title: Lactococcus garvieae carries a chromosomally encoded pentapeptide repeat protein that confers reduced susceptibility to quinolones in Escherichia coli producing a cytotoxic effect.
abstract: This study characterises a chromosomal gene of Lactococcus garvieae encoding a pentapeptide repeat protein designated as LgaQnr. This gene has been implicated in reduced susceptibility to quinolones in this bacterium, which is of relevance to both veterinary and human medicine. All of the L. garvieae isolates analysed were positive for the lgaqnr gene. The expression of lgaqnr in Escherichia coli reduced the susceptibility to quinolones, producing an adverse effect. The reduced susceptibility to ciprofloxacin was 16-fold in E. coli ATCC 25922 and 32-fold in E. coli DH10B, compared to the control strains. The minimum inhibitory concentration of nalidixic acid was also increased 4 or 5-fold. The effect of the expression of lgaqnr in E. coli was investigated by electron microscopy and was observed to affect the structure of the cell and the inner membrane of the recombinant cells.
authors: Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain. Electronic address: gibelloa@ucm.es.
authors: Alicia
authors: A
authors: Gibello
authors: Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla, 41009 Sevilla, Spain. Electronic address: pauladiaz@us.es.
authors: Paula
authors: P
authors: Díaz de Alba
authors: Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain. Electronic address: mmblanco@ucm.es.
authors: M Mar
authors: MM
authors: Blanco
authors: Unidad de Enfermedades Infecciosas y Microbiología Clínica, Hospital Virgen de la Macarena, 41007 Sevilla, Spain. Electronic address: jesmacbar@hotmail.com.
authors: Jesus
authors: J
authors: Machuca
authors: Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain. Electronic address: mtcutuli@ucm.es.
authors: M Teresa
authors: MT
authors: Cutuli
authors: Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla, 41009 Sevilla, Spain. Electronic address: jmrodriguez@us.es.
authors: José Manuel
authors: JM
authors: Rodríguez-Martínez
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002462:Cell Membrane / Q000648:ultrastructure; D002939:Ciprofloxacin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000648:ultrastructure; D015870:Gene Expression; D017045:Lactococcus / Q000187:drug effects / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D009268:Nalidixic Acid / Q000494:pharmacology; D015363:Quinolones / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D015363:Quinolones; D011994:Recombinant Proteins; D009268:Nalidixic Acid; D002939:Ciprofloxacin
keywords: Lactococcus garvieae; Pentapeptide repeat proteins; Qnr; Quinolone resistance