• Title/Summary/Keyword: Resistant bacterial strains

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Effects of Scutellaria scordifolia Fisch. ex Schrank Extracts on Biofilm Formation and the Activities of Klebsiella pneumoniae (Klebsiella pneumoniae균의 바이오 필름 형성과 활성에 대한 병두황진 추출물의 효과)

  • Yook, Keun-Dol;Ha, Nayoung
    • Korean Journal of Clinical Laboratory Science
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    • v.50 no.4
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    • pp.438-443
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    • 2018
  • The emergence of biofilms have generated urgent alarm in clinical and medicine manufacturing fields engaged in the search for novel antimicrobials from ethno-medicinal plants. The National Institutes of Health (NIH) has estimated that 70% of all microbial infections in the world are associated with biofilms. In addition, the emergence of strains resistant to conventional antibiotics has become a serious threat to global public health. Therefore, finding alternative medicines is a major issue in the field of integrative medicine. In this study, four different herb extracts were screened for biofilm formation and the activities of Klebsiella pneumoniae. Of them, Scutellaria scordifolia Fisch. ex Schrank extracts had inhibitory effects on bacterial growth and biofilm formation. The Scutellaia scordifolia Fisch. ex Schrank extracts did not cause any cytotoxicity to L929 cells. The growth of K. pneumoniae was inhibited compared to other comparators in the experimental group containing Scutellaia scordifolia Fisch. ex Schrank. In a group of experiments with plant extracts, a maximum of 60 times the level of living bacteria was confirmed compared to the controls without the addition of the Scutellaia scordifolia Fisch. ex Schrank extracts. In a group of experiments with a significantly lower level of fluorescence extraction, differential interference contrast imaging showed that the number of K. pneumonae was reduced. These results suggest that extracts of this plant be applied as antimicrobial agents against K. pneumoniae, particularly in biofilm forms.

Biochemical Properties and Application of Bacteriocins Derived from Genus Bacillus (Bacillus속 세균 유래 박테리오신의 특성과 응용)

  • Ji-Young Lee;Dae-Ook Kang
    • Journal of Life Science
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    • v.33 no.1
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    • pp.91-101
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    • 2023
  • Bacteriocins are antimicrobial peptides synthesized on ribosomes, produced by bacteria, that inhibit the growth of similar or closely related bacterial strains. Since the discovery of nisin, many bacteriocins with unique structures and various modes of antibacterial activity have been described, and genes encoding production, secretion, and immunity have been reported. Nisin is one of the bacteriocins applied in cheese, liquid eggs, sauces and canned foods. Many of the bacteriocins of the genus Bacillus belong to lantibiotics, which are modified peptides after translation. Other genus Bacillus also produce many non-lantibiotic bacteriocins. Bacteriocins of the genus Bacillus are sometimes becoming more important because of their broader antibacterial spectrum. Bacteriocins are considered attractive compounds in the food and pharmaceutical industries to prevent food spoilage and growth of pathogenic bacteria. Bacteriocins can be used as biological preservatives in a variety of ways in the food system. Biopreservation refers to extending shelf life and improving safety of foods using microorganisms and/or their metabolites. The demand for new antimicrobial compounds has generated great interest in new technologies that can improve food microbiological safety. Applications of bacteriocins are expanding from food to human health. Today, many researchers are shifting their interest in bacteriocins from food preservation to the treatment of bacteria that cause infections and antibiotic-resistant diseases. This exciting new era in bacteriocin research will undoubtedly lead to new inventions and new applications. In this review, we summarize the various properties and applications of bacteriocins produced by the genus Bacillus.

Alternate Prey: A Mechanism for Elimination of Bacterial Species by Protozoa (원생동물(原生動物)에 의한 세균류(細菌類)의 소거(消去)에 관(關)한 기작(機作))

  • Mallory, Larry M.;Yuk, Chang-Soo;Liang, Li-Nuo;Alexander, Martin
    • Korean Journal of Soil Science and Fertilizer
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    • v.16 no.4
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    • pp.358-367
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    • 1983
  • Antibiotic-resistant strains of Salmonella typhimurium and Klebsiella pneumoniae died readily after their addition to raw sewage, but they grew in sterilized sewage. The decline was not a result of antibiotic stresses, and because the bacteria were able to survive in large numbers for at least 15 days in solutions containing no organic nutrients, it was not a result of competition. Toxin production, bacteriophages, and Bdellovibrio did not cause the disappearance of the two bacterial species. A decline was also evident if the sewage was first passed through a $3-{\mu}m$ filter or treated with cycloheximide or cycloheximide plus nystatin, but protozoa developed under these conditions. Little or no decline occurred if the sewage was filtered and treated with the eucaryotic inhibitors before adding S. typhimurium or K. pneumoniae, and protozoa were not detected. S. typhimurium increased in abundance if cycloheximide, streptomycin, and erythromycin or large amounts of glucose were added to sewage. Tetrahymena thermophilus did not significantly reduce the population of S. typhimurium in buffer when the density of the bacterium was about $10^4/ml$. However, when more than $10^8$ Enterobacter agglomerans cells per ml were added to the buffer, T. thermophilus reduced the abundance of E. agglomerans and S. typhimurium to $10^6$ and 10/ml, respectively. The density of S. typhimurium was further decreased by a second increment of E. agglomerans cells. The disappearance of S. typhimurium and K. pneumoniae from sewage thus is the result of predation by protozoa. It is proposed that predators will eliminate a prey species from a natural environment when an alternate prey is present at concentrations above the threshold number for active feeing by the predator and when the rate of growth of the prey is less than the rate of predation.

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Examination of the Central Metabolic Pathway With Genomics in Lactiplantibacillus plantarum K9 (Lactiplantibacillus plantarum K9 유전체 분석을 통해 필수 물질대사 경로의 탐색)

  • Sam Woong Kim;Young Jin Kim;Hyo In Choi;Sang Won Lee;Won-Jae Chi;Woo Young Bang;Tae Wan Kim;Kyu Ho Bang;Sang Wan Gal
    • Journal of Life Science
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    • v.34 no.7
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    • pp.465-475
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    • 2024
  • Lactiplantibacillus plantarum K9 is a probiotic strain that can be utilized from various bioactive substances isolated from Protaetia brevitarsis seulensis larvae. In this study, a genetic analysis of L. plantarum K9 revealed the existence of a bacterial chromosome and three plasmids. The glycolysis pathway and pentose phosphate pathway were examined for their normal functioning via an analysis of the core metabolic pathways of L. plantarum K9. Since the key enzymes, fluctose-1,6-bisphospatase (EC: 3.1.3.11) and 6-phosphogluconate dehydratase (EC: 4.2.1.12)/2-keto-deoxy-6-phosphogluconate (KDPG) aldolase (EC: 4.2.1.55), of gluconeogenesis and the ED pathway were not identified from the L. plantarum K9 genome, we suggest that gluconeogenesis and the ED pathway are not performed in L. plantarum K9. Additionally, while some enzymes, related to fumarate and malate biosyntheses, involved in the TCA cycle were identified from L. plantarum K9, the enzymes associated with the remaining TCA cycle were absent, indicating that the TCA cycle cannot proceed. Meanwhile, based on our findings, we propose that the oxidative electron transport system performs class IIB-type (bd-type) electron transfer. In summary, we assert that L. plantarum K9 performs homolactic fermentation, executes gluconeogenesis and the pentose phosphate pathway, and carries out energy metabolism through the class IIB-type oxidative electron transport system. Therefore, we suggest that L. plantarum K9 has relatively high lactic acid production, and that it has excellent antibacterial activity, as a result, compared to other lactic acid bacterial strains. Moreover, we speculate that L. plantarum K9 has an oxidative electron transport capability, indicating that it is highly resistant to oxygen and suggesting that it has fine cultivation characteristics, which collectively make it highly suitable for use as a probiotic.

Characterization of Bacteriocin Produced from Isolated Strain of Bacillus sp. (Bacillus 속 분리주가 생산하는 박테리오신의 특성 조사)

  • Ham, Seung-Hee;Choi, Nack-Shick;Moon, Ja-Young;Baek, Sun-Hwa;Lee, Song-Min;Kang, Dae-Ook
    • Journal of Life Science
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    • v.27 no.2
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    • pp.202-210
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    • 2017
  • As an effort to find a potential biopreservative, we isolated bacterial strains producing bacteriocin from fermented foods. A strain was finally selected and characteristics of the bacteriocin were investigated. The selected strain was identified as Bacillus subtilis E9-1 based on the 16S rRNA gene analysis. The culture supernatant of B. subtilis E9-1 showed antimicrobial activity against Gram-positive bacteria. Subtilisin A, ${\alpha}$-chymotrypsin, trypsin and proteinase K inactivated the antimicrobial activity, which means its proteinaceous nature, a bacteriocin. The bacteriocin activity was fully retained at the pH range from 2.0 to 8.0 and stable at up to $100^{\circ}C$ for 60 min. Solvents such as ethanol, isopropanol and methanol had no effect on the antimicrobial activity at the concentration of 100% but acetone and acetonitrile reduced the activity at up to 100% concentration. Cell growth of four indicator strains was dramatically decreased in dose-dependent manner. Listeria monocytogenes was the most sensitive, but Enterococcus faecium was the most resistant. Bacillus cereus and Staphylococcus aureus showed the medium sensitivity. The bacteriocin showed its antimicrobial activity against B. cereus and L. monocytogenes via bactericidal action. The number of viable cells of L. monocytogenes started to reduce after addition of bacteriocin to the minced beef. The bacteriocin was purified through acetone concentration, gel filtration chromatography and RP-HPLC. The whole purification step led to a 6.82 fold increase in the specific activity and 6% yield of bacteriocin activity. The molecular weight of the purified bacteriocin was determined to be 3.3 kDa by MALDI-TOF/TOF mass spectrometry.

Brief Introduction of Research Progresses in Control and Biocontrol of Clubroot Disease in China

  • He, Yueqiu;Wu, Yixin;He, Pengfei;Li, Xinyu
    • 한국균학회소식:학술대회논문집
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    • 2015.05a
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    • pp.45-46
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    • 2015
  • Clubroot disease of crucifers has occurred since 1957. It has spread to the whole China, especially in the southwest and nourtheast where it causes 30-80% loss in some fields. The disease has being expanded in the recent years as seeds are imported and the floating seedling system practices. For its effective control, the Ministry of Agriculture of China set up a program in 2010 and a research team led by Dr. Yueqiu HE, Yunnan Agricultural University. The team includes 20 main reseachers of 11 universities and 5 institutions. After 5 years, the team has made a lot of progresses in disease occurrence regulation, resources collection, resistance identification and breeding, biological agent exploration, formulation, chemicals evaluation, and control strategy. About 1200 collections of local and commercial crucifers were identified in the field and by artificiall inoculation in the laboratories, 10 resistant cultivars were breeded including 7 Chinese cabbages and 3 cabbages. More than 800 antagostic strains were isolated including bacteria, stretomyces and fungi. Around 100 chemicals were evaluated in the field and greenhouse based on its control effect, among them, 6 showed high control effect, especially fluazinam and cyazofamid could control about 80% the disease. However, fluzinam has negative effect on soil microbes. Clubroot disease could not be controlled by bioagents and chemicals once when the pathogen Plasmodiophora brassicae infected its hosts and set up the parasitic relationship. We found the earlier the pathogent infected its host, the severer the disease was. Therefore, early control was the most effective. For Chinese cabbage, all controlling measures should be taken in the early 30 days because the new infection could not cause severe symptom after 30 days of seeding. For example, a biocontrol agent, Bacillus subtilis Strain XF-1 could control the disease 70%-85% averagely when it mixed with seedling substrate and was drenching 3 times after transplanting, i.e. immediately, 7 days, 14 days. XF-1 has been deeply researched in control mechanisms, its genome, and development and application of biocontrol formulate. It could produce antagonistic protein, enzyme, antibiotics and IAA, which promoted rhizogenesis and growth. Its The genome was sequenced by Illumina/Solexa Genome Analyzer to assembled into 20 scaffolds then the gaps between scaffolds were filled by long fragment PCR amplification to obtain complet genmone with 4,061,186 bp in size. The whole genome was found to have 43.8% GC, 108 tandem repeats with an average of 2.65 copies and 84 transposons. The CDSs were predicted as 3,853 in which 112 CDSs were predicted to secondary metabolite biosynthesis, transport and catabolism. Among those, five NRPS/PKS giant gene clusters being responsible for the biosynthesis of polyketide (pksABCDEFHJLMNRS in size 72.9 kb), surfactin(srfABCD, 26.148 kb, bacilysin(bacABCDE 5.903 kb), bacillibactin(dhbABCEF, 11.774 kb) and fengycin(ppsABCDE, 37.799 kb) have high homolgous to fuction confirmed biosynthesis gene in other strain. Moreover, there are many of key regulatory genes for secondary metabolites from XF-1, such as comABPQKX Z, degQ, sfp, yczE, degU, ycxABCD and ywfG. were also predicted. Therefore, XF-1 has potential of biosynthesis for secondary metabolites surfactin, fengycin, bacillibactin, bacilysin and Bacillaene. Thirty two compounds were detected from cell extracts of XF-1 by MALDI-TOF-MS, including one Macrolactin (m/z 441.06), two fusaricidin (m/z 850.493 and 968.515), one circulocin (m/z 852.509), nine surfactin (m/z 1044.656~1102.652), five iturin (m/z 1096.631~1150.57) and forty fengycin (m/z 1449.79~1543.805). The top three compositions types (contening 56.67% of total extract) are surfactin, iturin and fengycin, in which the most abundant is the surfactin type composition 30.37% of total extract and in second place is the fengycin with 23.28% content with rich diversity of chemical structure, and the smallest one is the iturin with 3.02% content. Moreover, the same main compositions were detected in Bacillus sp.355 which is also a good effects biocontol bacterial for controlling the clubroot of crucifer. Wherefore those compounds surfactin, iturin and fengycin maybe the main active compositions of XF-1 against P. brassicae. Twenty one fengycin type compounds were evaluate by LC-ESI-MS/MS with antifungal activities, including fengycin A $C_{16{\sim}C19}$, fengycin B $C_{14{\sim}C17}$, fengycin C $C_{15{\sim}C18}$, fengycin D $C_{15{\sim}C18}$ and fengycin S $C_{15{\sim}C18}$. Furthermore, one novel compound was identified as Dehydroxyfengycin $C_{17}$ according its MS, 1D and 2D NMR spectral data, which molecular weight is 1488.8480 Da and formula $C_{75}H_{116}N_{12}O_{19}$. The fengycin type compounds (FTCPs $250{\mu}g/mL$) were used to treat the resting spores of P. brassicae ($10^7/mL$) by detecting leakage of the cytoplasm components and cell destruction. After 12 h treatment, the absorbencies at 260 nm (A260) and at 280 nm (A280) increased gradually to approaching the maximum of absorbance, accompanying the collapse of P. brassicae resting spores, and nearly no complete cells were observed at 24 h treatment. The results suggested that the cells could be lyzed by the FTCPs of XF-1, and the diversity of FTCPs was mainly attributed to a mechanism of clubroot disease biocontrol. In the five selected medium MOLP, PSA, LB, Landy and LD, the most suitable for growth of strain medium is MOLP, and the least for strains longevity is the Landy sucrose medium. However, the lipopeptide highest yield is in Landy sucrose medium. The lipopeptides in five medium were analyzed with HPLC, and the results showed that lipopeptides component were same, while their contents from B. subtilis XF-1 fermented in five medium were different. We found that it is the lipopeptides content but ingredients of XF-1 could be impacted by medium and lacking of nutrition seems promoting lipopeptides secretion from XF-1. The volatile components with inhibition fungal Cylindrocarpon spp. activity which were collect in sealed vesel were detected with metheds of HS-SPME-GC-MS in eight biocontrol Bacillus species and four positive mutant strains of XF-1 mutagenized with chemical mutagens, respectively. They have same main volatile components including pyrazine, aldehydes, oxazolidinone and sulfide which are composed of 91.62% in XF-1, in which, the most abundant is the pyrazine type composition with 47.03%, and in second place is the aldehydes with 23.84%, and the third place is oxazolidinone with 15.68%, and the smallest ones is the sulfide with 5.07%.

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A Randomized, Double-Blind Study to Assess the Efficacy and Safety of Oral LB20304 (Gemifloxacin) at Doses of 160mg or 320mg (Equivalent to 200mg or 400mg of the Mesylate Salt) Once Daily for 7 Days for the Treatment of Acute Exacerbations of Chronic Bronchitis (AECB) in Korean Adult Population (한국인에서 만성기관지염의 급성악화를 치료하기 위한 LB20304(Gemifloxacin) 160mg 또는 320mg 1일 1회 7일간 투여의 유효성과 안전성에 대한 연구)

  • Kim, Young Whan;Shim, Young-Soo;Kim, Won Dong;Shim, Tae Sun;Kang, Hong Mo;Choi, ByoungWhui;Kim, Jae-Yeol;Kwon, O Jung;Kim, Hojoong;Kim, Ju Ock;Jung, Ki-Suck;Hyeon, In Gyou;Mo, Eun Kyung;Lee, Seung-Joon;Nam, Gui Hyun;Lee, Kye Young;Park, Jae Seuk
    • Tuberculosis and Respiratory Diseases
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    • v.55 no.1
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    • pp.69-87
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    • 2003
  • Background : LB20304(gemifloxacin) is a new fluoroquinolone antibacterial agent with excellent activity against both Gram-negative and Gram-positive organisms. In vitro studies using clinical isolates have shown gemifloxacin to be highly active against penicillin-resistant strains of S. pneumoniae and in contrast to other reference quinolones, gemifloxacin retained good activity against clinical isolates of S. pneumoniae that were resistant to other members of the quinolone class. Therefore, gemifloxacin is thought to be effective in treating acute bacterial exacerbation of chronic bronchitis(AECB). The objective of this study was to evaluate the efficacy and safety of oral gemifloxacin at doses of 160mg or 320mg once daily for 7 days for the treatment of AECB in Korean adult population. Methods : This was a randomized, multicenter, double-blind, parallel group Phase II study to assess the clinical and antibacterial efficacy and safety of oral gemifloxacin for the treatment of AECB. Treatment Group A (67 patients) took oral gemifloxacin 160mg once daily for seven days and treatment Group B (70 patients) took oral gemifloxacin 320mg once daily for seven days. Results : The demographic profiles of the two treatment groups were similar. The clinical response at follow-up was 84.2% in the gemifloxacin 160-mg group, and 88.7% in the gemifloxacin-320 mg group, showing no statistically significant difference between two treatment groups(p=0.49). The clinical response at the end of therapy was 96.5% in the 160-mg group, and 96.4% in the 320-mg group. The bacteriological response at the end of therapy and follow-up were 81.8% and 78.9%, respectively, in the 160-mg group, and 86.4% and 84.2%, respectively, in the 320-mg group, showing no statistically significant difference between two treatment groups(p=0.68 and 0.68, respectively). S. pneumoniae(12 isolates) and H. influenzae(10 isolates) were the most prevalent pathogens. The MICs were lower for gemifloxacin than other quinolones against these key pathogens, and for S. pneumoniae, the MICs for gemifloxacin were considerably lower(${\leq}0.03$ ug/mL) than those for other quinolones, beta-lactams and macrolides. In the period on-therapy plus 30 days post-therapy, a total of 18 patients(26.9%) in the gemifloxacin 160mg group and 22 patients(31.4%) in the 320mg group reported at least one adverse event(AE). The most frequently reported AE was abdominal pain(3/67 patients, 4.5%) in the gemifloxacin 160mg group and increased level of hepatic enzyme(5/70 patients, 7.1%) in the 320mg group. The overall AE profiles for the two treatment groups were similar. Two out of 67 patients(3.0%) in the gemifloxacin 160mg group and 1/70 patients(1.4%) in the 320mg group reported at least one serious AE, however, none of which was considered by the investigator to be of suspected or probable relationship to study medication. Conclusion : The results of this study showed that gemifloxacin at doses of 160mg or 320mg once daily for 7 days in the treatment of acute exacerbations of chronic bronchitis(AECB) in adult Koreans was a very effective and safe treatment both clinically and bacteriologically.