• Journal of the Korean Applied Science and Technology
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• v.39 no.6
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• pp.916-923
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• 2022

Water samples were collected from three spots(Namcheon, Changwoncheon and Cheongwoonji) in Changwon and genomic DNA was isolated from them. Quantitative PCR was performed with the isolated DNA as template and primers targeting five different class A extended-spectrum beta-lactamase(ESBL) genes(bla_OXA-1, bla_SHV, bla_TEM, bla_CTX-M-1, bla_CTX-M-9). The number of total ESBL genes from each sample showed large variations between each sample. Thirty nanograms of DNA from Namcheon contained 1.93×10⁶ copies of ESBL genes whereas the same amount of DNA from Changwoncheon contained 1.47×10⁵ copies of ESBL genes. However, the same amount of DNA from Cheongwoonji pond contained only 9.5×10³ copies of ESBL genes. The ratio of each ESBL genes showed little difference between Namcheon river and Changwoncheon river, but DNA from Cheongwoonji pond showed a large difference from the rest. bla_OXA-1 gene was present at 65.3%, and bla_CTX-M-1 gene 33.6% for Namcheon comprising together almost 99%. bla_OXA-1 gene was present at 64.1%, and bla_CTX-M-1 gene 19.1% for Changwoncheon comprising together over 83%. bla_CTX-M-1 gene was present at 87.5% and bla_CTX-M-9 genes 9.8% for Cheongwoonji, a pond which is a closed and isolated environment.

• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1716-1723
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• 2017

The rapid dissemination of extended-spectrum ${\beta}$-lactamase (ESBL)-producing Escherichia coli has significantly contributed to public health hazard globally. A total of 281 E. coli strains recovered from pigs and chickens between 2009 and 2015 in South Korea were analyzed for ESBL production. ESBL phenotypes were recognized in 14 E. coli isolates; ten and three ESBL-producing isolates carried only $bla_{CTX-M}$ and $bla_{CMY}$ genes, respectively, and one isolate harbored both genes. The predominant CTX-M and CMY types were CTX-M-15 (n = 8) and CMY-2 (n = 3). We also detected ESBL-producing isolates harboring $bla_{CTX-M-65}$, $bla_{CTX-M-14}$, $bla_{CMY-6}$, $bla_{DHA-1}$, and $bla_{TEM-1}$ genes. All ESBL-producing isolates showed resistance to the extent of the fourth generation cephalosporins, along with multidrug resistance. CTX-M-15-producing isolates showed higher MIC values than CTX-M-14- and CTX-M-65-producing isolates. The $bla_{CTX-M}$ and $bla_{CMY}$ genes have the potential to be transferable. The spreading of $bla_{CMY}$ and $bla_{CTX-M}$ genes was arbitrated mainly via Frep and IncI1 plasmids. Our isolates showed clonal diversity in PFGE analysis. This is the first report of E. coli isolates carrying $bla_{CMY-6}$ in chicken from South Korea. The emergence of CMY-6 ESBLs in a population of poultry suggests that extensive screening with long-term surveillance is necessary to prevent the dissemination of ESBL from chicken to human.

• Korean Journal of Microbiology
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• v.36 no.3
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• pp.221-227
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• 2000

This study was performed to investigate the biological characteristics of twenty isolates of extended spectnlm $\beta$-lactamase (ESBL) producing Klebsiellapnezm~onia collected kom the various clinical specimens of three hospitals in Pusan. Isoelectric focusing (IEF) and PCR were used to determine the types of $\beta$-lactamase gene in this study. Twenty isolates of ESBL producing Klebsiellnp~ieun~or~iae could be divided by PCR, such as TEM type (I1 strains), SHV type (8 strains); non TEM non SHV type (1 strain). In the isoelechic focusing test, the PI of TEM type was 5.2-6.0 and that of SHV type was 6.9-7.4. According to the pI value and PCR bands, twenty strains of ESBL Klebsiellapneumoniae were divided into 5 types: TEM type @I 5.2-6.0; 1080 bp on PCR band), TEM + SHV type (pI 5.2-6.0; andpI 7.0-7.4; 1080 bp and 599 bp on PCR band), SHV type (pl7.0-7.4; 599 bp on PCR band), non TEM non SHV type, and otber type (PCR result was SHV type but pI was not detected).

• Childhood Kidney Diseases
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• v.23 no.1
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• pp.29-35
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• 2019

Purpose: We aimed to determine characteristics of host, causative organisms, and antibiotic susceptibility of bacteria in pediatric patients with UTI living in metropolitan area of Korea. Methods: Retrospective investigation was done for the causative organisms of UTI in 683 pediatric cases treated at Ajou University Hospital from 2012 to 2017. Patients were classified into Escherichia coli and non-E. coli group, where E. coli group was subdivided into ESBL(+) and ESBL(-) groups based on whether the bacteria could produce extended spectrum beta-lactamase (ESBL). Antibiotic susceptibility of the causative organism was also determined. Results: A total of 683 UTIs occurred in 550 patients, of which 463 (67.8%) were first-time infection and 87 (32.2%) were recurrent ones (2-7 recurrences, 2.52 average), and 64.9% were male and 35.1% were female. The most common causative organism was E. coli (77.2%) and ESBL(+) E. coli was found in 126 cases. The susceptibility of E. coli to 3rd or 4th generation cephalosporin was relatively higher than that to ampicillin or amoxicillin/clavulanic acid. ESBL(+) E. coli showed higher resistance rate to 3rd or 4th generation cephalosporin than ESBL(-) E. coli. Conclusion: New treatment guideline should be considered due to the incidence of ESBL(+) E. coli increased up to one quarter of UTI cases.

• Korean Journal of Microbiology
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• v.50 no.2
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• pp.114-118
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• 2014

A total of 122 ESBL-producing intestinal bacteria were collected from regional hospitals in the Chungcheong area. Combination disk test (CDT) was performed for antimaicrobial susceptability using cefotaxime and cefotaxime/clavulanate according to Clinical Laboratory Standard Institute (CLSI). Mutiplex PCR using specific primers was performed for a detection of ESBL-genotypes and enterobacterial repetitive intergenic consensus (ERIC)-PCR was carried out for the tracking of molecular epidemiology. In the confirmation test using CDT, 73 out of 76 (96.1%) ESBL-producing Escherichia coli and 43 out of 46 (93.4%) ESBL-producing Klebsiella pnemoniae were positive. In the multiplex PCR, 60.5% of E. coil were positive for CTX-M-2 type gene and 56.5% of K. pneumoniae were positive for VEB -1 type gene. In the ERIC-PCR, E. coil isolates formed 5 clusters and K. pneumoniae isolates were grouped into 4 clusters depending on region. Genotypes of clinical isolates are useful for detection and differentiation of ESBL producing intestinal bacteria. The ERIC-PCR method is thought to be helpful for establishing a regional surveillance system for infection due to its formation of different clusters depending on region.

• Biomedical Science Letters
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• v.19 no.3
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• pp.275-279
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• 2013

Etiological agents of extended spectrum ${\beta}$-lactamase (ESBL) producing uropathogenic Escherichia coli (UPEC) have become a major problem in urinary tract infections. The purpose of this study was to compare the molecular characteristics of ESBL producing UPEC strains isolated from 1989 and 2010. A total of 301 strains of UPEC clinical isolates was collected from Korean healthcare facility in 1989 (126 strains) and in 2010 (175 strains). UPEC clinical isolates were analyzed by multiplex polymerase chain reaction method (ESBL related bla genes and phylogenetic groups) and amplified fragment length polymorphism (AFLP). Among 301 isolates, ESBL producing UPEC were 8 strains (6.3%) in 1989 isolates and 35 strains (20%) in 2010 isolates. The rate of bla genes in ESBL producing UPEC from 1989 isolates and 2010 isolates were $bla_{TEM}$ (75% and 85.7%), $bla_{CTX-M}$ (0% and 91.4%), $bla_{OXA}$ (25% and 20%), $bla_{PER}$ (0% and 2.9%). The distribution of phylogenetic groups in 1989 isolates and 2010 isolates were A (37.5% and 11.4%), B2 (12.5% and 51.4%), and D (50% and 37.1%). The most prevalent ESBL related bla gene and phylogenetic group were $bla_{CTX-M}$ (91.4%) and B2 (51.4%) in 2010 isolates, while $bla_{CTX-M}$ was not detected in 1989 isolates. Among 43 ESBL producing UPEC were grouped into 12 clusters up to 76% of genetic similarities by AFLP analysis. During past twenty one years, the rate of the ESBL producing UPEC strains in 2010 isolates was increased than that of in 1989 isolates. Also, the most prevalent ESBL related bla gene has been changed from $bla_{TEM}$ to $bla_{CTX-M}$.

• Journal of Life Science
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• v.17 no.10
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• pp.1426-1433
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• 2007

To investigate the antibiotic resistant patterns of the bacteria producing ESBL, we isolated one organism of Klebsiella pneumoniae from a clinical laboratory in Busan. The organism that produces ESBL gene was detected by double disk synergy test and the presence of three ESBL genes (TEM-1, SHV-12, CTX-M-15) was confirmed by polymerase chain reaction and DNA sequencing analysis. To analyse the characteristics of three ESBL genes, we performed transconjugation, transformation and cloning experiment with the organism. The MIC of Klebsiella pneumoniae was revealed that ceftazidime, cefotaxime and ceftriaxone were $256\;{\mu}g/ml,\;128\;{\mu}g/ml\;and\;128\;{\mu}g/ml$ respectively. The MIC of conjugant (E. coli $RG176^{Na(r)}$) af was revealed that ceftazidime, cefotaxime and ceftriaxone were $256\;{\mu}g/ml,\;64\;{\mu}g/ml\;and\;128\;{\mu}g/ml$ respectively. The MIC of transformant (E. cofi $DH5{\alpha}$) was revealed that ceftazidime, cefotaxime and ceftriaxone were $128\;{\mu}g/ml,\;32\;{\mu}g/ml,\;and\;32\;{\mu}g/ml$ respectively, The MIC of cloned organism of SHV-12 gene (E. coli $DH5{\alpha}$) was revealed that ceftazidime, cefotaxime and ceftriaxone were $128\;{\mu}g/ml,\;8\;{\mu}g/ml,\;and\;32\;{\mu}g/ml$ respectively. The results indicated that MIC of conjugant was higher than MIC of transformant and also SHV-12 gene were not resistant against cefotaxime antibiotic.

• 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 Digital Convergence
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• v.13 no.12
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• pp.313-318
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• 2015

We investigated the prevalence of extended spectrum ${\beta}$-lactamase (ESBL) genes and 16S rRNA methyltransferase genes to study antimicrobial resistance mechanisms of Enterobacter cloacae strains isolated from a university hospital in the Chungcheong province of Korea. Eight of the bacteria strains involved in this study contained CTX-M-15 type ESBL. Among 8 strains harboring the ESBL gene, 3 strains also harbored armA gene. The three isolates showed resistance to antimicrobial agents belonged to third cephalosporin, aminoglycoside, and fluoroquinolones. Furthermore, interspecies plasmid transfer of the antimicrobial resistant genes may induced horizontal spreading of the genes and emergence of multidrug resistant bacteria. Therefore, surveillance for existence of antimicrobial resistance determinants is important to prevent distribution of antimicrobial resistant strains.

• Journal of Yeungnam Medical Science
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• v.30 no.2
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• pp.83-89
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• 2013

Background: The prevalence of extended-spectrum ${\beta}$-lactamase (ESBL)-producing Escherichia coli is increasing rapidly worldwide. Treatment options for ESBL-producing E. coli are limited, and infections caused by this organism are associated with improper antibiotic use, a long hospital stay, and increased mortality. Thus, the assessment and early recognition of the risk factors of nosocomial infections due to ESBL-producing E. coli are important for the infection control and proper treatment. Methods: A case-control study was performed that included nosocomial episodes of ESBL-producing E. coli bacteremia at a tertiary care hospital from January 2004 to December 2007. For each case patient, three controls were randomly selected and data on predisposing factors were collected. Results: Fifty-five cases of nosocomial ESBL-producing E. coli bacteremia were studied. Carbapenem usage (OR: 11.3, 95% CI: 1.1-115.9, p=0.041), quinolone usage (OR: 4.5, 95% CI: 1.1-18.8, p=0.042), biliary obstructive disease (OR: 11.8, 95% CI: 3.0-46.7, p<0.001) and the APACHE II score (OR: 1.3, 95% CI: 1.2- 1.5, p<0.001) were analyzed as independent risk factors of nosocomial ESBL-producing E. coli bacteremia. Conclusion: Our results showed that physicians caring for patients with risk factors of nosocomial bacteremia should consider ESBL-producing E. coli as the causative organisms of the disease.