• Korean Journal of Veterinary Service
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• v.38 no.1
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• pp.19-23
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• 2015

This study was carried out to investigate the genital tract bacterial flora of riding mare in Jangsu stud farm during March to September, 2014. The specimens were collected from vaginal and uterus using a swab from 104 riding mares. Colonies were selected on blood and MacConkey agar plates, and identified as standard biochemical properties and Maldi-Tof MS. From this study, we isolated 148 strains including Escherichia (E.) coli (14.19%), Streptococcus (S.) equi subsp. zooepidemicus (2.7%), Streptococcus (S.) dysgalactiae subsp. equisimilis (2.03%), Klebsiella (K.) pneumonia (1.35%) and other strains from riding mares. In antimicrobial agents susceptibility test, it showed a high sensibility to the antibiotics of the most. E. coli and S. zooepidemicus were visible to have a high sensibility to almost antibiotics used in this study. However, K. pnemoniae showed a high antibiotic resistance patterns. These results may provide the basic information to establish strategies for the treatment and prevention of reproductive diseases in riding mares in Korea.

• Journal of Veterinary Clinics
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• v.24 no.1
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• pp.19-25
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• 2007

This study carried out to investigate the genital tract bacterial flora of Thoroughbred mare in Jeju province during March and July, 2006. The specimens were collected from vaginal ucosa and clitorial fossa using a culture swab (BBL, USA) from 100 Thoroughbred mares. Colonies were selected blood and MacConkey agar plate, and identified as standard biochemical properties using Biolog system (Thermo, USA). In this study, 470 gram-negative strains were isolated more frequently than 249 gram-positive strains. We were Isolated Escherichia coli (19.8%), Proteus mirabillis (14.9%), Enterobacter nimipressuralis (7.4%), Enterobacter mobilis (4.7%), Aeromonas encheleia (4.3%), Pseudomonas aeroginosa (3.0%), Staphylococcus aureus (14.9%), Staphylococcus epidermidis (11.2%), Coagulasenegative Staphylococcus spp. (10.0%), Enterococcus faecalis (9.2%), Enterococcus faecium (8.0%), Actinomyces viscosus (7.2%), Micoroccus diversus(6.8%), Streptococcus dysgalactiae subsp. equisimilis(5.2%), Streptococcus equi subsp. zooepidemicus (3.2%), Other non-beta hemolytic Streptococcus spp. (2.0%) and many others from vaginal mucosa and clitorial fossa in Thoroughbred mares. No significant bacteria (Taylorella equigenitalis and Klebsiella pneumonia) were isolated from the mare genital tract. In antimicrobial agents susceptibility test, it shows a high sensibility in the antibiotics of the most which excepts the streptomycin and neomycinm, kanamycin, spectinomycin, compound sulfonamides. Especially, Staphylococcus epidermidis, Enterococcus spp. and Streptococcus spp. were visible a high sensibility in the all antibiotics. However, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus spp. and E. coli were showed a high antibiotic resistance patterns. These results may provide the basic information to establish strategies for the treatment and prevention of reproductive disease in Thoroughbred mares in Korea.

• Korean Journal of Veterinary Service
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• v.33 no.1
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• pp.59-66
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• 2010

This study was carried out to investigate the characters of Listeria monocytogenes isolated from food, animal feces, dry cattle food, and the environment in Seoul and Kyonggi province during the period from 1998 to 2003. Serotyping of 70 L. monocytogenes isolates was performed according to the manufacturer's instruction. Minimum inhibitory concentrations (MICs) were determined by the microdilution method according to the guidelines of the Clinical and Laboratory Standards Institute. All the isolates were tested against 20 antimicrobial agents. The serotypes of the 70 L. monocytogenes isolates were 1/2c (62.8%), 1/2a (20%) and 1/2b (17.2%). Of the 70 L. monocytogenes isolates, 67.1%, 57.1%, 11.4%, 5.7%, 2.8%, 1.4% and 1.4% were resistant to tetracycline (Te), minocycline (Mi), norfloxacin (Nor), ciprofloxacin (Cip), neomycin (N), chloramphenicol (C) and cephalothin (Cf), respectively. However, all isolates were 100% sensitive to antibiotics such as amikacin, ampicillin, erythromycin, gentamycin, imipenem, kanamycin, ofloxcin, streptomycin, penicillin, trimethoprim, trimethoprim/sulfamethoxazole, tobramycin, and vancomycin. Multiple resistance patterns of the isolates were observed in TeMiNor Cip (1.4%), TeMiNor (7.1%), TeMiCip (2.9%), TeMiN (1.4%) and TeMi (44.3%). The results of this study indicate that many L. monocytogenes isolates are resistant to antimicrobial agents including Te and Mi. The possibility that the isolates could increasingly acquire multiple antimicrobial resistant properties cannot be precluded.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.385-393
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• 2016

Pseudomonas syringae pv. actinidiae causes bacterial canker disease in kiwifruit. Owing to the prohibition of agricultural antibiotic use in major kiwifruit-cultivating countries, alternative methods need to be developed to manage this disease. Bacteriophages are viruses that specifically infect target bacteria and have recently been reconsidered as potential biological control agents for bacterial pathogens owing to their specificity in terms of host range. In this study, we isolated bacteriophages against P. syringae pv. actinidiae from soils collected from kiwifruit orchards in Korea and selected seven bacteriophages for further characterization based on restriction enzyme digestion patterns of genomic DNA. Among the studied bacteriophages, two belong to the Myoviridae family and three belong to the Podoviridae family, based on morphology observed by transmission electron microscopy. The host range of the selected bacteriophages was confirmed using 18 strains of P. syringae pv. actinidiae, including the Psa2 and Psa3 groups, and some were also effective against other P. syringae pathovars. Lytic activity of the selected bacteriophages was sustained in vitro until 80 h, and their activity remained stable up to 50℃, at pH 11, and under UV-B light. These results indicate that the isolated bacteriophages are specific to P. syringae species and are resistant to various environmental factors, implying their potential use in control of bacterial canker disease in kiwifruits.

• Korean Journal of Pharmacognosy
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• v.29 no.1
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• pp.22-27
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• 1998

This study was carried out to develop antitumor agents based on effects of the ethyl acetate soluble fraction of the methanolic extract of Lonicerae flos on human oral epitheloid carcinoma cells. Human oral epitheloid carcinoma cells were cultured in RPMI-1640 media containing 10% fetal bovine serum, antibiotic, and fungizone. After incubation for 24 hrs, the cells were treated with A, B, C, D, and E fractions for 48hrs under the same condition. MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazoliumbromide), NR (Neutral red) and SRB (Sulforhodamine B protein) assay were performed. The light microscopic findings were observed by inverted microscope. In MTT assay, fraction B was shown significant antitumor activity (P<0.001), fraction E was shown significant antitumor activities (P<0.05), but the other fractions were not shown. In NR assay, fraction B was shown significant antitumor activity (P<0.001). In SRB assay, fractions B was shown significant antitumor activities (P<0.01). fractions A and D were shown significant antitumor activities (P<0.05). but the other fractions were not shown. In light microscopy. the fraction B of the ethyl acetate soluble fraction of the methanolic extract of Lonicerae flos showed the highest antitumor activity. These finding suggested that fraction B possessed the most antitumorous agent.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.130-136
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• 2021

Persister cell formation and biofilms of pathogens are extensively involved in the development of chronic infectious diseases. Eradicating persister cells is challenging, owing to their tolerance to conventional antibiotics, which cannot kill cells in a metabolically dormant state. A high frequency of persisters in biofilms makes inactivating biofilm cells more difficult, because the biofilm matrix inhibits antibiotic penetration. Fatty acids may be promising candidates as antipersister or antibiofilm agents, because some fatty acids exhibit antimicrobial effects. We previously reported that fatty acid ethyl esters effectively inhibit Escherichia coli persister formation by regulating an antitoxin. In this study, we screened a fatty acid library consisting of 65 different fatty acid molecules for altered persister formation. We found that undecanoic acid, lauric acid, and N-tridecanoic acid inhibited E. coli BW25113 persister cell formation by 25-, 58-, and 44-fold, respectively. Similarly, these fatty acids repressed persisters of enterohemorrhagic E. coli EDL933. These fatty acids were all medium-chain saturated forms. Furthermore, the fatty acids repressed Enterohemorrhagic E. coli (EHEC) biofilm formation (for example, by 8-fold for lauric acid) without having antimicrobial activity. This study demonstrates that medium-chain saturated fatty acids can serve as antipersister and antibiofilm agents that may be applied to treat bacterial infections.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.587-593
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• 2021

Infertility is a key issue affecting mood and behavior in men. Microorganisms are one of the primary etiological agents that may be associated with infertility. The objective of the present study was to identify bacterial causative agents from the semen of infertile subjects and determine the effect of bacterial infection on sperm quality, as well as determine the susceptibility of these bacteria to drugs. Forty semen samples from 30 infertile patients and 10 fertile individuals were collected. The pH, volume, motility, and concentration of semen were analyzed. The samples were processed and identified by biochemical testing using API identification kits. The antibiotic susceptibility pattern was determined using the disc diffusion method. Abnormal sperm quality was observed. The mean age of the individual and their sperm morphology, concentration, progressive motility, pH level, and pus cell content were 31.9 years, 2.7%, 10.4 million/ml, 27.3%, 8.3, and 5.7, respectively. Among the tested samples, oligoasthenozoospermia was found to show the highest occurrence, at 27/30 samples, followed by teratozoospermia, at 25/30 samples, and asthenozoospermia, at 22/30 samples. Of the tested infertile patients' sperm, 19, 6, and 5 isolates were identified as Escherichia coli, Klebsiella pneumonia, and Staphylococcus epidermidis, respectively. The results also revealed multi-drug resistance in the bacteria. Compared to that shown by the other tested antibiotics, amikacin showed higher activity against all isolated bacteria. However, the bacteria exhibited maximum resistance against gentamicin, cefotaxime, levofloxacin, and ampicillin. In conclusion, leukocytospermia and bacterial infections are possibly responsible for sperm abnormalities. Multi-drug resistant bacteria were detected. Gentamicin, cefotaxime, levofloxacin and ampicillin were shown the highest resistance, while amikacin was the most effective antimicrobial agent against the isolated bacteria.

• Animal Bioscience
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• v.35 no.1
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• pp.138-146
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• 2022

Objective: The objective of the current study was to investigate the influences of conventional (CO) and deep litter (DE) systems on antimicrobial resistance in fecal Escherichia coli (E. coli). Methods: A cross-sectional study was carried out to detect antimicrobial resistance to E. coli in swine fecal samples in CO and DE systems located in western and northeastern Thailand. Individual rectal swab samples were taken only from healthy pigs. A total of 215 individual and healthy pigs were randomly selected for isolation and antimicrobial susceptibility test of E. coli by the disc diffusion method. The test panel included amoxicillin (AMX), colistin, doxycycline (DOX), enrofloxacin, gentamicin (GEN), kanamycin, neomycin (NEO), and trimethoprim-sulfamethoxazole (SXT). Results: There were significant (p<0.05) lower resistance levels for GEN, NEO, and SXT in the DE farms compared to those in the CO farms. There was a lower number of antimicrobial resistance agents (p<0.001) in the DE farms compared to those in the CO farms. This result was consistent with those in western (p<0.01) and northeastern (p<0.01) Thailand. Overall, antibiograms of AMX-SXT and AMX-DOX-SXT were found in the CO (19.09% and 20.91%, respectively) and the DE (16.19% and 24.76%, respectively) farms. No antimicrobial resistance (5.71%) was found and AMX (13.33%) resistant pigs in the DE farms, whereas the pattern of AMX-GEN-SXT (6.36%) and AMX-DOX-GEN-SXT (11.82%) resistant pigs was found in the CO farms. Conclusion: The DE system for pig farming was superior to conventional pig farming by lowering the resistance level of fecal E. coli to GEN, NEO, and SXT, with decreasing the number of antimicrobial resistance agents and inducing a small proportion of pigs to be free from antimicrobial resistance.

• Journal of Microbiology and Biotechnology
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• v.18 no.10
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• pp.1729-1734
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• 2008

Chitosan, a cationic polysaccharide, has been widely used as a dietary supplement and in a variety of pharmacological and biomedical applications. The antifungal activity and mechanism of action of low molecular weight water-soluble chitosan (LMWS-chitosan) were studied in fungal cells and vesicles containing various compositions of fungal lipids. LMWS-chitosan showed strong antifungal activity against various pathogenic yeasts and hyphae-forming fungi but no hemolytic activity or cytotoxicity against mammalian cells. The degree of calcein leakage was assessed on the basis of lipid composition (PC/CH; 10:1, w/w). Our result showing that LMWS-chitosan interacts with liposomes demonstrated that chitosan induces leakage from zwitterionic lipid vesicles. Confocal microscopy revealed that LMWS-chitosan was located in the plasma membrane. Finally, scanning electron microscopy revealed that LMWS-chitosan causes significant morphological changes on fungal surfaces. Its potent antibiotic activity suggests that LMWS-chitosan is an excellent candidate as a lead compound for the development of novel anti-infective agents.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.5
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• pp.351-355
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• 2017

Prior to the advent of efficacious antimicrobial agents, the mortality rate from cavernous sinus thrombosis (CST) was effectively 100%. There have been very few reports of CST associated with tooth extraction. A 40-year-old female presented to the emergency room with swelling over the right side of the face and history of extraction in the upper right region by an unregistered dental practitioner. The patient presented with diplopia, periorbital ecchymosis, and chemosis of the right eye. A computed tomography scan revealed venous dilatation of the right superior ophthalmic vein. The patient was immediately treated with incision and drainage, intravenous antibiotics, and heparin (low molecular weight). Unfortunately, the patient died two days after surgery due to complications from the disease. CST is a rare disease with a high mortality rate. Therefore, dental health education in rural areas, legal action against unregistered dental practitioners, early diagnosis, and aggressive antibiotic treatment can prevent future mortality resulting from CST.