• The Plant Pathology Journal
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• v.25 no.4
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• pp.361-368
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• 2009

The efficacy of the combination of Burkholderia cepacia B23 with 0.75% chitosan and 3% calcium chloride ($CaCl_2$) as a biocontrol treatment of anthracnose disease of papaya caused by Colletotrichum gloeosporioides, was evaluated during storage. The growth of B. cepacia B23 in papaya wounds and on fruit surfaces was not affected in presence of chitosan and $CaCl_2$ or combination throughout the storage period. The combination of B. cepacia B23 with chitosan-$CaCl_2$ was more effective in controlling the disease than either B. cepacia B23 or chitosan or other combination treatments both in inoculated and naturally infected fruits. Combining B. cepacia B23 with chitosan-$CaCl_2$ gave the complete control of anthracnose infection in artificially inoculated fruits stored at $14^{\circ}C$ and 95% RH for 18 days, which was similar to that obtained with fungicide $benocide^{(R)}$. Moreover, this combination offered a greater control by reducing 99% disease severity in naturally infected fruits at the end of 14 days storage at $14^{\circ}C$ and 95% RH and six days post ripening at $28\pm2^{\circ}C$, which was superior to that found with $benocide^{(R)}$ or other treatments tested. Thus, postharvest application of B. cepacia B23 with chitosan-$CaCl_2$ as enhancers represents a promising alternative to synthetic fungicides for the control of anthracnose in papaya during storage.

• Korean Journal of Organic Agriculture
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• v.23 no.1
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• pp.133-148
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• 2015

Although several adverse effects have been increased in recent years, synthetic agro-chemicals have been widely used to control diseases on paprika. This research was conducted to isolate and to characterize the antagonistic microorganism to control major paprika diseases, gray mold rot, fruit and stem rot, phytophthora blight, sclerotium rot, and wilt disease. Analysis of the fatty acid and analysis of the 16S rDNA gene sequence revealed that YKJ2 isolated in this research belongs to a group of Burkholderia cepacia. Specially, 16S rDNA gene sequence of YKJ2 showed 99% of sequence similarity with B. cepacia. Observation through the optical microscope revealed that YKJ2 was effective on suppression of the spore germination and the hyphal growth of pathogens. YKJ2 treatment on pathogens induced marked morphological changes like hyphal swelling and degradation of cell wall. In the case of phytophthora blight, the zoosporangium formation was restrained. On the basis of the results of this study, we propose that an antagonistic microorganism, B. cepacia, found in this study naming as "B. cepacia strain YKJ2" and has great potential as one of biological control agents against major diseases of paprika.

• Journal of Microbiology
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• v.45 no.3
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• pp.275-279
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• 2007

The aims of this study were to detect Burkholderia cepacia complex (Bcc) strains in a cohort of Cystic Fibrosis patients (n=276) and to characterize Bcc isolates by molecular techniques. The results showed that 11.23% of patients were infected by Bcc. Burkholderia cenocepacia lineage III-A was the most prevalent species (64.3%) and, of these, 10% was cblA positive and 50% esmR positive. Less than half of the strains were sensitive to ceftazidime, meropenem, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole. About half of the strains (41%) had homogeneous profiles, suggesting cross-transmission. The infection by B. cenocepacia was associated to a high rate of mortality (p=0.01).

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2211-2220
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• 2017

Chlorhexidine gluconate (CHX) and benzalkonium chloride (BZK) formulations are frequently used as antiseptics in healthcare and consumer products. Burkholderia cepacia complex (BCC) contamination of pharmaceutical products could be due to the use of contaminated water in the manufacturing process, over-diluted antiseptic solutions in the product, and the use of outdated products, which in turn reduces the antimicrobial activity of CHX and BZK. To establish a "afe use" period following opening containers of CHX and BZK, we measured the antimicrobial effects of CHX ($2-10{\mu}g/ml$) and BZK ($10-50{\mu}g/ml$) at sublethal concentrations on six strains of Burkholderia cenocepacia using chemical and microbiological assays. CHX (2, 4, and $10{\mu}g/ml$) and BZK (10, 20, and $50{\mu}g/ml$) stored for 42 days at $23^{\circ}C$ showed almost the same concentration and toxicity compared with freshly prepared CHX and BZK on B. cenocepacia strains. When $5{\mu}g/ml$ CHX and $20{\mu}g/ml$ BZK were spiked to six B. cenocepacia strains with different inoculum sizes ($10^0-10^5CFU/ml$), their toxic effects were not changed for 28 days. B. cenocepacia strains in diluted CHX and BZK were detectable at concentrations up to $10^2CFU/ml$ after incubation for 28 days at $23^{\circ}C$. Although abiotic and biotic changes in the toxicity of both antiseptics were not observed, our results indicate that B. cenocepacia strains could remain viable in CHX and BZK for 28 days, which in turn, indicates the importance of control measures to monitor BCC contamination in pharmaceutical products.

• Microbiology and Biotechnology Letters
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• v.33 no.1
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• pp.16-23
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• 2005

In order to develop a new microbial fungicide using endophytic bacteria for the control of anthracnoses occurring on various crops, a total of 260 bacterial strains were isolated from fresh tissues of 5 plant species. After they were cultured in broth medium, their antifungal activities were tested for in vivo antifungal activity against cucumber anthracnose caused by Colletotrichum orbiculare. As the results, liquid cultures of 28 strains showed potent antifungal activities more than $90\%$ against cucumber anthracnose. At 3-fold dilutions of liquid cultures, 18 strains inhibited the development of cucumber anthracnose of more than $70\%$. They were further tested for in vivo antifungal activity against red pepper anthracnose caused by C. coccodes and in vitro antifungal activity against C. acutatum, a fungal agent causing red pepper anthracnose. Among 18 strains, a bacterial strain EB215 isolated from cucumber roots displayed the most potent antifungal activity against Colletotrichum species. It was identified as Burkholderia cepacia based on its physiological and biochemical characteristics, Biolog test and 16S rDNA gene sequence. It also controlled effectively the development of rice blast (Magnaporthe grisea), rice sheath blight (Corticium sasaki), tomato gray mold (Botrytis cinerea), and tomato late blight (Phytophthora infestans). Studies on the characterization of antifungal substances produced by B. cepacia EB215 are in progress.