title: Mechanisms of resistance to chloramphenicol in Pseudomonas putida KT2440.
abstract: Pseudomonas putida KT2440 is a chloramphenicol-resistant bacterium that is able to grow in the presence of this antibiotic at a concentration of up to 25 μg/ml. Transcriptomic analyses revealed that the expression profile of 102 genes changed in response to this concentration of chloramphenicol in the culture medium. The genes that showed altered expression include those involved in general metabolism, cellular stress response, gene regulation, efflux pump transporters, and protein biosynthesis. Analysis of a genome-wide collection of mutants showed that survival of a knockout mutant in the TtgABC resistance-nodulation-division (RND) efflux pump and mutants in the biosynthesis of pyrroloquinoline (PQQ) were compromised in the presence of chloramphenicol. The analysis also revealed that an ABC extrusion system (PP2669/PP2668/PP2667) and the AgmR regulator (PP2665) were needed for full resistance toward chloramphenicol. Transcriptional arrays revealed that AgmR controls the expression of the pqq genes and the operon encoding the ABC extrusion pump from the promoter upstream of open reading frame (ORF) PP2669.
authors.affiliation: Bio-Iliberis Research and Development, I+D Department, Peligros, Granada, Spain. mfernandez@bioiliberis.com
authors.forename: Matilde
authors.initials: M
authors.lastname: Fernández
authors.forename: Susana
authors.initials: S
authors.lastname: Conde
authors.forename: Jesús
authors.initials: J
authors.lastname: de la Torre
authors.forename: Carlos
authors.initials: C
authors.lastname: Molina-Santiago
authors.forename: Juan-Luis
authors.initials: JL
authors.lastname: Ramos
authors.forename: Estrella
authors.initials: E
authors.lastname: Duque
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002701:Chloramphenicol / Q000494:pharmacology*; D003470:Culture Media; D004251:DNA Transposable Elements; D024881:Drug Resistance, Bacterial; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D008826:Microbial Sensitivity Tests; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D016958:Pseudomonas putida / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D059467:Transcriptome
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003470:Culture Media; D004251:DNA Transposable Elements; D002701:Chloramphenicol