• Korean Journal of Veterinary Service
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• v.32 no.3
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• pp.241-249
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• 2009

Shiga toxin (Stx)-producing Escherichia coli (STEC) strains can cause broad spectrum of human disease, including diarrhea, hemorrhagic colitis, and the life-threatening hemolytic uremic colitis (HUS). We examined 868 samples was taken from bovine feces and carcass from January to December 2008 in Seoul. Twenty two (9.5%) shiga toxin -producing Escherichia coli were isolated from the 230 of bovine feces, and two (0.31%) were isolated from the 638 of carcasses. Serotype of E. coli isolates were O157 (10, 41.6%), O26 (10, 41.6%), O111 (1, 4.2%) and UT (3, 12.6%). In PCR, the isolates displayed three different stx gene combination (stx1 [2, 8.4%]), stx2 [3, 12.6%] and stx1 and stx2 [19,87.5%]). The eaeA and hlyA gene were found in 11 (45.8%) of the 24 strains. Saa gene was present only one strains (4.2%). Toxin typing using reverse passive latex agglutination test showed the same result in VT 1. But it showed different result in VT 2. In antimicrobial susceptibility test, all isolates were sensitive to amikacin, amoxicillin/clavulanic acid, ciprofloxacin and colistin. Eighteen strains (75.0%) of 24 isolates showed the multi-resistant patterns with over 3 drugs. PFGE was performed after the genomic DNA of twenty four isolates was digested with Xba I. the 24 isolates showed 7 (A~G) PFGE type.

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.551-559
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• 2004

Shiga toxin-producing Escherichia coli (STEC) causes various clinical signs in human and animals, and has been indicated as a global enteropathogen with zoonotic importance. In this study, the feces of healthy pigs were collected from the slaughtered pigs of Daejon abattoir during the period from December 2001 to October 2002. Of 326 specimens, 13 STEC were confirmed by culture, PCR and colony hybridization. The isolates were further studied for toxin types, pathogenic factors, plasmid profiles, and antimicrobial resistance to characterize the genetic and toxigenic properties. In PCR, all of 13 isolates were evident to have shiga toxin gene (stx). Of 13 isolates stx1 gene was detected in 4 and stx2 gene in 9. The genes of eaeA, hlyA and rfbE were not present in any isolates. In colony hybridization using shiga toxin common primer (STXc), 2 to 9 per 100 colonies subcultured from 13 isolates showed the positive reaction. In the examination for plasmid profiles of the isolates, one to eleven plasmids with varying sizes of 1.0 Kb to 100 Kb were detected, and the 13 STEC could be classified into four groups by the plasmid patterns. The antimicrobial resistance patterns of the isolates were comparably corresponded with the plasmid profile patterns.

• Korean Journal of Veterinary Research
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• v.46 no.2
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• pp.135-142
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• 2006

Shiga toxin (stx) producing Escherichia coli (STEC) causes various clinical signs in animal and human. In this study, 255 fecal samples from calves showing diarrhea were collected from cattle farms in Chonnam province during the period from January 2005 to July 2005. Twenty six STEC (10%) were isolated from 255 fecal samples by PCR. The isolates displayed three different stx combinations (stx1 [69%], stx1 and stx2 [15%], and stx2 [38%]). The isolates were further studied for virulence associated genes and antimicrobial resistance to define the virulence properties. Intimin (eaeA), enterohemolysin (hlyA), and lipopolysaccharide (rfbE) virulence genes were detected in 6 (23%), 7 (26%), and 1 (3.8%) of the isolates, respectively, by PCR. One isolate possessing rfbE gene was typed as E. coli 0157 : H7 by agglutination test with O and H antisera. All 26 isolates showed susceptibility to amikacin (100%) and the majority of isolates showed high susceptibility to gentamicin (88.5%) and chloramphenicol (73.1%). But all isolates were resistant to penicillin. These results may provide the basic knowledge to establish strategies for the treatment and prevention of enteric disease in calves.

• Biomedical Science Letters
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• v.28 no.2
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• pp.127-136
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• 2022

Uropathogenic Escherichia coli (UPEC) is main causative agent of urinary tract infections. They are classified based on various types of O antigen. UPEC strains commonly possess many genes encoding virulece-associated factors. E. coli strains are generally divided into four main phylogenetic groups. The virulence factor (VF) profiles of UPEC are related with their O-serogroups in each strains. A total of 681 strains of UPEC clinical isolates were collected from Korean healthcare facility (1989: 123 strains and 2010-2014: 558 strains). The UPEC clinical isolates were analyzed by polymerase chain reaction (PCR) methods. A total of 14 O-serotypes (O1, O2, O4, O6, O7, O8, O15, O16, O18, O21, O22, O25, O75 and O83), 6 virulence factors (papC, fimG/H, sfaD/E, hly1, cnf1 and usp) and phylogenetic groups were identified. The most prevalent O-serogroups were O6 (11.1%) in 1989 UPEC strains and O25 (21.0%) in 2010-2014 UPEC strains. The identified VFs, phylogenetic groups in 1989 UPEC strains and 2010-2014 UPEC strains were fimG/H and B2 group. In this study, O6 serotype was revealed the close relationships with VFs. Also, the distribution of prevalence O-serogroups of UPEC has been changed from O6 to O25 and virulence of UPEC strains was increased during past twenty-one years.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.26-26
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• 2023

포스트 코로나 이후 먹거리에 대한 소비자의 인식전환으로 건강먹거리인 야콘에 대한 관심이 증가하고 있다. 야콘은 남미 안데스에서 도입된지 40여년 되었으며 달콤한 맛과 아삭아삭한 식감을 가져 생식용과 야콘즙으로 인기있으나 현재 국내 육종된 품종이 없다. 따라서, 다양한 유전자원을 확보하고 자원에 대한 평가를 통해 신품종 육성을 위한 기초 자료로 활용하고자 실시하였다. 연구에 사용된 재료는 국립식량과학원에서 보유하고 있는 5개 자원을 대상으로 초장, 엽수, 줄기수, 생체중, 관아수량, 괴근수량 등을 조사하였으며, 조사방법은 농촌진흥청 농업과학기술 연구조사 분석기준(RDA, 2012) 준하였다. 야콘 유전자원의 지상부 특성 결과, 초장이 92-127cm 범위를 보였으며, 줄기수는 8-12개, 경엽중은 1,433-2,855kg, 엽수는 152-195개의 범위를 보였다. 또한, 유전자원별 지하부 특성을 살펴보면, 유전자 원별 HY1이 관아수가 가장 많고, 관아수량도 352/10a으로 가장 무거웠다. 괴근수량을 살펴보면, HYL2가 총수량이 5,197 kg/10a, 상품수량이 4,213 kg/10a으로로 가장 많았으며, HYL3, HYL4, HYL5, HYL1 순이었다. 유전자원의 생리장해 결과를 조사한 결과, 열근 및 부패발생은 HYL1이 가장 심하였으며, HLY5가 상대적으로 약했다. 유전자원의 품질특성을 조사한 결과, 당도는 HYL5가 12.5로 가장 높았으며, HYL1이 8.7로 가장 낮았다. 이상의 결과를 바탕으로, 향후 야콘의 인공교배 단계에서부터 육종프로그램에 활용할 계획이다.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1324-1329
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• 1999

This study was carried out to investigate the distribution and characteristics of Listeria monocytogenes isolated from frozen Mandoo and pizza in 1998. A total 72 samples were examined and USDA, FDA and modified cold enrichment methods were used for the detection of Listeria spp. Overall prevalence of L. monocytogenes in frozen foods was 9.7% and L. monocytogenes was isolated from 11.1% of frozen Mandoo and 5.6% of frozen pizza. The highest detection rate of Listeria spp. in frozen Mandoo was found at USDA method and the serotype of L. monocytogenes isolates was 4. Isolated L. monocytogenes was confirmed by PCR method with Hly 1 and 2 as primers. It would be necessary to develop more rapid and specific method to isolate and confirm L. monocytogenes from foods because USDA and PCR methods used in this study took 3-4 days. D value of L. monocytogenes isolate in tryptic soy broth was 49.2 sec at $60^{\circ}C$ and 8.8 sec $at\;65^{\circ}C$, and D value of L. monocytogenes in foods with high distribution rate of Listeria spp. would be necessary to evaluate for the safe use of frozen foods.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.495-500
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• 2021

This study investigated the prevalence, serotypes, virulence genes, and antimicrobial resistance patterns of Listeria monocytogenes isolates collected from salmon products. A total of 16 out of 65 salmon products (24.6%) were positive for L. monocytogenes. Bacteria were most frequently identified in smoked salmon products (15/53, 28.3%). Serological tests revealed that serotype 1/2b (62.5%) was the predominant serotype of L. monocytogenes, followed by 1/2a (37.5%). All isolates harbored 10 virulence-associated genes (inlA, inlB, plcA, plcB, hlyA, actA, prf, fbpA, iap, and mpl), confirming their potential pathogenicity. The isolates of L. monocytogenes showed resistance to cefotetan (100%), cefotaxime (87.5%), cefepime (31.3%), erythromycin (6.3%), and tetracycline (6.3%); however, most of the strains were susceptible to antimicrobials except cephalosporins. These results provide useful information regarding the contamination of salmon products with L. monocytogenes, which may have implications for public health.

• Fisheries and Aquatic Sciences
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• v.26 no.9
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• pp.558-568
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• 2023

Vibrio vulnificus is an aquatic bacterium causing septicemia and wound infection in humans. To understand this pathogen at the genomic level, it was performed whole genome sequencing of a cefoxitin-resistant strain, V. vulnificus 1908-10 possessing virulence-related genes (vvhA, viuB, and vcgC) isolated from Gadeok island coastal seawater in South Korea. The genome of V. vulnificus 1908-10 consisted of two circular contigs and no plasmid. The total genome size was estimated to be 5,018,425 bp with a guanine-cytosine (GC) content of 46.9%. We found 119 tRNA and 34 rRNA genes respectively in the genome, along with 4,352 predicted protein sequences. Virulence factor (VF) analysis further revealed that V. vulnificus 1908-10 possess various virulence genes in classes of adherence, antiphagocytosis, chemotaxis and motility, iron uptake, quorum sensing, secretion system, and toxin. In the comparison of the presence/absence of virulence genes, V. vulnificus 1908-10 had fur, hlyU, luxS, ompU, pilA, pilF, rtxA, rtxC, and vvhA. Of the 30 V. vulnificus comparative strains, 80% of the C-genotype strains have all of these genes, whereas 40% of the E-genotype strains have all of them. In particular, pilA were identified in 80% of the C-type strains and 40% of the E-type strains, showing more difference than other genes. Therefore, V. vulnificus 1908-10 had similar VF characteristics to those of type C strains. Multifunctional-autoprocessing repeats-in-toxin (MARTX) toxin of V. vulnificus 1908-10 contained 8 A-type repeats (GXXGXXXXXG), 25 B.1-type repeats (TXVGXGXX), 18 B2-type repeats (GGXGXDXXX), and 7 C-type repeats (GGXGXDXXX). The National Center for Biotechnology Information (NCBI) Basic Local Alignment Search Tool (BLAST) showed that the RtxA protein of V. vulnificus 1908-10 had the effector domain in the order of cross-liking domain (ACD)-C58_PaToxP-like domain- α/β hydrolase-C58_PaToxP-like domain.

• Pediatric Infection and Vaccine
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• v.17 no.1
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• pp.16-22
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• 2010

Purpose : We aimed to investigate the clinical and phylogenetic characteristics of Escherichia coli Urinary Tract Infections (E. coli UTI). Methods : We enrolled patients with culture-proven E. coli UTI, who were admitted at the study hospital from September 2008 to August 2009. We investigated clinical data of patients with E. coli UTI and characteristics of isolated E. coli strains. The phylogenetic groups were classified using triplex polymerase chain reaction (PCR), and the distribution of nine virulent genes was determined by multiplex PCR. Results : A total of 47 patients have participated in this study. Thirty (63.8%) were under 6 months; eight (17.0%) were between 6-12 months; and nine (19.1%) were over 12 months. We compared two age groups between under 6-month and over 6-month. In the age group under 6-month, higher proportion of male (P =0.002) and group B2 strains (P =0.020) were observed. In contrast, higher proportion of female and group non-B2 strains were observed in age group over 6-month. Frequencies of papC, papGII, papGIII, sfa/foc, hlyC, cnf1, fyuA, iroN and iucC were estimated as 68.1%, 57.4%, 42.6%, 46.8%, 46.8%, 31.9%, 87.2%, 48.9% and 63.8%, respectively. In the comparison of phylogenetic groups, group B2 showed higher distribution of virulent genes, while group D included more strains resistant to trimethoprim/sulfamethoxazole (TMP/SMZ) than other groups. Conclusion : We showed the age group-specific difference in the distribution of sex ratios and phylogenetic groups; more male and group B2 strains in age group under 6-month, while more female and group non-B2 in age group over 6-month. However, further evaluation including larger number of patients will be necessary to confirm above thesis in future molecular epidemiological studies.