• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.158-162
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• 2006

Cyclic dipeptides isolated from Streptomyces sp. have been shown to have antimicrobial activity as well as other potentially useful biological activities. The purpose of this study was to compare the in vitro activity of two cyclic dipeptides combined against anaerobic bacteria with the activity of other antimicrobial agents. Specifically, the in vitro activity of the combination of two cyclic dipeptides was investigated against 140 clinical isolates of anaerobic bacteria by the agar dilution method and was compared with that of erythromycin, cefoxitin, imipenem, clindamycin, and metronidazole. The cyclic dipeptide combination and imipenem were the most active antimicrobial agents tested. In addition, the cyclic dipeptide combination had a radioprotective effect on five normal human lung fibroblast cells, showing survival rates higher $(>90\%)$ than either of the two cyclic dipeptides alone $(<80\%)$.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.1-10
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• 2004

Many bacteria monitor their population density and control the expression of specialized gene sets in response to bacterial cell density based on a mechanism referred to as quorum sensing. In all cases, quorum sensing involves the production and detection of extracellular signaling molecules, auto inducers, as which Gram-negative and Gram-positive bacteria use most prevalently acylated homoserine lactones and processed oligo-peptides, respectively. Through quorum-sensing communication circuits, bacteria regulate a diverse array of physiological functions, including virulence, symbiosis, competence, conjugation, antibiotic production, motility, sporulation, and biofilm formation. Many pathogens have evolved quorum-sensing mechanisms to mount population-density-dependent attacks to over-whelm the defense responses of plants, animals, and humans. Since these AHL-mediated signaling mechanisms are widespread and highly conserved in many pathogenic bacteria, the disruption of quorum-sensing system might be an attractive target for novel anti-infective therapy. To control AHL-mediated pathogenicity, several promising strategies to disrupt bacterial quorum sensing have been reported, and several chemicals and enzymes have been also investigated for years. These studies indicate that anti-quorum sensing strategies could be developed as possible alternatives of antibiotics.

• Journal of Life Science
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• v.9 no.5
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• pp.525-530
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• 1999

The isolation and identification of bacteria from freshwater plant root system were performed. Twenty four different strains were identified by microbiological identification system. Gram negative bacteria were isolated three times more than Gram positive ones. The ratio of rod and coccus was 11:1. The similarity above 0.5 was 37.5% from the tested samples in identification. Among these isolated bacteria, three dominant strains Pseudomonas cepacia JH10, Xanthomonas maltophilia JH12, Aeromonas salmonicida JH13 were selected to investigate biochemical properties and optimal growth conditions. These strains reached maximum growth after 24-36 hr of incubation in peptone broth, and their optimal temperature was 28$^{\circ}C$ and that of pH was between 7 and 8.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.6
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• pp.324-331
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• 2019

Objectives: This study investigated the types and antibiotic sensitivity of bacteria in odontogenic abscesses. Materials and Methods: Pus specimens from 1,772 patients were collected from affected areas during incision and drainage, and bacterial cultures and antibiotic sensitivity tests were performed. The number of antibiotic-resistant bacteria was analyzed relative to the total number of bacteria that were tested for antibiotic susceptibility. Results: Bacterial cultures from 1,772 patients showed a total of 2,489 bacterial species, 2,101 gram-positive and 388 gram-negative. For penicillin G susceptibility tests, 2 out of 31 Staphylococcus aureus strains tested showed sensitivity and 29 showed resistance. For ampicillin susceptibility tests, all 11 S. aureus strains tested showed resistance. In ampicillin susceptibility tests, 46 out of 50 Klebsiella pneumoniae subsp. pneumoniae strains tested showed resistance. Conclusion: When treating odontogenic maxillofacial abscesses, it is appropriate to use antibiotics other than penicillin G and ampicillin as the first-line treatment.

• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.1
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• pp.129-132
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• 2012

Silk fibroin films incorporated with tetracycline was prepared and characterized by Fourier-transform infrared spectrometer and differential scanning calorimeter and examined antibacterial effect. The conformation of silk fibroin was changed from random coil to $\hat{a}$ sheet structure with incorporation of tetracycline. Antibacterial activity of the materials was evaluated against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus epidermis, and Staphylococcus aures) using agar plate method showing clear inhibition zone around tetracycline silk film. It is concluded that tetracycline-incorporated SF films are highly effective against bacteria.

• Fibers and Polymers
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• v.7 no.1
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• pp.8-11
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• 2006

It has been reported for several decades that microbes, which naturally contaminate cotton fibres during crop growth and subsequent storage can have an adverse effect on the structural quality of cotton lint. Although several studies have analysed the relationship between numbers of Gram-negative bacteria or bacterial endotoxin and particular physical properties, these studies have been limited to cotton from the United States, and the possible effects of fungal contamination have not been examined in detail. This study quantified the Gram-negative bacteria and fungal cells, as well as measuring concentrations of bacterial endotoxin and fungal glucan, on cotton lint samples from international sources. Spearman's rank correlation coefficients calculated between these results and quality data analysed by an automated testing instrument revealed several significant correlations. Findings included inverse correlations between the biological contamination parameters and fibre elongation, micronaire and reflectance. The possible causes and implications of these findings were also discussed.

• Food Engineering Progress
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• v.13 no.4
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• pp.352-359
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• 2009

Lactic acid bacteria was isolated for the production of probiotic animal feed supplemented with garlic and its antimicrobial properties were investigated. A total of 112 strains of lactic acid bacteria which grew on the medium containing garlic extract were isolated from kimchi, jeotgal, and jangachi. Among them 14 strains were tested for acidand bile salt-resistance as well as antimicrobial activities against animal pathogenic bacteria such as Salmonella choleraesuis, Escherichia coli, Staphylococcus aureus, and Shigella flexneri. Of these strains, a strain P'GW50-2 from pickled scallion with most desirable properties was selected and identified as Lactobacillus plantarum TJ-LP-002. Antimicrobial activity of L. plantarum TJ-LP-002 showed relatively wide range of inhibition spectrum against Gram negative bacteria such as Aeromicrobium hydrophila, E. coli, Pseudomonas, Salmonella, Shigella, and some Gram positive bacteria such as Bacillus cereus, Staphylococcus aureus, Clostridium perfringens, and Propionibacterium.

• Journal of Korean Academy of Nursing
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• v.19 no.3
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• pp.240-248
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• 1989

The increase in size and numbers of general hospitals in the process of conspicuous development of modem medicine has been accompanied by a serious increase in hospital acquired infections. Hospital aquired infections cause pain and discomfort, may threaten life, adds an economic burden, and delays recovery and return to society. Even though respiratory hospital infection rates resulting for tracheostomy and respiratory inhalation therapy, may be low, they are serious because of their bad prognosis and high mortality rates. This study was designed to assess certain aspects of respiratory infections of patients with a tracheostomy and thus provide baseline data for further research related to preventive or therapeutic nursing interventions. The specific objectives were to determine the incidence of colonization in the trachea, clinical signs, type of colonized bacteria and sensitivity to antibiotics. Data were collected from July 1 to December 10, 1989 at two university Hospital in Seoul. Subjects were 20 patients with a tracheostomy admitted to the Intensive Care Unit or Cerebral Vascular Accident Center. Clinical signs related to respiratory infection were observed using a checklist based on previous study outcomes. Bacterial culture, sensitivity test to antibiotics, WBC counts and chest X-ray were also performed. Cultures were done on the day of tracheostomy, and on the third, fifth and seventh day. Cultures were then done on seventh days after the first colonization. The results were as follows : 1. The incidence of bacteria colonization in a week was 90%(18 patients) 50% (10/20 patients) on the day of tracheostomy, 70%(7/10 patients) on the third day, and 0% on the fifth day, and 33%(1/3 patient) on the seventh day. 3 of 18 patients (16.7%) were colonies of mixed growth isolated. 2. The observed clinical signs related to respiratory infection were high fever 38.9%(7 patients), prulent secretion 16.7%(12 patients) and infiltration seen on chest X-ray 33.3%(6 patients). 3. The total number of types of bacteria isolated among the 18 subjects was 21 ; gram negative 71.4%, gram postive 28.6%. The dominant bacteria type was Staphylococcus aureus(5 cases) for gram(equation omitted) and Pseudomonas aeruginosa(3 cases), Klebsiella (4 cases), Enterobacter(3 cases) for gram (equation omitted). The results of culture on 7th day after the first colonization, 6 cases showed same type of bacteria, 3cases showed different type of bacteria and 1 cases showed no growth. 4. The sensitivity tests to antibiotics showed that Pseudomonas aeruginosa and Staphylococcus were strongly resistant to most kinds of antibiotics, but Klebsiella and the rest of gram negative bacteria were moderately sensitive to antibiotics.

• Journal of radiological science and technology
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• v.31 no.3
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• pp.229-237
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• 2008

Purpose : For the number of microbes and the pollution level of bacteriology of IP Cassette and Table by laboratories, after identifying the bacteria before and after using alcohol and tissue including disinfectant and statistically testing, this research was intended to provide the basic data for the prevention and the right disinfection guideline for infection management of hospitals in diagnostic radiology. Subject and Method : The subject of this research was the general room of diagnostic radiology of a university hospital in Daejeon City. The research was conducted from Apr 5 to Apr 12, 2007. The number of microbes and the pollution level of bacteriology of IP Cassette and Table by laboratories were tested before and after using alcohol and tissue for disinfection including disinfectant. In order to collect specimens exactly, they were collected with the nurse who specialized in infection management of the hospital, and statistical processing was done with SPSS V13.0. To compare the results before and after using alcohol and tissue, T-test was implemented, and post-hoc test was conducted. Results : Bacteria were detected in 19 cases of 24 subjects(79.2%), however, they were not detected in 5 cases(20.8%). 7kinds of bacteria were detected as isolated bacteria, of which Methicillin Resistant coagulase-negative Staphylococci(MRCNS) were detected in 15 cases(62.5%), which was most, Methicillin Resistant Staphylococcus Aureus(MRSA) in 6 cases(16.7%), Enterococcus Faecium(EFM) in 5 cases(20.8%), Acinetobacter baumannii(ABA) in 2 cases(8.3%), and Bacillus sp, Coagulase-negative Staphylococci(CNS), and Enterococcus sp(ENT) in 1 case, respectively(4.2%). In all bacteria except ABA, Gram positive bacillia were detected in 30 cases(97%), and Gram negative bacilli were detected only in 1 case(3%). As for the kinds of bacteria and the number of groups before and after using 70% Alcohol by Groups, when the bacteria were identified after disinfecting IP Cassette and Table with 70% Alcohol, all the bacteria became extinct in both IP Cassette and Table Group(100%). As for the kinds and number of bacteria before and after using Tissue Cleaner by Groups, the bacteria in Tissue Cleaner Group became completely extinct only in 10 Groups(71.2%), and in 4 Groups, there was much decrease in bacteria, however, they were still detected. The extinction rate of all the bacteria was 91.5%. That is, though the other bacteria became extinct(100%), that of MRCNS bacteria was lowest(83.6%), followed by MRSA(95%). Conclusion : As a result of comparing the mean of the bacteria which were detected before and after using 70% Alcohol and Tissue Cleaner, there was statistically significant in the significant level of 5% in both of them.

• Journal of Environmental Health Sciences
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• v.30 no.5 s.81
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• pp.440-448
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• 2004

Airborne bacteria, gram negative bacteria (GNB) and fungi were measured in 70 class of 17 kindergartens. The objective of this study is to identify the factors influencing airborne concentrations of bacteria, GNB and fungi using multiple regression analysis. The average concentrations of bacteria and fungi exceeded $1,000\;CFU/m^3$. The average of GNB was $3.7{\times}10^2\;CFU/m^3$. This results indicated that air of kindergartens was contaminated with microbes such as bacteria and fungi. ANOVA test found that the concentrations of bacteria, GNB and fungi were significantly different by the characteristics of weather (rain, after rain, sunny) sampling date (July, August, September and October), the location of sampling site (ground level and basement) and the location of toilet (inside class, nearby class and away class). Multiple regression tests concluded that sampling date, the scale of city where kindergartens are located, the location of sampling site and ventilation efficiency can significantly affect the airborne concentration of bacteria, GNB and fungi. Most of these factors could be related moisture. Environmental factors that can cause the increment of moisture should be controlled in order to reduce airborne concentration of bacteria, GNB and fungi. Legal actions concerning prohibition on the presence of toilet inside class and ventilation criteria should be taken.