| There are a wide range of microbial species in the human intestinal tract,including a large number of pathogenic bacteria,which maintain a delicate balance with lactic acid bacteria and other bacteria in a certain range,and at the same time are related to the life and health of the human body.Lactic acid bacteria are probiotics in the general sense,with a variety of probiotic functions,such as improving and maintaining the body's immune system,producing antimicrobial substances,enhancing mucosal barrier function,etc.However,with the further development of research,people have found that the role of probiotics in human body is multi-faceted,such as the production of excessive biogenic amines,or the occurrence of bacterial translocation through the intestinal barrier causing bacteremia,etc.At the same time,conditioned food-borne pathogens are usually considered to be absolutely harmful.However,with the development of research,it has been gradually found that norovirus causing diarrhea can repair intestinal tissue damage and restore intestinal tissue structure and function,which suggests that we need to have a new understanding of pathogenic bacteria.Antibiotics are often used in clinical treatment of one of the treatment means,because of the overdependence on the use of antibiotics,bacterial drug resistance effect is more and more significant.When antibiotic action,however,intestinal pathogenic bacteria is how to gradually form resistance,in the process in an environment of lactic acid bacteria what roles to worth ponder,there is no research can give an answer,so this study lactic acid bacteria resistance effect on the formation of foodborne pathogenic bacteria an initial investigation on the influence of several mechanisms.In this study,bifidobacterium bifidum WBBI03 and Lactobacillus plantarum WLPL05 were selected as the representatives of lactic acid bacteria,Listeria monocytogenes CMCC 54001 and Escherichia coli O157:H7 were selected as the representatives of food-borne pathogenic bacteria to explore the co-incubation effect of lactic acid bacteria and food-borne pathogenic bacteria under the action of antibiotics at different concentrations.Ampicillin(10 ug/mL,25 ug/mL,50 ug/mL,100 ug/mL),chloramphenicol(4 ug/mL,8 ug/mL,16 ug/mL,32 ug/mL),kanamycin(2 ug/mL,5ug/mL,10 ug/mL,20 ug/mL)were tested,and the results showed that co-incubation effectively reduced the mortality of Listeria monocytogenes CMCC 54001 in three antibiotic environments,with increases of nearly 10%-30% in survival at different antibiotics and corresponding low concentrations.In order to confirm the universality of this conclusion,this study also discussed the effects of Escherichia coli O157:H7,Salmonella typhimurium and Lactobacillus Plantarum under the background of three antibiotics,and obtained the same conclusion as the enhanced resistance of Listeria monocytogenes CMCC 54001.In order to further explore the relevant mechanism of lactic acid bacteria enhancing drug resistance to food-borne pathogenic bacteria,this study co-incubated bifidobacterium bifidum WBBI03 and Listeria monocytogenes CMCC 54001 by iTRAQ and Label free proteomics quantitative analysis.Proteomic changes of Lactobacillus plantarum WLPL05 and Escherichia coli O157:H7 after incubation.A total of 1328 proteins were identified by iTRAQ,which involved translation,ribosome structure and biogenesis.The transport and metabolism of carbohydrates and the transport and metabolism of amino acids were the most active proteins.Similarly,labelfree results showed that among the proteins identified after co-incubation with Escherichia coli O157:H7,237 proteins involved in intracellular protein translation,ribosomal structure and biogenic origin were highly active,and 176 proteins were involved in carbohydrate transport and metabolism and amino acid transport and metabolism.There were also 175 genes involved in energy production.Finally,fluorescence quantitative PCR was used to detect some genes related to differential proteins,and the results showed that Lux S,GPMA and FAZ83-04550 were the upregulated genes,and the expressions of ZAPB and FAZ83-19295 were down-regulated.As a regulatory gene related to quorum sensing in Escherichia coli,the up-regulation of lux S expression was correlated with the significant up-regulation of quorum sensing protein before and after incubation in proteomics.At the same time,co-incubation promoted the up-regulation of GpsB of Listeria monocytogenes CMCC54001,which not only affected the cell wall division of Listeria monocytogenes,but also may block the binding of antibiotics to PBP.In conclusion,lactic acid bacteria co-incubated with food-borne pathogens,which promoted the quorum sensing effect of food-borne pathogens,and further promoted the resistance of food-borne pathogens to ?-lactam antibiotics.This study first of foodborne pathogenic bacteria of lactic acid bacteria resistant mechanism,further assess the possible risk of lactic acid bacteria,lactic acid bacteria is helpful to the establishment of pathogenic bacteria of gene regulation networks model,the molecular mechanism of interaction between lactic acid bacteria and pathogenic bacteria,and a comprehensive understanding of various microbes in the gut function,To help people more comprehensive understanding of probiotics and foodborne pathogens. |
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