scholarly journals Ag/ZnO Nanoparticles as Novel Antibacterial Agent Against of Escherichia coli infection, In vitro & In vivo

2015 ◽  
Vol 31 (3) ◽  
pp. 1437-1445 ◽  
Author(s):  
Masoomeh Khoshkbejari ◽  
Alireza Jafari ◽  
Mojhdeh Safari
Keyword(s):  
Escherichia Coli ◽  
Zno Nanoparticles ◽  
Antibacterial Agent ◽  
Escherichia Coli Infection

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

2019 ◽  
Vol 30 (8) ◽  
pp. 1385-1397 ◽  
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.

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

2007 ◽  
Vol 14 (5) ◽  
pp. 585-592 ◽  
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.

scholarly journals Effect of Zinc in Enteropathogenic Escherichia coli Infection

2007 ◽  
Vol 75 (12) ◽  
pp. 5974-5984 ◽  
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.

Безопасность соединений из группы терпенов ментанового ряда in vitro и in vivo

2020 ◽  
Vol 83 (4) ◽  
pp. 24-30
Author(s):  
Ирина Владимировна Акулина ◽  
Светлана Ивановна Павлова ◽  
Ирина Семеновна Степаненко ◽  
Назира Сунагатовна Карамова ◽  
Александр Владиславович Сергеев ◽  
...  
Keyword(s):  
Escherichia Coli

Проведено токсикологическое исследование соединений с антибактериальными свойствами из группы терпенов ментанового ряда в условиях in vitro и in vivo: лимонена (B34), его производного (+)-1,2-оксида лимонена (B60) и серосодержащего монотерпенового соединения 2-(1’-гидрокси-4’-изопренил-1’-метилциклогексил-2’-тио)метилэтаноата (B65). В условиях in vitro (культура опухолевых клеток HeLa) изучаемые монотерпены в диапазоне концентраций 2 – 200 мкг/мл обладали цитотоксичностью. Ингибирующая концентрация (ИК50) для B34 составила 231 (167 – 295) мкг/мл, для B60 – 181 (105 – 257) мкг/мл, ИК50 B65 – 229 (150 – 308) мкг/мл. Исследование генотоксичности показало, что B34 и B65 в диапазоне концентраций 50 – 1000 мкг/мл не индуцируют SOS мутагенез в клетках Escherichia coli PQ37, тогда как B60 в концентрациях 500 и 1000 мкг/мл проявляет генотоксичность. In vivo в остром эксперименте на беспородных мышах установлена низкая токсичность B34 и его производных при различных путях введения. Наименьший показатель острой токсичности имеет B65, в связи с чем дополнительно на крысах проведено изучение его хронической токсичности. Ежедневное внутрижелудочное введение B65 в разовых дозах, составляющих 1/10 и 1/20 ЛД50 (1000 мг/кг и 500 мг/кг), в течение 1 мес не вызывало гибели животных, значимых нарушений общего состояния, изменения динамики массы тела, морфопатологических изменений. Внутрижелудочное введение B65 крысам в высокой токсической дозе 2000 мг/кг (1/5 ЛД50) в течение месяца вызывает патоморфологические изменения структуры печени.

scholarly journals Antagonism of Ultraviolet-Light Mutagenesis by the Methyl-Directed Mismatch-Repair System of Escherichia coli

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 503-512 ◽  
Author(s):  
Hongbo Liu ◽  
Stephen R Hewitt ◽  
John B Hays
Keyword(s):  
Escherichia Coli ◽  
Mismatch Repair ◽  
Excision Repair ◽  
Spontaneous Mutation ◽  
Repair System ◽  
Uv Mutagenesis ◽  
Repair Protein ◽  
Mismatch Repair System

Abstract Previous studies have demonstrated that the Escherichia coli MutHLS mismatch-repair system can process UV-irradiated DNA in vivo and that the human MSH2·MSH6 mismatch-repair protein binds more strongly in vitro to photoproduct/base mismatches than to “matched” photoproducts in DNA. We tested the hypothesis that mismatch repair directed against incorrect bases opposite photoproducts might reduce UV mutagenesis, using two alleles at E. coli lacZ codon 461, which revert, respectively, via CCC → CTC and CTT → CTC transitions. F′ lacZ targets were mated from mut+ donors into mutH, mutL, or mutS recipients, once cells were at substantial densities, to minimize spontaneous mutation prior to irradiation. In umu+ mut+ recipients, a range of UV fluences induced lac+ revertant frequencies of 4–25 × 10−8; these frequencies were consistently 2-fold higher in mutH, mutL, or mutS recipients. Since this effect on mutation frequency was unaltered by an Mfd− defect, it appears not to involve transcription-coupled excision repair. In mut+ umuC122::Tn5 bacteria, UV mutagenesis (at 60 J/m2) was very low, but mutH or mutL or mutS mutations increased reversion of both lacZ alleles roughly 25-fold, to 5–10 × 10−8. Thus, at UV doses too low to induce SOS functions, such as Umu2′D, most incorrect bases opposite occasional photoproducts may be removed by mismatch repair, whereas in heavily irradiated (SOS-induced) cells, mismatch repair may only correct some photoproduct/base mismatches, so UV mutagenesis remains substantial.

Exploring Galleria mellonella larval model to evaluate antibacterial efficacy of Cecropin A (1-7)- Melittin against multi-drug resistant enteroaggregative Escherichia coli

2021 ◽  
Author(s):  
Jess Vergis ◽  
S V S Malik ◽  
Richa Pathak ◽  
Manesh Kumar ◽  
Nitin V Kurkure ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Galleria Mellonella ◽  
In Vivo Model ◽  
Drug Resistant ◽  
Physiological Concentration ◽  
Microbial Drug Resistance ◽  
Cecropin A ◽  
Screening And Identification

Abstract High throughput in vivo laboratory models is need for screening and identification of effective therapeutic agents to overcome microbial drug-resistance. This study was undertaken to evaluate in vivo antimicrobial efficacy of short-chain antimicrobial peptide- Cecropin A (1–7)-Melittin (CAMA) against three multi- drug resistant enteroaggregative Escherichia coli (MDR-EAEC) field isolates in a Galleria mellonella larval model. The minimum inhibitory concentration (MIC; 2.0 mg/L) and minimum bactericidal concentration (MBC; 4.0 mg/L) of CAMA were determined by microdilution assay. CAMA was found to be stable at high temperatures, physiological concentration of cationic salts and proteases; safe with sheep erythrocytes, secondary cell lines and commensal lactobacilli at lower MICs; and exhibited membrane permeabilisation. In vitro time-kill assay revealed concentration- and time-dependent clearance of MDR-EAEC in CAMA-treated groups at 30 min. CAMA- treated G. mellonella larvae exhibited an increased survival rate, reduced MDR-EAEC counts, immunomodulatory effect and proved non-toxic which concurred with histopathological findings. CAMA exhibited either an equal or better efficacy than the tested antibiotic control, meropenem. This study highlights the possibility of G. mellonella larvae as an excellent in vivo model for investigating the host-pathogen interaction, including the efficacy of antimicrobials against MDR-EAEC strains.

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