title: Evolution of chloramphenicol resistance, with emergence of cross-resistance to florfenicol, in bovine Salmonella Typhimurium strains implicates definitive phage type (DT) 104.
abstract: The prevalence of resistance to florfenicol, a phenicol drug newly introduced in veterinary therapy, was determined in 86 chloramphenicol-resistant Salmonella Typhimurium isolates from cattle collected during 1985-1995. All were highly resistant to chloramphenicol (MICs > or = 128 mg/L) and 38 were simultaneously resistant to florfenicol (MICs >16 mg/L) and to beta-lactam agents, spectinomycin, streptomycin, sulphonamides and tetracyclines. The isolates susceptible to florfenicol harboured the chloramphenicol acetyl transferase gene, cat of type I. All the florfenicol-resistant isolates harboured the floR resistance gene and the characteristic multiple resistance genetic locus, previously characterised in a S. Typhimurium DT104 strain and identified by a multiplex PCR. Plasmid profiles and ribotype patterns were determined for all the isolates. The florfenicol-resistant isolates were grouped into the same ribotyping pattern and presented similar plasmid profiles, whereas the florfenicol-susceptible isolates showed a wider genetic diversity that is usual for S. Typhimurium. Thus, the florfenicol-resistant isolates could represent a clonal cluster, closely related to, if not of DT104 phage type, which appeared in 1989 and is now predominant within chloramphenicol-resistant S. Typhimurium. The multiplex PCR provided a useful tool to survey further evolution of multiresistant S. Typhimurium strains.
authors.affiliation: *Station de Pathologie Aviaire et Parasitologie, Institut National de la Recherche Agronomique, Centre de Tours-Nouzilly, 37380 Monnaie and †Centre National d'Etudes Vétérinaires et Alimentaires, 31 avenue Tony Garnier, 69007 Lyon, France.
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Arcangioli
authors.affiliation: *Station de Pathologie Aviaire et Parasitologie, Institut National de la Recherche Agronomique, Centre de Tours-Nouzilly, 37380 Monnaie and †Centre National d'Etudes Vétérinaires et Alimentaires, 31 avenue Tony Garnier, 69007 Lyon, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Leroy-Setrin
authors.affiliation: *Station de Pathologie Aviaire et Parasitologie, Institut National de la Recherche Agronomique, Centre de Tours-Nouzilly, 37380 Monnaie and †Centre National d'Etudes Vétérinaires et Alimentaires, 31 avenue Tony Garnier, 69007 Lyon, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Martel
authors.affiliation: *Station de Pathologie Aviaire et Parasitologie, Institut National de la Recherche Agronomique, Centre de Tours-Nouzilly, 37380 Monnaie and †Centre National d'Etudes Vétérinaires et Alimentaires, 31 avenue Tony Garnier, 69007 Lyon, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Chaslus-Dancla
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001434:Bacteriophage Typing / Q000662:veterinary; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology; D002702:Chloramphenicol Resistance / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D004352:Drug Resistance, Microbial / Q000235:genetics; D018432:Drug Resistance, Multiple / Q000235:genetics; D007769:Lactams; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D011815:R Factors; D012189:Retrospective Studies; D012481:Salmonella Infections, Animal / Q000382:microbiology; D012486:Salmonella typhimurium / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D000198:Spectinomycin / Q000494:pharmacology; D013307:Streptomycin / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D013754:Tetracyclines; D013839:Thiamphenicol / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D007769:Lactams; D013449:Sulfonamides; D013754:Tetracyclines; D000198:Spectinomycin; C035534:florfenicol; D013839:Thiamphenicol; D013307:Streptomycin