• Korean Journal of Clinical Laboratory Science
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• v.54 no.3
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• pp.179-191
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• 2022

Carbapenem-resistant Enterobacteriaceae (CRE) poses an increasing public health threat and has limited treatment options with high associated mortality. Genotypes of carbapenemase that threaten public health (bla_KPC, bla_NDM, bla_IMP, and bla_VIM) and bla_OXA-48-like genes were detected by phenotypic and molecular diagnosis, and related gene distribution patterns were investigated. Phenotypic testing using the modified Hodge test confirmed positivity in all 41 strains examined, and carbapenemase inhibitory testing using meropenem+phenyl boronic acid or meropenem+EDTA confirmed positivity in 18 and 8 strains, respectively. Polymerase chain reaction revealed the presence of amplification products in 28 strains of bla_KPC, 25 strains of bla_NDM, 5 strains of bla_IMP, 1 strain of bla_VIM, and 13 bla_OXA-48-like strains. In addition, 7 strains of bla_KPC+bla_NDM, 1 strain of bla_KPC+bla_IMP, 1 strain of bla_NDM+bla_OXA-48-like, 1 strain of bla_NDM+bla_VIM, 4 strains of bla_KPC+bla_NDM+bla_IMP, and 4 strains of bla_KPC+bla_NDM+bla_OXA-48-like were identified. Melting curve analysis using real-time PCR was wholly consistent with PCR results. The study shows genetic identification of highly specific CRE by real-time PCR could be used to provide early diagnoses and infection control, improve surveillance, and prevent the transmission of CRE.

• Pediatric Infection and Vaccine
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• v.30 no.1
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• pp.47-54
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• 2023

With the widespread use of broad-spectrum antibiotics in clinical practice, the emergence of multidrug-resistant (MDR) gram-negative bacteria has become a global problem. The MDR Pseudomonas aeruginosa infection is especially difficult to treat and increases mortality in critically ill patients. Ceftolozane-tazobactam (Zerbaxa^TM) is a fifth-generation cephalosporin and beta-lactamase inhibitor that has proved to be effective for treating complicated urinary tract infections and complicated intra-abdominal infections caused by MDR P. aeruginosa. Herein, we report the first case of pediatric hematologic cancer in Korea that was successfully treated for MDR P. aeruginosa bacteremia with Ceftolozane-tazobactam.

• Journal of fish pathology
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• v.36 no.2
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• pp.277-286
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• 2023

Korean rockfish, Sebastes schlegelii, is a representative bony fish that belongs to the family Scorpaenidae and the order Scorpaeniformes. It has high ecological and economic value and is widely cultivated in many East Asian countries, including South Korea, Japan and China. One of streptococci, Streptococcus iniae, is Gram-positive cocci with a negative reaction for catalase and oxidase. The Korean rockfish shows clinical signs when infected with S. iniae, such as body darkening, bleeding, enlarged kidneys, blurred eyes, abdominal distension, etc., ultimately leading to death. The Korean rockfish causes significant economic losses every year in South Korea due to streptococcosis. In this study, we identified bacteria from the fish using polymerase chain reaction and conducted analyses of hemolytic activity and biochemical tests using API 20 STREP and API ZYM systems. Results of confirming the hemolytic activity (n=4) observed in alpha-type hemolysis (25%), beta-type hemol- ysis (50%), and gamma-type hemolysis (25%) of isolates. The biochemical test results exhibited sig- nificant variation among S. iniae. Additionally, we performed intraperitoneal injection with S. iniae in the fish and analyzed the phylogenetic tree using housekeeping genes of S. iniae, including cpsD, arcC, glnA, groEL, gyrB, mutS, pheT, prkC, rpoB, and tkt, via multilocus sequence typing (MLST). The lethal dose (LD₅₀) showed strong pathogenicity, such as 3.34 × 10 colony-forming unit (CFU)/ml for 23FBStr0601 strain and 7.16 × 10 CFU/ml for 23FBStr0602 strain. 23FBStr0603 strain showed relatively low pathogenicity at 1.73 × 10⁵ CFU/ml. The strains 23FBStr0601 and 23FBStr0602, which showed strong pathogenicity, clustered into one monophyletic group. The 23FBStr0603 strain showed weak pathogenicity and formed a monophyletic group with KCTC 3657.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.2
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• pp.171-180
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• 2024

The endotoxin test is based on the reaction between Limulus Amebocyte Lysate (LAL) and the lipopolysaccharides of Gram-negative bacteria. In this study, we sought to identify factors that interfere with the LAL testing of radiopharmaceuticals and evaluated acceptable ranges. A gel-clot LAL test and a chromogenic LAL test were used as endotoxin tests. We compared the performances of the Endosafe^Ⓡ LAL and recombinant Endosafe^Ⓡ Recombinant Cascade Reagent (rCR) cartridges for the chromogenic test. The factors that interfered with ⁶⁸Ga-DOTATOC injection were pH, 4-(2-hydroxyethyl) piperazine-1-ethanesulfonic acid (HEPES) buffer, and organic solvents, especially ethanol. However, interference by these factors was overcome by diluting the ⁶⁸Ga-DOTATOC injection tenfold. In addition, no interference was observed at pH values between 4 and 8, at a HEPES concentration of 2,000 ㎍/mL, or an ethanol concentration of <1%. Furthermore, results showed that interfering factors had similar effects on the performances of the Endosafe^Ⓡ LAL and Endosafe^Ⓡ rCR cartridges. The results of this study are expected to be useful for evaluating factors that interfere with the endotoxin testing of new radiopharmaceuticals.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.561-574
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• 2000

Poly-P has been used to prevent decomposition of foods and has been shown to have inhibitory effect on the growth of gram positive bacteria. The purpose of this study was to evaluate the effect of poly-P on the growth of Porphyromonas endodontalis, a gram negative obligate anaerobic rod, endodontopathic bacterium. P. endodontalis ATCC 35406 was in BHI broth containing hemin and vitamin K with or without poly-P. Inhibitory effect of each poly-P which was added at the beginning(lag phase) or during(exponential phase) the culture, MIC(minimum inhibitory concentration) was determined by measuring the optical density of the bacterial cell at 540nm. Viable cell counts were measured to determined whether poly-P has a bactericidal effect. Leakage of intracellular nucleotides from P. endodontalis was determined at 260nm and morphological change of P. endodontalis was observed under the TEM(transmission electron microscope). Binding of 32P-labeled poly-P to P. endodontalis was examined. SDS-polyacrylamide gel electrophoresis and zymography were performed to observe the changes in protein and enzyme profiles of P. endodontalis, respectively. The results from this study were as follows : 1. The minimal inhibitory concentration(MIC) of poly-P to P. endodontalis appeared to be 0.04~0.05%. 2. Poly-P added to the P. endodontalis culture during the exponential phase of P. endodontalis was as much effective as poly-P added at the begining of the culture, suggesting that the antibacterial effect of poly-P is not much dependent on the initial inoculum size of P. endodontalis. 3. Poly-P are bactericidal to P. endodontalis, demonstrating the decrease of the viable cell counts. 4. Intracellular nucleotide release from the P. endodontalis, was not increased in the presence of poly-P and was not reversed by the addition of divalent cations like $Ca^{2+}$ and $Mg^{2-}$. 5. Under the TEM, it was observed that fine electro-dense materials were prominent in the poly-P grown P. endodontalis, appearing locally in the cell, and the materials were more abundant and more dispersed in the cell as the incubation time with poly-P increased. In addition, highly electron dense granules accumulated in many poly-P grown cells, most of which were atypical in their shape. 6. Binding of 32P-labeled poly-P to P. endodontalis appeared to be 32.8 and 45.5 and 53.4% at 30 minutes, 1 hours and 2 hours, respectively. 7. In the presence of poly-P. the synthesis of proteins with apparent molecular masses of 25, 27, 35, 45 was lost or drastically decreased whereas expression of a protein with an apparent molecular mass of 75 was elevated. 8. Proteolytic activity of P. endodontalis was decreased by poly-P. The overall results suggest that use of poly-P may affect the growth of P. endodontalis, and the anti-bacterial activity of poly-P seems largely bactericidal. Changes in shape, protein expression, and proteolytic activity of P. endodontalis by poly-P may be directly and indirectly attributed to the antibacterial effect of poly-P. Further studies will be needed to confirm the effect of poly-P.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.358-366
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• 2013

The aim of this study was to evaluate the antimicrobial activities of Glycyrrhiza uralensis and Glycyrrhiza glabra extracts with various countries of origin. Three samples of licorice with various origins (Korea, China, and Uzbekistan) were evaluated for their antimicrobial activities against six skin microflora. The bioassay applied for determining the antimicrobial effects included the disc diffusion assay, minimum inhibitory concentration, and challenge test. The ethyl acetate fractions of G. uralensis and G. glabra extracts showed significant antimicrobial activities against two gram-positive (Bacillus subtilis, Propionibacterium acnes) and two gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. These samples had much more intensive antimicrobial activities than synthetic preservatives on B. subtilis, P. acnes, and P. aeruginosa, especially. Korean licorice showed the highest antimicrobial activity amongst the samples tested. In view of the observed inhibitory features of these G. uralensis and G. glabra extracts, it is suggested that they could be used as natural antiseptics against bacterial contamination in cosmetics and foods, instead of the common synthetic preservatives currently employed.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.3
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• pp.313-320
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• 2014

In this study, the antimicrobial activity of niaouli leaf extracts was evaluated against skin flora. The skin flora used for experiments were three gram-positive bacteria such as Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), Propionibacterium acnes (P. acnes), and two gram-negative, Escherichia coli (E. coli), Pseudomonas aeruginosa( P. aeruginosa), and the yeast, Plasmodium ovale (P. ovale). The bioassay applied for determining the antimicrobial effects of niouli leaf extracts or fraction included the disc diffusion assay and broth dilution assay. Minimum inhibitory concentration (MIC) values of 50% ethanol extract on B. subtilis, S. aureus, P. acnes, E. coli and P. aeruginosa were 0.25%, 0.50%, 1.00%, 0.13% and 0.25% respectively and the MIC values of water fraction were 0.25%, 0.25%, 4,00%, 0.25% and 0.25%. P. ovale did not show antimicrobial activities. The MIC values of methyl paraben used as positive control indicated 0.25%, 0.25%, 0.25%, 0.13% and 0.50%. Also, Minimum bactericidal concentration (MBC) values of 50% ethanol extract were 2.00%, 2.00%, 1.00%, 0.50% and 2.00% individually and the MBC values of water fraction were 0.50%, 0.25%, 4.00%, 0.50% and 1.00%. The MBC values of methyl paraben indicated 1.00%, 0.500%, 0.50%, 0.50% and 1.00%. These results showed that water fraction was as good as methyl paraben except for P. acnes. The 50% ethanol extract also showed activity similar with it. Thus, it is concluded that the 50% ethanol extract/fraction of niaouli could be applicable to cosmetics as a natural preservatives effective in antimicrobial activity against skin flora.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.238-244
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• 2007

To identify the useful biological activities and the superiority in quality of Korean traditional liquors, we prepared the alcohol-free concentrates from different types of commercial traditional liquors, Takju ($T1{\sim}T3$), Yakju/Cheongju ($Y-1{\sim}Y-5$), Fruit wine (F-1) and Soju (S-1, S-2), respectively. We investigate their compositions as well as antimicrobial, antioxidant, and anti-thrombosis activity. Among the 11 traditional liquors, Y-3, Y-4, Y-5 and F-1 showed higher total-polyphenol, total-flavonoids and reducing sugars than the others. The strong antibacterial and anti-thrombosis activities were identified in Y-3, Y-4, Y-5 and F-1, and a minor antioxidant activity was found in F-l. The antibacterial activity of the Y-3, Y-4, Y-5 and F-1 alcohol-free concentrates showed a broad-spectrum, and growth inhibition was found in gram-positive, gram-negative, and ampicillin-resistant bacteria. The sequential solvent fractionation of Y-3, Y-4, Y-5 and F-1, and following analysis showed that ethyl acetate fractions of Y-3, Y-4, Y-5 and F-1 possess strong antibacterial and anti-thrombosis activity. Especially, the ethyl acetate fractions of Y-3, Y-4 and F-1 showed superior anti-thrombosis activity compared than that of aspirin. Our results suggest that the useful substances are produced from substrates and edible plant added during the fermentation, and the Korean traditional liquors could be developed as strong antibacterial and anti-thrombosis agents.

• Microbiology and Biotechnology Letters
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• v.42 no.1
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• pp.58-66
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• 2014

In the course of study for a use for non-edible parts of broccoli (Brassica oleracea L), and the development of processed food utilizing these parts, edible floret and non-edible stalk were extracted with ethanol and different organic solvent fractions were prepared. With 10 different extracts and fractions, their useful components and various biological activities, such as antioxidant, antimicrobial and anti-proliferation activity, were investigated. The stalk has more abundant water soluble carbohydrate when compared with the floret, and floret has higher hexane-soluble pigments. Analysis of total flavonoid and total polyphenol contents showed that the floret has 1.5~1.99 times higher concentrations than the stalk. Among the fractions, ethylacetate (EA) fractions have the highest amount of total flavonoid and total polyphenol. The stalk and floret possessed 9.45 and 42.01 mg-total flavonoid/g, respectively. In the antioxidation activity assay, the EA fraction of floret showed strong radical scavenging activity and reducing power, while the n-hexane fraction of the stalk exhibited nitrite scavenging activity. In the antimicrobial activity assay, the EA fraction of floret showed a strong and broad-range of antibacterial activity, irrespective of gram positive or gram negative bacteria. In a while, the hexane and EA fractions revealed anti-proliferative effects against the human colorectal cancer cell HCT-116. Strong anti-proliferative activities were found in the hexane fraction of stalk (18.4% of cell viability), and the n-butanol fraction of floret (6.9% of cell viability). Our results suggest that the further study of the characterization of active fractions and the identification of active components from different parts of broccoli are needed to develop functional foods or novel plant-derived medicines.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.957-963
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• 1998

Several medicinal herbs, which are nontoxic and have been used widely in traditional folk medicine, were extracted and antimicrobial activity of the extracts was investigated against various foodborne pathogens or food poisioning microorganisms. The ethanol extract of Sansa, Hwangryun, Cheukbaek, and Seokchangpo showed strong antimicrobial activities against Gram postive and Gram negative bacteria, whereas those of Sakunja, Sukjihwang and Baekji had little antimicrobial activities on microorganisms tested. Among medicinal herb extracts, ethanol extract of Coptis chinensis Franch (hwangryun) showed the strongest antimicrobial activity. Antimicrobial activity of ethanol extract of Coptis chinensis Franch was not destroyed by heating at $100^{\circ}C$ for 60 min and at $121^{\circ}C$ for 30 min, which is very stable over heat. The pH effect on minimal inhibitory concentrations (MIC) of the extract of Coptis chinensis Franch indicated that MIC was reduced with increasing the pH value of the medium. The inhibitory effect of partially purified substance from the ethanol extract of Coptis chinensis Franch on the growth of Listeria monocytogenes and Staphylococcus aureus was investigated. Growth of those strains occurred at the concentration of $100{\;}{\mu}g/mL$ and were inhibited at $500{\;}{\mu}g/mL$, whereas those strains was completely inactivated in the presence of $1000{\;}{\mu}g/mL$.