is commonly resistant to ampicillin, yet the mechanisms underlying this phenomenon are not clear. In this study, a novel class A carbenicillin-hydrolyzing β-lactamase (CARB) family of β-lactamases, bla(CARB-17), was identified and found to be responsible for the intrinsic penicillin resistance in V. parahaemolyticus. Importantly, bla(CARB-17)-like genes were present in all 293 V. parahaemolyticus genome sequences available in GenBank and detectable in all 91 V. parahaemol ...[more]

PMID: 25801555

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Project description:In an effort to identify the regulatory gene controlling the expression of the tdh gene, encoding the thermostable direct hemolysin of Vibrio parahaemolyticus, we examined total DNA of AQ3815 (a Kanagawa phenomenon-positive strain) for sequences homologous to that of the toxR gene of Vibrio cholerae. The extracted DNA gave a weak hybridization signal under reduced-stringency conditions with a toxR-specific DNA probe. Cloning and sequence analysis of the probe-positive sequence revealed an operon (Vp-toxRS) which was highly similar to the toxRS operon of V. cholerae (Vc-toxRS) (52 and 62% similarities in the two genes, respectively). The deduced amino acid sequences of the Vp-toxRS gene products (Vp-ToxRS) contained regions similar to the proposed transmembrane and activity domains of the Vc-toxRS gene products (Vc-ToxRS). All clinical and environmental strains of V. parahaemolyticus examined possessed the Vp-toxRS genes. In the presence of Vp-ToxS, Vp-ToxR promoted expression of the tdh2 gene, one of two tdh genes (tdh1 and tdh2) carried by Kanagawa phenomenon-positive strains. The DNA sequence located 144 bp upstream of the tdh2 coding region was shown to be important for the Vp-ToxR-stimulated expression of the tdh2 gene in an Escherichia coli background. Comparative analysis of AQ3815 and its isogenic Vp-toxR null mutant gave the following results: (i) Vp-ToxR promoted, in an AQ3815 background, expression of the tdh gene to different degrees in various culture media, with KP broth (2% peptone, 0.5% NaCl, 0.03 M KH2PO4, pH 6.2) being most effective (12-fold); (ii) the promotion of tdh gene expression in KP broth was at the level of transcription; and (iii) Vp-ToxR was essential for demonstration of enterotoxic activity of AQ3815 in the rabbit ileal loop, a model previously used to demonstrate thermostable direct hemolysin-mediated enterotoxic activity of AQ3815. These results demonstrate that Vp-ToxR and Vc-ToxR share a strikingly similar function, i.e., direct stimulation at the transcriptional level of the gene encoding a major virulence determinant (enterotoxin) of a Vibrio species.

Dataset Information

CARB-17 family of ?-lactamases mediates intrinsic resistance to penicillins in Vibrio parahaemolyticus.

Publications

CARB-17 family of β-lactamases mediates intrinsic resistance to penicillins in Vibrio parahaemolyticus.

Similar Datasets

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