title: Plasmid profile and drug resistance pattern of zoonotic Salmonella isolates from Indian buffaloes.
abstract: BACKGROUND
  Buffalo is the major source of animal protein in south-east Asia, including India; therefore, the presence of multiple drug resistance in Salmonella strains of buffalo meat and milk products is of immense public health concern.
  
  
  METHODS
  Forty-six strains of Salmonella enterica subspecies enterica belonging to eight serovars (S. Anatum, 13; S. Weltevreden, 13; S. Rostock, 6; S. Typhimurium, 5; S. Gallinarum, 5; S. Stockholm, 1; S. Dublin, 1; and S. Orion, 2), isolated from buffalo meat and diseased buffaloes were studied for their antibiotic sensitivity and plasmid profile.
  
  
  RESULTS
  All except six strains of Salmonella had one or more plasmids. Virulence plasmid of ~35MdA was present in 39 isolates while 19 strains had one to six additional plasmids with molecular weight ranging from 1 Mda > 35 Mda. A plasmid-free S. Anatum strain was resistant to seven drugs including fluoroquinolones, while strains having six to seven plasmids were resistant to fewer antimicrobial drugs. One S. Anatum isolate, resistant to 11 antibiotics, had only one plasmid. Eight serovars of Salmonella could be divided into 28 resistotypes on the basis of antimicrobial sensitivity assay. Most strains were resistant to streptomycin (84.8%) followed by kanamycin (58.7%), gentamicin (52.2%), ampicillin (50%) and oxytetracycline (50%). Few strains were resistant to cefotaxime (2.2%), amoxycillin (2.2%) and newer fluoroquinolones (6.5%).
  
  
  CONCLUSIONS
  Multiple drug resistance was common among Salmonella isolates of buffalo origin, particularly against aminoglycosides, oxytetracycin, ampicillin and cephalexin. Presence of plasmids is not mandatory for occurrence of multiple drug resistance in S. enterica strains.
authors.affiliation: National Salmonella Centre, Division of Bacteriology and Mycology, Indian Veterinary Research Institute, Izatnagar, India. brs1762@yahoo.co.in
authors.forename: Bhoj Raj
authors.initials: BR
authors.lastname: Singh
authors.forename: Meenu
authors.initials: M
authors.lastname: Agarwal
authors.forename: Mudit
authors.initials: M
authors.lastname: Chandra
authors.forename: Meena
authors.initials: M
authors.lastname: Verma
authors.forename: Gautam
authors.initials: G
authors.lastname: Sharma
authors.forename: Jagdish Chandra
authors.initials: JC
authors.lastname: Verma
authors.forename: Vijay Pratap
authors.initials: VP
authors.lastname: Singh
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002020:Buffaloes / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial; D007194:India; D008460:Meat / Q000382:microbiology*; D010957:Plasmids / Q000032:analysis*; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D019779:Salmonella enterica / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents