Molecular characterization of Salmonella weltevreden isolated from poultry: evidence of conjugal transfer of plasmid and antibiotic resistance

Ten strains of Salmonella weltevreden isolated from poultry sources were ex amined and found to contain plasmid DNA ranging in size from 1.8 to 68.5 MD . All isolates were susceptible to carbenicillin, cephalothin, ceftriazone, gentamicin, kanamycin and nalidixic acid, but resistance to bacitracin (10 0%), penicillin G (100%), rifampicin (100%), sulphamethoxazole (100%), cefu roxime (80%) and tetracycline (60%) was recorded. The 55 MD plasmid of stra in SW5 determined resistance to penicillin G and tetracycline, which was tr ansmissible to the E. coli K12 recipient at a frequency of 3.52 x 10(-5) tr ansconjugants per input donor cell. The results of arbitrarily primed polym erase chain reaction (AP-PCR), using two 10-mer oligonucleotides and PCR-ri botyping to differentiate between the ten strains of S. weltevreden were co mpared. The strains were separated into ten different genome types by AP-PC R but were indistinguishable by PCR-ribotyping. These results suggest that poultry may constitute a reservoir for disseminating antibiotic resistance and that AP-PCR may be a valuable tool for epidemiological studies.