• Journal of Microbiology and Biotechnology
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• v.28 no.12
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• pp.2064-2070
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• 2018

Pseudomonas tolaasii 6264 is a representative strain that causes bacterial blotch disease on the cultivated oyster mushroom, Pleurotus ostreatus. Bacteriophages are able to sterilize the pathogenic P. tolaasii strains, and therefore, they can be applied in creating disease-free mushroom cultivation farms, through a method known as "phage therapy". For successful phage therapy, the characterization of phage-resistant strains is necessary, since they are frequently induced from the original pathogenic bacteria in the presence of phages. When 10 different phages were incubated with P. tolaasii 6264, their corresponding phage-resistant strains were obtained. In this study, changes in pathogenic, genetic, and biochemical characteristics as well as the acquired phage resistance of these strains were investigated. In the phylogenetic analyses, all phage-resistant strains were identical to the original parent strain based on the sequence comparison of 16S rRNA genes. When various phage-resistant strains were examined by three different methods, pitting test, white line test, and hemolytic activity, they were divided into three groups: strains showing all positive results in three tests, two positive in the first two tests, and all negative. Nevertheless, all phage-resistant strains showed that their pathogenic activities were reduced or completely lost.

• Journal of Dairy Science and Biotechnology
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• v.39 no.1
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• pp.1-8
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• 2021

The surroundings of livestock farms, including dairy farms, are known to be a major source of development and transmission of antibiotic-resistant bacteria. To control antibioticresistant bacteria in the livestock breeding environment, farms have installed livestock wastewater treatment facilities to treat wastewater before discharging the final effluent in nearby rivers or streams. These facilities have been known to serve as hotspots for inter-bacterial antibiotic-resistance gene transfer and extensively antibiotic-resistant bacteria, owing to the accumulation of various antibiotic-resistant bacteria from the livestock breeding environment. This review discusses antibiotic usage in livestock farming, including dairy farms, livestock wastewater treatment plants as hotspots for antibiotic resistant bacteria, and nonenteric gram-negative bacteria from wastewater treatment plants, and previous findings in literature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.3
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• pp.151-155
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• 2005

This study was carried out to get information for diversifying of resistant genes to bacterial blight (BB) in Japonica cultivar breeding programs. TWo hundred nine rice varieties were tested for qualitive resistance to four races of BB; HB9101 isolate for race K1, HB9102 isolate for race K2, HB9103 isolate for race K3, and HB01001 isolate for race K3a. Two hundred nine rice varieties were divided into five groups according to their race reaction. Fourteen Tongil-type varieties and ninetyseven Japonica varieties showed susceptible reaction to four races; Kl, K2, K3 and K3a. Thirteen Tongil-type varieties and thirty-one Japonica varieties were resistant to only one race; K1. Nine Tongil-type varieties and one Japonica variety were resistant to two races; K1 and K2. One Tongil-type variety and twenty-eight Japonica varieties were resistant to the three races; K1, K2, and K3. Fourteen Tongil-type varieties and one Japonica variety were resistant to four races; K1, K2, K3, and K3a. A number of Tongil-type varieties showed broad spectrum resistance to four races, while a number of Japonica varieties showed broad spectrum resistance to three races; K1, K2, and K3.

• Korean Journal of Breeding Science
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• v.43 no.4
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• pp.282-287
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• 2011

Bacterial pustule (BP) is a leaf disease of soybean that is most common in Korea. Inoculation of 8ra, pathogen strain, to resistant and susceptible cultivars for finding the BP resistance gene (rxp) was much tried but the sequence of the exact gene is not found. This research performed in order to confirm the rxp gene near molecular marker by using the resistant and susceptible cultivars. Soybean BP resistance gene which related to region of near molecular marker could select the resistant cultivar. For the near molecular marker of rxp, reference genomics data available at sequenced Phytozome was used for designing molecular markers. The rxp was mapped between Satt372 and Satt486 on chromosome 17. According to previous study, rxp released in find mapping 7.2 Mbp to 7.3 Mbp on chromosome 17. In this study, we developed 3 random markers near from 6.6 Mbp to 7.3 Mbp on chromosome 17 identified to increase the genetic resolution of the rxp gene region using resistant and susceptible cultivars. Particularly, Rxp17-700 marker was mostly coincided resistance and susceptible genotype to rxp. This result suggests that Rxp17-700 marker will be more tightly linked to rxp gene.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.1
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• pp.23-27
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• 2022

Disposable wet wipes provided by general restaurants in the Jeju Special Self-Governing Province were evaluated for compliance with the labeling requirements and the degree of bacterial contamination set by the Ministry of Food and Drug Safety. Of the 32 types of disposable wipes, five types of disposable wipes did not indicate the name and location of the business office of the manufacturer. Only 12 types of wet wipes were marked with the date of manufacture and expiration date. Bacterial contamination was seen in 9 types of wet wipes through bacterial culture but these were absent in the remaining 23 types (71.9%). The results of the antimicrobial susceptibility test for the 9 identified strains showed no methicillin-resistant coagulase-negative staphylococci (MRCNS) or multidrug-resistant bacteria. Through this study, it is recommended that the date of manufacture and expiration date must be indicated on the surface of disposable wet wipes designated as hygiene products, and clean uncontaminated wet wipes must comply with storage standards. In addition, the results are expected to contribute to the enhancement and improvement of hygiene management supervision, personal hygiene management, and an improvement in national health.

• Plant Disease and Agriculture
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• v.5 no.2
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• pp.95-99
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• 1999

Chemical control of bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae was attempted by spraying of streptomycin sulfate ·oxytetracycline WP streptomycin WP streptomycin ·copper hydroxide WP kasugamycin SL kasugamycin·copper oxychloride WP and copper hydroxide WP. The control efficacies of the bactericides were variable depending upon the spraying schedule,. Application of streptomycin WP and streptomycin sulfate·oxytetracycline WP from middle April to early May was found to be the most effective in controlling the bacterial canker. For copper hydroxide WP the spraying from middle January to early February showed the highest control efficacy. Kasugamycin SL was the most effective in controlling the disease by spraying from middle April to early May but it was still relatibvely effective during other spray periods. Foliar application of copper hydroxide WP and copper-antibiotic formulaions after middle April caused severe phytotoxicity. Kasgamycil SL streptomycin WP streptomycin·copper hydroxide WP and copper hydroxide WP were potential bactericides which could substitute streptomycin sulfate·oxytetracycline WP. Selective applications of the bactericides according to their optimum spray time can enhance the control efficacies against bacterial canker of kiwifruit and retard the emergency of resistant strains of P. syringae pv. actinidiae to the bactericides. The optimum spray number of streptomycin sulfate·oxytetracycline WP was 3 times with 15-day-intervals or 4 times with 10-day-intervals. The result suggested that the potential bactericides to bacterial canker of kiwifruit should be also used according to their optimum spray schedules in order to get their highest control efficacies.

• Membrane and Water Treatment
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• v.10 no.6
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• pp.395-404
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• 2019

The influence of chlorine on marine bacterial communities was examined in this study. A non-chlorine-adapted marine bacterial community (NCAM) and a chlorine-adapted bacterial community (CAM, bacterial community treated with $0.2mg-Cl_2/L$ chlorine) were cultivated for 1 month. A distinct difference was observed between the NCAM and CAM, which shared only eight operational taxonomic units (OTUs), corresponding to 13.1% of the total number of identified OTUs. This result suggested that chlorine was responsible for the changes in the marine bacterial communities. Kordiimonas aquimaris was found to be a chlorine-resistant marine bacterium. The effect of intermittent chlorination on the two marine biofilm communities formed on the reverse osmosis (RO) membrane surface was investigated using various chlorine concentrations (0, 0.2, 0.4, 0.6 and 0.8 mg $Cl_2/L$). Although the average number of adherent marine bacteria on the RO membrane over a period of 7 weeks decreased with increasing chlorine concentration, disinfection efficiencies showed substantial fluctuations throughout the experiment. This is due to chlorine depletion that occurs during intermittent chlorination. These results suggest that intermittent chlorination is not an effective disinfection strategy to control biofilm formation.

• Archives of Pharmacal Research
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• v.28 no.6
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• pp.660-666
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• 2005

The intestinal microbiota are important to the host with regard to resistance they impart against bacterial infections and their involvement in mediating metabolic functions. Lactic acid producing bacteria such as Lactobacillus play an important physiological role in these matters. The aim of the present study was to isolate Lactobacillus sp. that inhibits enteric pathogens. Initially, 17 isolates from healthy Koreans were collected on Lactobacillus selective medium. Resistance of the isolates to antibiotics including rifampicin, streptomycin, clindamycin and vancomycin was measured. One of the isolate was identified as Lactobacillus ruminus on the basis of bacterial cell morphology, cultural characteristic and biochemical characteristics, 16S rRNA sequence analysis and PCR-RAPD. Antimicrobial activity of the bacterium against Vancomycin Intermediate Resistant Staphylococcus aureus (VISA) and Vancomycin-Resistant Enterococci (VRE) was measured. About $10^4$ cells of VISA or VRE were mixed with 1, 5, and 9 mL of L. ruminus SPM 0211 and the final volume was adjusted to 10 mL with brain heart infusion (BHI) broth. The cell suspension was incubated for 3, 6, 9, and 24 h, serially diluted and then plated on BHI agar plates. As numbers of L. ruminus SPM 0211 were increased, viable cell count of VISA and VRE decreased. The strongest antimicrobial activity of SPM 0211 was observed after 9 h incubation in any mixture, almost completely inhibiting the growth of these two bacteria. The results suggest that the freshly isolated L. ruminus SPM 0211 may be used as a pro-biotic microbe that prevents the colonization of enteric pathogens and can thereby promote good gastrointestinal health.

• Research in Plant Disease
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• v.13 no.2
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• pp.88-92
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• 2007

A total of 41 Pseudomonas syringae pv. syringae, the causal agent of bacterial blossom blight, were isolated from kiwifruit plants in Korea. Among them, two strains showing streptomycin resistance were examined to investigate the structure of resistant determinants by PCR and nucleotide sequence analysis. PCR results suggested that the streptomycin resistance is mediated by strA-strB genes carried on Tn5393a. Insertion sequences, IS6100 and IS1133, which were located within or downstream of tnpR gene in Xanthomonas campestris and Erwinia amylovora were not found. Nucleotide sequences of strA-strB were 100% identical with Tn5393a. Two stretomycin resistant strains had three plasmids. Southern blot hybridization using strA-strB probe indicated that the resistant genes were carried on a 100kb plasmid.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.408-420
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• 2016

This study proposes an alternative approach for the use of chitosan silver-based dressing for the control of foot infection with multidrug-resistant bacteria. Sixty-five bacterial isolates were isolated from 40 diabetic patients. Staphylococcus aureus (37%) and Pseudomonas aeruginosa (18.5%) were the predominant isolates in the ulcer samples. Ten antibiotics were in vitro tested against diabetic foot clinical bacterial isolates. The most resistant S. aureus and P. aeruginosa isolates were then selected for further study. Three chitosan sources were tested individually for chelating silver nanoparticles. Squilla chitosan silver nanoparticles (Sq. Cs-Ag⁰) showed the maximum activity against the resistant bacteria when mixed with amikacin that showed the maximum synergetic index. This, in turn, resulted in the reduction of the amikacin MIC value by 95%. For evaluation of the effectiveness of the prepared dressing using Artemia salina as the toxicity biomarker, the LC₅₀ was found to be 549.5, 18,000, and 10,000 μg/ml for amikacin, Sq. Cs-Ag⁰, and dressing matrix, respectively. Loading the formula onto chitosan hydrogel dressing showed promising antibacterial activities, with responsive healing properties for the wounds in normal rats of those diabetic rats (polymicrobial infection). It is quite interesting to note that no emergence of any side effect on either kidney or liver biomedical functions was noticed.