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Novel small molecule modulators of quorum sensing in avian pathogenic Escherichia coli (APEC).

ABSTRACT: Colibacillosis caused by avian pathogenic E. coli (APEC), is an economically important bacterial disease of poultry. APEC are a subgroup of extra intestinal pathogenic E. coli (ExPEC) and poultry are considered potential sources of foodborne ExPEC to humans. Currently, APEC infections in poultry are controlled by antibiotics and/or vaccination; however, their effect is limited due to emergence of antibiotic resistant strains and infections with heterologous serotypes. Therefore, novel approaches are needed. Here, using the bioluminescent quorum sensing (QS) autoinducer 2 (AI-2) indicator Vibrio harveyi BB170, we screened the cell free culture supernatant of APEC O78 prepared from cultures grown in the presence of 4,182 small molecules (SMs; 100 ?M). A total of 69 SMs inhibited > 75% of APEC O78 AI-2 activity in the indicator bacteria. Ten SMs that showed highest AI-2 inhibition were selected for further studies. Most of these SMs inhibited the AI-2 activity of other APEC serotypes and significantly reduced APEC O78 biofilm formation and motility. Most compounds showed minimal toxicity on human intestinal cells (Caco-2), chicken macrophage (HD-11), and chicken and sheep red blood cells, and reduced APEC survival in HD-11 and THP-1 macrophages. The SMs induced no or minimal toxicity and conferred protection against APEC in wax moth larval model. SMs affected the expression of APEC O78 QS, virulence, biofilm and motility associated genes providing insight on their potential mode(s) of action. Further testing in chickens will facilitate development of these SMs as novel therapeutics to control APEC in poultry and thereby also reduce zoonotic transmission.

SUBMITTER: Helmy YA

PROVIDER: S-EPMC7000209 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Novel small molecule modulators of quorum sensing in avian pathogenic Escherichia coli (APEC).

Helmy Yosra A YA Deblais Loic L Kassem Issmat I II Kathayat Dipak D Rajashekara Gireesh G

Virulence 20180101 1

Colibacillosis caused by avian pathogenic E. coli (APEC), is an economically important bacterial disease of poultry. APEC are a subgroup of extra intestinal pathogenic E. coli (ExPEC) and poultry are considered potential sources of foodborne ExPEC to humans. Currently, APEC infections in poultry are controlled by antibiotics and/or vaccination; however, their effect is limited due to emergence of antibiotic resistant strains and infections with heterologous serotypes. Therefore, novel approaches ...[more]

PMID: 30270715

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Project description:Many reports show an association between the Pst system, the Pho regulon related genes and bacterial virulence. Our previous results showed that a functional Pst system is required for full virulence, resistance to serum, polymyxin B and acid shock However, the interplay between the Pst system and virulence has an unknown molecular basis. To understand global APEC virulent strain responses to Pho regulon activation, we conducted transcriptome profiling experiments comparing the isogenic Pst mutant with its wild type strain chi7122 using the Affymetrix GeneChipÂ® E. coli Genome 2.0 Array. To understand the global responses to Pho regulon activation of APEC, we use the Affymetrix technology. We conducted transcriptome profiling experiments comparing the APEC chi7122 strain and its isogenic Pst mutant grown in rich phosphate medium using the Affymetrix GeneChipÂ® E. coli Genome 2.0 Array. The Affymetrix GeneChipÂ® E. coli Genome 2.0 Array contains the genome of the E. coli MG1655 and three pathogenic E. coli strain (EDL933, Sakai and CFT073) representing 20,366 genes. While comparing genes expression between Pst mutant and the wild type chi7122 strain, 471 genes are either up- (254) or down-regulated (217) of at least 1.5-fold, with a p-value inferior or equal to 0.05 and a false discovery rate of 2.71%. Experiment Overall Design: RNA extraction was performed onto the chi7122 and K3 strains on four biological replicates. An overnight culture grown at 37Â°C was diluted 100-fold into 5 ml of LB broth and was allowed to grow to mid-log phase (OD600 0,6). Cultures were centrifuged and RNAs were isolated by using the RiboPureâ¢-Bacteria Kit (Ambion, Austin, TX), according to the manufacturerâs recommendations, with the exception that the DNAse 1 treatment was performed twice. RNA extractions were performed on four different days (the chi7122 and K3 RNA were extracted at the same time) and a total of eight hybridizations were performed. Hybridization was carried out at McGill University & Genome Quebec Innovation Centre according to the Affymetrix recommendation (Affymetrix Expression Manual Section 3 701029 rev. 4). GeneChip scan was carried out at McGill University & Genome Quebec Innovation Centre according to the Affymetrix recommendation (Affymetrix Expression Manual Section 3 701029 rev. 4), and data were processed using the FlexArray software (Michal Blazejczyk, Mathieu Miron, Robert Nadon (2007). FlexArray: A statistical data analysis software for gene expression microarrays. Genome Quebec, Montreal, Canada). Raw data were normalized using the RMA algorithm and log2 were generated. The expression value was generated by subtracting the mean value of each replicate of the mutant strain by wild-type strain.

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Novel small molecule modulators of quorum sensing in avian pathogenic Escherichia coli (APEC).

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Novel small molecule modulators of quorum sensing in avian pathogenic Escherichia coli (APEC).

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