• Korean Journal of Clinical Laboratory Science
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• v.45 no.2
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• pp.43-47
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• 2013

This study was designed to evaluate the prevalence of ESBL genes and monitor antimicrobial resistance pattern in Escherichia coli, isolated from a hospital and a community. We tested 200 E. coli strains isolated in the hospitals and community in Chungcheong area from January to March 2012. Antimicrobial susceptibilities were tested by using the disk diffusion method. A search for ESBL genes was conducted by PCR amplification, and the genotypes were determined by direct nucleotide sequence analysis of the amplified products. An Epidemiologic study was performed by repetitive extragenic palindromic sequence-based PCR (REP-PCR). The percentage of ESBL-producing isolates was 17% for hospital associated E. coli and 11% for community associated E. coli. The ESBL gene sequencing results showed that the most common ESBL in E. coli was CTX-M-14 (19/28), followed by CTX-M-15 (9/28). The REP-PCR study also showed the genetic diversity, but there was no difference between the hospital and community associated E. coli. In this study, the most common types of class A ESBLs identified were CTX-M in the hospital and the community in Chungcheong area. ESBL-producing E. coli isolates showed diverse clonality.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.206-212
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• 2000

Since some cyanobacterial isolates under selective culturing conditions are lacking of characteristic specialized cells or showing altered morphology, the morpho-taxonomic criteria are not accurate enough to discriminate between species. Instead of morphological parameters, a method based on the single or the combination of repetitive oligonucleotides in a single PCR, repetitive oligonucleotides-primed PCR (ROP-PCR), was applied to generate DNA profiles for members of the cyanobacterial genera Anabaena and Oscillatoria, both of which are responsible for causing poisonous blooms in various freshwater systems. ROP-PCR performed on 10 isolates of the cyanobacteria with ERIC and REP sequences from gram-negative bacteria, STRR1A and LTRR sequences derived from cyanobacterial genome, and eukaryotic repetitive sequences, led to the identification of distinct genotypes, and provided specific and repeatable DNA fingerprints for cyanobacterial isolates. Grouping analysis of cyanobacterial isolates showed a signifiant difference depending on the primer used in PCR.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1643-1649
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• 2016

The aims of this study were to characterize the molecular epidemiological profiles of CTX-M-producing uropathogenic Escherichia coli isolates from a tertiary hospital in Daejeon, Korea, and to investigate the genetic diversity and compare the prevalence of sequence types (STs) in different areas. Extended spectrum β-lactamase-producing E. coli strains isolated from urine were analyzed for CTX-M, integrons, and insertion sequence common regions (ISCRs) by PCR and sequencing. Multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), phylogenetic analysis, and rep-PCR were also used for molecular typing of the isolates. Of 80 CTX-M producers, 31 and 46 expressed CTX-M-15 and CTX-M-14, respectively. MLST analysis indicated that the most prevalent ST was ST131 (n = 34, 42.5%), followed by ST38 (n = 22, 27.5%), ST405 (n = 8, 10.0%), and ST69 (n = 6, 7.5%). Most CTX-M producers harbored class 1 integrons. ST131 strains belonged to phylogenetic group B2 and showed identical rep-PCR patterns, whereas ST69, ST38, and ST405 strains belonged to phylogenetic group D; the ST38 and ST405 strains displayed the same rep-PCR pattern, respectively. ST131 and ST38 isolates showed 21 and 19 distinct types, respectively, by PFGE. In Daejeon, D-ST38 CTX-M-14 producers were relatively more prevalent than in other countries and Korean cities. Our results indicate that CTX-M-producing E. coli isolates belonged mostly to ST131 or ST38 and were more related to hospital-onset than to community-onset infections and that the bla_CTX-M gene may vary according to the ST.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.76-88
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• 2004

The purpose of this study was to investigate the distribution of Enterococci isolated from clinical specimens, and identify the aspect of antibiotic susceptibility and analyze the genetic difference by executing Rep-PCR over the strains resistant to aminoglycoside-typed antibiotics. From an assortment of the clinical specimens, 100 strains were isolated. The collection consisted of 49 strains of E. faecalis, 34 strains of E. faecium, 9 strains of E. avium, 4 strains of E. gallinarum, 3 strains of E. casseliflavus, and 1 strain of E. hirae. Ninety five were isolated from inpatients, and five strains were isolated from outpatient. Most of the E. faecalis and E. faecium were originated from urine, pus, and sputum. Most Enterococci showed 80% resistance to the cephalosprin-typed antibiotics. E. faecium showed the high resistance to all the antibiotic substances. One tenths of Enterococci showed the resistance to vancomycin. And also, most Enterococci showed the high resistance to amikacin and gentamicin as aminoglycoside-typed antibiotics. Genetic diversity of the resistant strains to aminoglycoside estimated using Rep-PCR was not significanty different.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.171.1-171
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• 1998

No Abstract, See Full Text

• Journal of Digital Convergence
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• v.14 no.10
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• pp.349-354
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• 2016

The emergence and dissemination of extended-spectrum ${\beta}$-lactamse (ESBL) producing Klebsiella pneumoniae isolates make it more difficult to treatment of bacterial infections. In our study, we detected ESBL genes and investigated antimicrobial susceptibility of K. pneumoniae isolates in Chungcheong province. In addition, clonality among the isolates was analyzed by repetitive element sequence (REP)-PCR. Twenty-one of 102 K. pneumoniae isolates produced CTX-M-14 and/or CTX-M-15 and showed high level (over 70%) resistance to third cephalosporins. CTX-M type ESBL producing K. pneumoniae strains isolated in our study showed diverse clonality and some of the isolates have been disseminated in the community. Enhancing infection control will be needed to prevent dissemination of the K. pneumoniae isolates. In addition, for more effective control of resistant bacteria it is considered necessary to monitor the database constructed through convergence of biological investigation and statistical analysis of antimicrobial resistance genes.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.169-178
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• 2010

The microbial community structure in Thailand soils contaminated with low and high levels of arsenic was determined by denaturing gradient gel electrophoresis. Band pattern analysis indicated that the bacterial community was not significantly different in the two soils. Phylogenetic analysis obtained by excising and sequencing six bands indicated that the soils were dominated by Arthrobacter koreensis and $\beta$-Proteobacteria. Two hundred and sixty-two bacterial isolates were obtained from arsenic-contaminated soils. The majority of the As-resistant isolates were Gramnegative bacteria. MIC studies indicated that all of the tested bacteria had greater resistance to arsenate than arsenite. Some strains were capable of growing in medium containing up to 1,500 mg/l arsenite and arsenate. Correlations analysis of resistance patterns of arsenite resistance indicated that the isolated bacteria could be categorized into 13 groups, with a maximum similarity value of 100%. All strains were also evaluated for resistance to eight antibiotics. The antibiotic resistance patterns divided the strains into 100 unique groups, indicating that the strains were very diverse. Isolates from each antibiotic resistance group were characterized in more detail by using the repetitive extragenic palindromic-PCR (rep-PCR) DNA fingerprinting technique with ERIC primers. The PCR products were analyzed by agarose gel electrophoresis. The genetic relatedness of 100 bacterial fingerprints, determined by using the Pearson product-moment similarity coefficient, showed that the isolates could be divided into four clusters, with similarity values ranging from 5-99%. Although many isolates were genetically diverse, others were clonal in nature. Additionally, the arsenic-resistant isolates were examined for the presence of arsenic resistance (ars) genes by using PCR, and 30% of the isolates were found to carry an arsenate reductase encoded by the arsC gene.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.218-224
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• 1997

Purpose: The antimicrobial resistance of S. pneumoniae has encountered with increasing frequency from around the world. In our country, penicillin resistant strains of S. penumococci are rapidly increasing. It has been known that colonized pneumococci in upper respiratory tract cause sinisitis, otitis media, meningitis and pneumonia. We tried to reveal the colonization rate of pneumonocci in upper respiratory tract, their antimicrobial resistance and DNA fingerprinting pattern in normal children. Methods: We got specimens from 117 children of day-care center in Seoul through oropharyngeal swab. After incubation on BAP, optochin test and slide latex agglutination test were used for identification. Antimicobial susceptibility test to penicillin, vancomycin, erythromycin and TMP-SMZ was done with disk diffusion method. Penicillin MIC was gotten through the broth microdilution method. Genotyping of 45 pneumococci was done by rep-PCR using REP1R-Dt and REP2-Dt primer. Results: The carriage rate of pneumococci in the day-care center children was 38%(45/117). The resistance of penicillin, erhthromycin, TMP/SMZ, vancomycin by the disk diffusion method are 89%, 91%, 64% and 0%, respectively. 64% of the isolates showed multiple resistance. 7 types of DNA fingerprinting were gotten and 78% of isolates belonged to three types. Conclusion: We found that the antimicrobial resistance of children attending the day-care center in Seoul was much higher than expected. We assumed that this might be due to their easy and frequent exposure to antimicrobial agents and crowded day-care center environment.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.672-677
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• 2005

The standard reference collection of strains for E. coli, the ECOR collection, was analyzed by a genome-based typing method. Seventy-one ECOR strains were subjected to repetitive extragenic palindromic PCR genome fingerprinting with BOX primers (BOX-PCR). Using a similarity value of 0.8 or more after cluster analysis of BOX-PCR fingerprinting patterns to define the same genotypes, we identified 28 genotypes in the ECOR collection. Shannon's entropy-based diversity index was 3.07, and the incident-based coverage estimator indicated potentially 420 genotypes among E. coli populations. Chi-square test of goodness-of-fit showed statistically significant association between the genotypes defined by BOX-PCR fingerprinting and the groups previously defined by multi-locus enzyme electrophoresis. This study suggests that the diversification of E. coli strains in natural populations is actively ongoing, and rep-PCR fingerprinting is a convenient and reliable method to type E. coli strains for the purposes ranging from ecology to quarantine.ine.

• Korean Journal of Microbiology
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• v.49 no.3
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• pp.228-236
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• 2013

Campylobacter jejuni is one of important food-borne pathogens causing human gastroenteritis. We isolated 42 strains of C. jejuni from diarrhea patients and 4 food-poisoning outbreaks in 2010, Gyeonggi-do. In this study, 42 strains were tested for genetic characteristics, the serotype distribution and antimicrobial resistant rate. The presence of hipO (100%), cdtB (100%), and mutated gyrA (95.2%) genes was detected in C. jejuni by polymerase chain reaction (PCR). Detection of mutated gyrA gene correlated with ciprofloxacin resistance. Forty isolates had mutated gyrA gene and were actually resistant to ciprofloxacin. Furthermore, comparing the gyrA DNA sequence data, ciprofloxacin-resistant isolates had a mutation of the DNA sequence from ACA (threonine) to ATA (isoleucine). But 41 strains (97.6%) of patient isolates were susceptible to erythromycin and azithromycin. A total of 35.7% among 42 C. jejuni isolates were identified into 4 different serotypes. The serotype distribution of C. jejuni strains were shown to be HS2(B), HS3(C), HS4(D), HS19(O). To investigate the genotypes of C. jejuni isolated in Gyeonggi province, repetitive sequence polymerase chain reaction (rep-PCR) analysis and SmaI-digested pulsed-filed gel electrophoresis (PFGE) profile analysis were performed. From the PFGE analysis of 42 C. jejuni strains, 12 clusters of PFGE profile were obtained. On the other hand, 11 clusters of rep-PCR profile were obtained from 42 strains of C. jejuni.