Article: Cloning and characterization of a chromosomal class C β-lactamase and its regulatory gene in Laribacter hongkongensis

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TitleCloning and characterization of a chromosomal class C β-lactamase and its regulatory gene in Laribacter hongkongensis
AuthorsLau, SKP1
Ho, PL1
Li, MWS1
Tsoi, HW1
Yung, RWH2
Woo, PCY1
Yuen, KY1
Issue Date2005
PublisherAmerican Society for Microbiology.
CitationAntimicrobial Agents And Chemotherapy, 2005, v. 49 n. 5, p. 1957-1964 [How to Cite?]
DOI: http://dx.doi.org/10.1128/AAC.49.5.1957-1964.2005
AbstractLaribacter hongkongensis, a newly discovered bacterium recently shown to be associated with community-acquired gastroenteritis, is generally resistant to most β-lactams except the carbapenems. We describe the cloning and characterization of a novel chromosomal class C β-lactamase and its regulatory gene in L. hongkongensis. Two genes, ampC and ampR, were cloned by inserting restriction fragments of genomic DNA from L. hongkongensis strain HLHK5 into pBK-CMV to give the recombinant plasmid pBK-LHK-5. The ampR and ampC genes and their promoters were divergently oriented, with the ampR gene immediately upstream of the ampC gene and an intercistronic Lys-R motif, typical of inducible ampC-ampR regulatory systems. The deduced amino acid sequence of the cloned AmpC β-lactamase (pi 8.1) contained consensus motifs characteristic of class C β-lactamases but had identities no greater than 46% to known class C β-lactamases. The kinetic properties of this AmpC were also compatible with those of a class C β-lactamase. PCR of 20 clinical isolates of L. hongkongensis, including HLHK5, showed the presence of both ampC and ampR genes in all isolates. Southern hybridization suggested that the ampC gene of HLHKS was chromosomally encoded. Subcloning experiments showed that the expression of the ampC gene of HLHK5 was regulated by its ampR gene, which acts as a repressor. The β-lactamase characterized from strain HLHK5 was named LHK-5 (gene, blaLHK-5) and represents the first example of AmpC β-lactamase in the β subdivision of proteobacteria. Copyright © 2005, American Society for Microbiology. All Rights Reserved.
ISSN0066-4804
2011 Impact Factor: 4.841
2011 SCImago Journal Rankings: 0.486
DOIhttp://dx.doi.org/10.1128/AAC.49.5.1957-1964.2005
PubMed Central IDPMC1087626
ReferencesReferences in Scopus
DC Field
Value
dc.contributor.authorLau, SKP
dc.contributor.authorHo, PL
dc.contributor.authorLi, MWS
dc.contributor.authorTsoi, HW
dc.contributor.authorYung, RWH
dc.contributor.authorWoo, PCY
dc.contributor.authorYuen, KY
dc.date.accessioned2010-09-06T07:52:25Z
dc.date.available2010-09-06T07:52:25Z
dc.date.issued2005
dc.description.abstractLaribacter hongkongensis, a newly discovered bacterium recently shown to be associated with community-acquired gastroenteritis, is generally resistant to most β-lactams except the carbapenems. We describe the cloning and characterization of a novel chromosomal class C β-lactamase and its regulatory gene in L. hongkongensis. Two genes, ampC and ampR, were cloned by inserting restriction fragments of genomic DNA from L. hongkongensis strain HLHK5 into pBK-CMV to give the recombinant plasmid pBK-LHK-5. The ampR and ampC genes and their promoters were divergently oriented, with the ampR gene immediately upstream of the ampC gene and an intercistronic Lys-R motif, typical of inducible ampC-ampR regulatory systems. The deduced amino acid sequence of the cloned AmpC β-lactamase (pi 8.1) contained consensus motifs characteristic of class C β-lactamases but had identities no greater than 46% to known class C β-lactamases. The kinetic properties of this AmpC were also compatible with those of a class C β-lactamase. PCR of 20 clinical isolates of L. hongkongensis, including HLHK5, showed the presence of both ampC and ampR genes in all isolates. Southern hybridization suggested that the ampC gene of HLHKS was chromosomally encoded. Subcloning experiments showed that the expression of the ampC gene of HLHK5 was regulated by its ampR gene, which acts as a repressor. The β-lactamase characterized from strain HLHK5 was named LHK-5 (gene, blaLHK-5) and represents the first example of AmpC β-lactamase in the β subdivision of proteobacteria. Copyright © 2005, American Society for Microbiology. All Rights Reserved.
dc.description.naturelink_to_OA_fulltext
dc.identifier.citationAntimicrobial Agents And Chemotherapy, 2005, v. 49 n. 5, p. 1957-1964 [How to Cite?]
DOI: http://dx.doi.org/10.1128/AAC.49.5.1957-1964.2005
dc.identifier.doihttp://dx.doi.org/10.1128/AAC.49.5.1957-1964.2005
dc.identifier.epage1964
dc.identifier.hkuros114670
dc.identifier.isiWOS:000228982600040
dc.identifier.issn0066-4804
2011 Impact Factor: 4.841
2011 SCImago Journal Rankings: 0.486
dc.identifier.issue5
dc.identifier.openurl
dc.identifier.pmcidPMC1087626
dc.identifier.pmid15855519
dc.identifier.scopuseid_2-s2.0-18244391437
dc.identifier.spage1957
dc.identifier.urihttp://hdl.handle.net/10722/79251
dc.identifier.volume49
dc.languageeng
dc.publisherAmerican Society for Microbiology.
dc.publisher.placeUnited States
dc.relation.ispartofAntimicrobial Agents and Chemotherapy
dc.relation.referencesReferences in Scopus
dc.rightsAntimicrobial Agents and Chemotherapy. Copyright © American Society for Microbiology.
dc.subject.meshProteobacteria - enzymology - genetics
dc.subject.meshBeta-Lactamases - chemistry - genetics
dc.subject.meshAmino Acid Sequence
dc.subject.meshDNA, Bacterial - genetics
dc.subject.meshDrug Resistance, Bacterial
dc.titleCloning and characterization of a chromosomal class C β-lactamase and its regulatory gene in Laribacter hongkongensis
dc.typeArticle
Author Affiliations
  1. The University of Hong Kong
  2. Pamela Youde Nethersole Eastern Hospital