• Korean Journal of Microbiology
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• v.45 no.2
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• pp.163-169
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• 2009

This study was performed to investigate the type of extended-spectrum $\beta$-lactamases (ESBL) produced by bacteria isolated from the sewage of wastewater treatment plant at Minragdong, Suyong-gu in Busan. The facility is located at sushi restaurants and guides its drain water to the wastewater treatment plant at Yonghodong, Nam-gu in Busan. Samples were collected on January, 2009. A total of 19 strains were selected as potential ESBL positive strains through a double disk synergy test. On the basis of the results from biochemical tests including indole, methyl-red, Voges-Proskauer, Simmon's citrate, decarboxylase-dihydrolase and sugar-fermentation tests, the 19 strains were identified with 16 strains of Escherichia coli and 3 strains of Klebsiella pneumoniae. Out of 19 strains, 4 transconjugants against Escherichia coli J53, which is sodium azide resistant recipient strain, were obtained. The plasmids isolated from transconjugants were used for PCR analysis. The type of each extended-spectrum $\beta$-lactamase (ESBL) produced by the strains was determined on the basis of isoelectric focusing analysis and DNA sequencing. The results indicated that the types of ESBL from Klebsiella pneumoniae were SHV-12 (3 strains), and Escherichia coli was SHV-12/TEM-1 (1 strain), respectively.

• Biomedical Science Letters
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• v.13 no.4
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• pp.293-304
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• 2007

The emergence of extended spectrum $\beta$-lactamase (ESBL) producing bacteria is worldwide concern. Until recently, the most frequently identified strains in the Republic of Korea were E. coli and Klebsiella spp. The incidence of resistance to extended spectrum $\beta$-lactam antibiotics is increasing in Wonju city, Korea. Total 57 strains of ESBL producing E. coli and Klebsiella species were isolated from Wonju Christian Hospital during a 9 month-period from April to December, 2003. To determine the prevalence and genotypes of the ESBL producing clinical isolates, antibiotic susceptibility and ESBL activity test by VITEK system and double disk synergy (DDS) test, and PCR based genotyping were performed. Fourteen (82%) isolates of 17 ESBL producing E. coli were found to have $bla_{TEM}$ gene and 5 (29%) isolates were found to have $bla_{CTX-M}$ gene by polymerase chain reaction (PCR). Thirty (75%) isolates of 40 ESBL producing Klebsiella species with $bla_{TEM}$ gene, 38 (95%) isolates with $bla_{SHV}$ gene, and 7 (20%) isolates with $bla_{CTX-M}$ type gene were also identified. Enterobacterial repetitive intergenic consensus (ERIC) PCR and similarity index by dendrogram for genetical similarity to band pattern of each clinical isolates were examined. ESBL producing E. coli were grouped into 6 clusters up to 84% of similarity index and Klebsiella species were grouped into 12 clusters up to 76% of similarity index. In conclusion, ESBL producing clinical isolates were characterized with the results from antimicrobial resistance pattern and genetical similarity using ERiC PCR.

• Journal of Life Science
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• v.23 no.5
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• pp.703-709
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• 2013

The aim of this study was to investigate the prevalence of Extended-spectrum ${\beta}$-lactamase (ESBL) gene and quinolone resistance determinant (qnr) and the pattern of antibiotic resistance in the ESBL-producing Escherichia coli clinical isolates. The 42 ESBL-producing strains from total 274 isolates were detected using a double disk synergy test. They were isolated from various specimens, such as urine (28 strains), sputum (6 strains), pus (3 strains), wound (2 strains), blood (2 strains), and tissue (1 strain). Using the PCR with the specific primers ESBL, ESBL and qnr gene types were determined. Thirty-five strains possessed one or two ESBL genes. CTX-M-1 type was the most abundant followed by CTX-M-9 type and TEM, but SHV, CTX-M-2, and CTX-M-8 gene types were not detected. qnr gene types were detected from ten isolates in the order of qnrB4, qnrB1, and qnrS. Coexistence of ESBL and qnr genes was found. ESBL-producing isolates showed high resistance against some antibiotics, such as cefotaxmie (80.0%), levofloxacin (82.9%), and ampicillin (100%). Neither a synergy effect from the coexistence of ESBL and qnr genes on antibiotic resistance nor a correlation between the production of qnr gene and quinolone resistance were found.

• Pediatric Infection and Vaccine
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• v.22 no.1
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• pp.29-35
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• 2015

Purpose: The purpose of this study was to investigate the clinical characteristics and outcome of febrile urinary tract infections (UTIs) caused by community-acquired extended-spectrum ${\beta}$-lactamase (CA-ESBL)-producing and -nonproducing bacteria. Methods: We analyzed febrile UTIs in children hospitalized at Gachon University Gil Medical Center from January 2011 to December 2013 through retrospective data collection from their medical records. Results: Among pathogens causing 374 episodes of UTIs, the proportion of ESBL-producing bacteria was 13.1% (49/374). The proportion of ESBL-producing Escherichia coli and Klebsiella spp. was 13.6% (48/354) and 5.0% (1/20), respectively. There was no significant difference between the CA-ESBL and CA non-ESBL groups in duration of fever ($4.2{\pm}2.7$ vs. $3.7{\pm}2.1$ days, P=0.10) and bacterial eradication rate with empirical antibiotics (100% vs. 100%). The risk of cortical defects on renal scan significantly depended on existence of vesicoureteral reflux rather than ESBL production of pathogen. Conclusions: There was no significant difference between the CA-ESBL and CA non-ESBL groups in renal cortical defects and clinical outcome. Careful choice of antibiotics is important for treatment of community-acquired UTI in children.

• Pediatric Infection and Vaccine
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• v.23 no.3
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• pp.223-228
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• 2016

Shigella is a common cause of bacterial enteritis worldwide. Shigella sonnei accounts for 90% of Shigella infections and Shigella flexneri is rarely reported in Korea. Although the incidence of Shigella infection has decreased, the incidence of organisms with antibiotic resistance has gradually increased in Korea. An outbreak of extended-spectrum ${\beta}-lactamase$ (ESBL)-producing S. sonnei in children was reported in Korea; however, ESBL-producing S. flexneri has not yet been reported. We report the first two cases of multidrug-resistant CTX-M-14-producing S. flexneri infections in Korean children.

• Biomedical Science Letters
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• v.12 no.3
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• pp.267-274
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• 2006

Klebsiella pneumoniae is the leading cause of nasocomial infection and the most commonly isolated from clinical specimens. $Extended-spectrum-{\beta}-lactamase$ (ESBL) producing K. pneumoniae infection was associated with a significantly longer duration of hospital stay and greater hospital charges. The purpose of this study is to investigate the antibiotic resistant patterns and the DNA fingerprint types of extended-spectrum ${\beta}-lactamase$ (ESBL) producing K. pneumoniae. 223K. pneumoniae strains were collected from three general hospitals with more than 500 beds in Busan, Korea from September 2004 to October 2005. The minimum inhibitory concentration (MIC) of antibiotics was measured using the Gram negative susceptibility (GNS) cards of VITEK (Vitek system, Hazelwood Inc., MO). Random amplified polymorphic DNA method was used to detect DNA fingerprint of the organisms. Of the 226 K. pneumoniae isolates 65 ESBL-producing K. pneumoniae strains were detected by the Vitek system and confirmed by the double-disk synergy test. All the 65K. pneumoniae strains were resistant cefazolin, cefepime, ceftriaxone and aztreonam, and 83.0% of the organisms were resistant to ampicillin/sulbactam, 66.1% to tobramycin, 67.6% to piperacillin/tazobactam, 61.5% to ciprofloxacin, and 47.6% to trimethoprim/sulfamethoxazole and 43.0% to gentamicin. The RAPD patterns were distincted as 10 types by three random 10-mer primers (208, 272, 277). Among ten type patterns, three types (Ic, IIb, IIIe) were remarkably represented at patient of internal department, nerve surgery department, general surgery department, and neonatal room. These results indicate that RAPD can be useful for DNA of strains typing in the epidemiological investigations. Therefore more investigation are needed in order to prevent the ESBL type-producing K. pneumoniae from spreading resistance to oxyimino cephalosphorin antibiotics.

• 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 the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2295-2302
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• 2014

The study aims primarily to evaluate the resistance of antibiotics and the prevalence of these enzymes among Escherichia coli the most frequent isolate of Enterobacteriaceae producing Extended-Spectrum ${\beta}$-Lactamase(ESBLs), to differentiate the types of enzymes in these isolates. Total 74(26.2%) Strains of producing ESBLs among the 282 E. coli isolates were isolated from hospitals of Chungcheong area (Daejeon, Chungnam, and Chungbuk) during a 6 month-period from February to July, 2013. 282 E. coli isolates including ESBL shown resistance rates of aztreonam 30.8%, Cefotaxim 30.9%, and Ceftazidime 32.2%, 74 isolates producing ESBLs in E. coli were resistant rates to Aztreonam 58.1%, Cefotaxim 100%, and Ceftazidime 63.5% of ${\beta}$-lactam antibiotics. CTX-M-2 (48 isolates) was the most prevalent type of ESBLs identified. Followed the order of frequency by PER-1 (28 isolates), VEB-1 (26 isolates) and CTX-M-8 (20 isolates), of the 74 isolates, 2 isolates only showed GES-1 in Chungnam province. Accurate identification type of ESBLs would aid in hospital infection control. This would give aid to the physician to prescribe more appropriate antibiotics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1191-1196
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• 2013

Among Gram-negative pathogens in Korea, the incidence of resistance to third generation cephalosporins is becoming an ever-increasing problem. The production of extended-spectrum ${\beta}$-lactamase (ESBL) is the main mechanism of bacterial resistance to a third-generation cephalosporins and monobactams. Accurate identification of the ESBL genes are necessary for surveillance and epidemiological studies of the mode of transmission in the hospital. This study was conducted to detect the genes encoding ESBL of 46 K. penumoniae isolated from Daejeon, Chungnam and Chungbuk regional university hospitals from February to August in 2012. The phenotypes of the isolated specimens were examined according to the combination disc test (CDT) by the Clinical and Laboratory Standards Institute (CLSI). Forty two ESBL producing K. penumoniae isolates could be detected using ceftazidime (CAZ) discs with and without clavulanate (CLA). By CDT, 42 K. pneumoniae strains were confirmed to be ESBL strains. Genotyping was performed by multiplex PCR with type-specific primers. By PCR analysis, TEM gene in 46 strains, SHV gene in 37 strains and CTX-M genes in 14 strains were identified. Ten isolates did carry genes encoding ESBLs of all types TEM, SHV and CTX-M. The multiplex polymerase chain reaction (PCR) analysis was better to detect and differentiate ESBL producing K. penumoniae strains in clinical isolates.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.590-596
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• 2001

A new extended-spectrum ${\beta}-lactamase$ with an isoelectric point (pl) of 6.2 was detected in Klebsiella pneumoniae Fl 61 that was isolated from a patient with infection. This strain was highly resistant to the third or fourth generation cephalosporins such as cceftazidime ceftriaxone, cefoperzaone, and cefpirome. Analysis of this strain by the double disk diffusion test showed synergies between amoxicillin-clavulanate (AMX-CA) and cefotaxime, and AMX-CA and aztreonam, which suggested that this strain produced a extended-spectrum ${\beta}-lactamase$ (ESBL). Cenetic analysis revealed that the resistance was due to the presence of a 9.4-kb plasmic, designated as pkpl 61, encoding for new ${\beta}-lactamase$ gene (bla). Sequence analysis showed that a new bla gene of pkpl 61 differed from $bla_{TEM-1}$ by three mutations leading to the following amino acid substitutions: $Val_{84}{\rightarrow}lie,{\;}Ala_{184}{\rightarrow}Val,{\;}and{\;}Gly_{238}{\rightarrow}Ser$. These mutations have not been reported previously in the TIM type ${\beta}-lactamases$ produced by clinical strains. The novel ${\beta}-lactamase$ was overexpressed in E. coli and purified by ion exchange chromatography on Q-Sepharose and CM-Sepharose, and then further purified by gel filtration on Sehadex G-200. The catalytic activity of th8 purified ${\beta}-lactamase$ was confirmed by the nitrocefin disk.