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Title: A MULTIPLEX PCR FOR THE SIMULTANEOUS CONFIRMATION OF LISTERIA SPECIES AND LISTERIA MONOCYTOGENES

Author
item Wesley, Irene
item HARMON, K - 3625-30-15

Submitted to: International Virtual Conference on Infectious Diseases of Animals
Publication Type: Abstract Only
Publication Acceptance Date: 5/2/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A multiplex polymerase chain reaction (PCR) was designed to identify isolates of the genus Listeria and Listeria monocytogenes. Two primer sets were used. Set I targets a 938-bp 16S rRNA sequence of the genus Listeria. Set II amplifies a 174-bp region of the listeriolysin gene which is unique to L. monocytogenes. Amplification of ATCC strains of Listeria grayii, L. innocua, L. ivanovii, L. seeligeri, and L. welshimeri yielded an only single 938-bp product. ATCC strains of L. monocytogenes generated both the 174-bp and the 938-bp fragments. The 176- and 938-bp products were also seen with reference strains of L. monocytogenes serotypes 1a, 1b, 1c, 3a, 3b, 3c, 4a, 4b, 4c, 4d, and 4e, and epidemic strains from the Jalisco cheese (n=18) and the Canadian cole slaw (n=21) outbreaks. Listeria strains (n=55) were examined which had been evaluated in an earlier comparison of methods to identify L. monocytogenes. The multiplex PCR, based on the presence of the 176- and 938-bp products, confirmed 41 isolates as L. monocytogenes. The single 938-bp product validated the remaining 13 isolates as Listeria species, but not L. monocytogenes. The multiplex PCR can be performed rapidly using either purified DNA or on a crude cell extract as the template and yields unambiguous results.