• Biomedical Science Letters
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• v.11 no.1
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• pp.9-13
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• 2005

A total of 22 Salmonella enterica serotype Enteritidis (S. Enteritidis) isolates from human and chicken sources were analyzed by pulsed field gel electrophoresis (PFGE) using XbaI restriction enzyme to assess the genetic relationships between strains from different sources. PFGE permitted the resolution of XbaI restriction fragments of the 22 S. Enteritidis into 6 distinct PFGE types (PFT), designated PFT1 to PFT6, and 2 subtypes within PFT2, and allowed to detect between 9 and 10 bands with fragments sizes in the range of $25\~635\;kb$. Four of twelve isolates from human showed an identical PFGE patterns with 2 isolates from chickens. Also, another one isolate from human showed an identical PFGE patterns with other 5 isolates from chickens. Only one isolate from chicken, however, showed a different pattern compared to other PFTs. These results suggested that sporadic human food-poisoning cases infections caused by S. Enteritidis in this study were due to the consumption of contaminated chicken meats and that a clonally highly similar strains exist and spread between human and chicken sources.

• Korean Journal of Veterinary Research
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• v.39 no.2
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• pp.338-342
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• 1999

Twenty three strains of Escherichia (E) coli O157 : H7 isolated from Korea, Japan, USA were analyzed by pulsed-field gel electrophoresis (PFGE) of XbaI-digested chromosomal DNA and multiplex polymerase chain reaction. Various PFGE patterns of E. coli O157 : H7 were found on the same farm. Most of the E, coli O157 : H7 strains had shiga-like toxin (slt) II gene only (43.5%) or both slt I and slt II genes(30.4%). eaeA gene was highly conserved in the E. coli O157 : H7. There was no correlation between PFGE and slt gene patterns. The results indicate that various genotypes of E. coli O157 : H7 have spread throughout the country and genomic DNA patterns generated by PFGE are highly specific for different strains and have significant value in epidemiologic investigations of infectious disease outbreaks.

• Journal of Microbiology
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• v.42 no.2
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• pp.80-86
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• 2004

Pulsed-field gel electrophoresis (PFGE) typing was applied to the epidemiological investigation of 21 Candida tropicalis isolates collected from urine specimens of 11 patients and one healthcare worker, in an intensive care unit (ICU) over a 4-month period. Seventeen epidemiologically unrelated strains from 14 patients were also tested to determine the discriminatory power of PFGE. PFGE typing consisted of electrophoretic karyotyping (EK) and restriction endonuclease analysis of genomic DNA (REAG), using two restriction enzymes (BssHII and SfiI). The EK pattern was the same in all 38 isolates, while REAG using SfiI separated the isolates into nine types. However, 16 different PFGE types were iden-tified by REAG with BssHII, and the same results were obtained when the results of both REAG tests were combined. In serial urinary isolates from 10 patients, all strains from each patient had the same PFGE pattern. While the epidemiologically unrelated strains from 14 patients consisted of 13 different PFGE types, the 20 isolates from the 11 ICU patients fell into only two PFGE types (types Cl and C2), and these apparently originated from the two different outbreaks. All strains of type Cl (n = 12) were isolated from six patients, between November 1999 and January 2000, and all of the type C2 strains (n=8) were isolated from five patients, during January and February 2000. This study shows two con-secutive clusters of C. tropicalis candiduria in an ICU, defined by PFGE typing, and also demonstrates that a PFGE typing method using BssHII is perhaps the most useful method for investigating C. tropi-calis candiduria.

• Biomedical Science Letters
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• v.11 no.3
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• pp.295-299
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• 2005

Staphylococcus aureus is an important animal and human pathogen implicated in a variety of disease including food-poisoning caused by staphyloccal enterotoxins (SEs). In order to investigate the difference in genomic types and to monitor the transmission of S. aureus isolates, a total of 25 S. aureus isolates from different sources were determined for their genotypic characteristics by pulsed-field gel electrophoresis (PFGE) in addition to their ability to enterotoxin production and antibiotic resistance patterns in this study. All the isolates were susceptible to amikacin, and the resistance pattern to ampicillin and penicillin were most common among 14 different patterns. Eleven of 24 isolates produced one of three SEs, SEA, SEC or SED. Sixteen representative PFGE patterns were obtained by Smal restriction fragments of S. aureus isolates. Analysis of dendrogram based on PFGE band patterns suggested that food-poisoning outbreaks be caused by the diverse sources of food, of which their raw materials were infected with S. aureus. Also, it could be concluded that PFGE was a powerful tool for epidemiological tracing of infection source for food-initiated outbreaks.

• Journal of Yeungnam Medical Science
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• v.12 no.2
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• pp.366-385
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• 1995

Epidemiological studies are important in both the prevention and treatment of mycobacterial infections. This study was initiated to establish the pulsed-field gel electrophoresis (PFGE) method, which are not yet extensively studied. The most apprpriate restriction endonucleases included DraI, AsnI, and XbaI. The optimal PFGE condition was different according to the enzymes used. Two stage PFGE was performed, in case of DraI first stage was performed with 10 seconds of initial pulse and 15 seconds of final pulse, while the second stage was performed with 60 seconds of initial pulse and 70 seconds of final pulse. The electrophoresis time for DraI-PFGE was 14 hours for each stage. Electrophoresis was performed for 22 hours, in case of XbaI, with 3 seconds of initial pulse and 12 seconds of final pulse. Electrophoresis was performed for 22 hours, in case of AsnI, with 5 seconds of initial pulse and 25 seconds of final pulse. In all cases the voltage of the electrophoresis was maintained constantly at 200 voltage. Standard mycobacterial strains, which included Mycobacterium bovis BCG, M. tuberculosis, and M. fortuitum, could not be differentiated by PFGE analysis. PFGE analysis was performed to differentiate 9 clinically isolated M. fortuitum strains using AsnI. All M. fortuitum strains showed different genotypes except 2 strains. Cluster analysis divided M. fortuitum strains into 2 large groups. PFGE analysis was performed to further differentiate M. fortuitum isolates using XbaI. The undifferentiated 2 M. fortuitum strains showed different PFGE patterns with Xba I. Cluster analysis of the XbaI-PFGE patterns showed more complex grouping than AsnI-PFGE patterns, which showed that XbaI-PFGE analysis was better than AsnI-PFGE in M. fortuitum genotyping. The top dissimilarity values of AsnI-PFGE and XbaI-PFGE were 0.74 and 0.75, respectively. This value was higher than that of arbitrarily primed polymerase chain reaction (AP-PCR) analysis and lower than that of restriction fragment length polymorphism (RFLP) analysis. This suggested that PFGE can be used as a supportive or alternative genotyping method to RFLP analysis.

• Journal of Microbiology
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• v.41 no.1
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• pp.1-6
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• 2003

The genetic relatedness of multidrug-resistant pneumococcal isolates of serotypes 19F and 23F was investigated. The DNA fragments digested with Sma I were resolved by pulsed-field gel electrophoresis (PFGE). PFGE analysis of 365. pneumoniae isolates showed 13 different patterns. Among 22 isolates of serotype 19F, 9 different PFGE patterns were present and 14 isolates of serotype 23F isolates represented 5 distinct PFGE patterns. Two isolates of serotype 19F and six isolates of serotype 23F shared the same PFGE pattern (Pattern I). Based on the genetic relatedness within the strains (one genetic cluster was defined as having more than 85% homology), we divided the pneumococcal strains into genefic clusters (Ⅰ, II, III, IV, V, and VI). The 22 strains of serotype 19F belonged to five distinct genetic clusters (I, II, III, IV, V and VI) and 14 strains of serotype 23F represented two genetic clusters (I and II ). These results showed that strains of serotype 19F are genetically more diverse than those of serotype 23F, Serotype 19F isolates with PFGE patterns H and I appeared to be less related to those of the remaining PFCE patterns (A to G) (less than 60% genetic relatedness), but those strains were genetically closely related with serotype 23f. These results suggest that the latter isolates originated from horizontal transfer of the capsular type 19F gene locus to 23F pneumococcal genotypes. In conclusion, the multidrug-resistant pneumococcal isolates of serotype 19f and 23F isolated in Korea are the result of the spread of a limited number of resistant clones.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1814-1818
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• 2006

Vibrio cholerae O1 El Tor isolates (n=242), collected in Korea between 1991 and 2002, were classified by NotI-digested pulsed-field gel electrophoresis (PFGE). The major types were Al before 1998 and B after 1999, among both domestic and imported cases. The prevalent PFGE types among domestic cases were consistent with the prevalent types among imported cases in the same year. These results suggest a close relationship between the domestic and imported cases of cholera in Korea.

• Journal of Microbiology and Biotechnology
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• v.5 no.1
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• pp.1-5
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• 1995

A genomic DNA of alkaliphilic bacterium, Micrococcus sp. Y-l, was analysed using the physical mapping method of pulsed-field gel electrophoresis (PFGE). Five restriction enzymes of Sspl, Hpal, Xbal, Ndel or EcoRI, which recognize the Adenine-Thymine-rich sequences of genomic DNA, were used for the generation of few (7 to 20) distinctly separate fragments, with average sizes in the range of 200～500 kb. However, the sites for Notl and SfiI, 8 base-recognizing enzymes, were highly frequent. The genome size of this strain was determined to be 4 mega base pairs (Mb) from restriction fragments separated by PFGE. This is the first case of restriction mapping in alkaliphilic bacterium.

• Korean Journal of Veterinary Research
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• v.43 no.1
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• pp.77-86
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• 2003

Pullorum disease due to Salmonella enterica subspecies enterica bioserovar Pullorum (S. pullorum) is reported to be an endemic disease in domestic poultry flocks. The pulsed-field gel electrophoresis (PFGE) subtyping method was used to assess the extent of genetic diversity and clonality of most of salmonella serotypes and other diverse bacterial species from animals and environmental samples in worldwide. Nowadays, PFGE has already been evaluated as a gold standards for molecular subtyping of salmonella serotypes compared with other molecular analysis methods. PFGE of XbaI digested chromosomal DNA from 23 strains of S. pullorum gave 5 distinctive pulsotypes (from SXPI to SXPV) with 5% confidence range of Dice coefficients, indicating that PFGE is very discriminative and that multiple clones of S. pullorum have been existed and diffused all of domestic poultry flocks industries since 1995. Two dominant pulsogroups (SXA & SXB) appeared as a major clones in this country, because they had consistently been recovered from diverse sources including both chicken organs and raw feed materials between 1995 and 1998. In addition, the matching percentage of PFGE profiles (PFP) among strains from both chickens and feed ingredients provides indirect evidence of the possible transmission of pullorum disease from contaminated raw feed ingredients for chicken production. In calculating of discrimination index (DI) for PFGE method by Simpson's index, DI was appeared as 0.917. Therefore, this index suggested that the present PFGE would seem to be a desirable and confident molecular typing method for S. pullorum strains. To our knowledge for pullorum disease, this is the first study to compare S. pullorum strains from chicken organs and feed samples using the PFGE.

• Journal of Microbiology
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• v.43 no.5
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• pp.424-429
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• 2005

In previous studies, it has been reported that both S. enteritidis, the most common serotype, and S. enteritidis Phage Type 4 (SEPT 4) isolates were identified as the most prevalent PT in domestic poultry and also in humans in Korea until 2002. The aim of this study was to analyze the genetic diversity and epidemiological properties of both PT isolates, and also to trace the source of SEPT 4 isolates from domestic poultry and humans by Pulsed-field gel electrophoresis (PFGE). In order to understand the molecular epidemiologic properties of SEPT 4 isolates, which have very similar phenotypic properties to our preliminary investigations (serotyping, phage typing, large plasmids and antibiograms), PFGE analysis with XbaI enzyme was performed on the representative SEPT 4 isolates. Thirty-six SEPT 4 isolates were analyzed and differentiated with 10 pulsed-field profiles (PFP) expressing very high discriminative ability (SID: 0.921). In PFP, SEPT 4 isolates from human patients showed a perfect genetic match with those from broiler chickens and meats. Therefore, this study was able to successfully trace the major source of SEPT 4 isolates and also to determine the usefulness of the PFGE method for genetic analysis of epidemic strains.