title: Antimicrobial resistance in non-typhoidal Salmonella from human sources, Spain, 2001-2003.
abstract: OBJECTIVE
  To determine the current state of antimicrobial resistance among non-typhoidal Salmonella strains isolated from humans in Spain.
  
  
  METHODS
  All strains of Salmonella from human sources received in the reference laboratory from 2001 to 2003 were serotyped and phage types were determined in the most common serovars. A systematic sampling procedure was carried out in order to obtain a random sample for susceptibility testing. The selected strains were tested for susceptibility to 12 different antimicrobial agents by a disc diffusion method using Mueller-Hinton agar. Results were scored as susceptible, moderately susceptible or resistant, according to CLSI criteria.
  
  
  RESULTS
  From 2001 to 2003, 5777 strains of Salmonella were tested for susceptibility. Fifty per cent of strains of Salmonella Enteritidis were resistant to nalidixic acid. This was the most frequent resistance pattern of this serovar and it was characteristic of PT1, the most frequent phage type of Salmonella Enteritidis in Spain. Seventy-four per cent of Salmonella Typhimurium strains were resistant to four antibiotics or more. Resistance to ampicillin, chloramphenicol, streptomycin, sulphonamide and tetracycline was the most frequent resistance pattern of Salmonella Typhimurium and it was characteristic of DT104, the most frequent phage type in Spain. Sixty-nine per cent of Salmonella Hadar strains were resistant to at least four antibiotics.
  
  
  CONCLUSIONS
  The results of our study showed both a worrying percentage of strains of Salmonella Enteritidis resistant to nalidixic acid and of strains of Salmonella Typhimurium with a pattern of resistance to four antibiotics or more. Surveillance of antimicrobial resistance should carry on and improve in order to be able to evaluate the control measures carried out for decreasing resistance in Salmonella, specifically that addressed to the prudent use of antimicrobial agents by farmers and veterinarians.
authors.affiliation: Centro Nacional de Epidemiología, Instituto de Salud Carlos III Sinesio Delgado, 6, Madrid 28029, Spain. psoler@isciii.es
authors.forename: Pilar
authors.initials: P
authors.lastname: Soler
authors.forename: Rubén
authors.initials: R
authors.lastname: González-Sanz
authors.forename: María J
authors.initials: MJ
authors.lastname: Bleda
authors.forename: Gloria
authors.initials: G
authors.lastname: Hernández
authors.forename: Aurora
authors.initials: A
authors.lastname: Echeíta
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Usera
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001434:Bacteriophage Typing; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D012475:Salmonella / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification; D012480:Salmonella Infections / Q000382:microbiology*; D012703:Serotyping; D013030:Spain
chemical_list: D000900:Anti-Bacterial Agents