title: [Molecular characterization of resistance mechanisms to chloramphenicol in Shigella flexneri strains isolated from Chilean children with acute diarrhea].
abstract: BACKGROUND
  Chloramphenicol is one of the therapeutic options for shigellosis, but resistance to this antimicrobial is increasing.
  
  
  OBJECTIVE
  To characterize molecular mechanisms conferring resistance to chloramphenicol (Cm) in Shigella flexneri strains isolated from Chilean children with acute diarrhea.
  
  
  METHODS
  Thirty one Shigella filexneri strains, including 22 with the Cm phenotype were analyzed. Strains were tested for antimicrobial susceptibility by plate dilution and for the presence of an internal fragment of the cat gene encoding for chloramphenicol o-acetyl-transferase, by polymerase chain reaction and Southern blot analysis.
  
  
  RESULTS
  All Cm strains had a minimal inhibitory concentration over 64 micrograms/ml and amplified the internal fragment of the cat gene. Southern blot analyses indicated that this gene was located in the bacterial chromosome.
  
  
  CONCLUSIONS
  Resistance to chloramphenicol in this group of Shigella flexneri strains was mediated by a chromosomally located cat gene.
authors.affiliation: Programa de Microbiología, ICBM, Facultad de Medicina, Universidad de Chile, Unidad de Microbiología, Departamento Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Farfán
authors.forename: Oscar
authors.initials: O
authors.lastname: Flores
authors.forename: Niurka
authors.initials: N
authors.lastname: Navarro
authors.forename: Valeria
authors.initials: V
authors.lastname: Prado
authors.forename: Guido
authors.initials: G
authors.lastname: Mora
authors.forename: Cecilia
authors.initials: C
authors.lastname: Toro
mesh_terms: D000208:Acute Disease; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015139:Blotting, Southern; D002648:Child; D002701:Chloramphenicol / Q000494:pharmacology*; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D002702:Chloramphenicol Resistance / Q000235:genetics*; D002876:Chromosomes, Bacterial / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D012763:Shigella flexneri / Q000187:drug effects* / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D002701:Chloramphenicol; D015500:Chloramphenicol O-Acetyltransferase
vernacular_title: Caracterización molecular de mecanismos de resistencia a cloranfenicol en cepas de Shigella flexneri aisladas en niños chilenos con diarrea aguda.