Molecular fingerprinting of Riemerella anatipestifer by repetitive sequence PCR

Riemerella anatipestifer is a Gram-negative rod-shaped bacterium associated with epizootic infections in poultry. A total of 35 R. anatipestifer isola tes including the type strain ATCC11845(T), reference and field strains for 18 different serotypes were characterized by repetitive sequence based-PCR (rep-PCR) with outwardly-directed primers based on the repetitive extragen ic palindromic (REP) consensus sequence. This technique was applied by usin g either extracted genomic DNA or preparation of whole bacterial cells harv ested directly from plate cultures. Rep-PCR discriminated the R. anatipesti fer isolates into 19 electrophoretic types. DNA fingerprints obtained from rep-PCR of extracted genomic DNA or from preparations of whole cells yielde d comparable patterns. Substantial variation was seen among the rep-PCR fin gerprints of different serotypes. Moreover, different polymorphisms of the rep-PCR fingerprints were evident among epidemiologically unrelated isolate s of the same serotype. These results suggest the presence of repetitive ex tragenic palindromic-like elements within the genome of R. anatipestifer th at can be used in some isolates to discriminate between different strains b elonging to the same serotype. Rep-PCR may serve as a useful molecular tool for subtyping R. anatipestifer isolates for epidemiologic investigations. The whole cell procedure offers the advantage of ease of performance requir ing only small quantities of cells. (C) 1999 Elsevier Science B.V. All righ ts reserved.