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The recent genomic sequencing of L. monocytogenes EGD and of a strain of ECI (serotype 4b) opens the wayfor genomics-based approaches to generate lineage-specific molecular reagents for ECIIand ECIII. In this project, polymerase chain reaction (PCR),localized DNA microarraysand sequencing of multiple loci will be used to identify sequences unique to the genomes of ECII and ECIII strains.
Ready-to-eat (RTE) foods, especially dairy, meat and poultry products, have beenfrequently implicated in epidemics of invasive illness due to Listeria (listeriosis). Inaddition to their obvious public health consequences, such outbreaks can severely erode consumer confidence in the safety of RTE foods and result in serious economic losses tothe food industry. To be able to prevent them, it is crucial to understand the bacteriathemselves that cause the outbreaks. Three distinct lineages (Epidemic clones I, II andIII) have caused major epidemics of food-borne listeriosis in the United States.EpidemicClone I (ECI) has also been implicated in numerous epidemics abroad. Epidemic ClonesII and III (ECII and ECIII) were implicated in multistate outbreaks in 1998-1999(contaminated hotdogs) and 2000 (turkey deli meats), respectively.
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Such lineage-specific sequences will be valuable as tools tomonitor and distinguish these strains, and to identify their vectors and reservoirs. These equences may also contribute to the identification of potentially unique genetic attributes of these strains which may render them capable of causing epidemic illness.