This study was performed to characterize 35 L. monocytogenes isolates from animals, foods, environmental samples collected between 1997 and 2007 with no apparent epidemiological relations, and five reference isolates using serotypic, genotypic and molecular typing methods to understand the pattern of strain distribution in Korea. For this study, we used serotyping and detected 6 different virulence-associated genes (inlA, inlB, plcA, plcB, hlyA, and actA) and 16s rRNA using multiplex-PCR. We also compared RAPD and PFGE to determine genetic characterization of L. monocytogenes strains to define the genetic diversity. Serotype patterns of the 30 L. monocytogenes strains was as follows; 9 isolates (30.0%) belonged to serotype, 7 isolates (23.3%) belonged to serotype 4b, 4 isolates (13.3%) belonged to serotype 1/2b, 3 isolates (10.0%) belonged to serotype 1/2c, 2 (6.7%) isolates belonged to4c, 2 (6.7%) isolates belonged to NT (Non Type), one isolate (3.2%) belonged to3aand 3b, and4a, respectively. Although, a limited number of isolates were analyzed in this study, molecular typing with RAPD and PFGE indicated that PFGE is more discriminatory for the subtyping L. monocytogenes than RAPD. Some L. monocytogenes isolates by RAPD and PFGE types are associated with specific sources. And, combining data obtained by these methods will increases the likelihood of strain discrimination.
 J. Bille and J. Rocourt, “WHO International Multicenter Listeria monocytogenes Subtyping Study-Rationale and Set-Up of the Study,” International Journal of Food Microbiology, Vol. 32, No. 3, 1996, pp. 251-262. doi:10.1016/S0168-1605(96)01140-3
 A. Vines and B. Swaminathan, “ Identification and Characterization of Nucleotide Sequence Differences in Three Virulence-Associated Genes of Listeria monocytogenes Strains Representing Clinically Important Serotypes,” Current Microbiology, Vol. 36, No. 5, 1998, pp. 309-318. doi:10.1007/s002849900315
 M. K. Miettinen, K. J. Bjorkroth and H. J. Korkeala, “Characterization of Listeria monocytogenes from an Ice Cream Plant by Serotyping and Pulsed-Field Gel Electrophoresis,” International Journal of Food Microbiology, Vol. 46, No. 3, 1999, pp. 187-192. doi:10.1016/S0168-1605(98)00185-8
 H. Even, A. L. Bjorn, J. R. Ole, V. Traute, K. Georg and N. Truls, “Molecular Epidemiology and Disinfectant Susceptibility of Listeria monocytogenes from Meat Processing Plants and Human Infections,” International Journal of Food Microbiology, Vol. 96, No. 1, 2004, pp. 85-96. doi:10.1016/j.ijfoodmicro.2004.03.014
 F. X. Riedo, R. E. Weaver, B. D. Plikaytis and C. V. Broome, “A Point-Source Foodborne Listeriosis Outbreak: Documented Incubation Period and Possible Mild Illness,” The Journal of Infectious Diseases, Vol. 170, No. 3, 1994, pp. 693-696. doi:10.1093/infdis/170.3.693
 S. J. Yong, F. Joseph, R. Frank, E. Brackett and C. Jinru, “Polymerase Chain Reaction Dection of Listeria monocytogenes on Frankfurters Using Oligonucleotide Primers Targeting the Genes Encoding Internalin AB,” Journal of Food Protection, Vol. 66, No. 2, 2003, pp. 237-241.
 M. Gianfranceschi, G. Fransiosa, A. Gattuso and P. Aureli, “Detection of Two Phospholipases C by Means of Plate Tests for the Rapid Identification of Pathogenic Listeria monocytogenes,” Archiv fur Lebensmittelhygiene, Vol. 49, No. 3, 1998, pp. 54-57.
 D. K. Winters, T. P. Maloney and M. G. Johnson, “Rapid Detection of Listeria monocytogenes by a PCR Assay Specific for an Aminopeptidase,” Molecular and Cellular Probes, Vol. 13, No. 2, 1999, pp. 127-131. doi:10.1006/mcpr.1999.0224
 B. Jersek, E. Tcherneva, N. Rijpens and L. Herman, “Repetitive Element Sequence-Based PCR for Species and Strain Discrimination in the Genus Listeria,” Letters in Applied Microbiology, Vol. 23, No. 1, 1996, pp. 55-60.
 C. Luca, S. Simone, N. Raffaella, B. Elena, C. Carlo and C. Giuseppe, “Analysis of PCR-Based Methods for Characterization of Listeria monocytogenes Strains Isolated from Different Sources,” International Journal of Food Microbiology, Vol. 103, No. 2, 2005, pp. 167-178. doi:10.1111/j.1472-765X.1996.tb00028.x
 Z. Xiaohui, J. Xinan and M. Wiedmann, “Listeria monocytogenes in the Chinese Food System: Strain Characterization through Partial actA Sequencing and Tissue-Culture Pathogenicity Assays,” Journal of Medical Virology, Vol. 54, No. 3, 2005, pp. 217-224. doi:10.1016/j.ijfoodmicro.2004.12.027
 O. Okwumabua, M. O'Connor, E. Shull, K. Strelow, M. Hamacher, T. Kurzynski and D. Warshauer, “Characterization of Listeria monocytogenes Isolates from Food Animal Clinical Cases: PFGE Pattern Similarity to Strains from Human Listeriosis Cases,” FEMS Microbiology Letters, Vol. 249, No. 2. 2005, pp. 275-281. doi:10.1016/j.femsle.2005.06.018
 K. Wernars, P. Boerlin, A. Audurier, E. G. Russell, G. D. Curtis, L. Herman and N. van der Mee-Marquet, “The WHO Multicenter Study on Listeria monocytogenes Subtyping: Random Amplification of Polymorphic DNA (RAPD),” International Journal of Food Microbiology, Vol. 32, No. 3, 1996, pp. 325-341. doi:10.1016/S0168-1605(96)01146-4
 L. M. Graves and B. Swaminathan, “PulseNet Standardized Protocol for Subtyping Listeria monocytogenes by Macrorestriction and Pulsed-Field Gel Electrophoresis,” International Journal of Food Microbiology, Vol. 65, No. 1-2, 2001, pp. 55-62. doi:10.1016/S0168-1605(00)00501-8
 P. R. Hunter and M. A. Gaston, “Numerical Index of the Discriminatiory Ability of Typing Systems and Application of Simpson’s Index of Diversity,” Journal of Clinical Virology, Vol. 26, No. 11, 1988, pp. 2456-2466.
 P. D. MacDonald, R. E. Whitwam, J. D. Boggs, J. N. MacCormack, K. L. Anderson, J. W. Reardon, J. R. Saah, L. M. Graves, S. B. Hunter and J. Sobel, “Outbreak of Listeriosis among Mexican Immigrants as a Result of Consumption of Illicitly Produced Mexican-Style Cheese,” Clinical Infectious Diseases, Vol. 40, No. 5, 2005, pp. 677-682. doi:10.1086/427803
 S. S. Jang, C. Euiyoung, H. Kiseon, M. Takahisa, H. Sunggi and R. Sangryeol, “Antibiotic Resistance and Genetic Diversity of Listeria monocytogenes Isolated from Chicken Carcasses in Korea,” Journal of Microbiology and Biotechnology, Vol. 16, No. 8, 2006, pp. 1276-1284.
 H. C. Chung and C. Wang, “Genetic Relatedness between Listeria monocytogenes Isolates from Seafood and Humans Using PFGE and REP-PCR,” International Journal of Food Microbiology, Vol. 110, No. 2, 2006, pp. 135-148. doi:10.1016/j.ijfoodmicro.2006.02.003
 Z. W. Jaradat, G. E. Schutze and A. K. Bhunia, “Genetic Homogeneity among Listeria monocytogenes Strains from Infected Patients and Meat Products from Two Geographic Locations Determined by Phenotyping, Ribotyping and PCR Analysis of Virulence Genes,” International Journal of Food Microbiology, Vol. 76, No. 1-2, 2002, pp. 1-10. doi:10.1016/S0168-1605(02)00050-8
 M. Wiedmann, J. L. Bruce, C. Keating, A. E. Johnson, P. L. McDonough and C. A. Batt, “Ribotypes and Virulence Gene Polymorphisms Suggest Three Distinct Listeria monocytogenes Lineages with Differences in Pathogenic Potential,” Infection and Immunity, Vol. 65, No. 7, 1997, pp. 2707-2716.
 O. F. Rasmussen, T. Beck, J. E. Olsen, L. Dons and L. Rossen, “Listeria monocytogenes Isolates Can be Classified into Two Major Types According to the Sequence of the Listeriolysin Gene,” Infection and Immunity, 1991, Vol. 59, pp. 3945-3951.
 A. Bubert, I. Hein, M. Rauch, A. Lehner, B. Yoon, W. Goebel and M. Wagner, “Detection and Differentiation of Listeria spp. by a Single Reaction Based on Multiplex PCR,” Applied and Environmental Microbiology, Vol. 65, No. 10, 1999, pp. 4688-4692.
 H. Ericsson, P. Stalhandske, M. L. Danielsson-Tham, E. Bannerman, J. Bille, C. Jacquet, J. Rocourt and W. Tham, “Division of Listeria monocytogenes Serovar 4b Strains into Two Groups by PCR and Restriction Enzyme Analysis,” Applied and Environmental Microbiology, Vol. 61, No. 11, 1995, pp. 3872-3874.
 C. Jacquet, E. Gouin, D. Jeannel, P. Cossart and J. Rocourt, “Expression of ActA, Ami, InlB, and Listeriolysin O in Listeria monocytogenes of Human and Food Origin,” Applied and Environmental Microbiology, Vol. 68, No. 2, 2002, pp. 616-622. doi:10.1128/AEM.68.2.616-622.2002
 I. Lasa, V. David, E. Gouin, J. B. Marchand and P. Cossart, “The Amino-Terminal Part of ActA Is Critical for the Actin-Based Motility of Listeria monocytogenes; The Central Proline-Rich Region Acts as a Stimulator,” Molecular Microbiology, Vol. 18, No. 3, 1995, pp. 425-436. doi:10.1111/j.1365-2958.1995.mmi_18030425.x
 G. A. Smith, J. A. Theriot and D. A. Portnoy, “The Tandem Repeat Domain in the Listeria monocytogenes Act a Protein Controls the Rate of Actin-Based Motility, the Percentage of Moving Bacteria, and the Localization of Vasodilator-Stimulated Phosphoprotein and Profiling,” The Journal of Cell Biology, Vol. 135, No. 3, 1996, pp. 647-660. doi:10.1083/jcb.135.3.647
 J. G. Williams, A. R. Kubelik, K. J. Livak, J. A. Rafalski and S. V. Tingey, “DNA Polymorphisms Amplified by Arbitrary Primers Are Useful as Genetic Markers,” Nucleic Acids Research, Vol. 25, No. 22, 1990, pp. 6531-6535. doi:10.1093/nar/18.22.6531
 A. Kerouanton, A. Brisabois, E. Denoyer, F. Dilasser, J. Grout, G. Salvat and B. Picard, “Comparison of Five Typing Methods for the Epidemiological Study of Listeria monocytogenes,” International Journal of Food Microbiology, Vol. 43, No. 1-2, 1998, pp. 61-71. doi:10.1016/S0168-1605(98)00098-1
 M. Louie, P. Jayaratne, I. Luchsinger, J. Devenish, J. Yao, W. Schlech and A. Simor, “Comparison of Ribotyping, Arbitrarily Primed PCR, and Pulsed-Field Gel Electrophoresis for Molecular Typing of Listeria monocytogenes,” Journal of Clinical Virology, Vol. 34, No. 1, 1996, pp. 15-19.
 S. I. Mazurier and K. Wernars, “Typing of Listeria Strains by Random Amplification of Polymorphic DNA,” Research in Microbiology, Vol. 143, No. 5, 1992, pp. 499-505. doi:10.1016/0923-2508(92)90096-7
 C. Niederhauser, C. H?felein, M. Allmann, P. Burkhalter, J. Lüthy and U. Candrian, “Random Amplification of Polymorphic Bacterial DNA: Evaluation of 11 Oligonucleotides and Application to Food Contaminated with Listeria monocytogenes,” Journal of Applied Bacteriology, Vol. 77, No. 5, 1994, pp. 574-582. doi:10.1111/j.1365-2672.1994.tb04404.x
 L. M. Graves, S. B. Hunter, A. R. Ong, D. Schoonmaker-Bopp, K. Hise, L. Kornstein, W. E. DeWitt, P. S. Hayes, E. Dunne, P. Mead and B. Swaminathan, “Microbiological Aspects of the Investigation That Traced the 1998 Outbreak of Listeriosis in the United States to Contaminated Hot Dogs and Establishment of Molecular Subtyping-Based Surveillance for Listeria monocytogenes in the PulseNet Network,” Journal of Clinical Virology, Vol. 43, No. 5. 2005, pp. 2350-2355.
 R. Brosch, M. Brett, B. Catimel, J. B. Luchansky, B. Ojeniyi and J. Rocourt, “Genomic Fingerprinting of 80 Strains from the WHO Multicenter International Typing Study of Listeria monocytogenes via Pulsed-Field Gel Electrophoresis (PFGE),” International Journal of Food Microbiology, Vol. 32, No. 3, 1996, pp. 343-355. doi:10.1016/S0168-1605(96)01147-6
 M. L. Suihko, S. Salo, O. Niclasen, B. Gudbjornsdóttir, G. Torkelsson, S. Bredholt, A. M. Sjoberg and P. Gustavsson, “Characterization of Listeria monocytogenes Isolates from the Meat, Poultry and Seafood Industries by Automated Ribotyping,” International Journal of Food Microbiology, Vol. 72, No. 1-2, 2002, pp. 137-146. doi:10.1016/S0168-1605(01)00631-6
 E. Heir, B. A. Lindstedt, O. J. R?tterud, T. Vardund, G. Kapperud and T. Nesbakken, “Molecular Epidemiology and Disinfectant Susceptibility of Listeria monocytogenes from Meat Processing Plants and Human Infections,” International Journal of Food Microbiology, Vol. 96, No. 1, 2004, pp. 85-96.
 I. Martinez, L. M. Rorvik, V. Brox, J. Lassen, M. Seppola, L. Gram and V. B. Fonnesbech, “Genetic Variability among Isolates of Listeria monocytogenes from Food Products, Clinical Samples and Processing Environments, Estimated by RAPD Typing,” International Journal of Food Microbiology, Vol. 84, No. 3, 2003, pp. 285-297. doi:10.1016/S0168-1605(02)00423-3
 T. Autio, J. Lundon, A. M. Fredriksson, J. Bjorkroth, A. M. Sjoberg and H. Korkeala, “Similar Listeria monocytogenes Pulsotypes Detected in Several Foods Originating from Different Sources,” International Journal of Food Microbiology, Vol. 77, No. 1-2, 2002, pp. 83-90. doi:10.1016/S0168-1605(02)00055-7
 A. Margolles, B. Mayo and C. G. de los Reyes-Gavilan, “Polymorphism of Listeria monocytogenes and Listeria Innocua Strains Isolated from Short-Ripened Cheeses,” Journal of Applied Microbiology, Vol. 84, No. 2, 1998, pp. 255-262. doi:10.1046/j.1365-2672.1998.00339.x
 C. A. Nadon, D. L. Woodward, C. Young, F. G. Rodgers and M. Wiedmann, “Correlations between Molecular Subtyping and Serotyping of Listeria monocytogenes,” Journal of Clinical Virology, Vol. 39, No. 7, 2001, pp. 2704-2707.
 I. Giovannacci, C. Ragimbeau, S. Queguiner, G. Salvat, J. L. Vendeuvre, V. Carlier and G. Ermel, “Listeria monocytogenes in Pork Slaughtering and Cutting Plants. Use of RAPD, PFGE and PCR-REA for Tracing and Molecular Epidemiology,” International Journal of Food Microbiology, Vol. 53, No. 2-3, 1999, pp. 127-140. doi:10.1016/S0168-1605(99)00141-5
 F. M. Wallace, J. E. Call, A. C. Porto, G. J. Cocoma and J. B. Luchansky, “Recovery Rate of Listeria monocytogenes from Commercially Prepared Frankfurters during Extended Refrigerated Storage,” Journal of Food Protection, Vol. 66, No. 4, 2003, pp. 584-591.
 M. T. Destro, M. Leitao and J. M. Farber, “Use of Molecular Typing Methods to Trace the Dissemination of Listeria monocytogenes in a Shrimp Processing Plant,” Applied and Environmental Microbiology, Vol. 62, No. 5, 1996, pp. 1852-1853.
 P. Boerlin, E. Bannerman, F. Ischer, J. Rocourt and J. Bille, “Typing Listeria monocytogenes: A Comparison of Random Amplification of Polymorphic DNA with 5 Other Methods,” Research in Microbiology, Vol. 146, No. 1, 1995, pp. 35-49. doi:10.1016/0923-2508(96)80269-5