Seroepidemiological Survey of Zoonotic Diseases in Small Mammals with PCR Detection of Orientia tsutsugamushi in Chiggers, Gwangju, Korea

Serosurveillance for zoonotic diseases in small mammals and detection of chiggers, the vector of Orientia tsutsugamushi, were conducted from September 2014 to August 2015 in Gwangju Metropolitan Area. Apodemus agrarius was the most commonly collected small mammals (158; 91.8%), followed by Myodes regulus (8; 4.6%), and Crocidura lasiura (6; 3.5%). The highest seroprevalence of small mammals for O. tsutsugamushi (41; 26.3%) was followed by hantaviruses (24; 15.4%), Rickettsia spp. (22; 14.1%), and Leptospira (2; 1.3%). A total of 3,194 chiggers were collected from small mammals, and 1,236 of 3,194 chiggers were identified with 7 species of 3 genera: Leptotrombidium scutellare was the most commonly collected species (585; 47.3%), followed by L. orientale (422; 34.1%), Euchoengastia koreaensis (99; 8.0%), L. palpale (58; 4.7%), L. pallidum (36; 2.9%), Neotrombicula gardellai (28; 2.3%), and L. zetum (8; 0.6%). L. scutellare was the predominant species. Three of 1,236 chigger mites were positive for O. tsutsugamushi by PCR. As a result of phylogenetic analysis, the O. tsutsugamushi strain of chigger mites had sequence homology of 90.1-98.2% with Boryong. This study provides baseline data on the distribution of zoonotic diseases and potential vectors for the development of prevention strategies of vector borne diseases in Gwangju metropolitan area.

The Genetic Diversity of Norovirus from Children with Diarrhea in Gwangju Metropolitan City, Korea: 2008-2012

In order to study the characteristics of norovirus in Gwangju metropolitan city, We examined norovirus in 13,931 fecal specimens collected through five years (2008-2012) from children admitted with a chief complain of acute diarrhea. Among a total of norovirus (NoV) was most frequently detected (3,025 cases, 21.7%). Concerning the frequency of virus detected by month, NoV tended to break out frequently from October to March in the following year. NoV was detected most highly in 0~3 year infants. Through examinations on NoV genotypes, among 3,025 cases that turned out to be positive, the genotypes of 2,652 cases were determined with various results including 13 types of GI and 17 types of GII. The results of analysis on GI genotypes were as follows: GI-4 (21.9%), GI-2 (15.2%), and GI-6 (10.5%). GII genotypes were as follows: GII-4 (63.9%), GII-3 (18.9%), GII-8 (4.2%), GII-2 (3.9%), GII-6 (3.3%), and GII-1 (1.9%). Eight types of variants for GII-4 genotype (427 cases) were identified. The majority of the GII-4 variants was GII-4_Farmington (181 cases, 42.4%), which peaked in 2012, while GII-4_2008b (173 cases, 40.5%) showed a high prevalence in 2011. Concerning the circulation of variants, as many as eight types of GII-4 variants were identified in 2012, showing more varieties than in other years. Therefore, this study can be used as fundamental data for the development of vaccine candidate for the prevention of viral diarrheal diseases with high-incidence.

Molecular Epidemiology of Mumps Virus Circulated in Gwangju

The recent mumps epidemic in South Korea has generated a large amount of public concern. This study has attempted to analyze molecular epidemiological changes of mumps virus circulating in Gwangju metropolitan area, South Korea. 953 throat swab samples were collected from patients with parotitis from May 2013 to July 2014. The majority (71.5%) of these cases have occurred in middle or high school students aged from 15 to 19 years. All samples were tested using a reverse transcription polymerase chain reaction (RT-PCR) that targets the short hydrophobic (SH) gene of the virus. Mumps virus SH gene was detected in 39.2% (374/953) of samples. And 82 RT-PCR products were randomly selected for nucleotide sequencing analysis. All of these sequences were determined as genotype I by phylogenetic analysis and showed the highest nucleic acid similarity (99%) with Dg1062/Korea/98 (GenBank accession no. AY309060). These results suggested that appearance of new genotype or genetic variation at the nucleotide level could be ruled out to evaluate main cause of recent mumps outbreak in Gwangju metropolitan area.

The Molecular Epidemiology of Circulating Group A Rotavirus in Gwangju Metropolitan City, Korea: 2008~2012

Group A rotaviruses are a major cause of acute gastroenteritis in young children worldwide. For the proper management of rotavirus infections, knowledge of the distribution of G and P genotypes including detection of emerging genotype is crucial. Therefore, the aim of this study is to describe epidemiological changes in rotavirus gastroenteritis in Gwangju metropolitan city, South Korea. Stool samples were collected from 14,314 patients with diarrhea, who visited hospitals in Gwangju from 2008 to 2012. Samples were screened for rotavirus with Enzyme-Linked Immunosorbent Assay (ELISA) method and rotavirus P (VP4), G (VP7) genotypes were determined by reverse-transcription polymerase chain reaction. And we performed nucleotide sequencing analysis. Among a total of 14,314 samples investigated 1,982 samples (13.8%) were ELISA positive. Genotyping of Rotavirus was performed using 526 rotavirus samples. The most prevalent circulating G genotype was G1 (40.5%), followed by G2 (27.6%), G3 (19.4%), G9 (9.7%), G4 (2.5%) and G12 (0.4%). The predominant type of P genotypes was P[8] (69.6%), followed by P[4] (27.8%) and P[6] (2.3%). In this study, 13 G-P combinations were detected. From 2008 to 2010, G1P[8] was the most prevalent, followed by G3P[8]. Whereas, 2011 and 2012, G2P[4] was the most common, followed by G1P[8]. Rotavirus gastroenteritis is a common disease associated with significant morbidity, mortality and economic burden. Ongoing rotavirus surveillance to understand the distribution of G and P genotypes will be critical for the development of effective prevention measurements.

Characterization of Community-Associated Methicillin-Resistant Staphylococcus aureus in Gwangju, Korea

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important nosocomial pathogens worldwide. This study was performed to investigate the characterization of MRSA isolated from healthy persons in Gwangju area. A total of 404 nasal swab samples was collected during October 2011 and May 2012 in Gwangu, Korea. A survey on MRSA was conducted with meat distributors (n=230), pre-school children (n=108), officers (n=66), respectively. To confirm the MRSA, polymerase chain reaction (PCR) for the S. aureus specific gene and mecA gene was performed. A total of 34 (8.4%) MRSA isolates was isolated from 404 nasal swab samples: 6.1% (14/230) from meat distributors, 16.7% (18/108) from pre-school children, and 3.0% (2/66) from officers samples, respectively. The most prevalent antimicrobial resistance observed in the MRSA isolates was to ampicillin 100% (34/34), followed by penicillin 97.1% (33/34), oxacillin 94.1% (32/34) and erythromycin 52.9% (18/34). All MRSA isolates were then characterized by panton-valentine leukocidin (pvl) gene detected by PCR, staphylococcal cassette chromosome mec (SCCmec) typing, and pulsed-field gel electrophoresis (PFGE) with Sma I digestion. 34 MRSA isolates from nasal carriage were pvl gene negative, SCCmec type IV; 73.5% (25/34), type II; 17.6% (6/34), type III; 2.9% (1/34), and untypable; 5.9% (2/34), respectively. 34 MRSA isolates showed 16 PFGE patterns. These results indicated that isolation rates of community-associated methicillin-resistant S. aureus (CA-MRSA) from healthy persons were low (8.4%), but continuous surveillance and monitoring should be performed to prevent the spread of MRSA in the community.

Profile of Antimicrobial Resistance of Staphylococcus aureus and Molecular Epidemiologic Characterization of Methicillin-resistant Staphylococcus aureus (MRSA) Isolated from Hands of People Using Multitude Facilities / 감염과화학요법

BACKGROUND: The purpose of this study was to investigate perception of hand hygiene and actual hand washing practices of people who used public facilities as well as the presence of indicator bacteria and food-borne pathogens on their hands. Data from this study will be used as a tool for public education and provide basic information on the potential risk for the spread of infectious disease by hands. MATERIALS AND METHODS: Sixty S. aureus and 15 methicillin-resistant S. aureus (MRSA) were recovered from 500 swab samples from hands of people in public places, including super markets and amusement facilities in Gwangju Metropolitan City during February to May 2011. Using conventional methods and the Vitek system, all of the isolates were confirmed as Staphylococcus auerus (S. aureus). Antimicrobial susceptibility was determined by performing disk diffusion testing according to the Clinical Laboratory Standard Institute guidelines. The minimum inhibition concentrations (MICs) of MRSA isolates were tested using E-test strips. To confirm the MRSA, polymerase chain reaction (PCR) for the S. aureus-specific gene and mecA gene was performed. Gene detection using PCR, SCCmec typing, Panton-Valentine Leukocidin (PVL), and Multilocus sequence typing (MLST) were performed on all isolates of MRSA. RESULTS: Of 60 S. aureus isolates, 48 (80%) harbored at least one type of enterotoxin gene: two, three, four, and five types of enterotoxin gene were found in 16 (26.7%), seven (11.7%), 10 (16.7%), and eight (13.3%) isolates, respectively. The most prevalent antimicrobial resistance observed in the S. aureus isolates was to penicillin (92%, 55/60), followed by erythromycin (35%, 21/60), oxacillin (32%, 19/60), and ampicillin (23%, 14/60). No resistance was observed against vancomycin, clindamycin, linazolid, rifampin, imipenem, trimethoprim/sulfamethoxazole, and telithromycin. In this study, based on molecular characterization of MRSA isolates, all MRSA, except for one isolate, belonged to ST72 and SCCmec type IV. Eleven of 15 (78.6%) MRSA were ST72:SCCmecIV:t324. CONCLUSIONS: In this study, we detected serious pathogens, including S. aureus and MRSA, from swab samples of peoples' hands. Most S. aureus isolates harbored the enterotoxin gene and the types of MRSA isolated in this study were community-associated MRSA, indicating the importance of washing hands for public health.

Enterotoxigenic Escherichia coli Outbreak in a High School / 감염과화학요법

BACKGROUND: Enterotoxigenic Escherichia coli (ETEC) has been well known pathogen as a cause of travelers' diarrhea. Nowadays, however, ETEC is also increasingly recognized as the cause of foodborne or waterborne outbreaks. We investigated an outbreak of a high school in Gwangju metropolitan city to trace the source of infection and the mode of transmission of ETEC. MATERIALS AND METHODS: All symptomatic persons were interviewed and filled out the questionnaires. We surveyed their clinical symptoms and the foods that they ate. We checked the facilities of the school, dinning room and water supply system. Microbiologic examination were carried out on above symptomatic persons and many environmental specimens. All gathered samples were examined in Gwangju city Health & Environment Research Institute. ETEC isolates were submitted to Korea Center for Disease Control and Prevention (KCDC) for Pulsed-field gel electrophoresis (PFGE). We also requested water quality analysis of water samples to Waterworks Research Institute. RESULTS: The 39 students and one sibling who visited and ate school meal showed symptoms. All staffs and cooks showed no symptom. Among 51 stool specimens, ETEC was isolated from 19 (18: students, 1:cook). ETEC was also isolated from specimens from a purifier and a water tap of the dinning room and water tank (underground water). In PFGE test, isolates from 18 persons showed identical pattern, but the PFGE patterns from water were different. Isolates of water samples showed different PFGE patterns even within the same sample. Investigation of the water distribution system revealed that contaminated underground water had been supplied to the dinning room and students of the school were exposed to it. CONCLUSION: This is the outbreak of ETEC infection occurred in a high school. Besides students, ETEC was also isolated from water samples. Considering some epidemiologic features, we suspect the mode of transmission may be waterborne despite the inconsistent PFGE results.

Enterotoxigenic Escherichia coli Outbreak in a High School / 감염과화학요법

BACKGROUND: Enterotoxigenic Escherichia coli (ETEC) has been well known pathogen as a cause of travelers' diarrhea. Nowadays, however, ETEC is also increasingly recognized as the cause of foodborne or waterborne outbreaks. We investigated an outbreak of a high school in Gwangju metropolitan city to trace the source of infection and the mode of transmission of ETEC. MATERIALS AND METHODS: All symptomatic persons were interviewed and filled out the questionnaires. We surveyed their clinical symptoms and the foods that they ate. We checked the facilities of the school, dinning room and water supply system. Microbiologic examination were carried out on above symptomatic persons and many environmental specimens. All gathered samples were examined in Gwangju city Health & Environment Research Institute. ETEC isolates were submitted to Korea Center for Disease Control and Prevention (KCDC) for Pulsed-field gel electrophoresis (PFGE). We also requested water quality analysis of water samples to Waterworks Research Institute. RESULTS: The 39 students and one sibling who visited and ate school meal showed symptoms. All staffs and cooks showed no symptom. Among 51 stool specimens, ETEC was isolated from 19 (18: students, 1:cook). ETEC was also isolated from specimens from a purifier and a water tap of the dinning room and water tank (underground water). In PFGE test, isolates from 18 persons showed identical pattern, but the PFGE patterns from water were different. Isolates of water samples showed different PFGE patterns even within the same sample. Investigation of the water distribution system revealed that contaminated underground water had been supplied to the dinning room and students of the school were exposed to it. CONCLUSION: This is the outbreak of ETEC infection occurred in a high school. Besides students, ETEC was also isolated from water samples. Considering some epidemiologic features, we suspect the mode of transmission may be waterborne despite the inconsistent PFGE results.

Investigation of Outbreak caused by Shigella flexneri / 감염과화학요법

BACKGROUND: Most of the shigellosis outbreak in Korea was caused by Shigella sonnei since late 1990's. In contrast, outbreak by Shigella flexneri were rare since late 1990's. Currently, we experienced the shigellosis outbreak by S.flexneri and described the results of investigation. METHODS: We recruited employees from company "A" who had a meal at least once at the company's cafeteria from Dec 23th, 2002 to Dec 26th, 2002. We surveyed the symptoms, food items, and history of travel of eligible persons and their family members. For the microbiological examination, we collected specimen from eligible persons and their family. Collected specimens were cultured for bacteriologic agents and viruses. Epidemiological relationship among the isolates were analyzed by pulsed field gel electrophoresis (PFGE). RESULTS: Among the eligible persons, one hundred ten were symptomatic (110/258, 42,6%). Eighty- two were confirmed bacteriologically. Day of symptom onset showed a unipolar pattern. Diarrhea was the most common symptom among the symptomatic patients (110/110, 100%). The other symptoms included abdominal pain (81.8%), tenesmus (70.0%), headache (63.6%), nausea (61.8%), febrile sense (59.1%), and vomiting (24.5%). Lunch on 24th Dec was the most significant risk factor of the outbreak (RR=6.46, 3.56< or =95% CI< or =11.75). All isolates of the outbreak has the same pattern on PFGE analysis and the PFGE pattern was not similar compared with other S.flexneri isolates from Korea. CONCLUSION: This is the largest and unique outbreak by S.flexneri since 2000 in Korea. The outbreak has the same origin according to the PFGE pattern and epidemic characteristics. Considering rarity of S.flexneri among shigellosis in Korea, surveillance for S.flexneri should be enhanced.

Investigation of Outbreak caused by Shigella flexneri / 감염과화학요법

BACKGROUND: Most of the shigellosis outbreak in Korea was caused by Shigella sonnei since late 1990's. In contrast, outbreak by Shigella flexneri were rare since late 1990's. Currently, we experienced the shigellosis outbreak by S.flexneri and described the results of investigation. METHODS: We recruited employees from company "A" who had a meal at least once at the company's cafeteria from Dec 23th, 2002 to Dec 26th, 2002. We surveyed the symptoms, food items, and history of travel of eligible persons and their family members. For the microbiological examination, we collected specimen from eligible persons and their family. Collected specimens were cultured for bacteriologic agents and viruses. Epidemiological relationship among the isolates were analyzed by pulsed field gel electrophoresis (PFGE). RESULTS: Among the eligible persons, one hundred ten were symptomatic (110/258, 42,6%). Eighty- two were confirmed bacteriologically. Day of symptom onset showed a unipolar pattern. Diarrhea was the most common symptom among the symptomatic patients (110/110, 100%). The other symptoms included abdominal pain (81.8%), tenesmus (70.0%), headache (63.6%), nausea (61.8%), febrile sense (59.1%), and vomiting (24.5%). Lunch on 24th Dec was the most significant risk factor of the outbreak (RR=6.46, 3.56< or =95% CI< or =11.75). All isolates of the outbreak has the same pattern on PFGE analysis and the PFGE pattern was not similar compared with other S.flexneri isolates from Korea. CONCLUSION: This is the largest and unique outbreak by S.flexneri since 2000 in Korea. The outbreak has the same origin according to the PFGE pattern and epidemic characteristics. Considering rarity of S.flexneri among shigellosis in Korea, surveillance for S.flexneri should be enhanced.

Norovirus Outbreak after a School Trip among Girls' High School Students

Norovirus is one of the common causative agents of viral gastroenteritis in developed countries. A large outbreak of gastroenteritis occurred among girls' high school students in Cheongju city, Chungbuk province, who had attended a school trip to Cheju island from 19 to 21 May 2003. One hundred and ninety six students were consistent with case definition and attack rate was 54.9%. The epidemic curve was characteristic of a point-source outbreak. The frequency of diarrhea was 1 to 6 times (76.8%) and the duration of diarrhea was within two days (85.1%) in most cases. The most common symptom with diarrhea was abdominal pain followed by headache, tenesmus, febrile sense, chill and vomiting. The following bacterial organisms, Salmonella spp, Shigella spp, Vibrio spp, Staphylococcus aureus, and E coli O157 were examined in 196 stool specimens, but no suspicious organism was detected. In virological examinations, Norovirus was dectected in 3 out of 25 stool specimens from the sick students. Among the 22 stool specimens of the food handlers during the school trip, both bacterial and virological examinations were all negative. Among the 13 environmental specimens, the groundwater of the hotel, where the students had stayed during their school trip, was contaminated with general bacteria and E. Coli. However, we could not detect Norovirus in the groundwater of the hotel. We concluded that Norovirus might be a possible cause of this outbreak, and the water supply of the hotel might be a probable source of this outbreak.

Epidemiologic Characteristics and DNA Sequencing of SRSV Causing Gastroenteritis Outbreak in Two Elementary School / 감염과화학요법

BACKGROUND: Small round structured virus (SRSV) is one of the common etiologic agents of viral gastroenteritis in childhood. However, SRSV has not easily been detected in many diarrheal outbreaks. Therefore, we experienced simultaneous outbreak of SRSV enteritis in two elementary schools, therefore, we analyzed the result of the surveillance. METHODS: We interviewed the pupil of two schools and questioned their demographic data, presence of gastrointestinal symptoms, contact with symptomatic persons within the last two weeks, and dietary history within the last one week in school. The specimens of the symptomatic pupil were collected for identification of bacteria (Shigella spp, Salmonella spp, E.coli O157 : H7) and viruses (Norwalk agent, SRSV, adenovirus, and astrovirus). RESULTS: The number of symptomatic patients was 193 (193/2843, 6.8%) and the distribution of symptom onset was unipolar. Frequent symptoms of the patients were abdominal pain (176/193, 91.2%), headache (111/193, 57.5%), vomiting (102/193, 52.8%), diarrhea (83/ 193, 43.0%), febrile sense (79/193, 40.9%), nausea (73/193, 37.8%), chilling (49/193, 25.4%), and tenesmus (8/193, 4.1%). We identified SRSV in 9 cases by PCR method, and analyzed the RNA polymerase gene by DNA sequencing; 2 genogroup (Genogroup I, II) and 3 genotype. CONCLUSION: We confirmed SRSV enteritis with different genotypes in two concurrent outbreaks. DNA sequencing and comparison of genotype among the isolated SRSV in near future are be necessary

A Molecular Epidemiologic Study by Plasmid DNA and Random Amplified Polymorphic DNA Analyses of Salmonella enterica serotype Enteritidis Isolated in Food Borne Outbreaks in Gwangju, 1997 / 감염과화학요법

BACKGROUND: During the past 10 years, there has been an increased incidence of gastrointestinal infections caused by salmonellae in Korea. In 1999, there were several outbreaks and sporadic occurrences of food borne infections due to Salmonella enterica serotype Enteritidis in Gwangju. Thus, there is a need for careful monitoring of its occurrence. METHODS: Salmonella Enteritidis were isolated from feces samples of patients with foodborne diarrhea in Gwangju, 1999. We performed antigen typing, examination of biochemical properties, anibiotic susceptibility test, plasmid typing and RAPD analysis to characterize of S. Enteritidis isolates. RESULTS: There were three Salmonella outbreaks (April, July, October), and 203 isolates of S. Enteritidis were isolated from the 286 patients. Eighteen isolates were obtained from the patients of sporadic occurrences. Antigenic types of the isolates were O antigen; D1 (1, 9, 12), H antigen phase 1; (g, m), serotype; Enteritidis. The isolates were susceptible to most of the antibiotics. We performed plasmid DNA analysis of the isolates, and the results showed 3 plasmids (8, 6, 3.8 kb) in 14 of 14 strains from outbreaks; 3 plasmids (8, 6, 3.8 kb) in 2 isolates from sporadic cases; 4 plasmids (8, 6, 3.8, 2 kb) in 10 isolates from sporadic occurrences, and 2 isolates from food specimens. However, 1 isolate from patients and 2 isolates from Ham-Yang, Kyung Nam, did not contain plasmids. RAPD analysis showed that all isolates from Gwangju in 1999 showed relatively uniform characteristics which were different from those derived from Ham-Yang, Kyung-Nam. CONCLUSION: The present data demonstrated that most food poisoning cases by S. Enteritidis in Gwangju, 1999, were originated from the same Salmonella Enteritidis strains.

Epidemiologic Characteristics and DNA Sequencing of SRSV Causing Gastroenteritis Outbreak in Two Elementary School / 감염과화학요법

BACKGROUND: Small round structured virus (SRSV) is one of the common etiologic agents of viral gastroenteritis in childhood. However, SRSV has not easily been detected in many diarrheal outbreaks. Therefore, we experienced simultaneous outbreak of SRSV enteritis in two elementary schools, therefore, we analyzed the result of the surveillance. METHODS: We interviewed the pupil of two schools and questioned their demographic data, presence of gastrointestinal symptoms, contact with symptomatic persons within the last two weeks, and dietary history within the last one week in school. The specimens of the symptomatic pupil were collected for identification of bacteria (Shigella spp, Salmonella spp, E.coli O157 : H7) and viruses (Norwalk agent, SRSV, adenovirus, and astrovirus). RESULTS: The number of symptomatic patients was 193 (193/2843, 6.8%) and the distribution of symptom onset was unipolar. Frequent symptoms of the patients were abdominal pain (176/193, 91.2%), headache (111/193, 57.5%), vomiting (102/193, 52.8%), diarrhea (83/ 193, 43.0%), febrile sense (79/193, 40.9%), nausea (73/193, 37.8%), chilling (49/193, 25.4%), and tenesmus (8/193, 4.1%). We identified SRSV in 9 cases by PCR method, and analyzed the RNA polymerase gene by DNA sequencing; 2 genogroup (Genogroup I, II) and 3 genotype. CONCLUSION: We confirmed SRSV enteritis with different genotypes in two concurrent outbreaks. DNA sequencing and comparison of genotype among the isolated SRSV in near future are be necessary

A Molecular Epidemiologic Study by Plasmid DNA and Random Amplified Polymorphic DNA Analyses of Salmonella enterica serotype Enteritidis Isolated in Food Borne Outbreaks in Gwangju, 1997 / 감염과화학요법

BACKGROUND: During the past 10 years, there has been an increased incidence of gastrointestinal infections caused by salmonellae in Korea. In 1999, there were several outbreaks and sporadic occurrences of food borne infections due to Salmonella enterica serotype Enteritidis in Gwangju. Thus, there is a need for careful monitoring of its occurrence. METHODS: Salmonella Enteritidis were isolated from feces samples of patients with foodborne diarrhea in Gwangju, 1999. We performed antigen typing, examination of biochemical properties, anibiotic susceptibility test, plasmid typing and RAPD analysis to characterize of S. Enteritidis isolates. RESULTS: There were three Salmonella outbreaks (April, July, October), and 203 isolates of S. Enteritidis were isolated from the 286 patients. Eighteen isolates were obtained from the patients of sporadic occurrences. Antigenic types of the isolates were O antigen; D1 (1, 9, 12), H antigen phase 1; (g, m), serotype; Enteritidis. The isolates were susceptible to most of the antibiotics. We performed plasmid DNA analysis of the isolates, and the results showed 3 plasmids (8, 6, 3.8 kb) in 14 of 14 strains from outbreaks; 3 plasmids (8, 6, 3.8 kb) in 2 isolates from sporadic cases; 4 plasmids (8, 6, 3.8, 2 kb) in 10 isolates from sporadic occurrences, and 2 isolates from food specimens. However, 1 isolate from patients and 2 isolates from Ham-Yang, Kyung Nam, did not contain plasmids. RAPD analysis showed that all isolates from Gwangju in 1999 showed relatively uniform characteristics which were different from those derived from Ham-Yang, Kyung-Nam. CONCLUSION: The present data demonstrated that most food poisoning cases by S. Enteritidis in Gwangju, 1999, were originated from the same Salmonella Enteritidis strains.