• Clean Technology
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• v.29 no.2
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• pp.135-144
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• 2023

Pseudomonas aeruginosa and Staphylococcus aureus are the two most frequently encountered pathogens responsible for chronic wound infections, often coexisting in such cases. These infections exhibit heightened virulence compared to single infections, leading to unfavorable patient outcomes. The interaction among microorganisms within polymicrobial infections has been shown to exacerbate disease progression. Polymicrobial infections, prevalent in various contexts such as the respiratory tract, wounds, and diabetic foot, typically involve diverse microorganisms, with Pseudomonas aeruginosa and Staphylococcus aureus being the most commonly identified pathogens. This study aimed to compare the growth patterns of bacteria under a concentration gradient of toxic chemicals, focusing on a Gram-negative strain of Pseudomonas aeruginosa and a Gram-positive strain of Staphylococcus aureus. The minimum inhibitory concentration (MIC), which signifies the concentration at which bacterial growth is inhibited, was determined by performing broth microdilution and assessing the bacteria's growth curves. The growth curves of both Pseudomonas aeruginosa and Staphylococcus aureus were confirmed, and the exponential growth phases were applied to calculate the doubling times of bacteria. The MIC value for each toxic chemical was determined through broth microdilution. These results allowed for the identification of disparities in growth rates between Gram-positive and Gram-negative bacteria, as well as differences in resistance to individual toxic substances. We expect that this approach has a strong potential for further development towards the innovative treatment of bacteria-associated infections.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.1020-1026
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• 1996

Chitosan is the deacetylation product of chitin. Chitosan was converted to N-alkyl chitosan derivatives using proper aldehyde having different alkyl chains, then chitosan derivatives with quaternary ammonium salt were producted by quaternization with methyl iodide. Their antibacterial activities aganst S. aureus(ATCC 6538P) and E. coli (ATCC 14339), gram-positive bacteria and gram-negative bacteria, respectively, as introduced alkyl length were evaluated by shake flask method using colony count. The antibacteiral activity was found to be increased as alkyl chains. hydrophobic goups. These antibacterial agents were more active against S. aureus than E. coli. It may be due to the different of structure of cytoplasmic membrane.

• Pediatric Infection and Vaccine
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• v.17 no.1
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• pp.36-48
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• 2010

Purpose : In children on anticancer chemotherapy, bloodstream infections (BSIs) are a major cause of morbidity and mortality. We investigated febrile episodes and bloodstream infections in pediatric cancer patients to guide proper selection of empiric antibiotics for febrile pediatric hemato-oncologic patients. Methods : All febrile episodes treated in the division of hematology-oncology, the department of pediatrics, Hanyang University Hospital, between July 2005 and June 2008 were reviewed. Episodes with and without bloodstream infections were compared. Results : Forty cases (18.9%, 25 patients) of BSI occurred in 212 febrile episodes (63 patients). Thirty-seven cases (23.6%, 22 patients) of BSI occurred in 157 febrile episodes with neutropenia (54 patients). Microorganisms identified in BSI corresponded to 23 gram-positive bacteria (51.2%), 20 gram-negative bacteria (44.5%), and 2 fungi (4.4%). Rates of BSI between those who had received umbilical cord blood transplantation and those who had received transplantation from other source were significantly different (55.0% vs. 7.7%, P =0.001). No differences in mortality rate were observed among organisms in BSI patients. For febrile episodes the rate of BSI was higher among those with Chemoport than those with Hickman catheter (P =0.029) and gram-positive pathogens were more likely to be associated with Chemoport (P =0.001). Conclusion : The study showed the rate of BSI, distribution of pathogens with regard to neutropenia, transplantation, central venous catheters, and antimicrobial susceptibility of pathogens in order to help guide in the choice of optimal empiric antibiotics in pediatric febrile neutropenic hemato-oncologic patients.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.368-374
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• 2008

Dry formulation is a limiting step for successful development of microbial bio-pesticides with the antagonistic Gram-negative bacteria because their survival rates are too low during drying and storage. The high concentration of sodium chloride (NaCl) in culture medium that induces osmolyte in bacterial cells is known to increase of survival rate during drying in many Gram-negative bacteria. Effect of NaCl on survival of antagonistic non-pathogenic Erwinia carotovora subsp. carotovora 9-3 (Ecc 9-3) during drying and storage was studied. Growth rate of Ecc 9-3 was not much different up to 0.5 M NaCl in NB while it was lower significantly with 0.7 M NaCl. Survival rates were twice and 3 times higher with 0.5 M NaCl than with no additional NaCl during drying at room temperature and freeze-drying, respectively. Survival rate was also higher with high NaCl in culture medium during storage after drying. It was not much different on storage at $4^{\circ}C$ both of drying at room temperature and freeze-drying. However, the survival rate was higher on storage at $27^{\circ}C$ and $37^{\circ}C$ with high NaCl concentration. Among the additives tested, lactose affects most to survival rate both of drying at room temperature and freeze-drying, and dextrin influenced significantly to survival rate of drying at room temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1214-1220
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• 2003

Antimicrobial activity of Rhus javanica (RJ) extract against animal husbandry disease-related bacteria was determined by a paper disc method. The RJ extracts showed a significant antimicrobial activity against Gram positive (+) bacteria and especially the activity was most potent against L. monocytogenes and S. epidermidis. Minimum inhibitory concentrations (MIC) of the MeOH and EtOH extracts of RJ were in the range of 0.8 ∼ 16 mg/mL and 0.8 ∼ 10 mg/mL, respectively. Furthermore, among five solvent fractions (n-hexane, CHC1$_3$, EtOAc, n-BuOH and $H_2O$ frs.) from MeOH extract of RJ, the EtOAc fr. exhibited the most significant antimicrobial activity The antimicrobial activities of RJ extracts against most microbial strains were unstable by either heat treatment or acid treatment. The inhibitory effect of RJ extracts on microbial cell growth was further examined by the addition of 0, 100, 300, and 500 ppm of RJ extracts into growth medium. The growth of gram positive (+) bacteria, S. aureus, S. epidermidis and L. monocytogenes was inhibited for 72 hours when at least 300 ppm of RJ extracts added, but the growth of gram negative (-) bacteria was only inhibited when at least 500 ppm of RJ extracts were added. Taken together, tile antimicrobial activities of RJ extracts were more effective against gram positive (+) bacteria compared to those against gram negative (-) bacteria.

• Microbiology and Biotechnology Letters
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• v.34 no.4
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• pp.306-310
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• 2006

For screening of the compounds exhibiting antimicrobial activities against the D-alanyl-D-alanine of Gram positive bacteria, approximately 2,500 actinomycetes isolated from soil were examined far antimicrobial activity. In consequence, we recently isolated the Streptomyces sp. G91353 strain produced an active compound, A91353, that inhibits the growth of Gram positive bacteria. A91353 was identified as N-acetyl-phenylalanine by various spectroscopic methods. The minimum inhibitory concentration (MIC) values of N-acetyl-phenylalanine on Gram positive bacteria such as Streptococcus pyogenes 308A, Streptococcus pyogenes 77A were determined as $50{\mu}g/ml$, respectively, but did not effect on Gram negative strains. These results indicate that N-acetyl-phenylalanine have an antimicrobial activity, which may be caused by the disturbance of D-alanyl-D-alanine synthesis.

• The Journal of the Korea Contents Association
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• v.9 no.2
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• pp.339-349
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• 2009

Garlic (Allium sativum, L.) has a long history of reputed value and actual use for its medicinal, antimicrobial, and pesticidal properties. This study was conducted to find possible developments to natural food preservatives from garlic extracts. Garlic extracts were prepared from fresh crushed garlic and diluted with sterilize distilled water. The sensitivity test was conducted to investigate the antimicrobial effect of garlic extract against six strains of food poisoning bacteria such as Staphylococcus aureus, Escherichea coli, Salmonella typhimurium, Vibrio parahemolyticus, Bacillus subtilis, and Listeria monocytogenes. The results of sensitivity test were then compared with those of Vancomycin and Imipenem which were used as treatment for G. (+) bacteria and G. (-) bacteria, respectively. All of the 6 tested strains exhibited strong or moderate activity. V. parahemolyticus exhibited susceptible only in undiluted solution, but not in diluted garlic extracts.

• Journal of Yeungnam Medical Science
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• v.5 no.2
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• pp.161-169
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• 1988

Neonatal sepsis is a frequent and important cause of morbidity and mortality in the neonatal period. This study was undertaken to observe the 55 cases of proven neonatal sepsis among 6,717 newborn infants under 4 weeks of age, admitted to the nursery of Yeungnam University Hospital from May 1, 1983 to April 30, 1988. We observed following results : 1. The morbidity rate of male(1.12%) was higher than that of female(0.44%) significantly (p<0.05). 2. The morbidity rate of prematurity(2.65%) was higher than that of full term(0.76%) significantly (p<0.05). 3. The incidence of perinatal obstetric complications in early onset neonatal sepsis was higher than that of late onset neonatal sepsis (38.5% vs 10.3%, p<0.05). 4. The common clinical manifestations were poor feeding(52.7%), jaundice(45.5%), diarrhea(30.9%) and irritability (30.9%). 5. Among the causative organisms, gram positive organisms were predominated and Staphylococcus epidermidis was the most common organism. There was no difference in the causative organisms between early onset and late onset sepsis.

• Journal of Aquaculture
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• v.14 no.3
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• pp.157-163
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• 2001

The antibacterial effect of fish diet soaked in the extract of Salvia miltiorriza was tested to determine its levels of antibacterial activity, minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC). The extract showed strong activity against gram positive bacteria, but was weak against gram negative bacteria. Concentration levels of 13.4~40.3 and 67.2~403.0 $\mu\textrm{g}$/ml were determined as the MIC and MBC, respectively. However, levels above 403.0 $\mu\textrm{g}$/ml was neither bacteriostatic nor bactericidal against Edwardsiella tarta, a gram negative strain. The fish diet, soaked in the extract of Salvia miltiorriza, inhibited the growth of all strains of Streptococcus genus and Vibrio anguillarum. The relationship formula between weight of fish diet and Salvia miltiorriza extract absorbed into the fish diet was Y＝2.4953X＋3.3276 ($R^2$= 0.9999). The antibacterial activity of the fish diet, soaked in the extract, was stable from 10 to 35$^{\circ}C$ during the storage period of 28 days.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.28 no.1
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• pp.166-185
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• 2002

Aroma oils extracted from the natural material have antibacterial, antivirus, antiinflammatory, and preservative effect. The preserve efficacy testing between aroma oils and parabens as an artificial preservative had been performed and then it had been suggested that aroma oil was possibile to apply to the cosmetics. Aroma oils were pine, rosemary, lemon and eucalyptus, and parabens were methylparaben, blitylparaben. Antiseptic concentrations of aroma oils and parabens having 0.0, 0.1, 0.2, 0.4, 0.8, 1.0wt% were tested respectively. Escherichia coil(ATCC No.8739), Pseudomonas aeruginosa(ATCC No. 9027) which are gram-negative and Staphylococcus aureus (ATCC No. 6538), Bacillus subtilis(ATCC No. 6633) which are gram-positive were used as the test organisms. Disk paper and broth dilution methods were used as the methods of preservative efficacy testing. The antibacterial activity of aroma oils and parabens for gram-positive were better than that for gram-negative. For the antibacterial activity aroma oils were better than parabens. Among the aroma oils, rosemary and pine having superior antibacterial activity were selected and blended to illuminate if there is any synergy, There was synergical effect and optimum ratio of aroma blend is 3 : 1(rosemary pine) in this study.