Protective effects of indigenous Escherichia coli against a pathogenic E. coli challenge strain in pigs

2017 ◽  
Vol 8 (5) ◽  
pp. 779-783 ◽  
Author(s):  
W. Vahjen ◽  
T. Cuisiniere ◽  
J. Zentek
Keyword(s):  
Escherichia Coli ◽  
Inhibitory Activity ◽  
Inhibitory Effect ◽  
Coli Strain ◽  
Protective Effects ◽  
Macconkey Agar ◽  
Challenge Strain ◽  
E Coli ◽  
Pathogenic Factors

To investigate the inhibitory effect of indigenous enterobacteria on pathogenic Escherichia coli, a challenge trial with postweaning pigs was conducted. A pathogenic E. coli strain was administered to all animals and their health was closely monitored thereafter. Faecal samples were taken from three healthy and three diarrhoeic animals. Samples were cultivated on MacConkey agar and isolates were subcultured. A soft agar overlay assay was used to determine the inhibitory activity of the isolates. A total of 1,173 enterobacterial isolates were screened for their ability to inhibit the E. coli challenge strain. Colony forming units of enterobacteria on MacConkey agar were not different between healthy and diarrhoeic animals in the original samples. Furthermore, numbers of isolates per animal were also not significantly different between healthy (482 isolates) and diarrhoeic animals (691 isolates). A total of 43 isolates (3.7%) with inhibitory activity against the pathogenic E. coli challenge strain were detected. All inhibitory isolates were identified as E. coli via MALDI-TOF. The isolates belonged to the phylotypes A, C and E. Many isolates (67.4%) were commensal E. coli without relevant porcine pathogenic factors, but toxin- and fimbrial genes (stx2e, fae, estIb, elt1a, fas, fan) were detected in 14 inhibitory isolates. Healthy animals showed significantly (P=0.003) more inhibitory isolates (36 of 482 isolates; 7.5%) than diseased animals (7 of 691 isolates; 1.0%). There were no significant correlations regarding phylotype or pathogenic factors between healthy and diseased animals. This study has shown that a small proportion of indigenous E. coli is able to inhibit in vitro growth of a pathogenic E. coli strain in pigs. Furthermore, healthy animals possess significantly more inhibitory E. coli strains than diarrhoeic animals. The inhibition of pathogenic E. coli by specific indigenous E. coli strains may be an underlying principle for the containment of pathogenic E. coli in pigs.

Lactobacillus inhibitor production against Escherichia coli and coaggregation ability with uropathogens

1988 ◽  
Vol 34 (3) ◽  
pp. 344-351 ◽  
Author(s):  
Gregor Reid ◽  
Jacqueline A. McGroarty ◽  
Rosanne Angotti ◽  
Roger L. Cook
Keyword(s):  
Escherichia Coli ◽  
Defense Mechanism ◽  
Inhibitory Effect ◽  
Second Phase ◽  
Vitro Assay ◽  
E Coli ◽  
Host Defense Mechanism ◽  
Important Host ◽  
Two Phases

Previous investigations have shown that certain strains of lactobacilli can competitively exclude uropathogens from attaching to uroepithelial cells and from causing urinary tract infection in animals. The finding of an inhibitory effect produced by Lactobacillus casei ssp. rhamnosus GR-1 against the growth of uropathogens was investigated further using two Escherichia coli indicator strains Hu 734 and ATCC 25922. There were two phases to the inhibitor studies. The first one using an agar sandwich technique showed that the inhibitor activity was heat stable and inhibitory to the E. coli. The second phase showed that MRS broth provided optimum lactobacilli growth and inhibitor production. In addition, the inhibition was present under conditions buffering for acid and pH. The data indicated that the inhibitory effect was not due to bacteriophages or hydrogen peroxide. Strain GR-1 was found to coaggregate with E. coli ATCC 25922 in urine, a phenomenon that has not previously been reported for urogenital bacteria. An in vitro assay system was developed to study the coaggregation of various lactobacilli and uropathogens. The results demonstrated that highest coaggregation scores occurred after 4 h incubation at 37 °C with lactobacilli and two type-1 fimbriated E. coli strains. Of the nine lactobacilli strains tested, each was found to coaggregate with 2 or more of the 13 uropathogens. The dominance of inhibitor-producing lactobacilli on the urogenital epithelium and the ability of these organisms to interact closely with uropathogens would constitute an important host defense mechanism against infection.

scholarly journals Role of F1C Fimbriae, Flagella, and Secreted Bacterial Components in the Inhibitory Effect of Probiotic Escherichia coli Nissle 1917 on Atypical Enteropathogenic E. coli Infection

2014 ◽  
Vol 82 (5) ◽  
pp. 1801-1812 ◽  
Author(s):  
Sylvia Kleta ◽  
Marcel Nordhoff ◽  
Karsten Tedin ◽  
Lothar H. Wieler ◽  
Rafal Kolenda ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Molecular Mechanisms ◽  
Inhibitory Effect ◽  
Host Cells ◽  
Single Infection ◽  
Content Type ◽  
E Coli ◽  
Initial Adhesion

ABSTRACTEnteropathogenicEscherichia coli(EPEC) is recognized as an important intestinal pathogen that frequently causes acute and persistent diarrhea in humans and animals. The use of probiotic bacteria to prevent diarrhea is gaining increasing interest. The probioticE. colistrain Nissle 1917 (EcN) is known to be effective in the treatment of several gastrointestinal disorders. While bothin vitroandin vivostudies have described strong inhibitory effects of EcN on enteropathogenic bacteria, including pathogenicE. coli, the underlying molecular mechanisms remain largely unknown. In this study, we examined the inhibitory effect of EcN on infections of porcine intestinal epithelial cells with atypical enteropathogenicE. coli(aEPEC) with respect to single infection steps, including adhesion, microcolony formation, and the attaching and effacing phenotype. We show that EcN drastically reduced the infection efficiencies of aEPEC by inhibiting bacterial adhesion and growth of microcolonies, but not the attaching and effacing of adherent bacteria. The inhibitory effect correlated with EcN adhesion capacities and was predominantly mediated by F1C fimbriae, but also by H1 flagella, which served as bridges between EcN cells. Furthermore, EcN seemed to interfere with the initial adhesion of aEPEC to host cells by secretion of inhibitory components. These components do not appear to be specific to EcN, but we propose that the strong adhesion capacities enable EcN to secrete sufficient local concentrations of the inhibitory factors. The results of this study are consistent with a mode of action whereby EcN inhibits secretion of virulence-associated proteins of EPEC, but not their expression.

scholarly journals Novel Plasmid-Mediated 16S rRNA m1A1408 Methyltransferase, NpmA, Found in a Clinically Isolated Escherichia coli Strain Resistant to Structurally Diverse Aminoglycosides

2007 ◽  
Vol 51 (12) ◽  
pp. 4401-4409 ◽  
Author(s):  
Jun-ichi Wachino ◽  
Keigo Shibayama ◽  
Hiroshi Kurokawa ◽  
Kouji Kimura ◽  
Kunikazu Yamane ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
16S Rrna ◽  
Recombinant Plasmid ◽  
Coli Strain ◽  
Methyltransferase Activity ◽  
Ribosomal Subunits ◽  
E Coli ◽  
Rrna Molecule ◽  
A Site

ABSTRACT We have isolated a multiple-aminoglycoside-resistant Escherichia coli strain, strain ARS3, and have been the first to identify a novel plasmid-mediated 16S rRNA methyltransferase, NpmA. This new enzyme shared a relatively low level of identity (30%) to the chromosomally encoded 16S rRNA methyltransferase (KamA) of Streptomyces tenjimariensis, an actinomycete aminoglycoside producer. The introduction of a recombinant plasmid carrying npmA could confer on E. coli consistent resistance to both 4,6-disubstituted 2-deoxystreptamines, such as amikacin and gentamicin, and 4,5-disubstituted 2-deoxystreptamines, including neomycin and ribostamycin. The histidine-tagged NpmA elucidated methyltransferase activity against 30S ribosomal subunits but not against 50S subunits and the naked 16S rRNA molecule in vitro. We further confirmed that NpmA is an adenine N-1 methyltransferase specific for the A1408 position at the A site of 16S rRNA. Drug footprinting data indicated that binding of aminoglycosides to the target site was apparently interrupted by methylation at the A1408 position. These observations demonstrate that NpmA is a novel plasmid-mediated 16S rRNA methyltransferase that provides a panaminoglycoside-resistant nature through interference with the binding of aminoglycosides toward the A site of 16S rRNA through N-1 methylation at position A1408.

scholarly journals Uji Daya Hambat Ekstrak Daun Sawo terhadap Bakteri Escherichia coli secara In Vitro

2017 ◽  
Vol 6 (2) ◽  
pp. 289
Author(s):  
Nastasha Mufti ◽  
Elizabeth Bahar ◽  
Dessy Arisanti
Keyword(s):  
Escherichia Coli ◽  
Coli Strain ◽  
Manilkara Zapota ◽  
E Coli

Daun sawo merupakan bagian dari tanaman sawo (Manilkara zapota) yang sering digunakan masyarakat sebagai obat antidiare. Daun sawo mengandung senyawa saponin, tanin, dan flavonoid yang dapat bersifat sebagai antibakteri sehingga diduga mampu menghambat pertumbuhan bakteri penyebab diare. Tujuan penelitian ini adalah menentukan daya hambat ekstrak daun sawo terhadap bakteri Escherichia coli (E. coli) strain patogen secara in-vitro. Jenis penelitian adalah eksperimental laboratorium menggunakan 6 bakteri uji E. coli berbeda dengan 2 kali pengulangan menggunakan metode difusi. Penelitian dilakukan di Laboratorium Kimia Organik FMIPA dan Laboratorium Mikrobiologi FK UNAND pada bulan Agustus 2016 sampai April 2017. Sampel yang digunakan adalah daun sawo yang telah dilakukan proses ekstraksi maserasi menggunakan etanol. Hasil penelitian menunjukkan ekstrak daun sawo dengan konsentrasi 15%, 30%, 45%, 60%, dan 100% memiliki daya hambat yang berbeda-beda terhadap bakteri uji E. coli. Konsentrasi ekstrak daun sawo yang paling efektif yaitu konsentrasi 100%. Dari penelitian ini disimpulkan bahwa ekstrak daun sawo mempunyai sifat antibakteri terhadap bakteri uji Escherichia coli strain patogen.

In Vitro Inactivation of Escherichia coli O157:H7 in Bovine Rumen Fluid by Caprylic Acid

2004 ◽  
Vol 67 (5) ◽  
pp. 884-888 ◽  
Author(s):  
THIRUNAVUKKARASU ANNAMALAI ◽  
MANOJ KUMAR MOHAN NAIR ◽  
PATRICK MAREK ◽  
PRADEEP VASUDEVAN ◽  
DAVID SCHREIBER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Caprylic Acid ◽  
Rumen Fluid ◽  
Bacterial Load ◽  
Anaerobic Bacteria ◽  
Inhibitory Effect ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Bovine Rumen

The antibacterial effect of caprylic acid (35 and 50 mM) on Escherichia coli O157:H7 and total anaerobic bacteria at 39° C in rumen fluid (pH 5.6 and 6.8) from 12 beef cattle was investigated. The treatments containing caprylic acid at both pHs significantly reduced (P < 0.05) the population of E. coli O157:H7 compared with that in the control samples. At pH 5.6, both levels of caprylic acid killed E. coli O157:H7 rapidly, reducing the pathogen population to undetectable levels at 1 min of incubation (a more than 6.0-log CFU/ml reduction). In buffered rumen fluid at pH 6.8, 50 mM caprylic acid reduced the E. coli O157:H7 population to undetectable levels at 1 min of incubation, whereas 35 mM caprylic acid reduced the pathogen by approximately 3.0 and 5.0 log CFU/ml at 8 and 24 h of incubation, respectively. At both pHs, caprylic acid had a significantly lesser (P < 0.05) and minimal inhibitory effect on the population of total anaerobic bacteria in rumen compared with that on E. coli O157:H7. At 24 h of incubation, caprylic acid (35 and 50 mM) reduced the population of total anaerobic bacteria by approximately 2.0 log CFU/ml at pH 5.6, whereas at pH 6.8, caprylic acid (35 mM) did not have any significant (P > 0.05) inhibitory effect on total bacterial load. Results of this study revealed that caprylic acid was effective in inactivating E. coli O157:H7 in bovine rumen fluid, thereby justifying its potential as a preslaughter dietary supplement for reducing pathogen carriage in cattle.

scholarly journals 611. Fosfomycin Resistance of Multidrug-Resistant Escherichia coli and Mechanisms of Fosfomycin Resistance

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S285-S285
Author(s):  
Hyeri Seok ◽  
Ji Hoon Jeon ◽  
Hee Kyoung Choi ◽  
Won Suk Choi ◽  
Dae Won Park ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Resistance Rate ◽  
Coli Strain ◽  
Resistant Bacteria ◽  
E Coli ◽  
Broth Microdilution Method ◽  
Fosfomycin Resistance

Abstract Background Fosfomycin is one of the antibiotics that may be a candidate for the next-generation antimicrobial agents againt multidrug-resistant bacteria. To date, it is known that the resistance rate is not high for Escherichia coli. However, it is necessary to update the fosfomycin resistance rates in E. coli according to the studies that extended spectrum β-lactamase (ESBL) producing E. coli strains are highly resistance to fosfomycin. We evaluated the resistance rate of fosfomycin, the resistant mechanism of fosfomycin in E. coli, and the activity of fosfomycin against susceptible and resistant strains of E. coli. Methods A total of 283 clinical isolates was collected from patients with Escherichia coli species during the period of January 2018 to June 2018, in three tertiary hospitals of Republic of Korea. In vitro antimicrobial susceptibility tests were performed in all E. coli isolates using the broth microdilution method according to the Clinical and Laboratory Standard Institute (CLSI). Multilocus sequence typing (MLST) of the Oxford scheme was conducted to determine the genotypes of E. coli isolated. Fosfomycin genes were investigated for all fosfomycin-resistant E. coli strains. Results The overall resistance rate to fosfomycin was 10.2%, compared with 53.4%, 46.3%, 41.3%, 31.1%, 10.6%, 2.5%, and 2.1% for ciprofloxacin, cefixime, cefepime, piperacillin/tazobactam, colistin, ertapenem, and amikacin, respectively. The 29 fosfomycin-resistant isolates did not show a clonal pattern on the phylogenetic tree. MurA and glp genes were identified in all strains. FosA3 were identified in two strains and uhp gene were identified in 4 strains. In time-kill curve studies, fosfomycin was more bactericidal than cefixime against all sensitive E. coli strain. Morever, fosfomycin was more bactericidal than piperacillin/tazobactam against ESBL-producing E. coli strain. Conclusion The resistant rate of fosfomycin to E. coli is still low. Fosfomycin was active against E. coli including ESBL producing strains. Disclosures All authors: No reported disclosures.

scholarly journals Virulence Potential of a Multidrug-Resistant Escherichia coli Strain Belonging to the Emerging Clonal Group ST101-B1 Isolated from Bloodstream Infection

2020 ◽  
Vol 8 (6) ◽  
pp. 827 ◽  
Author(s):  
Ana Carolina M. Santos ◽  
Rosa M. Silva ◽  
Tiago B. Valiatti ◽  
Fernanda F. Santos ◽  
José F. Santos-Neto ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Bloodstream Infection ◽  
Galleria Mellonella ◽  
Multidrug Resistant ◽  
Coli Strain ◽  
Pathogenic Potential ◽  
E Coli ◽  
Antimicrobial Resistance Genes

Escherichia coli EC121 is a multidrug-resistant (MDR) strain isolated from a bloodstream infection of an inpatient with persistent gastroenteritis and T-zone lymphoma that died due to septic shock. Despite causing an extraintestinal infection, previous studies showed that it did not have the usual characteristics of an extraintestinal pathogenic E. coli. Instead, it belonged to phylogenetic group B1 and harbored few known virulence genes. To evaluate the pathogenic potential of strain EC121, an extensive genome sequencing and in vitro characterization of various pathogenicity-associated properties were performed. The genomic analysis showed that strain EC121 harbors more than 50 complete virulence genetic clusters. It also displays the capacity to adhere to a variety of epithelial cell lineages and invade T24 bladder cells, as well as the ability to form biofilms on abiotic surfaces, and survive the bactericidal serum complement activity. Additionally, EC121 was shown to be virulent in the Galleria mellonella model. Furthermore, EC121 is an MDR strain harboring 14 antimicrobial resistance genes, including blaCTX-M-2. Completing the scenario, it belongs to serotype O154:H25 and to sequence type 101-B1, which has been epidemiologically linked to extraintestinal infections as well as to antimicrobial resistance spread. This study with E. coli strain EC121 shows that clinical isolates considered opportunistic might be true pathogens that go underestimated.

Enhanced Inhibition of Escherichia coli O157:H7 by Lysozyme and Chelators

2003 ◽  
Vol 66 (10) ◽  
pp. 1783-1789 ◽  
Author(s):  
J. S. BOLAND ◽  
P. M. DAVIDSON ◽  
J. WEISS
Keyword(s):  
Escherichia Coli ◽  
Inhibitory Activity ◽  
Chelating Agents ◽  
Inhibitory Effect ◽  
Escherichia Coli O157 ◽  
Inhibitory Effects ◽  
Antimicrobial Spectrum ◽  
E Coli ◽  
Dilution Assay ◽  
Microbroth Dilution

This study examined the effects of three chelating agents (EDTA, disodium pyrophosphate [DSPP], and pentasodium tripolyphosphate [PSTPP]) on the inhibition of the growth of Escherichia coli O157:H7 by lysozyme. The objective of this study was to identify replacement chelators that exhibit synergistic properties similar to those of EDTA. The inhibitory effects of EDTA at 300 to 1,500 μg/ml and of DSPP and PSTPP at 3,000 to 15,000 μg/ml in combination with lysozyme at 200 to 600 μg/ml for up to 48 h at pHs of 6.0, 7.0, and 8.0 on four strains of E. coli O157:H7 was studied with the use of a microbroth dilution assay. The addition of EDTA enhanced lysozyme's inhibitory effect on strains of E. coli O157:H7. EDTA at ≥300 μg/ml combined with lysozyme at 200 to 600 μg/ml was sufficient to inhibit the growth of the strains at pHs of 6.0 and 8.0. At pH 7.0, lysozyme at 200 to 600 μg/ml and EDTA concentrations of ≥1,000 μg/ml were effective in inhibiting three of the four strains. DSPP at pH 6.0 was inhibitory at ≥10,000 μg/ml when combined with lysozyme at 200 to 300 μg/ml. In contrast, PSTPP increased the inhibitory activity of lysozyme more effectively at pH 8.0. Lysozyme at 200 to 600 μg/ml was effective against two strains of E. coli O157:H7 when used in conjunction with PSTPP at ≥5,000 μg/ml. The remaining strains were inhibited by PSTPP at ≥10,000 μg/ml. Our results indicate that inhibition occurred with each lysozyme-chelator combination, but the concentrations of phosphates required to increase the antimicrobial spectrum of lysozyme against E. coli O157:H7 were higher than the EDTA concentrations required to achieve the same effect.

scholarly journals Human Neutrophil Chemotaxis Is Modulated by Capsule and O Antigen from an Extraintestinal Pathogenic Escherichia coli Strain

2003 ◽  
Vol 71 (11) ◽  
pp. 6435-6445 ◽  
Author(s):  
Thomas A. Russo ◽  
Bruce A. Davidson ◽  
Diana M. Topolnycky ◽  
Ruth Olson ◽  
Stacy A. Morrill ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ex Vivo ◽  
Specific Antigen ◽  
Lavage Fluid ◽  
Coli Strain ◽  
Neutrophil Chemotaxis ◽  
Gram Negative ◽  
E Coli ◽  
O Antigen

ABSTRACT Gram-negative enteric bacilli, such as Escherichia coli, are common causes of nosocomial pneumonia. The interaction between pulmonary neutrophils and the infecting pathogen is a critical step in determining the outcome. Previous studies from our laboratory, for which a rat model of pneumonia was used, established that pulmonary neutrophil recruitment was modulated by the E. coli virulence factors capsule and O-specific antigen. To begin to understand the mechanism by which this recruitment occurs, we conducted in vitro and ex vivo chemotaxis assays, for which we used a clinically relevant E. coli isolate (CP9) and isogenic derivatives that were deficient in only the O antigen (CP921) or capsule (CP9.137) as chemoattractants with or without the high-affinity N-formylmethionyl-leucyl-phenylalanine receptor antagonist N-tert-butoxycarbonyl-methionine-leucine-phenylalanine (N-t-BOC). Given that only live E. coli was used for the initial in vitro chemotaxis assays, it was predicted that only N-t-BOC-sensitive chemotaxis would occur. However, both N-t-BOC-sensitive and -insensitive chemotaxis was observed. N-t-BOC-insensitive chemotaxis was mediated in part by interleukin 8, which was produced by neutrophils that had migrated toward E. coli. N-t-BOC-insensitive chemotaxis was only observed when live E. coli bacteria, not cell-free E. coli culture supernatants, were used as chemoattractants, suggesting that a direct E. coli-neutrophil interaction was necessary. The presence of both capsule and O antigen diminished total, N-t-BOC-sensitive, and N-t-BOC-insensitive neutrophil chemotaxis in vitro. The presence of capsule significantly decreased total, N-t-BOC-sensitive, and N-t-BOC-insensitive neutrophil chemotaxis ex vivo when cell-free bronchoalveolar lavage fluid from infected rats was used as the source of chemotactic factors. These effects of E. coli capsule and O antigen on neutrophil chemotaxis are novel, and they expand our understanding of the mechanisms by which these virulence traits contribute to the pathogenesis of gram-negative pneumonia and other extraintestinal infections.

Inhibitory effect of Zanthoxylum bungeanum essential oil (ZBEO) on Escherichia coli and intestinal dysfunction

2017 ◽  
Vol 8 (4) ◽  
pp. 1569-1576 ◽  
Author(s):  
Lei Hong ◽  
Wu Jing ◽  
Wang Qing ◽  
Su Anxiang ◽  
Xue Mei ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Essential Oil ◽  
Inhibitory Effect ◽  
Intestinal Health ◽  
Inhibitory Effects ◽  
E Coli ◽  
Zanthoxylum Bungeanum

The inhibitory effects of Zanthoxylum bungeanum essential oil (ZBEO) on Escherichia coli (E. coli) in vitro and in vivo were investigated, as well as its function of improvement of intestinal health.

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