Mj. Mauel et al., DEVELOPMENT OF POLYMERASE CHAIN-REACTION ASSAYS FOR DETECTION, IDENTIFICATION, AND DIFFERENTIATION OF PISCIRICKETTSIA-SALMONIS, Diseases of aquatic organisms, 26(3), 1996, pp. 189-195
A nested polymerase chain reaction (PCR) was developed to detect genom
ic DNA of Pisci-rickettsia salmonis, the causative agent of an epizoot
ic disease in salmonids. The nested PCR assay, which used general bact
erial 16S rDNA primers in the first amplification reaction, and Fl sal
monis-specific primers in a second reaction, allowed detection of less
than 1 P. salmonis tissue culture infectious dose 50 (TCID50). Using
the Fl salmonis-specific primers in a single PCR reaction allowed the
detection of 60 TCID50. The specificity of the PCR was assessed with a
panel of 1: salmonid and 15 bacterial genomic DNA preparations. Ampli
fication products were produced only with I? salmonis DNA. Restriction
fragment length polymorphism (RFLP) analysis of the complete 16S gene
PCR products demonstrated that 1 isolate, EM-90, was unique. Two addi
tional primers were developed and used in PCR assays that differentiat
ed EM-90 from the 4 other P. salmonis isolates tested.