DETECTION OF MULTIDRUG-RESISTANT SALMONELLA TYPHIMURIUM DT104 IN POULTRY BY SELECTIVE ENRICHMENT AND CLOTH-BASED HYBRIDIZATION ARRAY SYSTEM.

A rapid method was devised for the selective enrichment and detection of multi-antibiotic-resistant Salmonella enterica subsp. enterica serotype Typhimurium (S. Typhimurium) DT104 in poultry. The target organism was pre-enriched in trypticase soy broth supplemented with chloramphenicol, followed by plating on modified semisolid Rappaport Vassiliadis medium and sampling a portion of the swarming growth. The presence of S. Typhimurium DT104 was determined by testing the growth using a cloth-based hybridization array system (CHAS) targeting antibiotic resistance and other marker genes associated with this organism. In this CHAS, a multiplex polymerase chain reaction incorporating digoxigenin–dUTP was used to simultaneously amplify seven target gene sequences, with subsequent rapid detection of the amplicons by hybridization with an array of probes immobilized on polyester cloth and immunoenzymatic assay of the bound label. This procedure permitted the rapid determination of S. Typhimurium DT104 in chicken carcass rinse, powdered egg and feed samples inoculated with different levels of the target organism. PRACTICAL APPLICATIONS The combined selective enrichment and CHAS procedure will enable the rapid screening of poultry and related products for the presence of multidrug resistant Salmonella Typhimurium DT104. The convenience of this approach lies in the fact that samples containing salmonellae requiring more comprehensive analysis can be rapidly identified on the basis of a simple preliminary enrichment procedure involving examination of MSRV plating media for characteristic swarming growth. The swarming growth is readily sampled and analyzed by the DT104 CHAS to determine the presence of key marker genes associated with the multidrug resistant pathogen, obviating the need for time- and labor-consuming conventional purification and antimicrobial susceptibility testing procedures. [ABSTRACT FROM AUTHOR]