title: Prevalence of R-type ACSSuT in strains of Salmonella serovar Typhimurium DT193 isolated from human infections in Brazil.
abstract: OBJECTIVE
  To determine the prevalence of resistance to ampicillin, chloramphenicol, streptomycin, sulphonamides, and tetracyclines (ACSSuT) in Salmonella serovar Typhimurium definitive [phage] type (DT) 193 strains isolated from human sources over the last four decades.
  
  
  METHODS
  From 2008 to 2010, 553 DT193 isolates out of 810 human-origin Salmonella ser. Typhimurium phage-typed strains isolated from the 1970s through 2008 were selected and tested for ACSSuT resistance: 91 strains isolated during the 1970s, 65 from the 1980s, 70 from the 1990s, and 327 from 2000-2008. Resistance profiles were determined using the disk diffusion method.
  
  
  RESULTS
  An antimicrobial susceptibility assay indicated 20.9%, or 116, of all isolates tested were ACSSuT-resistant, 52.0% (287) were resistant to one or more drugs in the ACSSuT profile, and 27.1% (150) were nonresistant (susceptible to antimicrobials). Based on the assay, overall antimicrobial resistance was extremely high in the 1970s (affecting 99.0% of isolates from that period) and remained high during the 1980s, when 95.4% of isolates had some type of antimicrobial resistance and incidence of Salmonella ser. Typhimurium DT193 R-type ACSSuT increased to 73.8%. R-type ACSSuT dropped to 27.1% (19 isolates) during the 1990s, and to 5.2% (17) during 2000-2008, despite a substantial increase in the number of isolates tested (397 versus 204, 111, and 98, respectively, for the previous three decades).
  
  
  CONCLUSIONS
  Although prevalence of Salmonella ser. Typhimurium DT193 R-type ACSSuT in Brazil has decreased since the 1970s, ACSSuT resistance markers continue to circulate. Therefore, continuous surveillance should be conducted to evaluate the occurrence of Salmonella ser. Typhimurium DT193 and its antimicrobial resistance.
authors.affiliation: Laboratório de Enterobactérias, Instituto Oswaldo Cruz, Rio de Janeiro, RJ, Brazil. emer@ioc.fiocruz.br
authors.forename: Eliane Moura Falavina
authors.initials: EM
authors.lastname: dos Reis
authors.forename: Dalia dos Prazeres
authors.initials: Ddos P
authors.lastname: Rodrigues
authors.forename: Angela Corrêa
authors.initials: AC
authors.lastname: de Freitas-Almeida
authors.forename: Ernesto
authors.initials: E
authors.lastname: Hofer
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001434:Bacteriophage Typing; D001938:Brazil / Q000453:epidemiology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D020387:Food Chain; D006801:Humans; D011815:R Factors / Q000235:genetics*; D012189:Retrospective Studies; D012480:Salmonella Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D012481:Salmonella Infections, Animal / Q000382:microbiology; D012486:Salmonella typhimurium / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D012703:Serotyping; D015047:Zoonoses
chemical_list: D000900:Anti-Bacterial Agents