• 디지털융복합연구
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• 제13권12호
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• pp.313-318
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• 2015

본 연구에서는 세균의 항균제 내성기전을 연구하기 위해 일개의 대학병원에서 분리된 Enterobacter cloacae를 대상으로 extended spectrum ${\beta}$-lactamase (ESBL) 및 16S rRNA methyltransferase 유전자를 검출하고 항균제 감수성 양상을 조사하였다. 대상균주 중 총 8 균주가 CTX-M-15형 ESBL을 생성하는 것으로 확인되었으며 이 균주들 중 3 균주는 16S rRNA methyltransferase의 한 종류인 armA 유전자도 동시에 가지고 있는 것으로 나타났다. CTX-M-15형 ESBL 유전자와 armA 유전자를 동시에 가지고 있는 E. cloacae는 3세대 cephalosporin 계열 및 aminoglycoside 계열의 항균제 뿐 만 아니라 fluoroquinolone 계열의 항균제에도 내성을 보였다. 더구나 이러한 항균제 내성 유전자들은 플라스미드를 통해 다른 세균으로 전달 될 수 있어 다제내성 세균의 출현 및 확산을 촉진 할 수 있다. 따라서 E. cloacae를 대상으로 지속적인 항균제 내성 유전자를 모니터링 하는 것은 항균제 내성 확산방지를 위해 중요할 것으로 사료된다.

• 한국동물위생학회지
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• 제43권2호
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• pp.79-88
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• 2020

The aim of this study was to investigate the prevalence of CTX-M β-lactamase and plasmid-mediated quinolone resistance (PMQR) genes, and the pattern of antibiotic resistance in cefotaxime-resistant gramnegative bacteria. A total 126 gram-negative bacteria were isolated from hospitalized dogs and cats between 2018 and 2019. The most predominant isolates were E. coli (n=41), followed by Pseudomonas aeruginosa (n=25), Proteus mirabilis (n=14), Klebsiella pneumoniae (n=9), Sphingomonas paucimobilis (n=7), and Enterobacter cloacae and Serratia marcescens (respectively, n=5). Cefotaxime-resistant isolates were identified in 26.2% (33 isolates) of 126 gram-negative bacteria. CTX-M type β-lactamase were found in 15 isolates (10 E. coli, 1 Ent, cloacae and 4 K. pneumoniae, respectively). Among the CTX-M producing gram-negative bacteria, CTX-M-1 and CTX-M-9 were detected in 10 (66.7%) and 5 (33.3%) isolates, respectively. While, CTX-M-2 and CTX-M-8 were not found. PMQR genes were detected in 12 (36.4%) isolates (4 E. coli, 2 Ent, cloacae and 6 K. pneumoniae, respectively), and the predominant PMQR gene was aac(6')-lb-cr (n=9), followed by qnrB (n=8) and qnrS (n=1) alone or in combination. qnrA and qepA were not found. Additionally, 9 (60%) of 12 PMQR positive isolates were co-existence with CTX-M-1 or CTX-M-9. CTX-M or PMQR producing isolates showed highly resistance to penicillins (100%), cephalosporins (100~66.7%), monobactams (72.2%), and non-β-lactam antibiotics (94.4~61.1%) such as quinolones, trimethoprim/sulfamethoxazole, tetracycline and gentamicin. These findings showed CTX-M-1, CTX-M-9, aac(6')-lb-cr and qnrB were highly prevalent in cefotaxime-resistant Enterobacteriaceae isolates from companion animals in our region. Moreover, PMQR genes were closely associated with CTX-M type β-lactamase.

• 한국동물위생학회지
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• 제37권4호
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• pp.225-231
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• 2014

In this study, 185 cefotaxime-resistant Escherichia coli were isolated from different stages of a wastewater treatment plant (WWTP) in Daegu in Korea. Among them, 99.5% (184 isolates) originated from raw sewage and 0.5% (1 isolates) from the final effluent. Cefotaxime-resistant E. coli were high resistant to ampicillin, piperacillin, cefazolin, cephalothin, cefachlor and cefamandole (99.5~100%). About 93% of the cefotaxime-resistant E. coli were extended-spectrum ${\beta}$-lactamases (ESBL)-producing E. coli. The $bla_{TEM+CTX}$ gene was the most predominant of the ESBL genes (72.5%), followed by $bla_{CTX-M}$ (16.2%), $bla_{TEM}$ (8.7%), $bla_{TEM+CTX+SHV}$ (1.1%), $bla_{TEM+SHV}$, $bla_{TEM+OXA}$, and $bla_{TEM+CTX+SHV}$ (respectvely 0.5%). Class 1 and 2 integron were found in 49.7% and class 3 integron was not found. All of integron positive isolates were multiresistant (i.e. resistant to four or more antibiotics). Our findings showed WWTP is contaminated with antibiotic resistant bacteria with resistance genes.

• 생명과학회지
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• 제10권4호
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• pp.380-387
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• 2000

Recently Vibrio sp. are the most frequently isolated microorganism, which causing food poisoning. We investigated the detection of toxin genes and effect of chitosan to toxin genes with PCR. Thirty strains of Vibrio sp. were isolated from sea water and sea products through biological and biochemical tests. Out of 30 strains, 8 were identified as V. parahemolyticus, 7 as V. mimcus, 6 as V. damsela, 5 as V. vulnificus, 4 as V. alginoyticus. In detection of ctx, tdh, and t고 as food poisoning-causing toxin genes, ctx from 7 strains, trh from 4 strains and tdh from 6 strains were detected. Among toxin genes detected strains, we selected V. vulnificus-2 V. damsela-1 and V. parahemolyticus-7. As adding chitosan solution to PCR product of 3 strains, the amplified DNA bands were not detected over 450$\mu\textrm{g}$/$m\ell$ concentrantion of chitosan. Over the result, chitosan is thought to influence the detection of toxin gene.

• 대한의생명과학회지
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• 제11권3호
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• pp.389-396
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• 2005

Resent studies have reported increased isolation of extended-spectrum $\beta-lactamase$ (ESBL) producing strains at several hospital in Korea. We studied to investigate the isolation rates of ESBL strains from clinical isolates of Klebsiella pneumoniae and to characterize differences in types using analyses of genotyping and antibiotic susceptibility test. Antibiotic susceptibility test with confirmation of ESBL by double disk synergy test was performed on the 54 ESBL strains of Klebsiella pneumoniae from a hospital in Busan. Transfer of resistant gene in ESBL strains resistant to 3rd generated antibiotics was confirmed by transconjugation test using E. coli $RG176^{nal(r)}$. blaTEM, blaSHV, blaCTX-M genes were detected by PCR. ESBL producing strains had 100% of resistant rate to ampicillin, azteronam, cefazolin, cefepime and ceftriaxone ($\beta-lactam$ antibiotics). Forty strains of bla TEM$(74\%)$, 41 strains of bla SHV $(76\%)$, 23 strains of bla CTX-M $(43\%)$ were found, respectively. The strains had one or more genes. They had high resistant rates to $\beta-lactam$ antibiotics including cephalosporin. The resistant rates of strains with multiple resistant genes were higher than those of strains with single resistant gene.

• 생명과학회지
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• 제17권10호
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• pp.1426-1433
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• 2007

우리는 ESBL 유전자를 포함하는 세균의 항생제 내성 패턴을 조사하기 위해서 부산에 있는 임상실험실로부터 Klebsiella pneumoniae 한 균주를 수집하였다. 그 세균은 이중 디스크 확산법에 의해 ESBL을 생성하는 Klebsiella pneumoniae라는 것이 밝혀졌고 PCR과 DNA 염기서열분석을 통하여 세 가지의 ESBL gene (TEM-1, SHV-12, CTX-M-15)이 포함되어 있다는 것이 확인되었다. 그리고 그 세 가지 유전자의 특징을 알아내기 위해서 우리는 이 균주로부터 교차접합시험, 형질전환시험, 클로닝(SHV-12 gene)등을 이용하여 재조합균주를 배양하였다. 이렇게 각기 재조합된 균주들을 한천평판희석법을 이용하여 3세대 cephalosporin 항생제 (ceftazidime, cefotaxime, ceftriaxone)에 대한 최소억제농도의 측정하고 비교 분석하였다. Klebsiella pneumoniae (NO. 60031)의 MIC는 ceftazidime ($30\;{\mu}g/ml)$, cefotaxime ($30\;{\mu}g/ml$), ceftriaxone ($30\;{\mu}g/ml$)이 각각 ${\geq}256\;{\mu}g/ml,\;128\;{\mu}g/ml,\;128\;{\mu}g/ml$이었고, E. coli $RG176^{Na(r)}$에 교차접합 시킨 conjugant 균주의 MIC는 ceftazidime, cefotaxime, ceftriaxone이 각각 ${\geq}256\;{\mu}g/ml,\;64\;{\mu}g/ml,\;128\;{\mu}g/ml$이었다. E. coli $DH5{\alpha}$에 형질전환 시킨 transformant 균주의 MIC는 ceftazidime, cefotaxime, ceftriaxone이 각각 $128\;{\mu}g/ml,\;32\;{\mu}g/ml,\;32\;{\mu}g/ml$를 나타내었고, SHV-12 gene 만을 분리하여 E. coli $DH5{\alpha}$에 클로닝 시킨 균주는 ceftazidime, cefotaxime, ceftriaxone이 각각 $128\;{\mu}g/ml,\;8\;{\mu}g/ml,\;32\;{\mu}g/ml$을 나타내었다. 결국 conjugant 균주와 transformant 균주는 세 가지의 내성유전자를 가졌다는 공통점은 있으나 conjugant 균주의 MIC가 transformant 균주의 MIC보다 높게 나타나는 차이점을 보였다. 또한 SHV-12 gene 만을 분리하여 E. coli $DH5{\alpha}$에 클로닝 시킨 균주는 ceftazidime, ceftriaxone에 내성을 발현하였지만 cefotaxime에 대해서는 내성을 발현하지 않았다.

• Journal of Microbiology and Biotechnology
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• 제16권6호
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• pp.889-895
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• 2006

To investigate the antibiotic-resistant patterns and the gene types of extended-spectrum $\beta$-lactamase (ESBL)-producing Klebsiella pneumoniae, we collected 226 Klebsiella pneumoniae strains 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, U.S.A.). 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. TEM (Temoniera) type, SHV (sulfhydryl variable) type, and CTX-M (cefotaxime) type genes were detected by polymerase chain reaction. All 65 K. pneumoniae strains were resistant to ampicillin, 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. TEM-type ESBLs (TEM-1 type, -52 type) were found in 64.6% (42 of 65) of the isolates, SHV-type ESBLs (SHV-2a type, -12 type, -28 type) in 70.7% (46 of 65) of isolates, and CTX-M-type ESBLS (CTX-M-15 type) in 45% (29 of 65) of isolates. Of the 65 ESBL-producing K. pneumoniae strains, two strains were found to harbor blaSHV-28, which were detected in Korea for the first time. Therefore, more investigation and research on SHV-28 are needed in order to prevent the ESBL type-producing K. pneumoniae from spreading resistance to oxyimino cephalosporin antibiotics.

• 한국동물위생학회지
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• 제34권1호
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• pp.37-43
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• 2011

This study was conducted to investigate the prevalence and genotypes of extended-spectrum ${\beta}$-lactamase (ESBL) in 377 Escherichia coli isolated from healthy and sick animals. Two isolates (0.5%), each of which were isolated from diseased swine and chicken, respectively, were confirmed as ESBL producing isolates by double disk synergy test, and showed a multidrug resistant phenotype. Minimum inhibitory concentration of cefotaxime for the two ESBL producing isolates were 3~4 times higher than those of ceftazidime, respectively. By PCR and sequencing, one isolate from swine have both $bla_{CTX-15}$ and $bla_{TEM-1}$, and one isolate from chicken have $bla_{CTX-15}$ and $bla_{TEM-116}$. Also, these genes were transferred to E. coli J53 by conjugation. These two isolates showed unrelated pulsed-field gel electrophoresis. To our knowledge, this is the first time that $bla_{TEM-116}$ gene was identified in E. coli isolated from animals in Korea. These results suggest more prudent use of third- generation cephalosporins, and surveillance and monitoring for ESBL producing E. coli in both animals and their environments should be necessary.

• 대한임상검사과학회지
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• 제45권2호
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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.

• 생명과학회지
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• 제19권12호
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• pp.1718-1723
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• 2009

Chromosomal 인 SHV-11 $\beta$-lactamase가 plasmid를 매개로 다른 균주로 전달 되는 현상은 흔하지 않다. 본 연구에서는 플라스미드성 SHV-11 $\beta$-lactamase를 동시에 가지고 있는 ESBL생성 두 균주를 검출하였다. 따라서 이들 균주에 대한 유전적 특성과 임상적 의의에 대해 알아보고자 하였다. Vitek system과 이중디스크확산법을 이용하여 ESBL생성균주를 검출하였고, PCR과 DNA 염기서열분석을 이용하여 SHV-11 $\beta$-lactamase를 가지고 있는 ESBL생성균주를 확인 하였다. 이들 균주를 교차접합실험과 형질전환실험을 이용하여 유전자전이를 확인하고 액체배지 희석법으로 3세대 cephalosphorin 항생제에 대한 최소억제농도를 측정하였다. 이들 균주의 유전형 분석결과는 SHV-11 $\beta$-lactamase 유전자와 CTX-M-15 ESBL 유전자를 동시에 가지고 있었다. 3세대 cephalosphorin 항생제에 대한 최소억제농도는 SHV-11 $\beta$-lactamase와 CTX-M-15 ESBL 유전자를 동시에 가지고 있는 균주에서 $64{\mu}g/ml$ 이상이었고, SHV-11 $\beta$-lactamase 만을 가지고 재조합 한 균주에서 $0.5{\mu}g/ml$ 이하로 나타났다.