• 생명과학회지
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• 제20권8호
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• pp.1214-1220
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• 2010

대한민국 순천의 병원 입원 환자의 검체로부터 imipenem 내성 세균을 분리하였다. 54개의 분리균을 16S rRNA 유전자와 gyrB 유전자 염기서열 비교를 기초로 하여 계통분류학적으로 동정하였다. 분리균들은 Pseudomonas aeruginosa (30균주; 55.6%), Acinetobacter baumannii (21; 38.9%), Enterobacter hormaechei (2)와 Pseudomonas putida (2)에 속했다. 22개의 균주가 metallo-$\beta$-lactamase (MBL)를 생산하였으며 종별 구성은 다음과 같다; Acinetobacter baumannii 12균주, Pseudomonas aeruginosa 7균주, P. putida 2균주 그리고 Enterobacter hormaechei 1균주. 분리균들의 항생제 감수성은 디스크 확산법과 Vitek 을 이용하여 조사하였다. IMP 와 VIM 형의 metallo-$\beta$-lactamase를 생산하는 균주들은 OXA 와 SHV 형 $\beta$-lactamase를 생산하는 균주들에 비해 ceftazidime, aztreonam, amikacin과 gentamicin에 대한 내성율이 높았다.

• Journal of Microbiology
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• 제45권3호
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• pp.272-274
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• 2007

During May to July 2004, three strains of Providencia spp. with multidrug-resistance (MDR) were isolated from urinary specimen of three patients hospitalized with a same hospital room. By PCR analysis, all three strains have been found to carry both VIM-2 type $metallo-{\beta}-lactamase$ gene and PER-1 type extended spectrum ${\beta}-lactamase$ gene. One out of three strains carried additional resistance gene, armA, 16S rRNA methylase gene responsible for high level resistance to aminoglycosides. To our knowledge, this is the first report on the identification of Providencia spp. simultaneously carrying $bla_{VIM-2},\;bla_{PER-1}$, and armA genes.

• Journal of Microbiology and Biotechnology
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• 제25권7호
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• pp.1154-1162
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• 2015

The emergence of carbapenem resistance among Pseudomonas aeruginosa is an increasing problem in many parts of the world. In particular, metallo-$\beta$-lactamases (MBLs) and AmpC $\beta$lactamases are responsible for high-level resistance to carbapenem and cephalosporin. We studied the diversity and frequency of $\beta$-lactamases and characterized chromosomal AmpC $\beta$lactamase from carbapenem-resistant P. aeruginosa isolates. Sixty-one carbapenem-resistant P. aeruginosa isolates were collected from patients in a tertiary hospital in Daejeon, Korea, from January 2011 to June 2014. Minimum inhibitory concentrations (MICs) of four antimicrobial agents were determined using the agar-dilution method. Polymerase chain reaction and sequencing were used to identify the various $\beta$-lactamase genes, class 1 integrons, and chromosomally encoded and plasmid-mediated ampC genes. In addition, the epidemiological relationship was investigated by multilocus sequence typing. Among 61 carbapenem-resistant P. aeruginosa isolates, 25 isolates (41.0%) were MBL producers. Additionally, 30 isolates producing PDC (Pseudomonas-derived cephalosporinase)-2 were highly resistant to ceftazidime (MIC₅₀ = $256{\mu}g/ml$) and cefepime (MIC₅₀ = $256{\mu}g/ml$). Of all the PDC variants, 25 isolates harboring MBL genes showed high levels of cephalosporin and carbapenem resistance, whereas 36 isolates that did not harbor MBL genes revealed relatively low-level resistance (ceftazidime, p < 0.001; cefepime, p < 0.001; imipenem, p = 0.003; meropenem, p < 0.001). The coexistence of MBLs and AmpC $\beta$-lactamases suggests that these may be important contributing factors for cephalosporin and carbapenem resistance. Therefore, efficient detection and intervention to control drug resistance are necessary to prevent the emergence of P. aeruginosa possessing this combination of $\beta$-lactamases.

• 대한의생명과학회지
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• 제25권3호
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• pp.275-281
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• 2019

This study was performed to characterize the chromosomal metallo-${\beta}$-lactamases (MBLs) of Chryseobacterium indologenes isolated from Korea and to propose a clustering method of IND MBLs based on their amino acid similarities. Chromosomal MBL genes were amplified by PCR from 31 clinical isolates of E. indologenes. Nucleotide sequencing was performed by the dideoxy chain termination method using these PCR products. Antimicrobial susceptibilities were determined by the agar dilution method. PCR experiments showed that all 31 E. indologenes isolates contained all $bla_{IND}$ genes. DNA sequence analysis revealed that E. indologenes isolates possessed ten types of $bla_{IND}$ gene, including seven novel variants ($bla_{IND-8}$ to $bla_{IND-14}$). The most common combination of MBL was IND-2 (n = 18). Minimum inhibitory concentrations of imipenem and meropenem for the isolates harboring novel IND MBLs were ${\geq}16{\mu}g/mL$. IND MBLs were grouped in three clusters, based on amino acid similarities.

• 생명과학회지
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• 제22권9호
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• pp.1268-1276
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• 2012

사람의 감염증 치료에 사용되는 carbapenem계 약제에 대한 내성균의 출현 및 확산은 감염증 치료를 제한할 뿐만 아니라 집단 발병의 원인이 될 수 있다. 이에 본 연구에서는 ${\beta}$-lactam 약제에 내성을 갖는 Pseudomonas aeruginosa (P. aeruginosa)를 대상으로 metallo-beta-lactamase (MBL)의 유전형을 규명함으로써 내성세균의 감염증 치료지침 및 확산방지책 마련에 기초 자료를 제공하고자 하였다. 본 연구의 대상이 된 254개의 임상 검체 중에서 42주의 P. aeruginosa 를 분리하여 imipenem 혹은 meropenem에 내성을 나타내는 Hodge 변법과 EDST에서 각각 28주와 23주가 양성반응을 보였다. DNA의 염기서열 분석결과 $bla_{IMP-6}$ 유전자 보유균이 8주, $bla_{VIM-2}$ 유전자 보유균이 17주로 59.5%(25/42)가 MBL을 생성하는 것으로 나타났다. $bla_{IMP-6}$의 유전자 환경은 $bla_{IMP-6}$-qac-aacA4-$bla_{OXA-1}$-aadA1 유전자 배열을 지니고 있었다. 또한 ERIC PCR 결과 IMP-6과 VIM-2를 생성하는 일부 균주에서 역학적 연관성이 있음이 확인되었다. 본 연구에서 분리한 carbapenem계 항균제 내성 P. aeruginosa가 보유한 $bla_{IMP-6}$ 유전자는 대구지역에서 발병이 보고된 유전자의 gene cassette와 일치하는 것으로 확인되었다. 따라서 이들 세균이 지역사회에 정착하고 있고 이들을 보유한 세균에 의한 감염증 치료시 치료약제에 대한 선택압을 증가시킬 것으로 우려된다. 그러므로 항균제 내성 검사를 통하여 적절한 항균제를 선택하고, 항균제 내성균들의 출현과 확산을 막는 연구가 계속되어야 할 것으로 생각된다.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3644-3652
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• 2010

The metallo-$\beta$-lactamases ($M{\beta}Ls$) are clinically significant enzymes which readily hydrolyze most $\beta$-lactam antibiotics. Discovering potential inhibitors for the $M{\beta}Ls$ is an expensive, time consuming endeavor. Virtual screening can sieve out inhibitor candidates with incompatible features prior to synthesis, decreasing these costs. Using Autodock 4.0, the binding locations and energies of four previously-studied potential inhibitors and four additional compounds obtained from the National Cancer Institute (NCI) database were computationally calculated. Based on the docking models of these eight compounds, we then designed several hypothetical inhibitor structures, compounds A through F, and performed their respective docking experiments. The docking results for compound F showed that it binds to the zinc containing active sites with a lowest predicted binding energy of -6.70 kcal/mol, suggesting F is the most likely potential $M{\beta}L$ inhibitor.

• 대한미생물학회지
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• 제35권5_6호
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• pp.337-339
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• 2000

MRSA, erythromycin-resistant S. pyogenes, penicillin non-susceptible pneumococci, PPNG, ESBL-producing E. coli and K. pneumoniae, class C ${\beta}$-lactamase-producing E. coli, fluoroquinolone-resistant E. coli, aminoglycoside-resistant A. baumannii and P. aeruginosa are all prevalent in Korea, which suggest the presence of high levels of antimicrobial selective pressure and nosocomial spread of resistant bacteria. Rapid increase of VRE and emergence of fluoroquinolone-resistant gonococci and VIM-2 metallo-${\beta}$-lactamase-producing P. aeruginosa are recently observed new threats in Korea.

• 미생물학회지
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• 제44권4호
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• pp.339-345
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• 2008

국내 대학병원에서 분리되어 imipenem 에 대한 최소억제농도가 $8{\mu}g/ml$ 이상인 51개의 포도당비발효 그람음성 간균들 중 metallo-${\beta}$-lactamase (MBL)을 생성하는 균주들을 분리하고, 그들 중에서 내성이 강한 Pseudomonas aeruginosa에 대한 항균제 병합요법의 효과를 알아보기 위하여 상승효과를 보이는 항균제 조합을 찾아보았다. 9개의 균주(Pseudomonas aeruginosa 2주 및 Achromobacter xylosoxidans subsp. xylosoxidans 7주)가 MBL 양성을 나타냈으며, PCR 결과 9주 모두에서 $bla_{VIM-2}$ 유전자가 관찰되었다. 이들 중에서 P. aeruginosa DK569는 aztreonam (MIC; $8{\mu}g/ml$)을 제외하고 실험한 모든 ${\beta}$-lactam 항균제, aminoglycoside, ciprofloxacin에 내성을 보여 aztreonam 함유 배지를 이용하여 상승효과률 보이는 항균제를 찾고자 하였다. One disk synergy test 에서 선별된 항균제 조합을 이용하여 생존률 검사 실험을 한 결과, aztreonam (AZT)와 piperacillin-tazobactam (TZP)의 병합은 항균제 노출 6시간 후에 AZT 또는 TZP의 단독 항균제 노출시 보다 균수가 1/18.7로 감소하였다. 그리고 AZT와 amikacin (AN)의 병합에서도 항균제 노출 6 시간 후에 AZT 또는 AN의 단독항균제의 투여보다 균수가 1/17.1 로 감소하였다. 결국 위 두 조합은 의미있는 상승효과를 보이지 못하여 위 세 항균제를 조합하여 실험하였다. 위의 세 항균제를 병합하였을 때 항균제 노출 8시간 후에 AZT, TZP 및 AN의 단독 투여에 비하여 병합요법에 의해 균수가 1/183.3 로 감소하여 의미있는 상승효과를 보였다. 이 결과는 치료가 쉽지 앓은 MBL 생성균에 의한 감염에 대한 치료에 AZT, TZP 및 AN의 세 가지 항균제 병합요법이 유용할 것이라는 것을 의미한다.

• 대한의생명과학회지
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• 제25권4호
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• pp.321-330
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• 2019

Carbapenem is recently considered as the last resort of the therapeutics for gram negative bacterial infection. Increasing of organisms producing metallo-β-lactamase (MBL), we have difficulty in choosing the antimicrobial agents. Among 345 clinical isolates of Pseudomonas spp., 61 isolates (17.7%) were positive for the modified imipenem or meropenem-Hodge test and 55 isolates (15.9%) were positive for the imipenem-EDTA + SMA double disk synergy test (DDS). PCR and sequencing of bla_VIM-2-allele and bla_IMP-1-allele showed that 17 isolates of Pseudomonas aeruginosa, 9 isolates of Pseudomonas taiwnensis and 2 Pseudomonas plecoglossicida had bla_VIM-2, and 22 isolates of P. aeruginosa and one Pseudomonas otitidis had bla_IMP-6. These MBL genes were all in class 1 integron. The size of class 1 integron with bla_VIM-2 ranged from 3.5 kb to 5.5 kb in clinical isolates of Pseudomonas spp. including P. aeruginosa. bla_VIM-2 was most often located first in the class 1 integron, sometimes in the second or third position, and these integrons often had aacA4 or aadA1. Strict infection control measures are needed to more effectively prevent further spread of these MBL-producing Pseudomonas spp. In addition, MBL-producing Pseudomonas spp. is expected to continue to spread in various countries and regions.

• 대한의생명과학회지
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• 제17권2호
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• pp.135-140
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• 2011

We compared three EDTA-based phenotypic screening methods for detecting IMP-1 and VIM-2 type metallo-${\beta}$- lactamase (MBL)-producing isolates of Acinetobacter and Pseudomonas spp., EDTA-double disk synergy test (EDTADDST), Etest MBL, and imipenem (IPM)-EDTA disk test. A total of 183 isolates (65 Acinetobacter spp. and 118 Pseudomonas spp. showing IPM resistance), confirmed to MBL genes by PCR, were used. The criteria for MBL production were (i) presence of a synergistic zone between IPM and EDTA disks in EDTA-DDST, (ii) reduction of IPM minimal inhibitory concentration by ${\geq}$ 3 twofold dilutions in the presence of EDTA in the Etest MBL, and (iii) ${\geq}$ 7 mm increase in the inhibition zone around the IPM plus EDTA disks compared with a sole IPM disk in the IPM-EDTA disk test. In this study using 87 MBL-producing and 96 MBL-nonproducing isolates, the sensitivities/specificities of EDTA-DDST, Etest MBL and IPM-EDTA disk tests were 94.3/78.1%, 89.7/91.7%, and 97.7/95.8%, respectively. When the threshold for the increase of the inhibition zone around the IPM plus EDTA disk over a sole IPM disk was altered to ${\geq}$ 5 mm and ${\geq}$ 8 mm for Acinetobacter spp. and Pseudomonas spp., respectively, the sensitivity and specificity of the test were 98.9% and 96.9%, respectively. Of the three EDTA-based phenotypic tests, the IMP-EDTA disk test was superior for detection of MBL-producing isolates.