In vitro and in vivo evaluation of antimicrobials in Escherichia coli infection in broilers and evaluation of ciprofloxacin in induced colibacillosis

ABSTRACT Histidine biosynthesis is one of the most characterized metabolic routes for its antiquity and its central role in cellular metabolism; indeed, it represents a cross-road between nitrogen metabolism and de novo synthesis of purines. This interconnection is due to the activity of imidazole glycerol phosphate synthase, a heterodimeric enzyme constituted by the products of two his genes, hisH and hisF, encoding a glutamine amidotransferase and a cyclase, respectively. Despite their interaction was suggested by several in vitro experiments, their in vivo complex formation has not been demonstrated. On the contrary, the analysis of the entire Escherichia coli interactome performed using the yeast two hybrid system did not suggest the in vivo interaction of the two IGP synthase subunits. The aim of this study was to demonstrate the interaction of the two proteins using the Bacterial Adenylate Cyclase Two-Hybrid (BACTH) system. Data obtained demonstrated the in vivo interaction occurring between the proteins encoded by the E. coli hisH and hisF genes; this finding might also open the way to pharmaceutical applications through the design of selective drugs toward this enzyme.

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Ribonuclease 7 Shields the Kidney and Bladder from Invasive Uropathogenic Escherichia coli Infection

Journal of the American Society of Nephrology ◽

10.1681/asn.2018090929 ◽

2019 ◽

Vol 30 (8) ◽

pp. 1385-1397 ◽

Cited By ~ 5

Author(s):

Tad Eichler ◽

Kristin Bender ◽

Matthew J. Murtha ◽

Laura Schwartz ◽

Jackie Metheny ◽

...

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Transgenic Mice ◽

Urothelial Cells ◽

Bladder Urothelium ◽

Functional Studies ◽

Escherichia Coli Infection ◽

Study Participants

BackgroundEvidence suggests that antimicrobial peptides, components of the innate immune response, protect the kidneys and bladder from bacterial challenge. We previously identified ribonuclease 7 (RNase 7) as a human antimicrobial peptide that has bactericidal activity against uropathogenic Escherichia coli (UPEC). Functional studies assessing RNase 7’s contributions to urinary tract defense are limited.MethodsTo investigate RNase 7’s role in preventing urinary tract infection (UTI), we quantified urinary RNase 7 concentrations in 29 girls and adolescents with a UTI history and 29 healthy female human controls. To assess RNase 7’s antimicrobial activity in vitro in human urothelial cells, we used siRNA to silence urothelial RNase 7 production and retroviral constructs to stably overexpress RNase 7; we then evaluated UPEC’s ability to bind and invade these cells. For RNase 7 in vivo studies, we developed humanized RNase 7 transgenic mice, subjected them to experimental UTI, and enumerated UPEC burden in the urine, bladder, and kidneys.ResultsCompared with controls, study participants with a UTI history had 1.5-fold lower urinary RNase 7 concentrations. When RNase 7 was silenced in vitro, the percentage of UPEC binding or invading human urothelial cells increased; when cells overexpressed RNase 7, UPEC attachment and invasion decreased. In the transgenic mice, we detected RNase 7 expression in the kidney’s intercalated cells and bladder urothelium. RNase 7 humanized mice exhibited marked protection from UPEC.ConclusionsThese findings provide evidence that RNase 7 has a role in kidney and bladder host defense against UPEC and establish a foundation for investigating RNase 7 as a UTI prognostic marker or nonantibiotic-based therapy.

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In Vitro Susceptibility and In Vivo Efficacy of Antimicrobials in the Treatment of Bacteroides tragilis-Escherichia coli Infection in Mice

The Journal of Infectious Diseases ◽

10.1093/infdis/160.4.651 ◽

1989 ◽

Vol 160 (4) ◽

pp. 651-656 ◽

Cited By ~ 9

Author(s):

I. Brook

Keyword(s):

Escherichia Coli ◽

In Vitro Susceptibility ◽

In Vivo Efficacy ◽

Escherichia Coli Infection

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Validation of a Noninvasive, Real-Time Imaging Technology Using Bioluminescent Escherichia coli in the Neutropenic Mouse Thigh Model of Infection

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.45.1.129-137.2001 ◽

2001 ◽

Vol 45 (1) ◽

pp. 129-137 ◽

Cited By ~ 106

Author(s):

H. L. Rocchetta ◽

C. J. Boylan ◽

J. W. Foley ◽

P. W. Iversen ◽

D. L. LeTourneau ◽

...

Keyword(s):

Escherichia Coli ◽

Real Time ◽

Antimicrobial Agents ◽

Viable Cell ◽

Multicopy Plasmid ◽

In Vivo Evaluation ◽

Therapeutic Success ◽

Cell Counts

ABSTRACT A noninvasive, real-time detection technology was validated for qualitative and quantitative antimicrobial treatment applications. Thelux gene cluster of Photorhabdus luminescenswas introduced into an Escherichia coli clinical isolate, EC14, on a multicopy plasmid. This bioluminescent reporter bacterium was used to study antimicrobial effects in vitro and in vivo, using the neutropenic-mouse thigh model of infection. Bioluminescence was monitored and measured in vitro and in vivo with an intensified charge-coupled device (ICCD) camera system, and these results were compared to viable-cell determinations made using conventional plate counting methods. Statistical analysis demonstrated that in the presence or absence of antimicrobial agents (ceftazidime, tetracycline, or ciprofloxacin), a strong correlation existed between bioluminescence levels and viable cell counts in vitro and in vivo. Evaluation of antimicrobial agents in vivo could be reliably performed with either method, as each was a sound indicator of therapeutic success. Dose-dependent responses could also be detected in the neutropenic-mouse thigh model by using either bioluminescence or viable-cell counts as a marker. In addition, the ICCD technology was examined for the benefits of repeatedly monitoring the same animal during treatment studies. The ability to repeatedly measure the same animals reduced variability within the treatment experiments and allowed equal or greater confidence in determining treatment efficacy. This technology could reduce the number of animals used during such studies and has applications for the evaluation of test compounds during drug discovery.

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Maternal Milk Contains Antimicrobial Factors That Protect Young Rabbits from Enteropathogenic Escherichia coli Infection

Clinical and Vaccine Immunology ◽

10.1128/cvi.00468-06 ◽

2007 ◽

Vol 14 (5) ◽

pp. 585-592 ◽

Cited By ~ 24

Author(s):

Mélanie Gallois ◽

Thierry Gidenne ◽

Christian Tasca ◽

Cécile Caubet ◽

Cécile Coudert ◽

...

Keyword(s):

Escherichia Coli ◽

Protective Role ◽

Epec Strain ◽

Mammal Species ◽

Maternal Milk ◽

Escherichia Coli Infection ◽

In Vitro Antibacterial Activity

ABSTRACT Enteropathogenic Escherichia coli (EPEC) colibacillosis represents a major cause of lethal diarrhea in young children in developing countries. EPEC strains also infect numerous mammal species and represent a major economical problem in rabbit industry. Protection against this pathogen is a challenging goal both in humans and in other mammal species. Despite a good knowledge of the pathogenicity mechanisms of EPEC, the intrinsic and environmental factors that control the expression of EPEC virulence in mammals remain unknown. For instance, the exacerbated sensitivity of young mammals to EPEC infection is still unexplained. Our goal was to investigate if age or other factors, like milk consumption, could be determinants that trigger the disease. We used rabbits as an animal model to study the role of milk in the sensitivity to an EPEC infection. Weaned and suckling rabbits were orally inoculated with EPEC strain E22 (O103:H2:K−) at 28 days of age, and the evolution of the disease was investigated in the two groups. In addition, in order to better characterize the interactions between milk and EPEC, we determined in vitro bacterial growth and the abilities of EPEC cells to adhere to epithelial cells in the presence of milk. Our results demonstrate a protective role of milk in vivo in association with in vitro antibacterial activity. These effects are independent of the presence of specific anti-EPEC antibodies.

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Effect of Zinc in Enteropathogenic Escherichia coli Infection

Infection and Immunity ◽

10.1128/iai.00750-07 ◽

2007 ◽

Vol 75 (12) ◽

pp. 5974-5984 ◽

Cited By ~ 32

Author(s):

John K. Crane ◽

Tonniele M. Naeher ◽

Irina Shulgina ◽

Chengru Zhu ◽

Edgar C. Boedeker

Keyword(s):

Escherichia Coli ◽

Protein A ◽

Fluid Secretion ◽

Intestinal Cells ◽

Rabbit Ileum ◽

Beneficial Effects ◽

Escherichia Coli Infection ◽

Enterocyte Effacement

ABSTRACT Enteropathogenic Escherichia coli (EPEC) infection triggers the release of ATP from host intestinal cells, and the ATP is broken down to ADP, AMP, and adenosine in the lumen of the intestine. Ecto-5′-nucleotidase (CD73) is the main enzyme responsible for the conversion of 5′-AMP to adenosine, which triggers fluid secretion from host intestinal cells and also has growth-promoting effects on EPEC bacteria. In a recent study, we examined the role of the host enzyme CD73 in EPEC infection by testing the effect of ecto-5′-nucleotidase inhibitors. Zinc was a less potent inhibitor of ecto-5′-nucleotidase in vitro than the nucleotide analog α,β-methylene-ADP, but in vivo, zinc was much more efficacious in preventing EPEC-induced fluid secretion in rabbit ileal loops than α,β-methylene-ADP. This discrepancy between the in vitro and in vivo potencies of the two inhibitors prompted us to search for potential targets of zinc other than ecto-5′-nucleotidase. Zinc, at concentrations that produced little or no inhibition of EPEC growth, caused a decrease in the expression of EPEC protein virulence factors, such as bundle-forming pilus (BFP), EPEC secreted protein A, and other EPEC secreted proteins, and reduced EPEC adherence to cells in tissue culture. The effects of zinc were not mimicked by other transition metals, such as manganese, iron, copper, or nickel, and the effects were not reversed by an excess of iron. Quantitative real-time PCR showed that zinc reduced the abundance of the RNAs encoded by the bfp gene, by the plasmid-encoded regulator (per) gene, by the locus for the enterocyte effacement (LEE)-encoded regulator (ler) gene, and by several of the esp genes. In vivo, zinc reduced EPEC-induced fluid secretion into ligated rabbit ileal loops, decreased the adherence of EPEC to rabbit ileum, and reduced histopathological damage such as villus blunting. Some of the beneficial effects of zinc on EPEC infection appear to be due to the action of the metal on EPEC bacteria as well as on the host.

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