Topic
Cephamycin
About: Cephamycin is a research topic. Over the lifetime, 220 publications have been published within this topic receiving 5375 citations. The topic is also known as: cephamycin.
Papers published on a yearly basis
Papers
TL;DR: In E. coli, antibiotic resistance predicts phylogenetic background and virulence potential in a complex, context-dependent fashion and only among human isolate did resistance predict reduced virulence.
Abstract: In Escherichia coli infection, the implications of fluoroquinolone (FQ) and extended-spectrum cephalosporin plus cephamycin (AmpC) resistance for phylogenetic origin and virulence potential are undefined, as is the influence of ecological context on these associations. Accordingly, 106 E. coli isolates exhibiting FQ and/or AmpC resistance and 98 susceptible isolates were compared with regard to phylogenetic background and virulence profiles, stratified by host group (104 predominantly extraintestinal human isolates and 100 predominantly intestinal cattle and swine isolates). Although resistant isolates exhibited significant shifts in phylogenetic distribution and virulence profiles, human and animal isolates exhibited different phylogenetic shifts, and only among human isolates did resistance predict reduced virulence. Evidence for similar strains being resistant versus susceptible was scant. The O15:K52:H1 clonal group and the closely related "clonal group A" featured prominently among resistant and susceptible human isolates, respectively. Thus, in E. coli, antibiotic resistance predicts phylogenetic background and virulence potential in a complex, context-dependent fashion.
260 citations
TL;DR: The phenotype of Klebsiella pneumoniae HEL-1 indicates a plasmidic cephamycinase gene (blaCMY-2), which is classified as class C beta-lactamase that is closely related to the plasidic enzymes BIL-1 and LAT-2 and the chromosomal AmpC of Citrobacter freundii.
Abstract: The phenotype of Klebsiella pneumoniae HEL-1 indicates a plasmidic cephamycinase gene (blaCMY-2). Its sequence shows one open reading frame coding for a protein of 381 amino acids. CMY-2 is classified as class C beta-lactamase that is closely related to the plasmidic enzymes BIL-1 and LAT-1 and the chromosomal AmpC of Citrobacter freundii. The blaCMY-2 gene possibly was translocated onto a plasmid of C. freundii which spread to K. pneumoniae.
197 citations
TL;DR: A regulatory gene (ccaR), located within the cephamycin gene cluster of Streptomyces clavuligerus, is linked to a gene (blp) encoding a protein similar to a beta-lactamase-inhibitory protein, which resembles the ActII-ORF4, RedD, AfsR, and DnrI regulatory proteins of other Streptomers species, all of which share several motifs.
Abstract: A regulatory gene (ccaR), located within the cephamycin gene cluster of Streptomyces clavuligerus, is linked to a gene (blp) encoding a protein similar to a beta-lactamase-inhibitory protein. Expression of ccaR is required for cephamycin and clavulanic acid biosynthesis in S. clavuligerus. The ccaR-encoded protein resembles the ActII-ORF4, RedD, AfsR, and DnrI regulatory proteins of other Streptomyces species, all of which share several motifs. Disruption of ccaR by targeted double recombination resulted in the loss of the ability to synthesize cephamycin and clavulanic acid. Complementation of the disrupted mutant with ccaR restored production of both secondary metabolites. ccaR was expressed as a monocistronic transcript at 24 and 48 h in S. clavuligerus cultures (preceding the phase of antibiotic accumulation), but no transcript hybridization signals were observed at 72 or 96 h. This expression pattern is consistent with those of regulatory proteins required for antibiotic biosynthesis. Amplification of ccaR in S. clavuligerus resulted in a two- to threefold increase in the production of cephamycin and clavulanic acid.
170 citations
TL;DR: A 29.3 kb DNA segment from Streptomyces cattleya NRRL8057 was cloned that directed cephamycin C production in a heterologous host, StrePTomyces lividans 1326.
Abstract: Cephamycin C, a member of the 7-methoxycephalosporin family of β-lactam antibiotics, is widely produced among actinomycetes. A 29.3 kb DNA segment from Streptomyces cattleya NRRL8057 was cloned that directed cephamycin C production in a heterologous host, Streptomyces lividans 1326. Introduction of the gene cluster into another cephamycin C-producing Streptomyces increased the production of cephamycin C.
128 citations
TL;DR: The cosmid cloning vector pHC79 has been used to clone fragments of chromosomal DNA from the Streptomyces: S. clavuligerus, S. jumonjinensis and S. katsurahamanus as mentioned in this paper.
Abstract: The cosmid cloning vector pHC79 has been used to clone fragments of chromosomal DNA from the Streptomyces: S. clavuligerus, S. jumonjinensis and S. katsurahamanus. These strains all produce both the β-lactam antibiotic, cephamycin and the β-lactamase inhibitor, clavulanic acid. Although structurally related these two β-lactams are known to be derived from different biosynthetic precursors. Hybridisation studies and restriction mapping have shown that the gene clusters encoding the two biosynthetic pathways are chromosomally adjacent in these strains, thus creating a ‘super-cluster’ of genes involved in both the production and enhancement of activity of a β-lactam antibiotic.
117 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 3 |
| 2019 | 5 |
| 2018 | 1 |
| 2016 | 1 |
| 2015 | 2 |
| 2014 | 3 |