• The Plant Pathology Journal
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• v.36 no.3
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• pp.204-217
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• 2020

In nature, plants are always under the threat of pests and diseases. Pathogenic bacteria are one of the major pathogen types to cause diseases in diverse plants, resulting in negative effects on plant growth and crop yield. Chemical bactericides and antibiotics have been used as major approaches for controlling bacterial plant diseases in the field or greenhouse. However, the appearance of resistant bacteria to common antibiotics and bactericides as well as their potential negative effects on environment and human health demands bacteriologists to develop alternative control agents. Bacteriophages, the viruses that can infect and kill only target bacteria very specifically, have been demonstrated as potential agents, which may have no negative effects on environment and human health. Many bacteriophages have been isolated against diverse plant-pathogenic bacteria, and many studies have shown to efficiently manage the disease development in both controlled and open conditions such as greenhouse and field. Moreover, the specificity of bacteriophages to certain bacterial species has been applied to develop detection tools for the diagnosis of plant-pathogenic bacteria. In this paper, we summarize the promising results from greenhouse or field experiments with bacteriophages to manage diseases caused by plant-pathogenic bacteria. In addition, we summarize the usage of bacteriophages for the specific detection of plant-pathogenic bacteria.

• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.32-35
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• 2003

This study was carried out to determine the inhibitory effect of garlic juice against Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Shigella flexneri. Staphylococcus aureus, Streptococcus mutans, Virio. parahaemolyticus which are food pathogenic bacteria and Lactobacillus acidophilus, Lactobacillus brevis, Lactobacillus casei, Lactobacillus plantarum, Lactococcus. lactis, Leuconostoc mesenteroides which are lactic acid bacteria. An aqueous extract of garlic was bacteriocidal against Gram-positive and Gram-negative bacteria in all concentrations (0.1∼2.5(w/v)%) tested in this experiment. Especially 0.5(w/v)% garlic juice inactivated completely E. coli, S. typhimurium, S. flexineri, V. parahaemolyticus and 1.0(w/v)% garlic juice perfectly reduced P. aeruginosa, S. mutans. Generally, the experiment result indicate that garlic juice restrains the growth of the pathogenic bacteria better than the lactic acid bacteria. Therefore, garlic has potential for the preservation of processed foods.

• Journal of Dairy Science and Biotechnology
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• v.39 no.2
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• pp.68-77
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• 2021

This study aimed to evaluate the effects of antibacterial activity of Tibetan mushroom exopolysaccharide against foodborne pathogenic bacteria Staphylococcus aureus 305, Listeria monocytogenes ATCC19114, Escherichia coli O157:H7 ATCC42894 and Escherichia coli O55. The yield of exopolysaccharide isolated from Tibetan mushroom culture was 620 mg/L. The antibacterial activity of exopolysaccharide against foodborne pathogenic bacteria exhibited 15 mm and 12 mm clear zone against S. aureus 305 and L. monocytogenes ATCC 19114, respectively. However, no clear zone was observed against E. coli O157:H7 ATCC 42894 and E. coli O55. In conclusion, exopolysaccharide isolated from Tibetan mushroom culture have the antibacterial activity only against Gram-positive foodborne pathogenic bacteria.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1191-1197
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• 2007

The detection and kinetics of mucosal pathogenic bacteria binding on polysaccharide ligands were studied using a surface plasmon resonance biosensor. The kinetic model applied curve-fitting to the experimental surface plasmon resonance sensorgrams to evaluate the binding interactions. The kinetic parameters for the mucosal pathogenic bacteria (Pseudomonas aeruginosa, Pseudomonas fluorescens, Serratia marcescens) with the alginate ligand were determined from a kinetic model. In addition, the binding interactions of the mucosal pathogenic bacteria with polysaccharide binding pairs (Pseudomonas aeruginosa/alginate, Streptococcus pneumoniae/pneumococcal polysaccharide, Staphylococcus aureus/pectin) were also compared with their kinetic parameters. The rate constants of association for Pseudomonas aeruginosa with the alginate ligand were higher than those for Pseudomonas fluorescens. Serratia marcescens had no detectable interaction with the alginate ligand. The adhesion affinity of Pseudomonas aeruginosa with alginate was higher than that for the other binding pairs. The binding affinities of the pathogenic bacteria with their own polysaccharide were higher than that of Staphylococcus aureus with pectin. Measuring the contact angle was found to be a feasible method for detecting binding interactions between analytes and ligands.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.279-286
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• 2023

Rapid and accurate detection of pathogenic bacteria is crucial for various applications, including public health and food safety. However, existing bacteria detection techniques have several drawbacks as they are inconvenient and require time-consuming procedures and complex machinery. Recently, the precision and versatility of CRISPR/Cas system has been leveraged to design biosensors that offer a more efficient and accurate approach to bacterial detection compared to the existing techniques. Significant research has been focused on developing biosensors based on the CRISPR/Cas system which has shown promise in efficiently detecting pathogenic bacteria or virus. In this review, we present a biosensor based on the CRISPR/Cas system that has been specifically developed to overcome these limitations and detect different pathogenic bacteria effectively including Vibrio parahaemolyticus, Salmonella, E. coli O157:H7, and Listeria monocytogenes. This biosensor takes advantage of the CRISPR/Cas system's precision and versatility for more efficiently accurately detecting bacteria compared to the previous techniques. The biosensor has potential to enhance public health and ensure food safety as the biosensor's design can revolutionize method of detecting pathogenic bacteria. It provides a rapid and reliable method for identifying harmful bacteria and it can aid in early intervention and preventive measures, mitigating the risk of bacterial outbreaks and their associated consequences. Further research and development in this area will lead to development of even more advanced biosensors capable of detecting an even broader range of bacterial pathogens, thereby significantly benefiting various industries and helping in safeguard human health

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.600-605
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• 2012

In this study, we investigated the mechanism of inhibition of pathogenic bacteria by Pediococcus pentosaceus strain SH-10 isolated from hard Clam Meretrix meretrix sikhae. When P. pentosaceus SH-10 was co-cultured in MRS broth with pathogenic bacteria, including Bacillus cereus, Listeria monocytogenes, Salmonella choleraesuis and Staphyloccus aureus, no viable pathogenic cells were detected after 18 h of incubation. However, pediocin or a pediocin-like bacteriocin was not detected in cultures of P. pentosaceus SH-10 by the agar diffusion method. Organic acids were produced in MRS broth in proportion to the incubation time of P. pentosaceus SH-10. These results indicate that P. pentosaceus SH-10 inhibited the growth of pathogenic bacteria by lowering the pH of the growth medium through the production of organic acids, including sodium lactate, sodium acetate, and sodium citrate.

• 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.

• Journal of Environmental Health Sciences
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• v.42 no.3
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• pp.189-195
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• 2016

Objectives: To ensure the microbiological safety of groundwater, it was confirmed whether waterborne pathogenic bacteria in groundwater samples tested positive for total coliforms in the Chungcheongnam-do Province region. Methods: Total colony counts, total coliforms and fecal coliforms were tested according to the process mandated by the drinking water quality testing standards of Korea. DNA was extracted from the samples, tested positive for total coliforms, and then subjected to real-time PCR to detect waterborne pathogenic bacteria. Results: A total of 115 samples were inadequate for drinking water. Thirty-one cases (27%) showed positive for fecal coliforms and nine cases (7.8%) showed total colony counts exceeding drinking water standards. Twenty-seven cases (23.5%) showed three items (total colony counts, total coliforms and fecal coliforms). Using the real-time PCR method, waterborne pathogens were detected in 57 cases (49.6%) in 115 samples. Seventy-eight cases of waterborne pathogenic bacteria were detected (including duplications): 27 cases of pathogenic E. coli (EPEC (19), ETEC (5), EHEC (1), EAEC (1) and EIEC (1)); 45 of Bacillus cereus; two of Yersinia spp.; two of Salmonella spp.; one of Staphylococcus aureus; one of Clostridium perfringens. Conclusion: The real-time PCR method can offer rapid and accurate detection of waterborne pathogenic bacteria. Therefore, this assay could be an alternative to conventional culture methods and can further ensure the microbiological safety of groundwater.

• The Korean Journal of Food And Nutrition
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• v.13 no.1
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• pp.36-44
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• 2000

Survival of pathogenic bacteris(S. aureus, L. monocytogenes, E. coli and S. typhimurium) in tryptic soy broth containing green tea water extract(GTW), green tea ethanol extract(GTE), potassium sorbate (PS) and sodium benzoate(SB) stored at various pH was evaluated. Tryptic soy broth(TSB) containing 0∼2%(w/v) of green tea extracts and preservatives adjusted to pH 5.5, 6.0, 6.5 and 7.0 was inoculated approximately 105 CFU/ml of pathogenic bacteria and incubated at 35$^{\circ}C$ for 24∼48 hours. Survival of bacteria was determined by viable cell counts of bacterial culture at each pH. Minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) of green tea extracts and preservatives against pathogenic bacteria were derived from survival curves of each bacteria. Antibacterial activities of green tea extracts increased with increasing pH but those of preservatives decreased with increrasing pH. S. aureus was the most sensitive strain to GTW and GTE but the most resistant to PS and SB. The MICs of green tea extracts to S. aureus were 0.52∼0.98% at pH 5.5∼6.0 and non inhibitory at pH 7.0. S. typhimurium was the most resistant to green tea extracts while the most sensitive to SB. The MICs of green tea extracts to S. typhimurium were 0.46∼1.62% at pH 5.5∼6.0 and 2% of PS was bactericidal at pH 5.5. 1.0∼2.0% of GTE were bactericidal to all strains tested except L. m9oncytogenes at pH 7.0. GTE was most efficient at inactivating pathogenic bacteria, generally followed by GTW, PS and SB.

• Journal of Microbiology and Biotechnology
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• v.32 no.3
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• pp.355-364
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• 2022

From independent swab samples of the cloaca of indigenous gamecocks (CIG), anus of healthy baby goats (AHG), and vagina of goats (VG) originating from Phitsanulok, Thailand, a total of 263 isolates of lactic acid bacteria (LAB) were collected. Only three isolates, designated C707, G502, and V202, isolated from CIG, AHG, and VG, respectively, exhibited an excellent inhibitory zone diameter against foodborne pathogenic bacteria when evaluated by agar spot test. Isolates C707 and G502 were identified as Enterococcus faecium, whereas V202 was identified as Pediococcus acidilactici, based on 16S rRNA sequence analysis. When foodborne pathogenic bacteria were co-cultured with chosen LAB in mixed BHI-MRS broth at 39℃, their growth was suppressed. These LAB were found to be capable of surviving in simulated stomach conditions. Only the isolate G502 was able to survive in the conditions of simulated intestinal juice. This research suggests that selected LAB could be used as a food/feed supplement to reduce foodborne pathogenic bacteria and improve the safety of animal-based food or feed.