scholarly journals Organic horticulture: a current demand, whose proper management is the only guarantee of safe food

Biotemas ◽  
2019 ◽  
Vol 32 (3) ◽  
pp. 43-50
Author(s):  
Fernanda Pinto Ferreira ◽  
Roberta Lemos Freire ◽  
Eloiza Teles Caldart ◽  
Aline Ticiani Pereira Paschoal ◽  
Gabriela Bahr Arias ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
E Coli ◽  
Proper Management ◽  
Safe Food ◽  
Organic Horticulture ◽  
A Current

O estudo foi realizado entre julho de 2014 e maio de 2016, em 21 propriedades hortícolas do estado do Paraná, Brasil. Foram coletadas duas amostras de vegetais folhosos e uma amostra de água de irrigação por propriedade. As amostras de água foram analisadas pela técnica do substrato cromogênico para avaliar a contaminação por coliformes totais e Escherichia coli, e os vegetais foram avaliados pelas técnicas de Willis (1921), Hoffman et al. (1934), Faust et al. (1939) e quanto à contaminação por parasitas. Observou-se presença de E. coli em 80,95% (17/21) das amostras de água; com relação aos vegetais, 19 (45,23%) continham pelo menos uma espécie de parasita, tais como: ancilostomatídeos, Chilomatix spp., Dipillidium spp., Entamoeba spp., Strongyloides spp., Trichuris spp., larva de vida livre, larva de nematódeo, oocisto não-esporulado. Houve associação estatística entre o destino do esgoto (fossa seca) e a positividade aos parasitas. Os dados mostram contaminação fecal em número significativo de amostras e confirmam a necessidade de maiores exigências sanitárias durante o cultivo de hortaliças folhosas, que, na maioria das vezes, são consumidas cruas. 

Ability ofEscherichia coliO157:H7 isolates to colonize the intestinal tract of conventional adult CD1 mice is transient

2001 ◽  
Vol 47 (1) ◽  
pp. 91-95 ◽  
Author(s):  
J Wayne Conlan ◽  
Sonia L Bardy ◽  
Rhonda KuoLee ◽  
Ann Webb ◽  
Malcolm B Perry
Keyword(s):  
Escherichia Coli ◽  
Mouse Model ◽  
Intestinal Tract ◽  
Vaccine Development ◽  
Escherichia Coli O157 ◽  
Intestinal Colonization ◽  
E Coli ◽  
Cd1 Mice ◽  
A Current

In an attempt to improve upon a current mouse model of intestinal colonization by Escherichia coli O157:H7 used in this laboratory for vaccine development, nine clinical isolates of the pathogen were screened for their ability to persist in the intestinal tract of conventional adult CD-1 mice. None of the test isolates of E. coli O157:H7 were capable of colonizing these mice for a period of more than two weeks. Most of the isolates appeared to be benign for the experimental host, but one isolate was lethal. This virulence correlated with the ability of the latter isolate to produce large quantities of Shiga-like toxin 2 in vitro.

scholarly journals Evolution of diarrheagenic Escherichia coli pathotypes in India

2019 ◽  
Vol 11 (04) ◽  
pp. 346-351
Author(s):  
Pankaj Singh ◽  
Sharda C. Metgud ◽  
Subarna Roy ◽  
Shashank Purwar
Keyword(s):  
Escherichia Coli ◽  
Cross Sectional Study ◽  
Clinical Settings ◽  
Accurate Identification ◽  
Cross Sectional ◽  
E Coli ◽  
Medical College ◽  
Diarrheagenic Escherichia Coli ◽  
Proper Management ◽  
Heat Stable

Abstract CONTEXT: Diarrheagenic Escherichia coli (DEC) is the leading cause of infectious diarrhea in developing countries. On the basis of virulence and phenotypic characteristics, the DEC is categorized into multiple pathotypes. Each pathotype has different pathogenesis and geographical distribution. Thus, the proper management of disease relies on rapid and accurate identification of DEC pathotypes. AIMS: The aim of the study was to determine the prevalence of DEC pathotypes in India. MATERIALS AND METHODS: A cross-sectional study was carried out between January 2008 and December 2012 at Jawaharlal Nehru Medical College and KLES Dr. Prabhakar Kore Hospital and Medical Research Center, Belgaum (Karnataka), India. A total of 300 stool samples were collected from diarrhea patients with age >3 months. The DEC was identified by both conventional and molecular methods. RESULTS: Of 300 samples, E. coli were detected in 198 (66%) and 170 (56.6%) samples by culture and polymerase chain reaction, respectively. Among DEC (n = 198) isolates, eae gene (59.5%) was the most prevalent followed by stx (27.7%), east (27.2%), elt (12.6%), est (10.6%), ipaH (5.5%), and eagg (1.5%) genes. On the basis of virulence genes, enteropathogenic E. coli (33.8%) was the most common pathotype followed by Shiga toxin-producing E. coli (STEC, 23.2%), enterotoxigenic E. coli (ETEC, 13.6%), enteroinvasive E. coli (5.5%), enteroaggregative heat-stable enterotoxin 1-harboring E. coli (EAST1EC, 4.5%), STEC/ETEC (3.5%), STEC/enteroaggregative E. coli (STEC/EAEC, 1.0%), and EAEC (0.05%). CONCLUSIONS: The hybrid DEC is potentially more virulent than basic pathotypes. The pathotyping should be included in clinical settings for the proper management of DEC-associated diarrhea.

scholarly journals Molecular Diagnostic Platforms for Specific Detection of Escherichia coli

2021 ◽  
Author(s):  
Rehan Deshmukh ◽  
Utpal Roy
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Water Quality Monitoring ◽  
Molecular Techniques ◽  
Quality Monitoring ◽  
Molecular Diagnostic ◽  
Water Contaminants ◽  
E Coli ◽  
Highly Sensitive ◽  
Safe Food

Developing countries due to socio-economic conditions are more prone to frequent pathogenic outbreaks; inadequate sanitation and water quality monitoring are also responsible for such conditions. Therefore, it is of paramount importance to provide microbiologically safe food/water in order to protect public health. Several flaws in traditional culturing methods have sparked a surge in interest in molecular techniques as a means of improving the efficiency and sensitivity of microbiological food/water quality monitoring. Molecular identification of water contaminants, mainly Escherichia coli, has been extensively used. Several of the molecular-based techniques are based on amplification and detection of nucleic acids. The advantages offered by these PCR-based methods over culture-based techniques are a higher level of specificity, sensitivity, and rapidity. Of late, the development of a biosensor device that is easy to perform, highly sensitive, and selective has the potential to become indispensable in detecting low CFU of pathogenic E. coli in environmental samples. This review seeks to provide a vista of the progress made in the detection of E. coli using nucleic acid-based approaches as part of the microbiological food/water quality monitoring.

scholarly journals Occurrence of Tetracycline Resistance Genes among Escherichia coli Isolates from the Phase 3 Clinical Trials for Tigecycline

2007 ◽  
Vol 51 (9) ◽  
pp. 3205-3211 ◽  
Author(s):  
Margareta Tuckman ◽  
Peter J. Petersen ◽  
Anita Y. M. Howe ◽  
Mark Orlowski ◽  
Stanley Mullen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Clinical Trials ◽  
Tetracycline Resistance ◽  
Phase 3 ◽  
E Coli ◽  
Tetracycline Resistance Genes ◽  
Resistance Determinants ◽  
Resistant Strains ◽  
A Current ◽  
Antibacterial Spectrum

ABSTRACT Tigecycline, a member of the glycylcycline class of antibiotics, was designed to maintain the antibacterial spectrum of the tetracyclines while overcoming the classic mechanisms of tetracycline resistance. The current study was designed to monitor the prevalence of the tet(A), tet(B), tet(C), tet(D), tet(E), and tet(M) resistance determinants in Escherichia coli isolates collected during the worldwide tigecycline phase 3 clinical trials. A subset of strains were also screened for the tet(G), tet(K), tet(L), and tet(Y) genes. Of the 1,680 E. coli clinical isolates screened for resistance to classical tetracyclines, 405 (24%) were minocycline resistant (MIC ≥ 8 μg/ml) and 248 (15%) were tetracycline resistant (MIC ≥ 8 μg/ml) but susceptible to minocycline (MIC ≤ 4 μg/ml). A total of 452 tetracycline-resistant, nonduplicate isolates were positive by PCR for at least one of the six tetracycline resistance determinants examined. Over half of the isolates encoding a single determinant were positive for tet(A) (26%) or tet(B) (32%) with tet(C), tet(D), tet(E), and tet(M), collectively, found in 4% of isolates. Approximately 33% of the isolates were positive for more than one resistance determinant, with the tet(B) plus tet(E) combination the most highly represented, found in 11% of isolates. The susceptibilities of the tetracycline-resistant strains to tigecycline (MIC90, 0.5 μg/ml), regardless of the encoded tet determinant(s), were comparable to the tigecycline susceptibility of tetracycline-susceptible strains (MIC90, 0.5 μg/ml). The results provide a current (2002 to 2006) picture of the distribution of common tetracycline resistance determinants encoded in a globally sourced collection of clinical E. coli strains.

scholarly journals Genetic Functions Promoting Homologous Recombination in Escherichia coli: A Study of Inversions in Phage Λ

Genetics ◽  
1987 ◽  
Vol 115 (1) ◽  
pp. 11-24
Author(s):  
Don G Ennis ◽  
Susan K Amundsen ◽  
Gerald R Smith
Keyword(s):  
Escherichia Coli ◽  
Homologous Recombination ◽  
Molecular Model ◽  
Reca Protein ◽  
Dna Polymerase I ◽  
E Coli ◽  
The Right ◽  
Polymerase I ◽  
Recbcd Enzyme ◽  
A Current

ABSTRACT We have studied homologous recombination in a derivative of phage λ containing two 1.4-kb repeats in inverted orientation. Inversion of the intervening 2.5-kb segment occurred efficiently by the Escherichia coli RecBC pathway but markedly less efficiently by the λ Red pathway or the E. coli RecE or RecF pathways. Inversion by the RecBCD pathway was stimulated by Chi sites located to the right of the invertible segment; this stimulation decreased exponentially by a factor of about 2 for each 2.2 kb between the invertible segment and the Chi site. In addition to RecA protein and RecBCD enzyme, inversion by the RecBC pathway required single-stranded DNA binding protein, DNA gyrase, DNA polymerase I and DNA ligase. Inversion appeared to occur either intra- or intermolecularly. These results are discussed in the framework of a current molecular model for the RecBC pathway of homologous recombination.

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

The Influence of Glycosylation on the Catalytic and Fibrinolytic Properties of Pro-Urokinase

1992 ◽  
Vol 68 (05) ◽  
pp. 539-544 ◽  
Author(s):  
Catherine Lenich ◽  
Ralph Pannell ◽  
Jack Henkin ◽  
Victor Gurewich
Keyword(s):  
Escherichia Coli ◽  
Mammalian Cell ◽  
Human Gene ◽  
Culture Media ◽  
Mammalian Cell Culture ◽  
Glycosylation Site ◽  
Clot Lysis ◽  
Cell Culture Media ◽  
E Coli ◽  
The Uk

SummaryWe previously found that human pro-UK expressed in Escherichia coli is more active in fibrinolysis than recombinant human pro-UK obtained from mammalian cell culture media. To determine whether this difference is related to the lack of glycosylation of the E. coli product, we compared the activity of E. coli-derived pro-UK [(-)pro-UK] with that of a glycosylated pro-UK [(+)pro-UK] and of a mutant of pro-UK missing the glycosylation site at Asn-302 [(-) (302) pro-UK]. The latter two pro-UKs were obtained by expression of the human gene in a mammalian cell. The nonglycosylated pro-UKs were activated by plasmin more efficiently (≈2-fold) and were more active in clot lysis (1.5-fold) than the (+)pro-UK. Similarly, the nonglycosylated two-chain derivatives (UKs) were more active against plasminogen and were more rapidly inactivated by plasma inhibitors than the (+)UK.These findings indicate that glycosylation at Asn-302 influences the activity of pro-UK/UK and could be the major factor responsible for the enhanced activity of E. coli-derived pro-UK.

Usefulness of a Multiplex PCR for Detection of Diarrheagenic Escherichia coli in a Diagnostic Microbiology Laboratory Setting

2016 ◽  
Vol 1 (2) ◽  
pp. 38-42 ◽  
Author(s):  
Khairun Nessa ◽  
Dilruba Ahmed ◽  
Johirul Islam ◽  
FM Lutful Kabir ◽  
M Anowar Hossain
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Clinical Laboratory ◽  
Proteinase K ◽  
Microbiology Laboratory ◽  
Pcr Assay ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Multiplex Pcr Assay ◽  
Diagnostic Microbiology

A multiplex PCR assay was evaluated for diagnosis of diarrheagenic Escherichia coli in stool samples of patients with diarrhoea submitted to a diagnostic microbiology laboratory. Two procedures of DNA template preparationproteinase K buffer method and the boiling method were evaluated to examine isolates of E. coli from 150 selected diarrhoeal cases. By proteinase K buffer method, 119 strains (79.3%) of E. coli were characterized to various categories by their genes that included 55.5% enteroaggregative E. coli (EAEC), 18.5% enterotoxigenic E. coli (ETEC), 1.7% enteropathogenic E. coli (EPEC), and 0.8% Shiga toxin-producing E. coli (STEC). Although boiling method was less time consuming (<24 hrs) and less costly (<8.0 US $/ per test) but was less efficient in typing E. coli compared to proteinase K method (41.3% vs. 79.3% ; p<0.001). The sensitivity and specificity of boiling method compared to proteinase K method was 48.7% and 87.1% while the positive and negative predictive value was 93.5% and 30.7%, respectively. The majority of pathogenic E. coli were detected in children (78.0%) under five years age with 53.3% under one year, and 68.7% of the children were male. Children under 5 years age were frequently infected with EAEC (71.6%) compared to ETEC (24.3%), EPEC (2.7%) and STEC (1.4%). The multiplex PCR assay could be effectively used as a rapid diagnostic tool for characterization of diarrheagenic E. coli using a single reaction tube in the clinical laboratory setting.Bangladesh J Med Microbiol 2007; 01 (02): 38-42

Antagonistic activity of Bacillus subtilis strains isolated from various sources

2018 ◽  
Vol 8 (2) ◽  
pp. 354-364
Author(s):  
A. N. Irkitova ◽  
A. V. Grebenshchikova ◽  
A. V. Matsyura
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Wild Strain ◽  
Fish Farming ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
E Coli ◽  
Long Period ◽  
Test Culture ◽  
Agar Media

<p>An important link in solving the problem of healthy food is the intensification of the livestock, poultry and fish farming, which is possible only in the adoption and rigorous implementation of the concept of rational feeding of animals. In the implementation of this concept required is the application of probiotic preparations. Currently, there is an increased interest in spore probiotics. In many ways, this can be explained by the fact that they use no vegetative forms of the bacilli and their spores. This property provides spore probiotics a number of advantages: they are not whimsical, easily could be selected, cultivated, and dried. Moreover, they are resistant to various factors and could remain viable during a long period. One of the most famous spore microorganisms, which are widely used in agriculture, is <em>Bacillus subtilis</em>. Among the requirements imposed to probiotic microorganisms is mandatory – antagonistic activity to pathogenic and conditional-pathogenic microflora. The article presents the results of the analysis of antagonistic activity of collection strains of <em>B. subtilis</em>, and strains isolated from commercial preparations. We studied the antagonistic activity on agar and liquid nutrient medias to trigger different antagonism mechanisms of <em>B. subtilis</em>. On agar media, we applied three diffusion methods: perpendicular bands, agar blocks, agar wells. We also applied the method of co-incubating the test culture (<em>Escherichia coli</em>) and the antagonist (or its supernatant) in the nutrient broth. Our results demonstrated that all our explored strains of <em>B. subtilis</em> have antimicrobial activity against a wild strain of <em>E. coli</em>, but to varying degrees. We identified strains of <em>B. subtilis</em> with the highest antagonistic effect that can be recommended for inclusion in microbial preparations for agriculture.</p><p><em><br /></em><em></em></p>

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