Synergistic antibacterial effects of carvacrol and ε-polylysine

This study aimed to evaluate the antimicrobial efficacy of the combination of ɛ-polylysine (ɛ-PL) and carvacrol (Car) against foodborne pathogens, Escherichia coli and Staphylococcus aureus. The minimum inhibitory concentrations (MICs) of ɛ-PL (Car) against E. coli and S. aureus were 25 μg/mL (320 μg/mL) and 12.5 μg/mL (320 μg/ mL), respectively. Checkerboard assays showed that the combination of ɛ-PL and Car exerted synergistic effects against E. coli and S. aureus with fraction inhibitory concentration index (FICI) of 0.375 and 0.5, respectively. It demonstrated that the combination of ɛ-PL and Car significantly inhibited the growth of the two strains com-pared to single treatment. Furthermore, the mode of action of ɛ-PL (6.25 μg/mL) or Car (80 μg/mL) in inhibiting E. coli and S. aureus was researched by assessing their changes with regard to cellular membrane integrity, membrane permeability, respiratory activity, and membrane structure. A combination of ɛ-PL and Car increased the damage to cell membranes and their permeability and led to the release of 260 nm absorbing materials, decreased respiratory-chain dehydrogenase activity compared with ɛ-PL or Car treatment alone. These results demonstrated that the combination of ɛ-PL and Car could be used as a new promising naturally sourced food preservative.

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In vitro activity of allicin combined with two antibiotics on intestinal Shigella

Infection International ◽

10.1515/ii-2017-0152 ◽

2017 ◽

Vol 6 (1) ◽

pp. 25-29 ◽

Cited By ~ 1

Author(s):

Yuchi Jia ◽

Xiaomei Wu

Keyword(s):

Intestinal Tract ◽

Inhibitory Concentration ◽

Synergistic Effects ◽

Antagonistic Effect ◽

Additive Effects ◽

In Vitro Activity ◽

Antibacterial Effects ◽

Combined Application ◽

Combined Use

Abstract Objective We aimed to evaluate the combined antibacterial effects of allicin in combination with levofloxacin and ceftriaxone on Shigella isolated from the intestinal tract in vitro. Materials and Methods Using a checkerboard design, broth microdilution assay was used to test the effects of the compounds on the organism. We also determined the MIC of the two groups of antibacterial drugs against 30 strains of Shigella and calculated the fractional inhibitory concentration (FIC) index, to judge the combination effect. Result After the combined application of allicin and ceftriaxone the MIC decreased significantly. Distribution of the FIC index was as follows: FIC ≤0.5, accounting for 10%; 0.5< FIC ≤1.0, accounting for 60%; 1 < FIC ≤2, accounting for 30%; FIC >2, percentage is zero. After combined application of allicin and levofloxacin, distribution of FIC index was as follows: FIC≤0.5, ratio is zero; 0.5< FIC ≤1, accounting for 56.7%; 1 < FIC ≤2, accounting for 43.3%; FIC >2, ratio is zero. Conclusion After the combined use of ceftriaxone, levofloxacin, and allicin, most of the tests showed synergistic effects and additive effects on Shigella, while some of them showed no correlation and no antagonistic effect.

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Synergistic anti-biofilm effects of Brassicaceae plant extracts in combination with proteinase K against Escherichia coli O157:H7

Scientific Reports ◽

10.1038/s41598-020-77868-4 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Wen Si Hu ◽

Da Min Nam ◽

Joo-Sung Kim ◽

Ok Kyung Koo

Keyword(s):

Stainless Steel ◽

Inhibitory Concentration ◽

Synergistic Effects ◽

Combined Treatment ◽

Antimicrobial Activities ◽

Inhibitory Effect ◽

Proteinase K ◽

E Coli ◽

Log Reduction ◽

Food Contact Surfaces

AbstractBacteria can form biofilms, complex microbial communities protected from environmental stress, on food contact surfaces. Brassicaceae plant has been shown to contain bioactive compounds with antimicrobial activities. The objective of this study was to evaluate the synergistic effects of Brassicaceae species and proteinase K against E. coli O157:H7 biofilm. We determined the minimum biofilm inhibitory concentration, the fractional inhibitory concentration indexes, and the synergistic inhibitory effect of Raphanus sativus var. longipinnatus, R. sativus, and Brassica oleracea var. acephala extracts with proteinase K on E. coli O157:H7. The biofilm showed a 49% reduction with 2 mg/mL R. sativus. The combination of proteinase K 25 µg/mL significantly increased the effect of 2 mg/mL R. sativus var. longipinnatus and the combined treatment yielded up to 2.68 log reduction on stainless steel coupons. The results showed that the combination of R. sativus var. longipinnatus extract and proteinase K could serve as an anti-biofilm agent with synergistic effects for inhibiting E. coli O157:H7 biofilm on stainless steel surfaces.

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Rabbit Meat as a Source of Bacterial Foodborne Pathogens

Journal of Food Protection ◽

10.4315/0362-028x-69.5.1106 ◽

2006 ◽

Vol 69 (5) ◽

pp. 1106-1112 ◽

Cited By ~ 30

Author(s):

JOSE M. RODRÍGUEZ-CALLEJA ◽

ISABEL GARCÍA-LÓPEZ ◽

MARÍA-LUISA GARCÍA-LÓPEZ ◽

JESÚS A. SANTOS ◽

ANDRÉS OTERO

Keyword(s):

Foodborne Pathogens ◽

Staphylococcal Enterotoxin ◽

Contamination Rate ◽

E Coli ◽

Aeromonas Veronii ◽

Listeria Ivanovii ◽

Worldwide Production ◽

Rabbit Meat ◽

Listeria Seeligeri ◽

And Staphylococcus Aureus

Even though worldwide production of rabbit meat is >1,000,000 tons, little information is available for rabbit meat microbiology. This study provides data on the prevalence of Salmonella, Escherichia coli O157:H7, Yersinia enterocolitica, Listeria spp., motile Aeromonas spp., and Staphylococcus aureus on rabbit meat. A total of 24 rabbit carcasses from two abattoirs and 27 rabbit meat packages from supermarket displays were examined. In addition to culturing methods, associated virulence genes were investigated by PCR in suspect isolates and samples. Neither Salmonella nor E. coli O157:H7 was detected. All samples were negative for virulence-associated invA, stx1, and stx2 genes. At one abattoir, two carcasses (3.9%) carried Y. enterocolitica yst−, and two were positive for the yst gene, although viable Y. enterocolitica cells were not recovered from these samples. Seven samples (13.7%) were contaminated with Listeria. Of them, three were positive for hly and iap genes (Listeria monocytogenes hly+/iap+), two carried Listeria seeligeri, one carried Listeria ivanovii, and one carried Listeria innocua. For detectable motile Aeromonas spp. (average count, 1.77 ± 0.62 log CFU/g), the contamination rate was 35.3%, although ca. 90% of the samples were positive for the aerA and/or hlyA genes. The majority of aeromonad isolates were Aeromonas hydrophila aerA+/hlyA+. Aeromonas caviae, Aeromonas popoffii, Aeromonas schubertii, and the two biovars of Aeromonas veronii were also isolated. The prevalence of S. aureus contamination (average count, 1.37 ± 0.79 log CFU/g) was 52.9%. Among 27 S. aureus isolates, two harbored genes for staphylococcal enterotoxin B (seb), and two harbored genes for staphylococcal enterotoxin C (sec). The remaining isolates were negative for sea, seb, sec, sed, and see.

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Antibacterial Effect of Water-Soluble Arrowroot (Puerariae radix) Tea Extracts on Foodborne Pathogens in Ground Beef and Mushroom Soup

Journal of Food Protection ◽

10.4315/0362-028x-67.9.1953 ◽

2004 ◽

Vol 67 (9) ◽

pp. 1953-1956 ◽

Cited By ~ 23

Author(s):

S. KIM ◽

D. Y. C. FUNG

Keyword(s):

Foodborne Pathogens ◽

Salmonella Enteritidis ◽

Ground Beef ◽

Viable Cell ◽

Water Soluble ◽

Escherichia Coli O157 ◽

E Coli ◽

Cell Counts ◽

Tea Extract ◽

And Staphylococcus Aureus

Antimicrobial activity of water-soluble arrowroot tea extract was evaluated against Escherichia coli O157:H7, Salmonella enterica Serotype Enteritidis, Listeria monocytogenes, and Staphylococcus aureus in ground beef and mushroom soup. The concentrations of arrowroot tea used were 0, 3, and 6% (wt/wt) for ground beef and 0, 1, 5, and 10% (wt/vol) for mushroom soup. Samples without tea extract were considered controls. Each sample was stored for 0, 1, 3, 5, and 7 days at 7°C for ground beef and for 0, 1, 3, and 5 days at 35°C for mushroom soup. On each sampling time, proper dilutions were spread plated on each pathogen-specific agar. Viable cell counts of each pathogen were performed after incubation at 35°C for 24 to 48 h. For ground beef, Salmonella Enteritidis and L. monocytogenes were slightly suppressed by approximately 1.5 log, compared with the control, on day 7 at 3 and 6% arrowroot tea treatment. For mushroom soup, all test pathogens were suppressed by 6.5, 4.7, 3.4, and 4.3 log at 5% and 6.0, 4.7, 5.0, and 4.3 log at 10% against E. coli O157:H7, Salmonella Enteritidis, L. monocytogenes, and S. aureus, respectively, compared with the control on day 5. Mushroom soup with 1% arrowroot tea also showed 2.3- and 2.7-log growth suppression of Salmonella Enteritidis and S. aureus, respectively, compared with the control on day 5. This study showed that the use of arrowroot tea would effectively inhibit the microbial growth of both gram-negative and gram-positive foodborne pathogens in various foods, especially liquid foods.

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Biocide Potentiation Using Cinnamic Phytochemicals and Derivatives

Molecules ◽

10.3390/molecules24213918 ◽

2019 ◽

Vol 24 (21) ◽

pp. 3918 ◽

Cited By ~ 3

Author(s):

Malheiro ◽

Maillard ◽

Borges ◽

Simões

Keyword(s):

Escherichia Coli ◽

Bacterial Infections ◽

Concentration Index ◽

Cetyltrimethylammonium Bromide ◽

Inhibitory Concentration ◽

Surface Disinfection ◽

E Coli ◽

Bactericidal Efficacy ◽

Effective Combination ◽

And Staphylococcus Aureus

Surface disinfection is of utmost importance in the prevention of bacterial infections. This study aims to assess the ability of ten phytochemicals and related derivatives as potentiators of two commonly used biocides—cetyltrimethylammonium bromide (CTAB) and lactic acid (LA). LA in combination with cinnamic, hydrocinnamic, α-methylcinnamic, and α-fluorocinnamic acids had a factional inhibitory concentration index (FICI) ≤ 1 for Escherichia coli and Staphylococcus aureus. Several phytochemicals/derivatives in combination with biocides improved the biocidal efficacy against early sessile bacteria. The most effective combination was LA with allyl cinnamate (2.98 ± 0.76 log CFU.cm−2 reduction) against E. coli. The combination with CTAB was successful for most phytochemicals/derivatives with a maximum bactericidal efficacy against sessile E. coli when combined with allyl cinnamate (2.20 ± 0.07 log CFU.cm−2 reduction) and for S. aureus when combined with α-methylcinnamic acid (1.68 ± 0.30 log CFU.cm−2 reduction). This study highlights the potential of phytochemicals and their derivatives to be used in biocide formulations.

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Tellimagrandin II, A Type of Plant Polyphenol Extracted from Trapa bispinosa Inhibits Antibiotic Resistance of Drug-Resistant Staphylococcus aureus

International Journal of Molecular Sciences ◽

10.3390/ijms20225790 ◽

2019 ◽

Vol 20 (22) ◽

pp. 5790 ◽

Cited By ~ 2

Author(s):

Yu-Wei Chang ◽

Wan-Chun Huang ◽

Chun-Yu Lin ◽

Wen-Hung Wang ◽

Ling-Chien Hung ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Inhibitory Concentration ◽

Synergistic Effects ◽

Drug Resistant ◽

Penicillin Binding Protein ◽

Antibacterial Effects ◽

Transmission Electron ◽

Antistaphylococcal Activity ◽

Global Concern ◽

Tellimagrandin Ii

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has become a critical global concern. Identifying new candidates of anti-S. aureus agents is urgently required because the therapeutic strategies for infected patients are limited currently. Therefore, the present study investigated whether Tellimagrandin II (TGII), a pure compound extracted from the shells of Trapa bispinosa, exhibits antibacterial effects against MRSA. We first showed that TGII exerted potent inhibitory activity against MRSA with a minimum inhibitory concentration of 128 μg/mL. The obtained fractional inhibitory concentration suggested that TGII could alone exert antistaphylococcal activity, and TGII combined with low doses of antibiotics displayed synergistic effects against MRSA. Moreover, we found that TGII exerted bactericidal activity by reducing the expression of mecA followed by the negative regulation of the penicillin-binding protein 2a (PBP2a) of MRSA. Transmission electron microscopy (TEM) images further confirmed that TGII destroyed the integrity of the cell wall of MRSA and caused the loss of cytoplasm content. In conclusion, we evidenced the antibacterial effects of TGII against MRSA, which enables the effective dose of current antibiotics to be reduced and the predicament of drug-resistant S. aureus isolates to be overcome.

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Design, Synthesis and Antibacterial Evaluation of Novel 1,2,3-Triazole Derivatives Incorporating 3′-Deoxythymidine

Journal of Chemical Research ◽

10.3184/174751917x15094552081189 ◽

2017 ◽

Vol 41 (11) ◽

pp. 645-649 ◽

Cited By ~ 1

Author(s):

Long-Fei Mao ◽

Gui-Qing Xu ◽

Bin Sun ◽

Yu-Qin Jiang ◽

Wen-Pei Dong ◽

...

Keyword(s):

Antibacterial Activity ◽

Inhibitory Concentration ◽

Computational Simulations ◽

Design Synthesis ◽

Triazole Derivatives ◽

E Coli ◽

Structure Activity ◽

Antibiotic Drugs ◽

And Staphylococcus Aureus ◽

Antibacterial Evaluation

A series of novel 1,2,3-triazole derivatives incorporating 3′-deoxythymidine were designed, synthesised and characterised. Antibacterial activity against Escherichia coli and Staphylococcus aureus was evaluated for all of the synthesised compounds and compared against standard antibiotic drugs, streptomycin sulfate and doxycycline, as controls. Some compounds showed potential antibacterial activity towards E. coli, and the best minimum inhibitory concentration was 0.14 mM. Preliminary structure-activity relationships and computational simulations were also studied.

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Growth and Survival of Foodborne Pathogens in Beer

Journal of Food Protection ◽

10.4315/0362-028x.jfp-10-546 ◽

2011 ◽

Vol 74 (10) ◽

pp. 1670-1675 ◽

Cited By ~ 14

Author(s):

GARRY MENZ ◽

PETER ALDRED ◽

FRANK VRIESEKOOP

Keyword(s):

Salmonella Typhimurium ◽

Foodborne Pathogens ◽

Storage Temperature ◽

Escherichia Coli O157 ◽

Gram Negative ◽

Growth And Survival ◽

E Coli ◽

And Storage ◽

And Staphylococcus Aureus ◽

Storage Temperatures

This work aimed to assess the growth and survival of four foodborne pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus) in beer. The effects of ethanol, pH, and storage temperature were investigated for the gram-negative pathogens (E. coli O157:H7 and Salmonella Typhimurium), whereas the presence of hops ensured that the gram-positive pathogens (L. monocytogenes and S. aureus) were rapidly inactivated in alcohol-free beer. The pathogens E. coli O157:H7 and Salmonella Typhimurium could not grow in the mid-strength or full-strength beers, although they could survive for more than 30 days in the mid-strength beer when held at 4°C. These pathogens grew rapidly in the alcohol-free beer; however, growth was prevented when the pH of the alcohol-free beer was lowered from the “as received” value of 4.3 to 4.0. Pathogen survival in all beers was prolonged at lowered storage temperatures.

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Inhibitory Effects of Combinations of Chemicals on Escherichia coli, Bacillus cereus, and Staphylococcus aureus Biofilms during the Clean-in-Place Process at an Experimental Dairy Plant

Journal of Food Protection ◽

10.4315/jfp-19-505 ◽

2020 ◽

Vol 83 (8) ◽

pp. 1302-1306

Author(s):

EUN-SEON LEE ◽

JONG-HUI KIM ◽

MI-HWA OH

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Citric Acid ◽

Bacillus Cereus ◽

Foodborne Pathogens ◽

Combined Treatment ◽

Food Additives ◽

Inhibitory Effects ◽

E Coli ◽

And Staphylococcus Aureus

ABSTRACT In dairy plants, clean-in-place (CIP) equipment cannot be disassembled, making it difficult to clean the inner surface of pipes. In this study, the inhibitory effects of chemical agents on biofilms formed by three foodborne pathogens, Bacillus cereus, Escherichia coli, and Staphylococcus aureus, was evaluated in a dairy CIP system. The experiment was conducted on a laboratory scale. Each of the three bacteria (200 μL) was inoculated onto stainless steel (SS) chips (25 by 25 mm), and the effect of single cleaning agents was evaluated. Individual treatments with NaClO (30, 50, 100, and 200 ppm), NaOH (0.005, 0.01, 0.05, and 0.1%), citric acid (1, 3, 5, and 7%), and nisin (5, 10, 25, 50, 100, and 200 ppm) were used to clean the SS chip for 10 min. The most effective concentration of each solution was selected for further testing in a commercial plant. Simultaneous cleaning with 200 ppm of NaClO (10 min) and 7% citric acid (10 min) reduced the biofilms of B. cereus, E. coli, and S. aureus by 6.9, 7.0, and 8.0 log CFU/cm2, respectively. Both 7% citric acid and 0.1% NaOH were optimal treatments for E. coli. NaClO and citric acid are approved for use as food additives in the Republic of Korea. Our results revealed that a combined treatment with NaClO and citric acid is the most effective approach for reducing biofilms formed by common foodborne pathogens on CIP equipment. These findings can contribute to the production of safe dairy products. HIGHLIGHTS

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Relationship of cytochrome content to the sensitivity of bacteria to NaCl on freezing and thawing

Canadian Journal of Microbiology ◽

10.1139/m77-061 ◽

1977 ◽

Vol 23 (4) ◽

pp. 413-419 ◽

Cited By ~ 3

Author(s):

Sai K. Lee ◽

Peter H. Calcott ◽

Robert A. MacLeod

Keyword(s):

Sodium Chloride ◽

Respiratory Activity ◽

Membrane Integrity ◽

Model Organism ◽

Salt Sensitivity ◽

Freezing And Thawing ◽

Whole Cells ◽

E Coli ◽

Membrane Components ◽

Cytochrome Content

Eight species of bacteria representing rod, coccus, gram-positive, and gram-negative forms were tested for their sensitivity to sodium chloride during freezing and thawing. Six of the eight species tested were salt-sensitive, though to different degrees, while Lactobacillus casei and Streptococcus faecalis were resistant. Escherichia coli grown anaerobically exhibited only 38% of the salt sensitivity of aerobically grown cells. Analysis of cytochrome pigments in the organisms revealed that the six sensitive organisms all contained these pigments but in varying amounts, while the two resistant ones were devoid of them. Anaerobically grown E. coli contained 50% of the cytochromes of aerobically grown cells. A relationship between cytochrome content of the organisms and salt sensitivity during freezing and thawing was demonstrated with a correlation coefficient of 0.76 (P < 0.05); the higher the cytochrome content, the more salt-sensitive the organism. This indicated that 58% of the salt sensitivity was due to the cytochrome content.Using a model organism, E. coli, the effect of salt during freezing and thawing on the respiratory activity was examined. Freezing and thawing in water or saline decreased the respiration by whole cells of substrates expected to be NAD-linked while NADH-stimulated respiration was increased. In cell-free extracts derived from unfrozen cells or those frozen and thawed in water or saline, the respiration of ascorbate plus N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) was constant. The respiration of NADH, succinate, and lactate in cell-free extracts derived from cells frozen and thawed in saline was reduced compared with those extracts derived from unfrozen cells or cells frozen and thawed in water. Studies with E. coli showed that the decreased respiratory activity caused by disruptions in the electron-transport chain could not account for the salt sensitivity on freezing and thawing. More likely, salt sensitivity is related to the presence of bonds between cytochromes and other membrane components which are disrupted by sodium chloride on freezing and thawing. This would then result in loss of membrane integrity and function.

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