RESUMO
A colistin-resistant Escherichia coli isolate from a commercial poultry farm in China carried two colistin resistance genes, mcr-1 and variant of mcr-3, in an IncP plasmid. The variant of the mcr-3 gene, named mcr-3.11, encoded two amino acid substitutions compared with the mcr-3 gene. A novel genetic structure, ISKpn40-mcr-3-dgkA-ISKpn40, might be the key element mediating the translocation of mcr-3 through the formation of a circular form. The mcr-1 and mcr-3 genes, which are colocated on a plasmid, might pose a huge threat to public health.
Assuntos
Colistina/farmacologia , Proteínas de Escherichia coli/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Plasmídeos/genética , Polimixinas/farmacologia , Animais , Antibacterianos , Galinhas , Farmacorresistência Bacteriana , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Fazendas , Testes de Sensibilidade Microbiana , Transferases (Outros Grupos de Fosfato Substituídos)/genética , Transferases (Outros Grupos de Fosfato Substituídos)/metabolismoRESUMO
The novel 63,558-bp plasmid pSA-01, which harbors nine antibiotic resistance genes, including cfr, erm(C), tet(L), erm(T), aadD, fosD, fexB, aacA-aphD, and erm(B), was characterized in Staphylococcus arlettae strain SA-01, isolated from a chicken farm in China. The colocation of cfr and fosD genes was detected for the first time in an S. arlettae plasmid. The detection of two IS431-mediated circular forms containing resistance genes in SA-01 suggested that IS431 may facilitate dissemination of antibiotic resistance genes.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana Múltipla/genética , Fosfomicina/farmacologia , Plasmídeos/química , Infecções Estafilocócicas/veterinária , Staphylococcus/genética , Animais , Proteínas de Bactérias/metabolismo , Galinhas , China/epidemiologia , Fazendas , Sequenciamento de Nucleotídeos em Larga Escala , Testes de Sensibilidade Microbiana , Plasmídeos/metabolismo , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/microbiologia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus/efeitos dos fármacos , Staphylococcus/isolamento & purificação , Staphylococcus/metabolismoRESUMO
Recently, a novel variant of the CTX-M enzyme, CTX-M-98, was detected in Escherichia coli isolates from food animals. However, few plasmids carrying blaCTX-M-98 have been fully characterized. In this study, we sequenced the complete pHeBE7 plasmid, an 86,015-bp plasmid that contains the blaCTX-M-98b, blaTEM-1, rmtB, and traT genes, using whole-genome sequencing. The backbone of pHeBE7 shows a high similarity (>99%) to pMC-NDM, which carries the blaNDM-1 gene, however its mosaic regions remain relatively unique among sequenced plasmids. We discovered that a typical ISEcp1-blaCTX-M-IS903 element in the mosaic region harbors the blaCTX-M-98b gene. Conjugation and growth competition assays indicate that pHeBE7 can be easily transmitted and that it confers a limited fitness cost to the recipient cell. The genetic characterization of pHeBE7 may improve our knowledge of how antibiotic resistance disseminates in enterobacteria.
Assuntos
Escherichia coli/genética , Plasmídeos/genética , Animais , Antibacterianos/farmacologia , Galinhas/microbiologia , Conjugação Genética , Escherichia coli/isolamento & purificação , Genes Bacterianos , Fígado/microbiologia , Testes de Sensibilidade Microbiana , Doenças das Aves Domésticas/microbiologia , Virulência/genética , Resistência beta-Lactâmica/genética , beta-Lactamases/genética , beta-Lactamas/farmacologiaRESUMO
The mcr-1 gene was detected in 5.11% (58/1136) of Escherichia coli isolates of chicken origin from 13 provinces in China. A novel mcr-1 variant, named mcr-1.3, encoding an Ile-to-Val functional variant of MCR-1 was identified in a sequence type 155 (ST155) strain. An mcr-1.3-containing IncI2 plasmid, pHeN867 (60,757 bp), was identified. The transfer of pHeN867 led to a 32-fold increase in the MIC of colistin in the recipient, exhibiting an effect on colistin resistance that was similar to that of mcr-1.
