• Biomedical Science Letters
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• v.5 no.2
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• pp.213-217
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• 1999

In order to control resistant strains and to properly select the antimicrobial agents, it is of quite importance to know current trends of bacterial species and changing patterns of antimicrobial resistance rates. The authors studied the results of 542 Gram-positive strains among 1,689 strains isolated at Chung-buk National University Hospital in 1996. The frequently isolated Gram-positive microorganisms were Staphylococcus aureus, Streptococcus pneumoniae, Staphylococcus epidermidis and Enterococcus faecalis in descending order. S. aureus showed high resistance to penicillin, gentamicin, and susceptibility to teicoplanin and vancomycin. Coagulase negative Staphylococcus was highly resistant to all of the antibiotics used in this experiment except teicoplanin and vancomycin. Enterococcus were highly resistant to vancomycin, penicillin and tetracycline. MIC of Gram-positive oaganisms was appeared to be zig-zag pattern.

• Childhood Kidney Diseases
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• v.17 no.2
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• pp.65-72
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• 2013

Purpose: Urinary tract infection (UTI) caused by gram-positive uropathogens is usually hospital-acquired and associated with predisposing conditions. However, the incidence of gram-positive bacteria in community-acquired UTIs has recently increased worldwide. We aimed to investigate the clinical significance of UTI and associated genitourinary malformations in young children with febrile UTIs caused by gram-positive bacteria. Methods: We retrospectively reviewed the medical records of 566 patients (age, <1 year) who visited the Korea University Medical Center for febrile UTIs between January 2008 and May 2013. We classified the patients into the following two groups: gram-positive (P group) and gram-negative (N group), according to the results of urine culture. The fever duration; white blood cell (WBC) counts and C-reactive protein (CRP) levels in peripheral blood; and the presence of hydronephrosis, cortical defects, vesicoureteral reflux (VUR), and renal scarring were compared between the two groups. Results: The number of patients with gram-positive bacteria was 23 (4.1%) and with gram-negative bacteria was 543 (95.9%). The most common pathogen was Escherichia coli, and Enterococcus faecalis showed the highest incidence among gram-positive uropathogens. Patients with gram-positive bacteria showed longer fever duration compared to that in patients with gram-negative bacteria (P vs. N, $3.4{\pm}1.2$ vs. $2.9{\pm}1.6$ days, P <0.05). The incidence of VUR was increased in the gram-positive group compared to that in the gram-negative group (P vs. N, 55.6 vs. 17.8%, P<0.05). However, there were no significant differences in other laboratory and radiologic findings. Conclusion: The findings of our study show that community-acquired UTIs in patients younger than 1 year of age, caused by gram-positive uropathogens, can be associated with prolonged fever duration and the presence of VUR.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.1
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• pp.59-65
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• 2024

This study examined the fecal samples of striped field mice (Apodemus agrarius coreae) captured in Jeju Special Self-Governing Province. Fecal samples, including the colon and other intestinal organs, were collected and subjected to aerobic culture to investigate the distribution of intestinal microorganisms. Gram staining of the aerobic cultured bacterial colonies from 36 fecal samples revealed the predominant presence of gram-negative bacilli in all samples. Among the 36 samples, gram-negative bacilli were identified in 36 strains (100%), gram-positive cocci in 21 strains (58.3%), and gram-positive bacilli in 15 strains (41.7%), while no gram-negative cocci were observed. The gram-negative bacilli cultured from the 36 samples were identified using the Vitek 2 system, and all were determined to be Escherichia coli (E. coli) strains. In addition, one sample was concurrently identified with E. coli and Enterobacter cloacae strains. The antimicrobial susceptibility testing for the identified E. coli strains did not include all antibiotics, but one strain exhibited intermediate resistance to cefoxitin. No pathogenic bacteria were present in the fecal samples of the scrub typhus-infected rodents, which are vectors for chigger-borne diseases affecting humans and animals.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.2
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• pp.81-86
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• 2015

Soil management for orchard depends on the effects of soil microbial activities. The present study evaluated the soil microbial community of 25 orchard (5 sites for sandy loam, 7 sites for silt loam, and 13 sites for loam) in Gyeongnam Province by fatty acid methyl ester (FAME) method. The average values for 25 orchard soil samples were $270nmol\;g^{-1}$ of total FAMEs, $72nmol\;g^{-1}$ of total bacteria, $34nmol\;g^{-1}$ of Gram-negative bacteria, $34nmol\;g^{-1}$ of Gram-positive bacteria, $6nmol\;g^{-1}$ of actinomycetes, $49nmol\;g^{-1}$ of fungi, and $7nmol\;g^{-1}$ of arbuscular mycorrhizal fungi. In addition, silt loam soils had significantly low ratio of cy17:0 to $16:1{\omega}7c$ and cy19:0 to $18:1{\omega}7c$ compared with those of loam soils (p < 0.05), indicating that microbial activity increased. The average soil microbial communities in the orchard soils were 26.7% of bacteria, 17.9% of fungi, 12.6% of Gram-negative bacteria, 12.5% of Gram-positive bacteria, 2.5% of arbuscular mycorrhizal fungi, and 2.2% of actinomycetes. The soil microbial community of Gram-negative bacteria in silt loam soils was significantly higher than those of sandy loam and loam soils (p < 0.05).

• Journal of Pharmacopuncture
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• v.19 no.3
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• pp.225-230
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• 2016

Objectives: Mellitine, a major component of bee venom (BV, Apis mellifera), is more active against gram positive than gram negative bacteria. Moreover, BV has been reported to have multiple effects, including antibacterial, antivirus, and anti-inflammation effects, in various types of cells. In addition, wasp venom has been reported to have antibacterial properties. The aim of this study was to evaluate the antibacterial activity of BV against selected gram positive and gram negative bacterial strains of medical importance. Methods: This investigation was set up to evaluate the antibacterial activity of BV against six grams positive and gram negative bacteria, including Staphylococcus aureus (S. aureus), Salmonella typhimurium, Escherichia coli (E. coli) O157:H7, Pseudomonas aeruginosa, Burkholderia mallei and Burkholderia pseudomallei. Three concentrations of crude BV and standard antibiotic (gentamicin) disks as positive controls were tested by using the disc diffusion method. Results: BV was found to have a significant antibacterial effect against E. coli, S. aureus, and Salmonella typhyimurium in all three concentrations tested. However, BV had no noticeable effect on other tested bacteria for any of the three doses tested. Conclusion: The results of the current study indicate that BV inhibits the growth and survival of bacterial strains and that BV can be used as a complementary antimicrobial agent against pathogenic bacteria. BV lacked the effective proteins necessary for it to exhibit antibacterial activity for some specific strains while being very effective against other specific strains. Thus, one may conclude, that Apis mellifera venom may have a specific mechanism that allows it to have an antibacterial effect on certain susceptible bacteria, but that mechanism is not well understood.

• Journal of Dairy Science and Biotechnology
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• v.39 no.3
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• pp.121-127
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• 2021

Yogurt is produced by bacterial fermentation of milk and contains lactic acid bacteria (LAB), which produce various metabolites such as organic acid, hydrogen peroxide, and bacteriocin. This study aimed to investigate cell-free supernatants (CFS) of LAB isolated from Tibetan yogurt. CFS (TY1, TY2, TY3, TY4, TY5, TY6, and TY7) from selected strains of LAB were co-incubated with four different foodborne pathogenic bacteria, namely E. coli O157:H7, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. Inhibition of foodborne pathogenic bacterial growth was not affected in the presence of CFS (pH 6.5). In contrast, CFS without neutralization completely inhibited the growth of the bacteria. Furthermore, when the concentration of CFS (without neutralization) was changed to 1:4 and 1:8, a difference in inhibition was observed between Gram-positive and Gram-negative bacteria. CFS more effectively inhibited the growth of Gram-negative E. coli O157:H7 and S. Typhimurium than Gram-positive L. monocytogenes and S. aureus. These results suggest that organic acids in LAB may inhibit the growth of foodborne pathogenic bacteria, particularly Gram-negative bacteria.

• Applied Biological Chemistry
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• v.17 no.2
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• pp.117-124
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• 1974

The 23 representative bacteria were studied for the glucosamine contents which represent the glycolipid content of the cell wall. The distribution of glycolipid in various bacteria was examined and the relationship between the glycolipid contents and the Gram stain was elucidated. The results were as follows: 1. The contents of glucosamine in the glycolipid of Gram negative and variable bacterial cell wall were large ranging from the least 0.04 ${\mu}g$ of Proteus vulgaris to the largest 2.48 ${\mu}g$ of Aerobacter aerogenes. The Gram positive bacteria and only those Gram positive among Bacilli contained less than 0.02 ${\mu}g$ of glucosamine contents. The least glucosamine containing Gram positive bacteria were Corynebacterium sepedonicum and Staphylococcus aureus. It could generally be said that the Gram negative and variable bacteria contain the higher content of glucosamine in the cell wall than the positives. 2. The bacteria were better stained by the Gram solution after the extraction of glycolipid from the cell wall than those without extraction. 3. The four infrared spectra of glycolipids obtained from Aerobacter aerogenes, Bacillus circulans, Pseudomonas fluorescens, and Salmonella typhirurium showed all the similar characteristics. All showed the existence of groups; OH, C-O, C-O-C, $CH_2+CH_3$, amide band, fatty acid ester band and ester carbonyl bond.

• Archives of Pharmacal Research
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• v.26 no.8
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• pp.597-600
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• 2003

Silybin has a potent antibacterial activity, more potent than silymarin II, against gram-positive bacteria without hemolytic activity, whereas it has no antimicrobial activity against gram-negative bacteria or fungi. The mode of action of silybin against the gram-positive bacterial cell was examined by investigating the change in plasma membrane dynamics of bacterial cells using 1 ,6-diphenyl-1,3,5-hextriene (DPH) as a membrane probe and by assessing the inhibition of macromolecular synthesis using radiolabeled incorporation assay. The results showed that silybin inhibited RNA and protein synthesis on gram-positive bacteria.

• Pediatric Infection and Vaccine
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• v.19 no.3
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• pp.131-140
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• 2012

Purpose : This study was performed to identify the etiologic agents and antimicrobial susceptibility patterns of organisms responsible for bloodstream infections in pediatric cancer patients for guidance in empiric antimicrobial therapy. Methods : A 5-year retrospective study of pediatric hemato-oncologic patients with bacteremia in Seoul National University Children's Hospital, from 2006 to 2010 was conducted. Results : A total of 246 pathogens were isolated, of which 63.4% (n=156) were gram-negative, bacteria 34.6% (n=85) were gram-positive bacteria, and 2.0% (n=5) were fungi. The most common pathogens were Klebsiella spp. (n=61, 24.8%) followed by Escherichia coli (n=31, 12.6%), coagulase-negative staphylococci (n=23, 9.3%), and Staphylococcus aureus (n=22, 8.9 %). Resistance rates of gram-positive bacteria to penicillin, oxacillin, and vancomycin were 85.7%, 65.9%, and 9.5%, respectively. Resistance rates of gram-negative bacteria to cefotaxime, piperacillin/tazobactam, imipenem, gentamicin, and amikacin were 37.2%, 17.1%, 6.2%, 32.2%, and 13.7%, respectively. Overall fatality rate was 12.7%. Gram-negative bacteremia was more often associated with shock (48.4% vs. 11.9%, P<0.01) and had higher fatality rate than gram-positive bacteremia (12.1% vs. 3.0%, P=0.03). Neutropenic patients were more often associated with shock than non-neutropenic patients (39.6 % vs. 22.0%, P=0.04). Conclusion : This study revealed that gram-negative bacteria were still dominant organisms of bloodstream infections in children with hemato-oncologic diseases, and patients with gram-negative bacteremia showed fatal course more frequently than those with gram-positive bacteremia.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.671-678
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• 2018

Papiliocin, isolated from the swallowtail butterfly (Papilio xuthus), is an antimicrobial peptide with high selectivity against gram-negative bacteria. We previously showed that the N-terminal helix of papiliocin (PapN) plays a key role in the antibacterial and anti-inflammatory activity of papiliocin. In this study, we measured the selectivity of PapN against multidrug-resistant gram-negative bacteria, as well as its anti-inflammatory activity. Interactions between Trp2 of PapN and lipopolysaccharide (LPS), which is a major component of the outer membrane of gram-negative bacteria, were studied using the Trp fluorescence blue shift and quenching in LPS micelles. Furthermore, using circular dichroism, we investigated the interactions between PapN and LPS, showing that LPS plays critical roles in peptide folding. Our results demonstrated that Trp2 in PapN was buried deep in the negatively charged LPS, and Trp2 induced the ${\alpha}$-helical structure of PapN. Importantly, docking studies determined that predominant electrostatic interactions of positively charged arginine residues in PapN with phosphate head groups of LPS were key factors for binding. Similarly, hydrophobic interactions by aromatic residues of PapN with fatty acid chains in LPS were also significant for binding. These results may facilitate the development of peptide antibiotics with anti-inflammatory activity.