• Journal of dental hygiene science
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• v.18 no.3
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• pp.147-154
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• 2018

This study aimed to evaluate the antimicrobial effects of Acanthopanax sessiliflorum fruit (ASF; Ogaza) extracts on Streptococcus mutans and Streptococcus sobrinus, which are agents that cause dental caries, and on Streptococcus mitis and Streptococcus salivarius, the microbial flora of the oral cavity. The ASF extracts obtained using 70% ethanol were fractionated in the order of ethyl acetate and n-Butanol, concentrated under reduced pressure, and lyophilized to give powdery solvent extracts. The antimicrobial activity of ASF extracts from each solvent was examined using the disk diffusion method. As a result, only those extracts obtained using an ethyl acetate solvent showed antimicrobial activity. These extracts were selected, and the minimum inhibitory concentration was measured by disk diffusion method at various extract concentrations. Results showed a minimum inhibitory concentration of 32 mg/ml. The viable cell count was measured to confirm the minimum bactericidal concentration. Results showed a minimum bactericidal concentration of 64 mg/ml. In the cytotoxicity test using normal human dermal fibroblast cells, the absorbance value of the test group was similar to that of the control group at 0.64, 1.28, and 6.4 mg/ml. The bacteria and their colonies were examined using a scanning electron microscope. Boundaries between the antimicrobial activity region and non-antimicrobial activity region were observed around the paper disk, which was immersed in the extract with 32 mg/ml concentration. Bacterial colonization was not observed in the area with antimicrobial activity. This finding suggests that ASF extracts can inhibit the growth of some microorganisms in the oral cavity, in addition to the effects of these extracts known to date. In particular, ASF extracts may be used as a preparation for preventing dental caries by adding the extract to the toothpaste or oral mouthwash.

• Journal of Microbiology and Biotechnology
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• v.30 no.11
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• pp.1640-1650
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• 2020

Colorectal cancer (CRC) is the leading cause of common malignant neoplasm worldwide. Many studies have analyzed compositions of gut microbiota associated with various diseases such as inflammatory bowel diseases (IBD) and colon cancer. One of the most representative bacteria involved in CRC is enterotoxigenic Bacteroides fragilis (ETBF), a species belonging to phylum Bacteroidetes. We used ETBF colonized mice with azoxymethane (AOM)/dextran sulphate sodium (DSS) and zerumbone, a compound with anti-bacterial effect, to determine whether zerumbone could restore intestinal microbiota composition. Four experimental groups of mice were used: sham, ETBF colonized AOM/DSS group, ETBF colonized AOM/DSS group zerumbone 60 mg kg-1 (ETBF/AOM/DSS + Z (60)), and only zerumbone (60 mg kg^-1)-treated group. We performed reversible dye terminators-based analysis of 16S rRNA gene region V3-V4 for group comparison. Microbiota compositions of ETBF/AOM/DSS + Z (60) group and ETBF colonized AOM/DSS group not given zerumbone were significantly different. There were more Bacteroides in ETBF/AOM/DSS + Z (60) group than those in ETBF colonized AOM/DSS group, suggesting that B. fragilis could be a normal flora activated by zerumbone. In addition, based on linear discriminant analysis of effect size (LEfSe) analysis, microbial diversity decreased significantly in the ETBF colonized AOM/DSS group. However, after given zerumbone, the taxonomic relative abundance was increased. These findings suggest that zerumbone not only influenced the microbial diversity and richness, but also could be helpful for enhancing the balance of gut microbial composition. In this work, we demonstrate that zerumbone could restore the composition of intestinal microbiota.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.536-539
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• 2013

In this study, mixed plant extracts including Phellodendro namurense and Eucommia ulmides Oliv were tested for antimicrobial activity and safety. Antimicrobial activity was measured by disc diffusion method using normal skin flora and opportunistic microbes such as Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. As safety test, single dose oral toxicity test, single dose inhalation toxicity test and repeat dose inhalation toxicity test were done. From antimicrobial test, plant extracts showed significant antimicrobial activity Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, however, did not indicate any antibacterial effect on Escherichia coli. From 3 kinds of safety tests, toxicity of mixed plant extracts was not observed. From experimental results, mixed plant extracts including Phellodendro namurense and Eucommia ulmides Oliv showed good potential for natural antimicrobial agent.

• Archives of Pharmacal Research
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• v.29 no.5
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• pp.348-353
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• 2006

In this study, a 40% ethanol extract of Chinese yam flour (Dioscoreae rhizoma), containing $177{\pm}58{\mu}g/mL$ of dioscin, was tested in order to evaluate its pharmacological effects on the gastrointestinal tracts of Sprague-Dawley rats. Via the ingestion of the Chinese yam extract, the secretion of gastric acid was suppressed in the rats, and gastrointestinal motility increased by as much as 10%. The fecal quantity of rats fed on the Chinese yam extract also increased, by more than 40% as compared with that of the controls. The Chinese yam extract was found not to affect the growth of normal intestinal bacteria. However, a great deal of lactose-fermenting bacteria was observed in the fecal samples of rats fed for 6 weeks on 2% Chinese yam extract. This finding would appear to suggest that Chinese yam extract not only induces an improvement in digestive capability, but also affects the conversion of some intestinal flora to helpful bacteria. Our serochemical analyses indicated that serum glucose, neutral lipid, and total cholesterol levels were reduced to some degree by long-term feeding on Chinese yam extract. This finding bolsters the notion that Chinese yam extract may prove helpful as a digestion-aiding agent for patients suffering from hyperglycemia or hyperlipidemia.

• Korean Journal of Microbiology
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• v.9 no.2
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• pp.86-93
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• 1971

Escherichiae-like organisms were isolated from rectal specimens of 56 children who were either in preschool age or in elementary school. The isolated strains were subjected to tests to screen enteropathogens producing heat-labile enterotoxin and susceptibility test to various antibiotics by disc diffusion method on agar plates. Production of heat-labile enterotoxin by the strains was assyed in the sensitive and reproducible cultured adrenal tumor cell system. The assay was sterodogenesis of the cell in the presence of heat-labile enterotoxin. Among 56 strains, gave positive reaction in the test of toxin production. This meant that about 10% of the children population objected to the study harbored the toxigenic strain of enteropathogenes. Some of these toxigenic strains were resistant to the antibiotics employed in the test. This study suggested that considerable population in Korea may harbor entertoxigenic E. coli as a part of intestinal normal flora. The toxigenic strains which are resistant to antibiotics may bring issue of public health in the future.

• Journal of Veterinary Clinics
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• v.25 no.6
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• pp.447-451
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• 2008

This study was aimed to determine the prevalence of Helicobacter spp. in privately owned pet dog's oral cavity samples (saliva, dental plaque, vomitus) and fecal samples in Korea and to evaluate the potential route for transmission. Total 100 patients dogs attending one Veterinary Medical Teaching Hospital were examined by Helicobacter genus-specific PCR assay and these dogs were divided into two groups whether they had gastrointestinal signs (vomiting, nausea and diarrhea) or not. The total detection rate of Helicobacter spp. by PCR in saliva, dental plaque and fecal samples was 23%, 1% and 68% respectively. The difference of prevalence with regarding the gastrointestinal sings was not significant. In vomitus, two of seven samples had positive results. These results suggested that Helicobacter spp. are present in the oral cavity although they were present in very low number and are not like to be normal oral flora of the oral cavity and Helicobacter spp. in dogs could be transmitted through oral-oral, gastrooral and fecal-oral route.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.58-60
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• 2019

Anaerobic Gram-negative bacterium Prevotella intermedia is a part of normal flora of the oral cavity and associated with various types of oral and systemic diseases. We present here a draft genome sequence of P. intermedia ATCC 15032, originally isolated from cervicofacial actinomycosis. The genome is 2,848,426 bp in length and has a GC content of 43.45%. The genome includes 2,358 protein-coding genes, 5 rRNAs, and 43 tRNA. The sequence information will provide important clues in understanding the genome diversity within the bacterial species, and genetic basis for phenotypic differences among P. intermedia strains.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.64-66
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• 2019

Cutibacterium acnes is a member of normal flora of human skin, conjunctiva, intestinal tract, the external auditory canal as well as oral cavity. It has been identified as an opportunistic pathogen related to acne vulagris, endocarditis infections, sarcoidosis, brain abscess, periodontitis, and osteomyelitis of the humerus. C. acnes KCOM 1315 (= ChDC KB81) was isolated from a human jaw osteomyelitis lesion. Here, we present the complete genome sequence of C. acnes KCOM 1315.

• Korean Journal of Microbiology
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• v.55 no.2
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• pp.154-156
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• 2019

Eikenella corrodens is Gram-negative, facultatively anaerobic, and rod-shaped bacterium. It is a part of the normal human mucosal flora that can cause several systemic diseases such as endocarditis, liver abscess, and intracranial bacterial infection. E. corrodens KCOM 3110 (= JS217) was isolated from human subgingival dental plaque of periodontitis lesion. Here, we present the complete genome sequence of E. corrodens KCOM 3110.

• Journal of Microbiology and Biotechnology
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• v.32 no.1
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• pp.46-55
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• 2022

Clostridioides difficile infection (CDI) is a significant cause of hospital-acquired and antibiotic-mediated intestinal diseases and is a growing global public health concern. Overuse of antibiotics and their effect on normal intestinal flora has increased the incidence and severity of infections. Thus, the development of new, effective, and safe treatment options is a high priority. Here, we report a new probiotic strain, Bacillus amyloliquefaciens (BA PMC-80), and its in vitro/in vivo anti-C. difficile effect as a prospective novel candidate for replacing conventional antibiotics. BA PMC-80 showed a significant anti-C. difficile effect in coculture assay, and its cell-free supernatant (CFS) also exhibited a considerable anti-C. difficile effect with an 89.06 ㎍/ml 50% minimal inhibitory concentration (MIC) in broth microdilution assay. The CFS was stable and equally functional under different pHs, heat, and proteinase treatments. It also exhibited a high sensitivity against current antibiotics and no toxicity in subchronic toxicity testing in hamsters. Finally, BA PMC-80 showed a moderate effect in a hamster CDI model with reduced infection severity and delayed death. However, further studies are required to optimize the treatment condition of the hamster CDI model for better efficacy and identify the antimicrobial compound produced by BA PMC-80.