title: Bovine salmonellosis in northeast of Iran: frequency, genetic fingerprinting and antimicrobial resistance patterns of Salmonella spp.
abstract: OBJECTIVE
  To evaluate serovar and antimicrobial resistance patterns of Salmonella spp isolated from healthy, diseased and necropsied cows and calves in this observational study.
  
  
  METHODS
  Nineteen isolates recovered from feces and tissues of salmonellosis-affected animals of two commercial farms in north-east of Iran. In second part of the study, the two farms were sampled 4 times with an interval of 2 month. The samples included calves' feces, adult cows' feces, feeds, water, milk filters, and milk fed to calves. Five Salmonella were isolated from 332 fecal samples collected from calves and peri-parturient cows. No Salmonella was recovered from water, feed, milk filers and milk fed to calves.
  
  
  RESULTS
  Salmonella Typhimurium was the most frequently isolate among all sero-groups. S. Dublin was only accounted for 8% (two out of 24) of isolates. Isolated Salmonella strains were used for the ERIC PCR DNA fingerprinting assay. Our results grouped Salmonella isolates into 3 clusters, suggesting that specific genotypes were responsible for each sero-group of Salmonella. The results also revealed diversity among Salmonella isolates in cluster III (sero-group B). Eighteen out of 19 Salmonella spp. were resistant to oxytetracycline. Five isolates out of 19 showed more than one drug resistance. Multi-drug resistance was seen only among Salmonella Typhimurium isolates. Enrofloxacin was the most susceptible antibiotic against all isolates in this study.
  
  
  CONCLUSIONS
  The emergence of multiple antibiotic-resistant strains of Salmonella Typhimurium should be of great concern to the public. No correlation between ERIC fingerprinting and resistance patterns of Salmonella isolates was found, which indicates resistance to antimicrobial agents was not related to specific genetic background.
authors.affiliation: Center of Excellence in Ruminant Abortion and Neonatal Mortality and Department of Clinical Sciences, School of Veterinary Medicine, Ferdowsi Unversity of Mashhad, Mashhad, Iran.
authors.forename: Hessam A
authors.initials: HA
authors.lastname: Halimi
authors.forename: Hesam A
authors.initials: HA
authors.lastname: Seifi
authors.forename: Mehrnaz
authors.initials: M
authors.lastname: Rad
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle; D016172:DNA Fingerprinting; D024881:Drug Resistance, Bacterial; D005243:Feces / Q000382:microbiology; D007492:Iran / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D008892:Milk / Q000382:microbiology; D010802:Phylogeny; D012475:Salmonella / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D012481:Salmonella Infections, Animal / Q000453:epidemiology* / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antibiotic resistance; Dairy cattle; ERIC PCR; Salmonella Typhimurium