• Korean Journal of Clinical Pharmacy
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• v.9 no.1
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• pp.1-14
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• 1999

Vancomycin-resistant Enterococci (VRE) have recently emerged in Korean hospitals, as well as in those of other countries. VRE have been partially attributed to the overuse and misuse of vancomycin. The mecbanisms of VRE resistance are related to VanA, VanB, and VanC. Both VanA and VanB produce abnormal ligase enzymes to form D-ala-D-lactate termini in E. faecium and E. faecalis, instead of D-ala-D-ala termini. Meanwhile, Van C produces D-ser-D-ala termini in E. gallinarum and E. casseliflavus. These abnormal termini have a low affinity to vancomycin. As a result, VRE avoid the activity of vancomycin by these mechanisms. Unfortunately, there is no approved therapy for the treatment of VRE. Thus, available but uncommonly prescribed antibiotics (due to their toxicity or unproven efficacy) may become possible options. They include chloramphenicol, novobiocin, fosfomycin, and bacitracin. The combination therapy of available agents may also be the other options. They include high doses of a penicillin- or ampicillin-aminoglycoside combination, high doses of an ampicillin/sulbactam and aminoglyoosidcs combination, an ampicillin and vancomycin combination, and a ciprofloxacin, aminoglycosides, and rifampin combination. With respect to the near future, many types of investigational agents will most likely expand their treatment options for VRE. Teicoplanin, a glycopeptide, can be used for VanB- and VanC-related VRE. LY333328, a new generation of glycopeptide, is effective in treating VanA as well as VanB and VanC. RP59500 (quinupristin/dalfopristin), a streptogramin, is effective in treating vancomycin-resistant E. faecium. New generation quinolones (especially clinatloxacin) are potential options for the treatment of VRE, even though they cannot work as effectively against VRE as they can against Staphylococci. Both glycylcyclines (a new generation of tetracyclines) and ketolides (a new generation of macrolides) show good activity against Enterococci, regardless of vancomycin susceptibility. Oxazolidinones (i. e. eperezolid and 1inezolid) and everninomicins (i. e. SCH27899) are new groups of antibiotics, which also demonstrate good activity against VRE. It is imperative that clinical pharmacists take the responsibility of investigating new treatment options for VRE in order to combat this growing problem throughout the world.

• 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.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2003.06a
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• pp.123-123
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• 2003

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.226.1-226
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• 2000

No Abstract, See Full Text

• Korean Journal of Agricultural Science
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• v.43 no.5
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• pp.750-760
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• 2016

The use of antibiotics in Korean swine production has been changing to a restricted use of in-feed antibiotics. These antibiotics, which are also growth promoters, are powerful for disease control. Due to this issue, the swine industry is consistently looking for any kind of alternatives to antibiotics such as new feed ingredients, feed additives, feed formulation practices, or feeding methods to improve pig health and performance. In general, dietary factors provide bioavailable nutrients and/or affect physiological activity to modify the physiological condition, immune system, or microbial population of pigs to improve their performance and health. Thus, it is suggested that dietary factors may be important components in the growth and health management of pigs. Using an alternative grain feed such as rice, barley, and oats, low protein diets or low-high energy diets can be used as solutions to manage the effect of stress factors that cause growth and health problems at specific time points during the stages of pig production. Several studies support that these alternative feeds and dietary factors may improve pig growth and health by changes in intestinal conditions, immunity, or other physiological conditions compared with typical feed ingredients and diet management in pig production. Therefore, feed ingredients, low protein levels, and different energy contents in swine diets were reviewed to better understand how these dietary factors can contribute to improved pig performance and health under different physiological conditions.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.329-336
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• 1995

For the development of new antitumor antibiotics produced by microorganisms, Streptomyces sp. YBE-316 was isolated from soil. The productivity of the antitumor antibiotic from Streptomyces sp. YBE-316 gradually increased after 60 hours, and was maximum after 100 hours after inoculation in growth medium (2.0% sucrose, 1.0% soybean meal, 0.1% K$_{2}$HPO$_{4}$, pH 7.0) at 30$\circ$C, 150 rpm, 5 NL/min by 30 l jar fermentor. This antitumor antibiotic was present only in mycelium, and stable in pH 5.0-10.0 for 20 minutes at 100$\circ$C. Antitumor and antibiotic activities were maintained at neutral pH, and heat stability was low. This antitumor antibiotic was soluble in methanol and ethanol, and insoluble in water, ethyl acetate, chloroform, and n-hexane. This antitumor antibiotic was sequentially purified by acetone extraction from mycelium, butanol extraction, and silica gel column chromatography. Antitumor activity was low against most tested cell lines, but antibiotic activity was high and low against yeasts and bacteria, respectivelv. The visualization test showed that this antitumor antibiotic had higher hydroxyl, ketone, amino, carboxyl groups, and sugar(s) in its structure. Instrumental analyses showed that this antitumor antibiotic was a pentaene in polyene class antibiotics. In pentaene class antibiotics, this was considered as an eurocidin or capacidin type antibiotics. The molecular weight of this antitumor antibiotic was higher than 683.0 daltons, and this antitumor antibiotic might be glycosylated by other sugar(s), instead of mycosamine or perosamine, an amino sugar.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.474-483
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• 2023

Members of the genus Streptomyces produce more than 70% of antibiotics. The rise in antibiotic resistance globally enhanced the search for novel species with the ability to produce new bioactive compounds. This study was initiated to investigate different regions in Jordan for previously uncultured and rare Streptomyces species capable of producing novel antimicrobial compounds especially active against bacteria resistant to antibiotics. A total of 191 Streptomyces strains were isolated from 26 soil samples collected from different geographic regions in Jordan. Isolates were characterized based on colony and cellular morphology as well as using 16S rRNA gene sequencing. These isolates were screened for their ability to produce antibiotics by the perpendicular-cross streak method, and then tested by well diffusion method against tested pathogens. Fifty-four isolates showed potential to produce antimicrobial products especially active against resistant bacteria, 20.1% of the isolates showed inhibitory effect against Staphylococcus aureus, 16.9% against clinical MSSA strains, and 18.0% against MRSA: whereas only 4.2% against Esherichia coli, 3.2% against Klebsiella pneumonia, 2.7% against Pseudomonas aeruginosa, and 10.0% against clinical Candida albicans. Three isolates were selected for further identification due to their antibacterial activity against S. aureus, MRSA, and MSSA. These isolates were identified as follows; Streptomyces aburaviensis DSa3, Streptomyces alboniger SAb7 and Streptomyces misionensis ZAb2, based on cultural, biochemical characteristics and molecular analysis of the 16S rRNA.

• YAKHAK HOEJI
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• v.30 no.1
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• pp.24-30
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• 1986

New antibiotics having moieties of penicillanic acid, cephalosporanic acid and ampicillin on both ends of the central alkylene were synthesized by reacting 6-aminopenicillanic acid (6-APA), 7-aminocephalosporanic acid (7-ACA) and ampicillin with hexamethylene diisocyanate and sebacoyl chloride, respectively. Antibacterial activities of the compounds were also investigated. The compound derived from sabacic acid and ampicillin exhibited an enhanced antibacterial activities against gram-negative bacteria and was found to be a promising wide-spectrum antibiotic.

• Tuberculosis and Respiratory Diseases
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• v.75 no.3
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• pp.125-127
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• 2013

In this paper, we describe 72-year-old female patient without evidence of malignant disease presented with significantly elevated serum carbohydrate antigen (CA) 19-9 levels by respiratory infections. She was diagnosed with respiratory infections due to Mycobacterium avium complex and Pseudomonas aeruginosa. The serum CA 19-9 levels remarkably increased (1,453-5,300 U/mL; reference range, <37 U/mL) by respiratory infection and abruptly decreased (357-534 U/mL) whenever infection was controlled by specific treatments. This case suggests that serum CA 19-9 levels may be used as a diagnostic marker to indicate new or resistant infections to previous antibiotics in chronic lung diseases without significant changes in chest X-ray findings.

• The Plant Pathology Journal
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• v.18 no.1
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• pp.18-22
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• 2002

Two peptaibol antibiotics, peptavirins A and B, which exhibited strong inhibitory effect against Tobacco mosaic vials (TMV) infection, were isolated from steam-cooked rice culture of Apiocrea sp.14T. The peptavirins were identified as new derivatives of chrysospermins, which are 19-mer and have been reported to be produced in a fungal isolate. The physicochemical properties of the peptavirins were mostly identical with chrysospermins A through D except for the UV absorption spectrum. The peptavirins inhibited the growths of the Grampositive bacteria tested, including the plant pathogenic bacterium, Corynebacterium lilium, and the fungus, Aspergillus niger. Peptavirin A was somewhat cytotoxic to cancer cell lines, especially K562 (leukemia) and UACC 62 (melanoma), whereas peptavirin B only exhibited slight cytotoxicity.