Inappropriate and disproportionate use of antibiotics is contributing immensely to the development of antibiotic resistance in bacterial species associated with food contamination. The use of natural products in combination can be a potent alternative hurdle strategy to inactivate foodborne pathogens. Here, we explored the pro-oxidant properties of essential oil inalool and itamin C in combination with opper (LVC) in combating the foodborne pathogens and subsp. serovar Typhi using a three-dimensional (3D) checkerboard microdilution assay. Antibacterial activity in terms of the MIC revealed that the triple combination exerted a synergistic effect compared to the effects of the individual constituents. The bactericidal effect of the triple combination was confirmed by a live/dead staining assay. Reactive oxygen species (ROS) measurements with the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling assay and scanning electron microscopy imaging strongly suggested that the increase in ROS production is the underlying mechanism of the enhanced antibacterial potency of the LVC combination (linalool [1.298 mM], vitamin C [8 mM], copper [16.3 μM]). In addition, the hypersensitivity of oxidative stress regulator mutants (, , , and mutants) toward LVC corroborated the involvement of ROS in cell death. Live/dead staining and changes in cellular morphology revealed that oxidative stress did not transform the cells into the viable but nonculturable (VBNC) state; rather, killing was associated with intracellular and extracellular oxidative burst. Furthermore, the LVC combination did not display toxicity to human cells, while it effectively reduced the pathogen levels in acidic fruit juices by 3 to 4 log CFU/ml without adversely altering the organoleptic properties. This study opens a new outlook for combinatorial antimicrobial therapy. There is a need to develop effective antibacterial therapies for mitigating bacterial pathogens in food systems. We used a 3D checkerboard assay to ascertain a safe synergistic combination of food-grade components: vitamin C, copper, and the essential oil linalool. Individually, these constituents have to be added in large amounts to exert their antibacterial effect, which leads to unwanted organoleptic properties. The triple combination could exceptionally inhibit foodborne Gram-negative pathogens like and subsp. serovar Typhi at low concentrations (linalool, 1.298 mM; vitamin C, 8 mM; copper, 16.3 μM) and displayed potent microbial inhibition in acidic beverages. We found increased susceptibility in deletion mutants of oxidative stress regulators (, , , and mutants) due to ROS generation by Fenton's chemistry. The results of this study show that it may be possible to use plant-based antimicrobials in synergistic combinations to control microbial contaminants.
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http://dx.doi.org/10.1128/AEM.02487-18 | DOI Listing |
Vet Res Commun
January 2025
Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta N 36 Km 601, Río Cuarto City, 5800, Córdoba, Argentina.
Post-weaning diarrhea (PWD) is a major concern for pig producers, as stress and early weaning increase susceptibility to enteropathogens like enterotoxigenic Escherichia coli (ETEC) and Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium).
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January 2025
Microbiology and Cell Science Department, IFAS, University of Florida, Gainesville, Florida, USA.
infections pose significant public health challenges worldwide. The diversity of strains, particularly those isolated from environmental and clinical sources, necessitates innovative approaches to prevention and treatment. Previous research has shown that small extracellular vesicles (sEVs) produced by macrophages during Typhimurium infection can induce robust immune responses when used as a vaccine, offering complete protection in systemic infection models.
View Article and Find Full Text PDFAnimals (Basel)
January 2025
Experimental Zooprophylactic Institute of Lombardy and Emilia Romagna (IZSLER), "Bruno Ubertini", Diagnostic Section of Piacenza, Italy Via Strada Della Faggiola 1, 29027 Podenzano, PC, Italy.
is diffused worldwide, and subsp. is spread worldwide with many serovars associated with the infection of domestic bovines. The most spread are .
View Article and Find Full Text PDFRes Vet Sci
December 2024
Botswana University of Agriculture and Natural Resources, P/Bag BR 0027, Gaborone, Botswana.
Approximately 20 million cases and 0.15 million human fatalities worldwide each year are caused by Salmonellosis. A mechanistic compartmental model based on ordinary differential equations is proposed to evaluate the effects of temperature and pH on the transmission dynamics of Salmonellosis.
View Article and Find Full Text PDFMicrob Pathog
February 2025
Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, Food Research Center, University of São Paulo, Brazil.
Salmonella enterica subsp. enterica serovar Havana is a potential pathogenic serotype that can cause human foodborne illness. Therefore, we have conducted a microbiological and genomic surveillance study of Salmonella Havana from food in Brazil.
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