• Mycobiology
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• v.47 no.3
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• pp.335-339
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• 2019

Endophytic fungi have the ability to live inside the host plant tissues without causing neither symptoms of diseases/or harm. Opportunistic infections are accountable for majority of the outbreaks, thereby putting a burden on the health system. To investigate and characterize the bioactive compounds for the control of bacteria of clinical importance, extracts from endophytic fungi were isolated from indigenous South African medicinal plants. Extracts from endophytic fungi were isolated from 133 fungal strains and screened against Gram positive and negative bacteria namely Bacillus cereus, Escherichia coli, Enterococcus faecium, and E. gallinarum using disk diffusion. Furthermore, gas chromatography-mass spectrometry was performed to identify the bioactive compounds. Sixteen out of one hundred and thirty-three (12%) fungi extracts exhibited antibacterial properties against some of the selected bacteria. E. coli was found to be the most susceptible in contrast to E. faecium and E. gallinarum which were the most resistant. The isolate MHE 68, identified as Alternaria sp. displayed the greater spectrum of antibacterial activities by controlling selected clinical bacteria strains including resistant E. faecium and E. gallinarum. The chemical analysis of the extract from MHE 68 indicated that linoleic acid (9,12-octadecadienoic acid (Z,Z)) and cyclodecasiloxane could be accountable for the antibacterial activity. This is the first study conducted on the secondary metabolites produced by endophytic fungal strains isolated from the Pelargonium sidoides DC. possessing antibacterial properties.

• The Plant Pathology Journal
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• v.38 no.4
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• pp.334-344
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• 2022

Bacterial wilt is a re-emerging disease on dry bean and can affect many other crop species within the Fabaceae. The causal agent, Curtobacterium flaccumfaciens pv. flaccumfaciens (CFF), is a small, Gram-positive, rod-shaped bacterium that is seed-transmitted. Infections in the host become systemic, leading to wilting and economic loss. Clean seed programs and bactericidal seed treatments are two critical management tools. This study characterizes the efficacies of five bactericidal chemicals against CFF. It was hypothesized that this bacterium was capable of forming biofilms, and that the cells within biofilms would be more tolerant to bactericidal treatments. The minimum biocide eradication concentration assay protocol was used to grow CFF biofilms, expose the biofilms to bactericides, and enumerate survivors compared to a non-treated control (water). Streptomycin and oxysilver bisulfate had EC95 values at the lowest concentrations and are likely the best candidates for seed treatment products for controlling seed-borne bacterial wilt of bean. The results showed that CFF formed biofilms during at least two phases of the bacterial wilt disease cycle, and the biofilms were much more difficult to eradicate than their planktonic counterparts. Overall, biofilm formation by CFF is an important part of the bacterial wilt disease cycle in dry edible bean and antibiofilm bactericides such as streptomycin and oxysilver bisulfate may be best suited for use in disease management.

• Pediatric Infection and Vaccine
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• v.29 no.3
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• pp.173-178
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• 2022

Streptococcus intermedius is a small, non-motile, Gram-positive, non-sporeforming, and aerotolerant anaerobic coccus. It is a part of the normal microflora in the oral cavity and upper respiratory, gastrointestinal and female urogenital tracts. It is an opportunistic pathogen that causes serious infections in patients with immunocompromised states or cardiac diseases as a result of trauma or invasive procedures. We describe a case of septic arthritis of the hip caused by S. intermedius in an immunocompetent healthy 7-year-old boy without a history of periodontal disease or invasive procedures. He had hip joint pain three weeks ago, and the fever began on the day of the visit. He had been healthy and had not undergone any invasive procedures recently. Septic arthritis of the hip was indicated in the magnetic resonance imaging of the hip. S. intermedius was identified in the hip joint fluid aspiration and blood culture. He was successfully treated with surgical intervention and antibiotic therapy with ceftriaxone followed by amoxicillin for five weeks.

• Journal of Korean Academy of Dental Administration
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• v.6 no.1
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• pp.28-35
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• 2018

Halitosis is primarily caused by bacterial decay. The bacteria, which originate from biofilms such as dental plaque, show abnormal proliferation due to dental caries, periodontal diseases, soft tissue infections, and tongue diseases. Most studies on halitosis have exclusively focused on gram-negative bacteria in the oral cavity rather than on general oral microorganisms including oral fungi. This study analyzed oral fungal hyphae, as well as distribution and motility of oral microorganisms, and provided basic data on the control of halitosis. Our results revealed that the greater is the number of cocci bacteria, the higher is the halitosis value, or bad breath value (BBV), suggesting that cocci have a strongly positive correlation with halitosis (r=0.379, p=0.030). Moreover, there was no significant difference in the morphology or distribution of motile bacteria and motility score, with respect to BBV. Lastly, we investigated the relationship between halitosis and oral fungal hyphae. We found that a higher BBV corresponded with a greater number of fungal hyphae and that patients with fungal hyphae scored a higher BBV. However, this result was not statistically significant. In conclusion, this study provided the preliminary data on oral microorganisms and halitosis, but further studies are needed to analyze the relationship between oral microorganisms and halitosis.

• Journal of Pharmaceutical Investigation
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• v.32 no.3
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• pp.215-221
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• 2002

Cephradine is a first generation cephalosporin and has broad spectrum antibacterial activity against gram-positive and gram-negative microorganisms, through inhibition of bacterial cell wall synthesis. Cephradine is useful for treatment of infections of the urinary and respiratory tract, skin and soft tissues. The purpose of the present study was to evaluate the bioequivalence of two cephradine capsules, Cefradine Yuhan (YuHan Corporation) and Broadcef (Ilsung Pharmaceuticals Co. Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). The cephradine release from the two cephradine capsules in vitro was tested using KP VII Apparatus II method with various different kinds of dissolution media (pH 1.2, 4.0, 6.8 buffer solution and water). Twenty normal male volunteers, $23.10{\pm}2.90$ years in age and $67.69{\pm}8.04\;kg$ in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After one capsule containing 500 mg as cephradine was orally administered, blood was taken at predetermined time intervals and the concentrations of cephradine in serum were determined using HPLC method with UV detector. The dissolution profiles of two cephradine capsules were very similar at all dissolution media. Besides, the pharmacokinetic parameters such as $AVC_t,\;C_{max}\;and\;T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AVC_t\;and\;C_{max}$ and untransformed $T_{max}$. The results showed that the differences in $AVC_t,\;C_{max}\;and\;T_{max}$ between two capsules based on the Cefradine Yuhan were -2.87%, -0.96% and -4.85%, respectively. There were no sequence effects between two capsules in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of 1og(0.8) to log(1.25) $(e.g.,\;log(0.93){\sim}log(1.02)\;and\;log(0.88){\sim}log(1.13)\;for \;AVC_t\;and\;C_{max},\;respectively)$. The 90% confidence interval using untransformed data was within ${\pm}20%$ $(e.g., \;-17.54{\sim}7.78\;for\;T_{max})$. All parameters met the criteria of KFDA guideline for bioequivalence, indicating that Broadcef capsule is bioequivalent to Cefradine Yuhan capsule.

• Journal of Pharmaceutical Investigation
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• v.32 no.2
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• pp.135-140
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• 2002

Cefadroxil is a semi-synthetic cephalosporin active against many Gram-positive and Gram-negative bacteria. The drug has been used for the treatment of the urinary and respiratory tract infections when caused by susceptible strains of the designated microorganism. The purpose of the present study was to evaluate the bioequivalence of two cefadroxil capsules, Duricef (Bo Ryung Pharmaceutical Co. Ltd.) and Hanacef (Korean Pharmaceutical Co. Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). The cefadroxil release from the two cefadroxil capsules in vitro was tested using KP VII Apparatus II method with various different kinds of dissolution media (pH 1.2, 4.0, 6.8 buffer solution and water). Twenty four normal male volunteers, $21.58{\pm}2.43$ years in age and $70.74{\pm}10.29$ kg in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After one capsule containing 500 mg as cefadroxil was orally administered, blood was taken at predetermined time intervals and the concentrations of cefadroxil in serum were determined using HPLC with UV detector. The dissolution profiles of two cefadroxil capsules were very similar at all dissolution media. The pharmacokinetic parameters such as $AUC_t,\;C_{max}\;and\;T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t\;and\;C_{max}$ and untransformed $T_{max}$. The results showed that the differences in $AUC_t,\;C_{max}\;and\;T_{max}$ between two capsules based on the Duricef were 0.05%, -5.29% and 4.53%. There were no sequence effects between two capsules in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log(0.8) to log(1.25) $(e.g.,\;log(0.95){\sim}log(1.05)\;and\;log(0.87){\sim}log(1.02)$ for $AUC_t\;and\;C_{max}$, respectively). The 90% confidence interval using untransformed data was within ${pm}20%$ $(e.g.,\;-6.75{\sim}15.74\;for\;T_{max})$. All parameters met the criteria of KFDA guideline for bioequivalence, indicating that Hanacef capsule is bioequivalent to Duricef capsule.

• YAKHAK HOEJI
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• v.40 no.4
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• pp.428-437
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• 1996

The in vitro and in vivo antibacterial activities of a new fluoroquinolone, DWP20364(1-cyclopropyl-5-amino-6,8-difluoro-7-(2,7-diazabicyclo[3.3.0]oto-4-ene-7-yl)-1 ,4-di-hydro-4-oxoquinoline-3-carboxylic acid) were evaluated in comparison with those of ciprofloxacin(CPFX), sparfloxacin(SPFX) and ofloxacin(OFLX). DWP20364 was more potent than CPFX and OFLX against Staphylococcus spp., Streptococcus spp. and Enterococcus faecium MD8b and it was similarly or slightly less active than CPFX against Escherichia spp. and Pseudomonas spp.. For MRSA and OFLX resistant strains (Staphylococcus spp.(14),Enterococcus spp.(4), Acinetobacter spp.(2), Pseudomonas spp.(9), Klebsiella spp.(2) and Serratia spp.(6)),DWP20364(MICs for 90% of strains,0.025 and 12.5${\mu}$g/ml, respectively) was 4 to 32 folds more potent than SPFX and CPFX. The activity of DWP20364 decreased moderately in the presence of 5mM $Mg^{2+}$. However, various pHs and the concentrations of various serum had no effect on the activity of DWP20364. DWP20364 possessed a bacteriocidal effect at the 1MIC against gram positive and gram negative strains. The protective effect of DWP20364 against systemic infections in mice caused by S. aureus Smith or S. aureus L2379 was superior to that of CPFX and SPFX but it was less active than that of CPFX against infection by P. aeruginosa E-2.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.47-53
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• 2007

The DY1 strain of Gram-positive, rod-shaped bacteria was isolated from the soil sample collected from Daeam mountain, Korea. The culture filtrate of DY1 strain showed a broad spectrum of antimicrobial activity on various pathogenic and food poisoning enteric bacterial species tested in vitro. It showed significant growth-inhibitory effect on Salmonella enterica sp., Shigella sp., pathogenic Escherichia coli, Vibrio cholerae, Vibrio parahemolyticus, and Yersinia enterocolitica. For the identification of the DY1 strain, morphological, biochemical and molecular phylogenetic approaches were performed. The DY1 strain was found to be a member of the genus Paenibacillus on the basis of morphological and biochemical analyses. The 16S rDNA of DY1 showed the highest pairwise identity with Paenibacillus polymyxa with 99.79% (1,413 bp/1,416 bp). The antimicrobial entity from DY1 looked different from preciously reported ones and seems to have a great potential to be further studied as a candidate of new antibiotics to control multi-drug resistant pathogens.

• Journal of Life Science
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• v.33 no.10
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• pp.842-850
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• 2023

Pyrrolnitrin, pyrrolomycin, and pyoluteorin are functional halogenated phenylpyrrole derivatives (HPDs) derived from microorganisms with diverse antimicrobial activities. Pyrrolnitrin is a secondary metabolite produced from L-tryptophan through four-step reactions in Pseudomonas fluorescens, Burkholderia cepacia, Serratia plymuthica, etc. It is currently used for the treatment of superficial dermatophytic fungal infections, has high antagonistic activities against soil-borne and foliar fungal infections, and has many industrial applications. Since pyrrolnitrin is easily decomposed by light, it is difficult to widely use it outdoors. As an alternative, fludioxonil, a synthetically produced non-systemic surface fungicide that is structurally similar and has excellent light stability, has been commercialized for seed and foliar treatment of plants. However, due to its high toxicity to aquatic organisms and adverse effects in human cell lines, many countries have established maximum residue levels and strictly control its levels. Pyrrolomycin and pyoluteorin, which have antibiotic/antibiofilm activity against Gram-positive bacteria and high anti-oomycete activity against the plant pathogen Pythium ultimum, respectively, were isolated and identified from microorganisms. This review summarizes the biosynthesis and production of natural pyrrolnitrin derived from bacteria and the characteristics of synthetic fludioxonil and other natural phenylpyrrole derivatives among the HPDs. We expect that a plethora of highly effective, novel HPDs that are safe for humans and environments will be developed through the generation of an HPD library by microbial biosynthesis and chemical synthesis.

• Pediatric Infection and Vaccine
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• v.17 no.2
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• pp.83-90
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• 2010

Purpose : Although the incidence of polymicrobial bloodstream infection (PBSI) has increased, only a few studies have so far focused on children. Therefore, in an effort to prevent more serious situations in pediatric patients, we analyzed the clinical features, organisms, and laboratory results of PBSI. Methods : We performed a retrospective review of the case records of 97 patients with polymicrobial bloodstream infection in the Severance hospital, from 2001 to 2008. Using t-test and chi-square test, we analyzed the underlying medical conditions, clinical characteristics, organisms, and laboratory results of those patients. Results : Annual incidence of polymicrobial bloodstream infection increased from 1.4 % in 2001 to 10.9% in 2008 in pediatric patients. Immunocompromised hemato-oncological malignancy was found in 31 (31.9%) patients, and was the most common underlying medical condition; cardiovascular disease was found in 15 patients (15.4%), neurologic disease in 10 patients (10.3%), and so on. Gram positive organisms were recovered in 143 cases and gram negative organisms were recovered in 101 cases of PBSI. Staphylococcus epidermidis was the most common organism. Factors affecting mortality included underlying medical disease, immune status, nosocomial infection, and central catheter-related infection, for which the rate of mortality showed a greater increase (P<0.05). Conclusion : Due to the close connection between PBSI and fatal conditions or high mortality, it requires more aggressive management. Compared with previous studies, we discovered that immunocompromised hemato-oncological malignancy was the most common underlying medical condition and that frequency of gram-positive bacteria and fungus isolated has increased.