• Restorative Dentistry and Endodontics
• /
• v.9 no.1
• /
• pp.89-99
• /
• 1983

The rational approach to antimicrobial therapy of infected root canals is based on accurate identification of the infecting organism and on the organism's susceptibility to antimicrobial agents as measured by standardized techniques. In establishing criteria for the selection of antibiotics, a susceptibility test should be performed. The purpose of this study was to investigate the susceptibility of 224 aerobic and anaerobic microbial strains isolated from infected root canals to various antibiotics. This was performed by using 7 antibiotic sensi-disc: Penicillin (10 units), Ampicillin (10 mcg), Tetracycline (30 mcg), Streptomycin (10 mcg), Kanamycin (30 mcg), Lincomycin (2 mcg), and Clindamycin (2 mcg). The results were as follows; 1. Strains isolated from infected root canals was shown to be most susceptible to Clindamycin, while Streptomycin exhibited least antibacterial properties. 2. Anaerobes were found to be susceptible to Penicillin, Ampicillin, and Clindamycin. 3. Streptomycin and Kanamycin were shown to be effective against Staphylococcus aureus and Staphylococcus epidermis, however, unidentified G(+) cocci organisms were found to be resistant to these agents. 4. Bifidobacterium sp. was susceptible to Lincomycin while G(+) rods were resistant to it. 5. Staphylococcus aureus, Micrococcus sp., and anaerobes were highly susceptible to Clindamycin. 6. All of the antibiotics tested were shown to be very effective against Eubacterium sp.

• Microbiology and Biotechnology Letters
• /
• v.9 no.3
• /
• pp.117-121
• /
• 1981

Safety of yellow pigment produced by Monascus sp. CS-2 was evaluated. Acute oral toxicity, pyrogen test, and histamine test, as well as antimicrobial activity were determined. The results obtained were; LD oral in mice was 132.5 mg/20 g, pyrogen test in rabbit was 5 mg/kg, and histamine test in cat was 10 mg/kg. Also the pigment was particularly sensitive to Bacillus subtilis (ATCC 6633), Sarcina lutea (ATCC 9341) and Staphylococcus aureus (ATCC 6538 P), whereas not sensitive to Pseudomonas pyosyanea (ACTC 10490), Bacillus var. mycoides (ATCC 11778), Bordetella bronchiseptica (ATCC 4617) and Staphylococcus epidermidis(ATCC 12228).

• Microbiology and Biotechnology Letters
• /
• v.38 no.1
• /
• pp.77-83
• /
• 2010

The fructus of Crataegus pinnatifida Bunge (CBF) has been used as medicinal and food source in worldwide. In this study, antimicrobial activity of the methanol extract and its sequential organic solvent fractions of CBF against different pathogenic bacteria and fungi, including multidrug resistant Pseudomonas aeruginosa and Candida sp., were investigated. The methanol extract of CBF was active against various gram-positive and gram-negative bacteria, and the ethylacetate and butanol fractions of CBF showed strong antibacterial activity against Listeria monocytogenes, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Salmonella typhimurium, Proteus vulgaris, Escherichia coli and various multidrug resistant Pseudomonas aeruginosa with minimal inhibitory concentration of 1.0~7.5 mg/mL. Also the fractions showed anti-Candida activity against C. albicans, C. kruseis and C. geochares. The methanol extract of CBF and its solvent fractions, except n-hexane fraction, did not show any hemolytic activity against human red blood cell up to $500\;{\mu}g/mL$, respectively. The hemolysis in n-hexane fraction at $500\;{\mu}g/mL$ was less than 9.9%. Our results suggest that the CBF could be developed as a potent antibacterial agent, especially for multidrug resistant Pseudomonas aeruginosa.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.43 no.1
• /
• pp.33-38
• /
• 2010

Emerging of antibiotic resistance of pathogenic bacteria is now a very serious problem in the clinics to treat the diseases, which have been easy to cure by antibiotic treatments before. Unfortunately, antibiotics developed till now are not effective any more against the resistant bacteria. Lots of efforts to discover new antibiotics having novel and unique structures and functions are really urgent and undergoing in the whole world. In this study, we tried to screen and isolate Same unique bacterial strains producing antibacterial substances from the sea water, which is the poor environment for bacteria 10 make their growing. Three bacterial strains among 916 strains isolated showed inhibition clear zone on the marine agar plate growing pathogenic bacteria including Acinetobacter baumannii, Edwardsiella tarda, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella enterica. One of them, which was identified as Bacillus sp. DH-9 from 16S rRNA gene analysis, showed especially considerable antibacterial activity against S. aureus which is notorious for methicillin resistant S. aureus (MRSA). The growth of S. aureus was totally inhibited when the supernatant of Bacillus sp. DH-9 culture was treated on.

• KSBB Journal
• /
• v.26 no.2
• /
• pp.100-106
• /
• 2011

Strain BCNU 5011 was isolated from forest soil samples collected in the Taebaek mountain in the Gangwon province, Korea. The biochemical, physiological and 16S rRNA sequence analysis strongly indicated that this isolate was most closely related to Paenibacillus polymyxa. A maximum production level of antimicrobial substances of Paenibacillus sp. BCNU 5011 was achieved under aerobic incubation at $30^{\circ}C$ for 3 days in SST broth.Paenibacillus sp. BCNU 5011 showed a broad spectrum of activity against Gram positive and Gram negative bacteria, including methicllinresistant Staphylococcus aureus (MRSA). Paenibacillus sp. BCNU 5011 was also shown to inhibit the growth of different potential human pathogenic bacteria and fungi in vitro. Peptide extract showed better antimicrobial activity than solvent extracts. But active antimicrobial compounds might be included in both peptide extract and solvent extracts. Further separation, purification and identification of active principles leads project to develop antimicrobial agents and anti-MRSA agents.

• Microbiology and Biotechnology Letters
• /
• v.49 no.2
• /
• pp.131-137
• /
• 2021

This study aimed at isolating lactic acid bacteria with anti-MRSA (methicillin-resistant Staphylococcus aureus) bacteriocin activity from fermented shrimp. We selected three strains, named Weissella sp. S1, S2, and S3, using analysis based on 16S rRNA gene sequences. All strains showed appropriate growth in an MRS medium containing 5% (w/v) NaCl and showed antibacterial activities against Bacillus cereus, Escherichia coli, Staphylococcus aureus, and MRSA. The strains exhibited similar growth rates at 0-5% NaCl, with approximate reduction in growth rate observed at 9% NaCl. Weissella sp. S1, S2, and S3 exhibited maximum growth rates at pH 7, 9, and 8, respectively. The crude bacteriocin was prepared from Weissella sp. S3 and subjected to characterization. The remaining activities after 30 min of exposure at each temperature were 100%, beyond 75%, and 49% at 4℃ and 37℃, 50℃ and 70℃, and 100℃, respectively. The remaining activities after 24 h of exposure at each pH were 100%, 75%, and 49% at pH 3 and 5, 7 and 9, and 10, respectively. Use of 50% (v/v) ethanol or isopropanol treatment did not diminish the antibacterial activity of the bacteriocin, while the 50% (v/v) hexane treatment reduced the activity by 51%. The molecular weight of the bacteriocin was nearly 6 kDa that was quantified using tricine-SDS-PAGE. Our findings suggest that Weissella sp. S3 may be considered a probiotic and useful source of antimicrobial substances in the development of bio-preservatives for food or in MRSA treatment.

• Korean Journal of Veterinary Service
• /
• v.20 no.2
• /
• pp.151-159
• /
• 1997

This study was carried out to isolate of causative agents from CMT-positive and mean somatic cell count(SCC) $\geq$500,000 cells/ml mastitic milk, and evaluate to antimicrobial susceptibility of isolates in Iksan branch area from January to November, 1996. 1. The CMT-positivity(SCC 500,000 cells/ml) of 610 heads was 36.2% (221), and of 2,373 quarter milks was 16.1% (383). 2. The Gram-positive isolates were 153 strains which was Staphylococcus sp (115), Micrococcus sp (18), Streptococcus sp (10), Listeria monocytogenes (5) and Enterococcus faecalis(5). 3. The Gram-negative isolates were 66 strains including E coli(14), Yersinia sp (13), Shigella sp(8), Enterobacillus sp(8), Cedecea sp(5), Pseudomonas aeruginosa(5), Proteus sp(5), Klebsiella sp(4), Salmonella sp(2), kluyvera ascorbate(1) and Tatumella ptyseos (1). 4. The Gram positive strains of isolates were moderately susceptible to T/s, Cp, Fd, Imp, Aug, Rif, Cft and Va. And the Gram negative strains of Isolates were moderately susceptible to T/s, Cp, Imp, Pi and Ti, In order. 5. Multiple antimicrobial resistant patterns were encountered 62 and 36 from Gram positive and negative isolates, respectively.

• Korean Journal of Microbiology
• /
• v.52 no.3
• /
• pp.327-335
• /
• 2016

A novel Amycolatopsis strain KCTC 29142 was isolated and characterized based on the polyphasic taxonomic analysis including morphological observation, phylogenetic analysis, physiological and chemotaxonomic characteristics. The ethyl acetate extract of strain KCTC 29142 culture broth showed strong antibacterial activity and the active compound was identified as siderochelin A, a ferrous-ion chelating compound. In this study, siderochelin A showed good activity against multi-drug resistant pathogens, including Acinetobacter baumanii, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Staphylococcus aureus (VRSA), and Escherichia coli (E. coli). The minimum inhibitory activity against clinical isolates was also determined.

• KSBB Journal
• /
• v.21 no.2
• /
• pp.129-132
• /
• 2006

The importance of natural preservative has increased in recent years. The natural preservatives have been used in the field of foods, cosmetics and pharmacology. In the present work Artemisia sp., well recognized for their effect of antimicrobial activity, were extracted by methanol and water sequentially for selecting only water-soluble compounds that can be used as additives in food and cosmetics. Antimicrobial activities of water extracts from stem and leaf of Artemisia princeps var. orientalis were investigated by the disc diffusion method. Two gram positive bacteria(Staphylococcus aureus and Bacillus subtilis) and three gram negative bacteria(Escherichia coil, Agrobacterium tumefaciens and Pseudomonas putida) were used for antimicrobial activity studies. The water-soluble compounds from methanol extract showed higher antimicrobial activity than only water extract to these bacteria. Comparative evaluation of water-soluble metabolite profiles with caffeic acid that is known as an antimicrobial compound from Artemisia sp. was performed by high performance liquid chromatography with photo-diode array detection.

• Journal of Aquaculture
• /
• v.10 no.1
• /
• pp.9-15
• /
• 1997

The pathogenic organisms occurred in cultured marine fishes in Kamak Bay were investigated from March to November in 1993. The samples were collected at 7 sampling stations once a month. Nine species of pathogenic organisms (Vibrio sp., Edwardsiella sp., Flexibacter sp., Streptococcus sp., Micrococcus sp., Caligus sp., Trichodina sp., Lymphocystis and Staphylococcus sp.) were identified as pathogenic organisms from four different species of fish (Sebastes schlegeli, Paralichthys olivaceus, lateolabrax japonicus and Pagrus major) collected in the study areas. Most of pathogenic organisms were found at over 20^{\circ}C$ of sea water temperature from June to October in 1993. On the test of drug sensitivity, Vibrio sp. (KS-9303) was sensitive to oxytetracycline and chloramphenicol ; Edwardsiella sp. (KP-9315) to oxytetracycline ; Flexibacter sp. (KP-9318) to oxytetracycline, chloramphenicol and oxolinic acid ; Streptococcus sp. (KP-9319) to erythromycin, chlorampheicol and oxytetracycline. However, all these 4 isolated bacteria were resistant to ampicilin, steptomycin, sulfamethoxazole and nitrofurazone.