Infection Status with Clonorchis sinensis Metacercariae in Fish from Tamjin-gang (River) in Jeollanam-do, Republic of Korea.

The present study was performed to investigate the infection status with Clonorchis sinensis metacercariae (CsMc) in fishes from 2 sites, the middle and lower reaches, of Tamjin-gang (River) in Jeollanam-do, the Republic of Korea. Total 1,132 fishes in 22 species were collected from the middle reaches in Jangheung-gun for 4 years (2014-2017) and 517 fishes in 17 species were also collected from the lower reaches in Gangjin-gun in 2014 and 2017. They were all individually examined with the artificial digestion method in our laboratory. CsMc were detected in 322 (28.5%) out of 1,132 fishes from Jangheung-gun, and in 161 (31.1%) out of 517 fishes from Gangjin-gun, and their densities were 51 and 57 per fish infected each. In the fish species with CsMc, positive rates were 61.5% in Jangheung-gun and 62.7% in Gangjin-gun. A total of 222 Pungtungia herzi were examined and they were all infected with CsMc. The average intensity was 103 CsMc in the index fish, P. herzi (95 in Jangheung-gun and 121 in Gangjin-gun). In P. herzi bimonthly examined in 2017, the intensity was commonly most higher in March in 2 surveyed sites, however the significant seasonal endemicity was not showed. Conclusively, it was confirmed that CsMc is more or less prevalent in fishes from Tamjin-gang and their endemicity is higher in fish from the lower reaches in Gangjin-gun than the middle reaches in Jangheung-gun in Jeollanam-do, Korea.

Antibiotic Resistance Patterns and Serotypes of Salmonella spp. Isolated at Jeollanam-do in Korea.

OBJECTIVES: Few long-term studies have been conducted on the serotype and antibiotic resistance patterns of Salmonella speices (spp.) The aim of this study was to determine the serotypes and antibiotic resistance patterns of Salmonella spp. isolated at Jeollanam-do in Korea from 2004 to 2014. METHODS: A total of 276 Salmonella samples were evaluated. Serotyping was carried out according to the Kauffmann-White scheme. Antibiotic susceptibility was determined using the Vitek II system with an AST-N169 card. RESULTS: A total of 22 different serotypes were identified, and the major serotypes were Salmonella Enteritidis (116 strains, 42.0%) and Salmonella Typhimurium (60 strains, 21.7%). The highest resistance was observed in response to nalidixic acid (43.4%), followed by ampicillin (40.5%) and tetracycline (31.6%). Resistance to nalidixic acid was detected in 81.0% of S. Enteritidis. Multidrug resistance was detected in 43.3% of Salmonella spp. S. Enteritidis and S. Typhimurium presented the highest resistance (98.3%) and multidrug resistance rate (73.3%), respectively. The most highly observed antibiotic resistance pattern among Salmonella spp. in this study was ampicillin-chloramphenicol (14 strains, 5.7%). CONCLUSION: Overall, S. Enteritidis and S. Typhimurium showed higher antibiotic resistance than the other Salmonella serotypes tested in this study. Our study will provide useful information for investigating the sources of Salmonella infections, as well as selecting effective antibiotics for treatment.

Transmission of Enterobacter aerogenes septicemia in healthcare workers.

Enterobacter aerogenes is recognized as an important bacterial pathogen in hospital-acquired infections. This report describes two unusual cases of septicemia caused by E. aerogenes in immunocompetent healthcare workers. E. aerogenes was isolated from blood cultures of the two patients experiencing septicemia. The clinical isolates were initially identified as E. aerogenes using a VITEK II automated system and 16S rRNA sequence analysis, and; both isolates involved in the outbreak shared a common pulse-field gel electrophoresis pattern. The similarities between the two cases included the simultaneous development of gastroenteritis symptoms, severe sepsis and thrombocytopenia after taking intravenous injections of ketorolac tromethamine. A common source of normal saline, a 100 mL bottle, was used for diluting the analgesic in both cases. In addition to the general population, healthcare workers, especially those who are also intravenous drug abusers, should be considered subjects that could cause a transmission of Enterobacter infection.

Consecutive Outbreaks of Enterotoxigenic Escherichia coli O6 in Schools in South Korea Caused by Contamination of Fermented Vegetable Kimchi.

BACKGROUND: Two outbreaks of gastroenteritis occurred in South Korea, affecting a middle school in the Jeollanam-do province in 2013 (Outbreak 1) and 10 schools in the Incheon province in 2014 (Outbreak 2). We investigated the outbreaks to identify the pathogen and mode of transmission. METHODS: A retrospective cohort study was conducted in the Outbreak 1; and case-control studies were performed for the Outbreak 2. Samples from students, environments, and preserved food items were collected and pulsed-field gel electrophoresis (PFGE) was conducted to identify strains of pathogen. RESULTS: We identified 167 and 1022 students who met the case definition (≥3 loose stools in any 24-h period) in the Outbreaks 1 and 2, respectively. The consumption of cabbage kimchi and young radish kimchi were significantly associated with the illness. Adjusted odds ratios of kimchi were 2.62-11.74. In the Outbreak 1, cabbage kimchi was made and consumed in the school restaurant and in the Outbreak 2, young radish kimchi was supplied by food company X and distributed to all the 10 schools in the Incheon province. Enterotoxigenic Escherichia coli (ETEC) O6 was isolated from fecal samples in 375 cases (33.9%) and from kimchi samples. PFGE patterns of the outbreak strains isolated from cases and food were indistinguishable in each outbreak. CONCLUSION: The suspected food vehicle in these two consecutive outbreaks was kimchi contaminated with ETEC O6. We recommend continued monitoring and stricter sanitation requirements for the food supply process in Korea, especially in relation to kimchi.

A novel immunochromatographic test applied to a serological survey of Japanese encephalitis virus on pig farms in Korea.

Among vertebrate species, pigs are a major amplifying host of Japanese encephalitis virus (JEV) and measuring their seroconversion is a reliable indicator of virus activity. Traditionally, the hemagglutination inhibition test has been used for serological testing in pigs; however, it has several limitations and, thus, a more efficient and reliable replacement test is required. In this study, we developed a new immunochromatographic test for detecting antibodies to JEV in pig serum within 15 min. Specifically, the domain III region of the JEV envelope protein was successfully expressed in soluble form and used for developing the immunochromatographic test. The test was then applied to the surveillance of Japanese encephalitis (JE) in Korea. We found that our immunochromatographic test had good sensitivity (84.8%) and specificity (97.7%) when compared with an immunofluorescence assay used as a reference test. During the surveillance of JE in Korea in 2012, the new immunochromatographic test was used to test the sera of 1,926 slaughtered pigs from eight provinces, and 228 pigs (11.8%) were found to be JEV-positive. Based on these results, we also produced an activity map of JEV, which marked the locations of pig farms in Korea that tested positive for the virus. Thus, the immunochromatographic test reported here provides a convenient and effective tool for real-time monitoring of JEV activity in pigs.

Psychrobacter aestuarii sp. nov., isolated from a tidal flat sediment.

A Gram-negative-staining, non-motile, non-spore-forming and strictly aerobic bacterial strain, SC35(T), was isolated from tidal flat sediment collected from the South Sea, Korea, and subjected to a taxonomic study using a polyphasic approach. The organism grew optimally at 20-30 degrees C and with 1-2 % (w/v) NaCl. Strain SC35(T) contained ubiquinone-8 as the predominant respiratory lipoquinone and C(18 : 1)omega9c as the major fatty acid. The DNA G+C content was 48.5 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain SC35(T) formed a lineage within the genus Psychrobacter (94.3-96.5 % sequence similarity), forming a distinct branch in a clade also containing Psychrobacter pacificensis NIBH P2K6(T) and Psychrobacter celer SW-238(T). On the basis of phenotypic and phylogenetic data, strain SC35(T) (=KCTC 22503(T)=JCM 16343(T)) was placed in the genus Psychrobacter as the type strain of a novel species, for which the name Psychrobacter aestuarii sp. nov. is proposed.

Prevalence of antibodies in response to Legionella species, analysis of a healthy population from Jeollanam-do Province, Korea.

Seroepidemological investigation of antibodies to Legionella species in 500 healthy individuals from a single geographical location in Korea was conducted by indirect fluorescent antibody assay (IFA). Considering an antibody titer of > or =1:128 as positive reaction, 15.2% of total sera were positive. In males and females older than 40 years old, levels of IgM and IgG were 1.2% and 14%, respectively. The sera with antibody titers of > or =1:128 to Legionella species accounted for 85 sera, and 9 sera of these were reacted to more than one Legionella species. Reactivity to L. bozemanii, L. micdadei, L. longbeachae, L. pneumophila sg 6, and L. gormanii were 32.9%, 20%, 15%, 10.6%, and 8%, respectively. However, L. pneumophila sg 1, sg 2, and sg 3 did not react to any sera. Serological analysis revealed that the level of antibody in response to L. bozemanii was more prevalent than L. pneumophila. Our results suggest that the antibodies of non-L. pneumophila species, such as L. bozemanii, may be highly prevalent in healthy population within Korea. Although conclusions based on the findings of this study must be cautiously considered given that the population sampled were sourced from a single province, we have added to the knowledge base of serodiagnosis of infections due to non-L. pneumophila species in Korea.

Seroprevalence and risk factors for hepatitis C virus infection among female commercial sex workers in South Korea who are not intravenous drug users.

Several previous studies have reported a high prevalence of hepatitis C virus (HCV) infection among commercial sex workers (CSWs), but the situation is often compounded by coexisting factors, such as intravenous drug use. We conducted a seroepidemiologic study of 1,527 female CSWs in South Korea. All participants tested negative for human immunodeficiency virus and were not illicit intravenous drug users (IDUs). Twenty-one participants (1.4%) were positive for antibodies to HCV. According to the multivariate logistic regression analysis, a history of acupuncture and diabetes mellitus were associated with the seroprevalence of HCV, whereas time spent as a CSW showed only borderline significance. Sexual activity was not an independent predictor of increased risk for HCV infection in female CSWs who had never been illicit IDUs.