JAC Advance Access originally published online on July 6, 2007
Journal of Antimicrobial Chemotherapy 2007 60(3):645-648; doi:10.1093/jac/dkm249
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Emergence of multidrug-resistant clones of Salmonella Infantis in broiler chickens and humans in Hungary
1 Department of Phage-typing and Molecular Epidemiology, National Center for Epidemiology, Gyáli u. 2-6, H-1097 Budapest, Hungary 2 Department of Bacteriology, National Center for Epidemiology, Gyáli u. 2-6, H-1097 Budapest, Hungary 3 Microbiology Department, National Food Investigation Institute, Mester u. 81, H-1095 Budapest, Hungary 4 Veterinary Medical Research Institute of the Hungarian Academy of Sciences, Hungária krt. 21, H-1143 Budapest, Hungary
Received 9 February 2007; returned 5 April 2007; revised 8 June 2007; accepted 11 June 2007
* Corresponding author. E-mail: nogradyn{at}oek.antsz.hu
Objectives: The characterization of a Salmonella Infantis strain collection that was set up from isolates of animal and human origin obtained in Hungary in recent years.
Methods: All isolates were phage typed. Antimicrobial resistance was tested by the disc diffusion method, while the presence of the antimicrobial resistance genes and class 1 integrons was investigated by PCR. Genetic relatedness of the isolates was tested by PFGE and plasmid profiling.
Results: The majority of the isolates representing different parts of Hungary are characterized by phage types 213 and 217 and the nalidixic acid–streptomycin–sulphonamide–tetracycline resistance type. They harbour a class 1 integron with an aadA1 gene in the 855 bp variable region, a tet(A) gene, a >168 kb plasmid and 66% of them represent one genetic clone as determined by XbaI PFGE fingerprinting.
Conclusions: It seems that broiler chickens constitute a reservoir for one large and a few smaller multidrug-resistant Salmonella Infantis clones in Hungary, which might have spread to humans through chicken meat.
Keywords: multidrug resistance , class 1 integron , plasmid