Bile Salts Induce Resistance to Polymyxin in Enterohemorrhagic Escherichia coliO157:H7

Kus, Julianne V.; Gebremedhin, Ahferom; Dang, Vica; Tran, Seav-Ly; Serbanescu, Anca; Foster, Debora Barnett

doi:10.1128/jb.00200-11

Cited by 63 publications

(107 citation statements)

References 77 publications

(82 reference statements)

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“…Other responses, which do not appear to be required for resistance to bile itself, were also observed. Among them, the upregulation of genes whose products are responsible for lipid A modification conferring bacterial resistance to several cationic antimicrobial peptides, suggesting that bile may be acting as an environmental signal which triggers outer membrane modifications for resistance to defensins, part of the innate immune system in the small intestine (Kus et al, 2011).…”

Section: Resultsmentioning

confidence: 99%

“…It has been proposed that bile serves as an environmental signal that triggers the expression of adaptive responses, including expression of colonization and virulence genes in enteric bacteria permitting successful transit through the intestine (Prouty and Gunn, 2000;Begley et al, 2005;Merritt and Donaldson, 2009;Kus et al, 2011).…”

Section: Proteomic Analysis Of Stec M03mentioning

confidence: 99%

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Proteins differentially expressed by Shiga toxin-producing Escherichia coli strain M03 due to the biliar salt sodium deoxycholate

Ribeiro

Sobral²,

Tanaka³

et al. 2013

Genet. Mol. Res.

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ABSTRACT. Shiga toxin-producing Escherichia coli (STEC) can cause conditions ranging from diarrhea to potentially fatal hemolytic uremic syndrome. Enteropathogen adaptation to the intestinal environment is necessary for the development of infection, and response to bile is an essential characteristic. We evaluated the response of STEC strain M03 to the bile salt sodium deoxycholate through proteomic analysis. Cell extracts of strain M03 grown with and without sodium deoxycholate were analyzed by two-dimensional electrophoresis; the differentially expressed proteins were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Three proteins were found to be differentially expressed due to sodium deoxycholate. Glycerol dehydrogenase and phosphate acetyltransferase, which are involved in carbon metabolism and have been associated with virulence in some bacteria, were downregulated. The elongation factor Tu (TufA) was upregulated. This protein participates in the translation process and also has chaperone activities. These findings help us understand strategies for bacterial survival under these conditions.

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Section: Resultsmentioning

confidence: 99%

Section: Proteomic Analysis Of Stec M03mentioning

confidence: 99%

Proteins differentially expressed by Shiga toxin-producing Escherichia coli strain M03 due to the biliar salt sodium deoxycholate

Ribeiro

Sobral²,

Tanaka³

et al. 2013

Genet. Mol. Res.

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show abstract

“…The increased expression of the AcrAB efflux pump in the presence of bile salts not only would enable Shigella to resist the bactericidal effects of bile but could also potentially "prime" the bacteria for an antibiotic resistance phenotype. In fact, a recent study evaluating the bile salt effects on enterohemorrhagic E. coli (EHEC) found that increased expression of acrAB transcripts, as well as increased expression of lipopolysaccharide genes, conferred resistance to the antibiotic polymyxin (30). Furthermore, overexpression of AcrB has been linked to MDR resistance in S. Typhimurium (36,37).…”

Section: Figmentioning

confidence: 99%

“…efflux pumps (11,(27)(28)(29)(30)(31)(32)(33)(34). Efflux pumps are utilized by bacteria to expel antibiotics and other harmful substances from the bacterial cytosol.…”

Section: Figmentioning

confidence: 99%

Analysis of Shigella flexneri Resistance, Biofilm Formation, and Transcriptional Profile in Response to Bile Salts

et al. 2017

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The Shigella species cause millions of cases of watery or bloody diarrhea each year, mostly in children in developing countries. While many aspects of Shigella colonic cell invasion are known, crucial gaps in knowledge regarding how the bacteria survive, transit, and regulate gene expression prior to infection remain. In this study, we define mechanisms of resistance to bile salts and build on previous research highlighting induced virulence in Shigella flexneri strain 2457T following exposure to bile salts. Typical growth patterns were observed within the physiological range of bile salts; however, growth was inhibited at higher concentrations. Interestingly, extended periods of exposure to bile salts led to biofilm formation, a conserved phenotype that we observed among members of the Enterobacteriaceae. Characterization of S. flexneri 2457T biofilms determined that both bile salts and glucose were required for formation, dispersion was dependent upon bile salts depletion, and recovered bacteria displayed induced adherence to HT-29 cells. RNAsequencing analysis verified an important bile salt transcriptional profile in S. flexneri 2457T, including induced drug resistance and virulence gene expression. Finally, functional mutagenesis identified the importance of the AcrAB efflux pump and lipopolysaccharide O-antigen synthesis for bile salt resistance. Our data demonstrate that S. flexneri 2457T employs multiple mechanisms to survive exposure to bile salts, which may have important implications for multidrug resistance. Furthermore, our work confirms that bile salts are important physiological signals to activate S. flexneri 2457T virulence. This work provides insights into how exposure to bile likely regulates Shigella survival and virulence during host transit and subsequent colonic infection.

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“…These signals include factors that facilitate gastrointestinal adherence of the bacteria to the small intestinal or colonic epithelial cells (17,19). Studies investigating bile responses in E. coli include both commensals and diarrheagenic pathovars, including enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), and enterohemorrhagic E. coli (EHEC) (20)(21)(22)(23)(24)(25)(26)(27)(28). …”

Section: Escherichia Colimentioning

confidence: 99%

Survival of the Fittest: How Bacterial Pathogens Utilize Bile To Enhance Infection

et al. 2016

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SUMMARYBacterial pathogens have coevolved with humans in order to efficiently infect, replicate within, and be transmitted to new hosts to ensure survival and a continual infection cycle. For enteric pathogens, the ability to adapt to numerous host factors under the harsh conditions of the gastrointestinal tract is critical for establishing infection. One such host factor readily encountered by enteric bacteria is bile, an innately antimicrobial detergent-like compound essential for digestion and nutrient absorption. Not only have enteric pathogens evolved to resist the bactericidal conditions of bile, but these bacteria also utilize bile as a signal to enhance virulence regulation for efficient infection. This review provides a comprehensive and up-to-date analysis of bile-related research with enteric pathogens. From common responses to the unique expression of specific virulence factors, each pathogen has overcome significant challenges to establish infection in the gastrointestinal tract. Utilization of bile as a signal to modulate virulence factor expression has led to important insights for our understanding of virulence mechanisms for many pathogens. Further research on enteric pathogens exposed to thisin vivosignal will benefit therapeutic and vaccine development and ultimately enhance our success at combating such elite pathogens.

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Bile Salts Induce Resistance to Polymyxin in Enterohemorrhagic Escherichia coliO157:H7

Cited by 63 publications

References 77 publications

Proteins differentially expressed by Shiga toxin-producing Escherichia coli strain M03 due to the biliar salt sodium deoxycholate

Proteins differentially expressed by Shiga toxin-producing Escherichia coli strain M03 due to the biliar salt sodium deoxycholate

Analysis of Shigella flexneri Resistance, Biofilm Formation, and Transcriptional Profile in Response to Bile Salts

Survival of the Fittest: How Bacterial Pathogens Utilize Bile To Enhance Infection

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