• Journal of Microbiology and Biotechnology
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• v.10 no.2
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• pp.143-146
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• 2000

This study was conducted to compare the cellular fatty acid composition and genotypic analysis of Bifidobacterium longum MK-G7 originated from Koreans with other commercial type strains of bifidobacteria. The cellular fatty acid of Bif. longum MK-G7 was shown to be composed of $C_{160FAME},C_{181\;c18DMA},C_{18.1\;CIS9\; FAME},C_{14.0FAME},C_{19\;0cye9,10 DMA},Feature7(C_{17.2 FAME), and Feature 10(C_{181\; Cll/t9/t6 FAME}$. Bif. longum MK-G7 showed 99.9% homology and the highest relatedness with Bif. longum ATCC 15707 type strain. Both Bif. longum MK-G7 and Bif. longum ATCC 15707 showed 153 bp products on RAPD (randomly amplified polymorphic DNA) analysis, however, they showed quite different band patterns on PFGE (pulsed-field gel electrophoresis) analysis. Consequently, our present study showed that Bif. longum MK-G7 was different from any commercial type strains of Bif. longum tested.

• The Plant Pathology Journal
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• v.30 no.2
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• pp.117-124
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• 2014

The plant pathogenic bacterial genus Pectobacteirum consists of heterogeneous strains. The P. carotovorum species is a complex strain showing divergent characteristics, and a new subspecies named P. carotovorum subsp. brasiliensis has been identified recently. In this paper, we re-identified the P. carotovorum subsp. brasiliensis isolates from those classified under the subspecies carotovorum and newly isolated P. carotovorum subsp. brasiliensis strains. All isolates were able to produce plant cell-wall degrading enzymes such as pectate lyase, polygalacturonase, cellulase and protease. We used genetic and biochemical methods to examine the diversity of P. carotovorum subsp. brasiliensis isolates, and found genetic diversity within the brasiliensis subsp. isolates in Korea. The restriction fragment length polymorphism analysis based on the recA gene revealed a unique pattern for the brasiliensis subspecies. The Korean brasiliensis subsp. isolates were divided into four clades based on pulsed-field gel electrophoresis. However, correlations between clades and isolated hosts or year could not be found, suggesting that diverse brasiliensis subsp. isolates existed.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1276-1284
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• 2006

Listeria monocytogenes is a well-known high-risk foodborne pathogen that grows at refrigeration temperature and is responsible for outbreaks of listeriosis. We report here the incidence of L. monocytogenes in fresh chicken carcasses and present genetic diversity of L. monocytogenes isolates. In this study, 25 g of chicken carcasses from markets in Korea were examined according to the FDA method, and presumptive isolates were confirmed by multiplex PCR assay. L. monocytogenes isolates were analyzed by Pulsed-Field Gel Electrophoresis using restriction enzymes, ApaI and AscI, to obtain strain-specific DNA fragments profiles. Antimicrobial resistance of L. monocytogenes strains against generally used antibiotics (Penicillin G, Kanamycin, Tetracycline, Vancomycin, Cephalothin, Rifampicin, Erythromycin, Ampicillin, Gentamicin, Streptomycin, and Chloramphenicol) were analyzed by NCCLS protocols to examine the presence of antimicrobial resistance in natural L. monocytogenes. Of a total 274 chicken samples, 81 samples (29.6%) were positive for L. monocytogenes. Listeria innocua (50.1%), Listeria welshimeri (6.9%), and Listeria grayi (11.3%) were also detected. PFGE analysis, using restriction enzymes ApaI and AscI, showed 27 pulsotypes of L. monocytogenes. Antimicrobial resistance analysis confirmed the existence of antimicrobial resistance for penicillin G and tetracycline in isolated L. monocytogenes strains.

• Journal of Microbiology
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• v.45 no.5
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• pp.466-472
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• 2007

A total of 98 vancomycin-resistant Enterococcus faecium (VREF) isolates (58 isolates from patients and 40 isolates from poultry) were compared based on their antimicrobial susceptibility, Tn1546 element organization, and pulsed-field gel electrophoresis (PFGE) patterns. This comparison aided in determining the relationships between the groups of isolates. All the VREF isolates harbored the vanA gene; however, 29 (29.6%) of the isolates exhibited the VanB phenotype-vanA genotype. Furthermore, the VREF isolates from humans and poultry exhibited distinct antimicrobial resistance patterns. The PCR mapping of the Tn1546 elements exhibited 12 different transposon types (A to L). The VREF isolates of poultry were classified into types A to D, whereas the human isolates were classified into types E to L. A PFGE analysis demonstrated a high degree of clonal heterogeneity in both groups of isolates; however, the distinct VREF clones appeared in each group of isolates. The deletion of the vanX-vanY genes or insertion of IS1216V in the intergenic region from the vanX-vanY genes is directly associated with the incongruence of the VanB phenotype-vanA genotype in human VREF isolates. These data suggest that the VREF isolates exhibit distinct phenotypic and genotypic traits according to their origins, which suggests that no evidence exists to substantiate the clonal spread or transfer of vancomycin resistance determinants between humans and poultry.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.85-87
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• 2013

An outbreak of Staphylococcus aureus infections occurred in a university with an enrollment of 80 students in the city of Daejon, Republic of Korea. All nine S. aureus isolates from patients (n = 7), staff members (n = 1), and the fried chicken served as the lunch (n = 1) harbored the enterotoxin A gene and showed an identical antibioticresistant profile, PFGE banding pattern (STAS16.001), and sequence type, ST 6. These results suggested that the outbreak was associated with eating the fried chicken that had been handled by an infected staff member. This case report demonstrated a practical approach to identifying the source and transmission of an infection.

• Microbiology and Biotechnology Letters
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• v.47 no.2
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• pp.310-316
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• 2019

Distribution of Salmonella enterica serovars and their associated virulence determinants is wide-spread among food animals, which are continuously implicated in periodic salmonellosis outbreaks globally. The aim of this study was to determine and evaluate the diversity of five Salmonella serovar virulence genes (invA, pefA, cdtB, spvC and iroN) isolated from food animals and humans. Using standard microbiological techniques, Salmonella spp. were isolated from the feces of humans and three major food animals. Virulence determinants of the isolates were assayed using PCR. Clonal relatedness of the dominant serovar was determined via pulsed-field gel electrophoresis (PFGE) using the restriction enzyme, Xbal. Seventy one Salmonella spp. were isolated and serotyped into 44 serovars. Non-typhoidal Salmonella (NTS; 68) accounted for majority (95.8%) of the Salmonella serovars. Isolates from chicken (34) accounted for 47.9% of all isolates, out of which S. Budapest (14) was predominant (34.8%). However, the dominant S. Budapest serovars showed no genetic relatedness. The invA gene located on SPI-1 was detected in all isolates. Furthermore, 94% of the isolates from sheep harbored the spvC genes. The iroN gene was present in 50%, 100%, 88%, and 91% of isolates from human, chicken, sheep, and cattle, respectively. The pefA gene was detected in 18 isolates from chicken and a single isolate from sheep. Notably, having diverse Salmonella serovars containing plasmid encoded virulence genes circulating the food chain is of public health significance; hence, surveillance is required.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.326-333
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• 2010

A total of 105 nontyphoid Salmonella isolated from infants in Seoul from 2003 to 2009 was investigated for their serotype, antimicrobial resistance, characterization of integron, and the patterns of Pulsed-field gel electrophoresis (PFGE). Eighteen serotypes were detected in 105 isolates, and the two most common serotypes were S. Enteritidis (47.6%) and Montevideo (15.2%). Among the Salmonella serovars, a high level of antimicrobial resistance was found to ampicilin (60%), tetracycline (46.7%), streptomycin (35.2%) and nalidixic acid (28.6%). In the multi-drug resistance patterns, the predominant patterns were only nalidixic acid (15.7%), ampicillin-ampicillin/sulbactam-tetracycline (14.5%), and ampicillin-streptomycin-chloramphenicol-tetracycline (10.8%). PCR and DNA sequencing analysis revealed the presence of class 1 integron in 20 isolates (19%). Of the class 1 integron positive isolates 20% harboured the integron-associated gene cassettes : aadA2, blaP1, dfr17-aadA5, dfrA12-aadA2, and aadA7. PFGE was carried out to examine the genetic relatedness among S. Enteritidis isolates. Except for three strains, fifty strains were divided by three pulsotypes.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.381-389
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• 2023

Vibrio vulnificus, the most fatal waterborne and foodborne pathogens of 50% fatality rate in the world, is common in seawater and occurs particularly in warmer months. In this study, we investigated the toxin genes using reverse transcription-polymerase chain reaction (RT-PCR), antibiotic resistance status using Vitek, and genetic characteristics using pulsed-field gel electrophoresis (PFGE) of different V. vulnificus strains isolated from the Jeju Island seawater, distribution fishery products, and fish tanks. We examined a total of 487 samples and isolated a total of 46 strains (including overlapping strains) of V. vulnificus, 44 strains from seawater and 1 strain each from fishery products and fish tank. We detected toxin gene vvhA in all 46 strains and rtxA, viu in 8 strains (17.4%) and 9 strains (19.6%) strains, respectively. Antibiotic resistance tests indicated 100% resistance to cefoxitin antibiotics. The PFGE analysis of the 46 strains identified a total of 6 types showed 100% homology and the degree of similarity was 81.3-98.0%; however, there were no similarity between the regions and samples. These results indicate that V. vulnificus isolated from the seawater, fishery products, and fish tanks should be continuously monitored as cases of food poisoning caused by V. vulnificus with toxin genes have been reported in Jeju Island.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.116-124
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• 2012

Identification was performed in March 2008 for the 76 Enterococcus strains isolated from the Han-river, which is used as water supply for Seoul citizens. The antibiotic susceptibility, antibiotic resistant structural analysis, trans-conjugation, pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) were also carried out for the isolated strains. Among the isolated strains, 25 strains were E. casseliflavus, 4 strains were E. faecalis and 1 strain was E. hirae. Investigation of antibiotic susceptibility indicated that 15 strains demonstrated tolerance against vancomycin, and that 11 strains of E. faecium and 4 strains of E. casseliflavus were VRE. The vanA gene detection of the VRE strains revealed that 6 E. faecium strains were vancomycin-resistant Enterococcus faecium (VREF) possessing vanA. Analyses of transposon Tn1546 structure containing vanA demonstrated that Km36 and Km37 belonged to Tn1 type, Km20 and Km38 was Tn2 type, and Km39 and Km40 was Tn3 type. PFGE disclosed that among the 6 VREF strains, Km36 and Km37 exhibited equivalent subtype, while the rest 4 strains showed subtypes different to each other. MLST for the 6 VREF strains disclosed that 3 strains were ST78, while the rest 3 strains were ST18, ST192 and ST230, respectively. All these clonal complexes were derived from CC17 which has been isolated from clinical sources. 4 strains belonged to CC78, while the rest 2 strains were CC18 and CC192, respectively.

• Korean Journal of Veterinary Service
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• v.31 no.1
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• pp.1-16
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• 2008

Salmonella infections cause the disease in pigs but also some zoonotic Salmonella serotypes can be transmitted to human through swine products, resulting in food poisoning. The objective of this study was to investigate the bacteriological prevalence and detection of invA gene using Salmonella specific polymerase chain reaction (PCR), the epidemiological characteristics related to Salmonella strains cultured from pig samples in Gangwon areas using serotyping, random amplified polymorphic DNA (RAPD) and pulsed field gel electrophoresis (PFGE) methods. During the period of November 2001 through April 2002, 1,174 ileocecal lymph node were collected from the slaughtered pigs raised in 38 farms located in Gangwon province. The samples were submerged in boiling water and macerated in saline and lymph node homogenates were inoculated into Tetrathionate broth with iodine (TTB, Difco, 0.5% iodine was added) for enrichment growth. Then additional tests were performed using several mediums, and suspects were identified by API 20E kit (BioMerieux) and PCR. Of total 1,174 samples from 38 farms, 44 (3.7%) were isolated as Salmonella spp from 13 farms (34.2%). Of 44 isolates, 31 were in Yangyang region, followed by 9 in Goseong, 2 in both Gangneung and Sokcho. However, there was no difference in regional isolation frequency. All isolates have a 521bp amplified product in Salmonella specific PCR with primer invA which encodes in proteins for invasion of epithelial cells. Of 44 recovered serotypes, 23 (52.3%) were S Eingedi, 10 (22.7%) S Schwarzengrund, 9 (20.5%) S Typhimurium, and 2 (4.5%) S Mbandaka. In RAPD analysis, there appeared to be unique bands distinguishing each serotype, although similarities exist between the different serotypes. Four serotypes of 44 Salmonella isolates appeared to fall into 14 different RAPD types. In PFGE analysis, 9 S Typhimurium were tested with XbaI enzyme and SpeI enzyme. The combination of results obtained with two enzymes subdivided the 9 S Typhimurium into 4 PFGE types.