• YAKHAK HOEJI
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• v.34 no.4
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• pp.277-281
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• 1990

The isolation and identification of an antibacterial component, from Polygoni Radix against a cariogenic bacterium Streptococcus mutans OMZ 176, were carried out for development of anticariogenic agents. The bioactive component was identified to be emodin. The minimal inhibitory concentration (MIC) of emodin was $100\;{\mu}g/ml$ against S. mutans OMZ 176. The bioactive component emodin weakly inhibited ${\beta}-lactamase$ activity with the inhibition ratio of 1.7, 4.3 and 7.6% at the concentration of 50, 100, and 200 uM, respectively. Emodin exhibited slight phototoxicity when analysed by the photohemolysis method.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.579-582
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• 2009

본 연구는 혈액에서 분리되는 미생물의 균종과 항균제 감수성 검사 결과 양상은 환자의 일반적 특성에 따라 다르므로 혈액배양 결과를 분석한 자료는 감염증 환자의 경험적 치료를 위한 중요한 근거가 되고, 특히 ESBL을 생성하는 균주의 경우 항균제의 사용과도 밀접한 관련이 있어 이 연구를 하게 되었다. 대상은 중부지역 일개대학병원의 입원 및 외래환자의 2004-2006년 혈액배양 결과와 항균제 내성 결과를 분석하였다. 혈액배양은 Bact/Alert 3D (North Carolina, Durham, USA)를 이용하여 성인에서는 Bact/Alert S（Aerobic)(Biomerieux Brazil S.A)와 Bact/Alert SN（Anaerobic)(Biomerieux Brazil S.A) 배지를 사용하였고, 소아에서는 Bact/Alert PF (Biomerieux Brazil S.A)배지를 사용하여 5일간 배양하였고, 항균제 감수성 검사는 자동화 동정 및 감수성 장비인 VITEK (BioMerieux vitek. Hazelwood. Missori. USA)을 이용하였다.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.3
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• pp.173-178
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• 2006

The production of extended-spectrum ${\beta}$-lactamases ($ESBL_S$) is the main mechanism of bacterial resistance to third-generation cephalosporins and monobactams, whose prevalence varies depending on the different geographical areas. In the last years it has increased notably to the point of being considered a health problem of great importance. The characterization of the ESBLs producing Klebsiella penumoniae strains present in clinical isolates is time-consuming. I describe here the development of a new system, which consists of a multiplex PCR. I found 51 K. pneumoniae strains to be presumptive strains ESBLs producers by clinical and laboratory standards institute (CLSI) guidelines. The double disc synergy test showed 47 positive K. pneumoniae, which were K. pneumoniae isolates. All ESBLs producing K. pneumoniae strains were resistant to antibiotic amikacin, gentamicin and ciprofloxacin. By multiplex PCR analysis, $bla_{TEM}$ gene in 17 strains 44 $bla_{SHV}$ genes and $bla_{CTX}$ genes in 33 strains were identified. In this study, the multiplex polymerase chain reaction (PCR) assay was a good method to detect and differentiate ESBLs producing K. penumoniae strains in clinical isolates.

• Natural Product Sciences
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• v.25 no.2
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• pp.172-180
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• 2019

Infections with Pseudomonas aeruginosa are difficult to treat not only because it is often associated with multidrug-resistant infections but also it is able to form biofilm. The aim of this study was to evaluate the antibiofilm and anti-Quorum Sensing (QS) activities of Thymbra capitata essential oils (EOs) against Beta Lactamase (BL) producing P. aeruginosa and the reference strain P. aeruginosa 10145. GC/MS analysis showed that thymol (23.25%) is the most dominant compound in T. capitata EOs. The MICs of T. capitata EOs against P. aeruginosa (BL) and P. aeruginosa 10145 were 1.11%. At sub MIC (0.041, 0.014 and 0.0046%), the EOs of T. capitata remarkably inhibited the biofilm formation of both strains tested and complete inhibition of the biofilm formation was reported at 0.041%. The EOs of T. capitata were found to inhibit the swarming motility, aggregation ability and hydrophobic ability of P. aeruginosa (BL) and P. aeruginosa 10145. Interestingly, the EOs of T. capitata reduce the production of three secreted virulence factors that regulated by QS system including pyocyanin, rhamnolipids and LasA protease. The potent antibiofilm and anti-QS activities of T. capitata EOs can propose it as a new antibacterial agent to control pseudomonas infections.

• Biomedical Science Letters
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• v.18 no.3
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• pp.299-306
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• 2012

Recently, the prevalence of 16S rRNA methylase conferring high-level resistance to aminoglycosides has been increasing in Gram-negative bacilli globally. We determined the prevalence and genotype of these methylase-producing bacteria, and characterized the co-resistance to ${\beta}$-lactam antibiotics and quinolone in Gram-negative clinical isolates collected in 2010 at a hospital in Korea. Among 65 amikacin-resistant isolates screened from 864 Gram-negative bacilli (GNB), 16S rRNA methylase genes were detected from 49 isolates, including Acinetobacter baumannii (43), Klebsiella pneumoniae (2), Proteus mirabilis (2) and Serratia marcescens (1), Empedobacter brevis (1). All of the 16S rRNA methylase genotype was armA and no variant sequences of amplified PCR products for armA were noted. The 16S rRNA methylase producing bacteria showed much higher resistance to aminoglycoside for Enterobacteriaceae and glucose non-fermenting (NF)-GNB and to imipenem for glucose NF-GNB, than the non-producing isolates. All of the 16S rRNA methylase producing Enterobacteriaceae had the extended-spectrum-${\beta}$-lactamase. In addition, two K. pneumoniae concurrently produced both plasmid-mediated AmpC ${\beta}$-lactamase and qnrB gene. All of the amikacin-resistant A. baumannii (43) co-harbored armA 16S rRNA methylase and $bla_{OXA-23}$ carbapenemase. In conclusion, 16S rRNA methylase producing bacteria were very prevalent among GNB in South Korea, and were commonly associated with co-resistance, including carbapenem and quinolone.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1260-1268
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• 2014

Screening of a gene library from Paenibacillus sp. PBS-2 generated in Escherichia coli led to the identification of a clone with lipolytic activity. Sequence analysis showed an open reading frame encoding a polypeptide of 378 amino acid residues with a predicted molecular mass of 42 kDa. The esterase displayed 69% and 42% identity with the putative ${\beta}$-lactamases from Paenibacillus sp. JDR-2 and Clostridium sp. BNL1100, respectively. The esterase contained a Ser-x-x-Lys motif that is conserved among all ${\beta}$-lactamases found to date. The protein PBS-2 was produced in both soluble and insoluble forms when E. coli cells harboring the gene were cultured at $18^{\circ}C$. The enzyme is a serine protein and was active against p-nitrophenyl esters of $C_2$, $C_4$, $C_8$, and $C_{10}$. The optimum pH and temperature for enzyme activity were pH 9.0 and $30^{\circ}C$, respectively. Relative activity of 55% remained at up to $5^{\circ}C$ with an activation energy of 5.84 kcal/mol, which indicates that the enzyme is cold-adapted. Enzyme activity was inhibited by $Cd^{2+}$, $Cu^{2+}$, and $Hg^{2+}$ ions. As expected for a serine esterase, activity was inhibited by phenylmethylsulfonyl fluoride. The enzyme was remarkably active and stable in the presence of commercial detergents and organic solvents. This cold-adapted esterase has potential as a biocatalyst and detergent additive for use at low temperatures.

• Biomedical Science Letters
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• v.11 no.3
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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.

• Archives of Pharmacal Research
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• v.20 no.6
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• pp.647-651
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• 1997

The 6, 6-dibromopenam 6 was treated with $CH_{3}/MgBr$ and carbaldehyde 5 to afford the 6-bromo-6-(1-hydroxy-1-methyl)penicillanate 7, which was reacted with acetic anhybride to give acetoxy compound 8. The deacetobromination of 8 with zinc and acetic acid gave 6-exomethylenpenams, Z-isomer 9 and E-isomer 10, which were oxidized to sulfones 11 and 12 by m-CPBA. The p-methoxybenzyl compounds were deprotected by $AlCl_{3}$ and neutralized to give the sodium salts 13, 14, and 15.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.214-222
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• 2004

Purpose: Appropriate antibiotic therapy is important in childhood urinary tract infection and the selection of anibiotics is based on antimicrobial sensitivity of Escherichia coli. Extended-Spectrum ${\beta}-Lactamase(ESBL)$ is an enzyme produced by gram-negative bacilli that has the ability to hydrolyse penicillins, broad-spectrum cephalosporin and monobactam. There have been many reports of outbreaks of hospital infection by ESBL-producing organism. However, community-acquired infection with ESBL-producing organism are rare. This study was performed to retrospectively identify the incidence, characteristics and risk factors of ESBL (+) E. coli in community-acquired childhood UTI. Methods: In 288 children admitted in Ewha Womans University Hospital with E. coli UTI from Mar 2001 to February 2003, ESBL was isolated. ESBL was confirmed by the utilization of an automatized machine(Vitek GNS 433 card) using liquid medium dilution method according to National Committee for Clinical Laboratory Standard. The clinical characteristics, risk factors, antimicrobial resistance and treatment effectiveness were compared with ESBL(-) E. coli UTI. Results: Of 288 E. coli isolates, 31(10.8%) produced ESBL and 93.5%(29/31) occurred in infants younger than 6 month of age(P<0.01). No significant differences were noted in prior antibiotic use, prior admission history and underlying urogenital anomaly. Antimicrobial resistance was significantly higher in ESBL(+) E. coli compared with control patients (P<0.05). Although ceftriaxone showed 100% resistance in ESBL(+) E. coli, bacteriologic sterilization rate after ceftriaxone therapy was higher(96.8%). However, the recurrence rate of febrile UTI within 6 months was higher(25.8%) than control patients(6.6%). Conclusion: Epidemiologic study is required to find out any new risk factors of community-acquired ESBL(+) E. coli UTI and changes in selection of empirical antibiotics should be considered.

• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1733-1737
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• 2007

A total of 2,280 nonduplicate clinical isolates of Pseudomonas aeruginosa, obtained nationwide from Korean non-tertiary care hospitals from 2002 to 2005, were identified and their susceptibilities to aminoglycosides, antipseudomonal penicillins, carbapenems, cephalosporins, monobactams, and quinolones were studied, together with their production of ${\beta}$-lactamases. Using disk diffusion and minimum inhibitory concentration tests, it was found that 2.9% of isolates were multidrug-resistant (MDR) P. aeruginosa. An EDTA-disk synergy test, PCR amplification with specifically designed primers, and direct sequencing of the PCR products showed that the $bla_{OXA-10}$, $bla_{VIM-2}$, $bla_{OXA-2}$, $bla_{OXA-17}$, $bla_{PER-1}$, $bla_{SHV-12}$, and $bla_{IMP-1}$ genes were carried by 34.3%, 26.9%, 3.0%,3.0%, 1.5%, 1.5%, and 1.5% of 67 MDR P. aeruginosa isolates, respectively. The prevalence of MDR P. aeruginosa was three-fold higher, compared with that from the United States. More than two types of ${\beta}$-lactamase genes were carried by 10.4% of isolates. The most prevalent ${\beta}$-lactamase genes were $bla_{VIM-2}$ and $bla_{OXA-10}$. This study is the first description of MDR P. aeruginosa trom non-tertiary care hospitals in Korea and the coexistence of the $bla_{VIM-2}$, $bla_{IMP-1}$, or $bla_{PER-1} in these clinical isolates.