Displaying publications 1 - 20 of 35 in total

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  1. A fluorescence quenching based gene assay for Escherichia coli O157:H7 using graphene quantum dots and gold nanoparticles
    Saad SM, Abdullah J, Rashid SA, Fen YW, Salam F, Yih LH
    Mikrochim Acta, 2019 11 19;186(12):804.
    PMID: 31745737 DOI: 10.1007/s00604-019-3913-8
    A fluorometric assay is described for highly sensitive quantification of Escherichia coli O157:H7. Reporter oligos were immobilized on graphene quantum dots (GQDs), and quencher oligos were immobilized on gold nanoparticles (AuNPs). Target DNA was co-hybridized with reporter oligos on the GQDs and quencher oligos on AuNPs. This triggers quenching of fluorescence (with excitation/emission peaks at 400 nm/530 nm). On introducing target into the system, fluorescence is quenched by up to 95% by 100 nM concentrations of target oligos having 20 bp. The response to the fliC gene of E. coli O157:H7 increases with the logarithm of the concentration in the range from 0.1 nM to 150 nM. The limit of detection is 1.1 ± 0.6 nM for n = 3. The selectivity and specificity of the assay was confirmed by evaluating the various oligos sequences and PCR product (fliC gene) amplified from genomic DNA of the food samples spiked with E. coli O157:H7. Graphical abstractSchematic representation of fluorometric assay for highly sensitive quantification of Escherichia coli O157:H7 based on fluorescence quenching gene assay for fliC gene of E. coli O157:H7.
    Matched MeSH terms: Escherichia coli O157/genetics; Escherichia coli O157/isolation & purification*
  2. Fulltext Shiga toxin sub-type 2a increases the efficiency of Escherichia coli O157 transmission between animals and restricts epithelial regeneration in bovine enteroids
    Fitzgerald SF, Beckett AE, Palarea-Albaladejo J, McAteer S, Shaaban S, Morgan J, et al.
    PLoS Pathog, 2019 10;15(10):e1008003.
    PMID: 31581229 DOI: 10.1371/journal.ppat.1008003
    Specific Escherichia coli isolates lysogenised with prophages that express Shiga toxin (Stx) can be a threat to human health, with cattle being an important natural reservoir. In many countries the most severe pathology is associated with enterohaemorrhagic E. coli (EHEC) serogroups that express Stx subtype 2a. In the United Kingdom, phage type (PT) 21/28 O157 strains have emerged as the predominant cause of life-threatening EHEC infections and this phage type commonly encodes both Stx2a and Stx2c toxin types. PT21/28 is also epidemiologically linked to super-shedding (>103 cfu/g of faeces) which is significant for inter-animal transmission and human infection as demonstrated using modelling studies. We demonstrate that Stx2a is the main toxin produced by stx2a+/stx2c+ PT21/28 strains induced with mitomycin C and this is associated with more rapid induction of gene expression from the Stx2a-encoding prophage compared to that from the Stx2c-encoding prophage. Bacterial supernatants containing either Stx2a and/or Stx2c were demonstrated to restrict growth of bovine gastrointestinal organoids with no restriction when toxin production was not induced or prevented by mutation. Isogenic strains that differed in their capacity to produce Stx2a were selected for experimental oral colonisation of calves to assess the significance of Stx2a for both super-shedding and transmission between animals. Restoration of Stx2a expression in a PT21/28 background significantly increased animal-to-animal transmission and the number of sentinel animals that became super-shedders. We propose that while both Stx2a and Stx2c can restrict regeneration of the epithelium, it is the relatively rapid and higher levels of Stx2a induction, compared to Stx2c, that have contributed to the successful emergence of Stx2a+ E. coli isolates in cattle in the last 40 years. We propose a model in which Stx2a enhances E. coli O157 colonisation of in-contact animals by restricting regeneration and turnover of the colonised gastrointestinal epithelium.
    Matched MeSH terms: Escherichia coli O157/drug effects*; Escherichia coli O157/isolation & purification
  3. Fingerprints of resistant Escherichia coli O157:H7 from vegetables and environmental samples
    Abakpa GO, Umoh VJ, Kamaruzaman S, Ibekwe M
    J Sci Food Agric, 2018 Jan;98(1):80-86.
    PMID: 28543177 DOI: 10.1002/jsfa.8441
    BACKGROUND: Some routes of transmission of Escherichia coli O157:H7 to fresh produce include contaminated irrigation water and manure polluted soils. The aim of the present study was to determine the genetic relationships of E. coli O157:H7 isolated from some produce growing region in Nigeria using enterobacterial repetitive intergenic consensus (ERIC) DNA fingerprinting analysis. A total of 440 samples comprising leafy greens, irrigation water, manure and soil were obtained from vegetable producing regions in Kano and Plateau States, Nigeria. Genes coding for the quinolone resistance-determinant (gyrA) and plasmid (pCT) coding for multidrug resistance (MDR) were determined using polymerase chain reaction (PCR) in 16 isolates that showed MDR.

    RESULTS: Cluster analysis of the ERIC-PCR profiles based on band sizes revealed six main clusters from the sixteen isolates analysed. The largest cluster (cluster 3) grouped isolates from vegetables and manure at a similarity coefficient of 0.72.

    CONCLUSION: The present study provides data that support the potential transmission of resistant strains of E. coli O157:H7 from vegetables and environmental sources to humans with potential public health implications, especially in developing countries. © 2017 Society of Chemical Industry.

    Matched MeSH terms: Escherichia coli O157/classification; Escherichia coli O157/drug effects; Escherichia coli O157/genetics; Escherichia coli O157/isolation & purification*
  4. Fulltext Antibacterial Activity of the Epidermal Mucus of Barbodes everetti
    JIAZHEN LIM, YANG LEE, BADIOZAMAN SULAIMAN, LESLEY MAURICE BILUNG, YEE LING CHONG
    Trends in Undergraduate Research, 2018;1(1):0-0.
    MyJurnal
    The epidermal mucus of fish contains antimicrobial agents that act as biological defence against disease. This study aims to identify antibacterial activity and protein concentration of epidermal mucus of Barbodes everetti, a Bornean endemic freshwater fish. The epidermal mucus was extracted with 3% acetic acid, 0.85% sodium chloride and crude solvents. The mucus activity against eight strains of human pathogenic bacteria, including Bacillus cereus ATCC 33019, Escherichia coli O157:H7, Listeria monocytogenes ATCC 7644, Pseudomonas aeruginosa ATCC 27853, Salmonella braenderup ATCC BAA 664, Salmonella typhimurium, Staphylococcus aureus ATCC 25933, and Vibrio cholerae, were tested. The acetic acid mucus extract of B. everetti was able to inhibit five strains of bacteria and show no activity toward E. coli O157:H7, B. cereus ATCC 33019 and L. monocytogenes ATCC 7644. Moreover, the highest protein concentration was quantified in crude extract, followed by aqueous and acetic acid extracts. This study provides a preliminary knowledge on the activity of epidermal mucus of B. everetti towards five out of the eight human pathogens tested, therefore it may contain potential sources of novel antibacterial components which could be further extracted for the production of natural antibiotics towards human-related pathogenic bacteria.
    Matched MeSH terms: Escherichia coli O157
  5. Fulltext Simultaneous multiplex Polymerase Chain Reaction detection of Salmonella spp., Escherichia coli O157, Vibrio parahaemolyticus, Vibrio cholerae, Listeria monocytogenes and Campylobacter spp.
    Ling, S., Noramirah, R., Abidatul, A.A., Nurfarhanah, N.M.J., Noor-Azira, A.M., Jambari, N.N., et al.
    Food Research, 2018;2(3):240-246.
    MyJurnal
    Foodborne illness is a global burden that impacts a country politically, economically and
    socio-economically. The severity of the burden can be unmeasurable as foodborne illness
    is often an underestimated problem. In order to enlighten the burden, appropriate food
    safety control measures should be taken. This study aimed to optimize a multiplex
    Polymerase Chain Reaction (mPCR) detection method to identify foodborne pathogens
    simultaneously. Six foodborne pathogens namely, Salmonella spp., Escherichia coli O157,
    Vibrio parahaemolyticus, Vibrio cholerae, Listeria monocytogenes and Campylobacter
    spp., were targeted in the mPCR detection method. Each mPCR parameter was tested and
    the outcome was analysed to obtain a successful mPCR protocol to detect the targeted
    foodborne pathogens. The amplified PCR products showed that the optimized mPCR
    protocol will be a potential rapid diagnostic tool in foodborne pathogen detection.
    Matched MeSH terms: Escherichia coli O157
  6. Highly sensitive Escherichia coli shear horizontal surface acoustic wave biosensor with silicon dioxide nanostructures
    Ten ST, Hashim U, Gopinath SC, Liu WW, Foo KL, Sam ST, et al.
    Biosens Bioelectron, 2017 Jul 15;93:146-154.
    PMID: 27660016 DOI: 10.1016/j.bios.2016.09.035
    Surface acoustic wave mediated transductions have been widely used in the sensors and actuators applications. In this study, a shear horizontal surface acoustic wave (SHSAW) was used for the detection of food pathogenic Escherichia coli O157:H7 (E.coli O157:H7), a dangerous strain among 225 E. coli unique serotypes. A few cells of this bacterium are able to cause young children to be most vulnerable to serious complications. Presence of higher than 1cfu E.coli O157:H7 in 25g of food has been considered as a dangerous level. The SHSAW biosensor was fabricated on 64° YX LiNbO3 substrate. Its sensitivity was enhanced by depositing 130.5nm thin layer of SiO2 nanostructures with particle size lesser than 70nm. The nanostructures act both as a waveguide as well as a physical surface modification of the sensor prior to biomolecular immobilization. A specific DNA sequence from E. coli O157:H7 having 22 mers as an amine-terminated probe ssDNA was immobilized on the thin film sensing area through chemical functionalization [(CHO-(CH2)3-CHO) and APTES; NH2-(CH2)3-Si(OC2H5)3]. The high-performance of sensor was shown with the specific oligonucleotide target and attained the sensitivity of 0.6439nM/0.1kHz and detection limit was down to 1.8femto-molar (1.8×10(-15)M). Further evidence was provided by specificity analysis using single mismatched and complementary oligonucleotide sequences.
    Matched MeSH terms: Escherichia coli O157/isolation & purification*; Escherichia coli O157/pathogenicity
  7. Fulltext Risk of Escherichia coli O157:H7 infection linked to the consumption of beef
    Premarathne J.M.K.J.K., New, C.Y., Ubong, A, Nakaguchi, Y., Nishibuchi, M., Son, R.
    Food Research, 2017;1(3):67-76.
    MyJurnal
    Escherichia coli O157:H7 is a major food-borne pathogen that has resulted in numerous
    outbreaks around the world. Widespread distribution of the organism in various ecological
    niches impedes the control measures. This study aimed to detect and quantify E. coli O157:H7
    in beef sold in wet markets and hypermarkets in Malaysia and to determine the risk of E. coli
    O157:H7 infection linked to consumption of beef. The rfbO157 and flicH7 primers targeted on
    somatic antigen (O157) and flagellar antigen (H7) respectively of E. coli O157:H7 was used for
    the MPN-PCR method. A total of 99 beef samples were collected from local wet markets and
    hypermarkets. The highest E. coli O157:H7 contamination rate was observed in beef samples
    collected from wet markets (89.50%), whereas the contamination rate in hyper market A and B
    were compratively low (35.35 and 20% respectively). However, the microbial load was highest
    in the beef samples from hypermarket A (1100 MPN/g) while E. coli O157:H7 bacterial load
    in beef samples from hypermarket B and wet market ranged from 3 to 93 MPN/g and 3 to 240
    MPN/g, respectively. Using the Quantitative Microbial Risk Assessment (QMRA) approach
    the risk was estimated incorporating the findings of the prevalence study and predictions
    based on home storage, cooking and consumption patterns. Three different exposure pathways
    were investigated to estimate the risk associated with contaminated beef and Monte Carlo
    simulation was used to determine the level of uncertainty. The developed model predicated that
    consumption of contaminated beef can be accountable for 1.83E+06 E. coli O157:H7 cases per
    year in Malaysia. The reliability of the model, data gaps and further research needs, is discussed.
    Through continuous improvement Quantitative Microbial Risk Assessment provides valuable
    insight into controlling and prevention strategies.
    Matched MeSH terms: Escherichia coli O157
  8. Fulltext Potential of fermented papaya beverage in the prevention of foodborne illness incidence
    Koh, S.P., Aziz, N., Sharifudin, S.A., Abdullah, R., Hamid, N.S.A., Sarip, J.
    Food Research, 2017;1(4):109-113.
    MyJurnal
    Foodborne illness is recognized as an emerging infectious disease. The incidence of foodborne
    infections is common and the majority cases are undiagnosed or unreported. Apart from some
    diarrhea or minor gastrointestinal problem, some foodborne pathogenic microbes may cause
    death, particularly to those people with weakened immune system. In this study, we have
    developed a new fermented papaya beverage using symbiotic culture of yeast and acetic acid
    bacteria under controlled biofermentation process. An in-vitro assessment of fermented papaya
    beverage against few foodborne pathogenic microorganism was conducted to determine
    its minimum bactericidal concentration (MBC>99). Three types of foodborne pathogen:
    Escherichia coli O157, Salmonella enterica serovar Typhimurium ATCC 53648, Salmonella
    enterica serovar Enteritidis (isolated from infectious chicken) were selected. From minimum
    bactericidal concentration (MBC>99) assay, both fermented papaya pulp and leaves beverages
    have shown 100% killing rate against three selected foodborne pathogenic microbes. Inversely,
    non-fermented papaya pulp and leaves beverages indicated no inhibition at all. In fact, further
    dilution of fermented papaya pulp and leaves beverages demonstrated different degree of
    MBC>99 and brix value, but the pH value remained less than 3.5. These findings indicated
    the combination of soluble solid compounds presents in both fermented papaya beverage and
    product acidity play an important role in the inhibition of pathogenic microorganisms. The
    preliminary promising results of this work have shown that the great potential of fermented
    papaya beverages as a preventive measure to reduce the incidence of foodborne illness.
    Matched MeSH terms: Escherichia coli O157
  9. Effect of pore size and morphology of activated charcoal prepared from midribs of Elaeis guineensis on adsorption of poisons using metronidazole and Escherichia coli O157:H7 as a case study
    Ilomuanya MO, Nashiru B, Ifudu ND, Igwilo CI
    J Microsc Ultrastruct, 2016 05 12;5(1):32-38.
    PMID: 30023235 DOI: 10.1016/j.jmau.2016.05.001
    Agricultural waste obtained from Elaeis guineensis mid ribs can provide a veritable source of materials which can be used as precursor materials for the production of pharmaceutical grade activated charcoal. The pore size and surface morphology of activated charcoal defines the types of molecules that could be adsorbed unto it, as surface morphology plays a significant role in determining the surface availability and areas of adsorption. The activated charcoal samples prepared from Elaeis guineensis via either physical or chemical activation was characterized via surface area using the BET method and subsequently pore structure and size analyzed by scanning electron microscopy (SEM). Physically activated Elaeis guineensis fronds activated with nitrogen gas had wide spread microporosity with micropore volume of 0.232 cc/g compared to the chemically activated with 1M and 3M phosphoric acid respectively. The commercial activated charcoal/metronidazole combination in the in vitro-pharmacodynamic model reflected no re-growth after 4 hours, however for charcoal formulated from Elaeis guineensis via chemical activation with 3M phosphoric acid and metronidazole no regrowth was seen at the second hour and this was maintained throughout the duration of the experiment. Increased macroporosity enhanced bacterial adsorption and this was further facilitated by the presence of antibacterial metronidazole in the in vitro pharmacodynamic model. Activated charcoal produced from agricultural waste obtained from Elaeis guineensis dried mid ribs consisting of increased macroporosity with mixed meso/micro porosity and antibacterial metronidazole form the best model for bacterial adsorption and will be useful in the treatment of diarrhea caused by E. coli O157:H7.
    Matched MeSH terms: Escherichia coli O157
  10. Immune-stimulating properties of 80% methanolic extract of Ludwigia octovalvis against Shiga toxin-producing E. coli O157:H7 in Balb/c mice following experimental infection
    Kadum Yakob H, Manaf Uyub A, Fariza Sulaiman S
    J Ethnopharmacol, 2015 Aug 22;172:30-7.
    PMID: 26091966 DOI: 10.1016/j.jep.2015.06.006
    Ludwigia octovalvis is an aquatic plant widely distributed throughout the tropical and sub-tropical regions. It is commonly consumed as a health drink and traditionally used for treating various ailments such as dysentery, diarrhea, diabetes, nephritisn and headache. No information is available on its in vivo antibacterial activity against an important foodborne pathogen, Shiga toxin producing Escherichia coli O157:H7.
    Matched MeSH terms: Escherichia coli O157/drug effects*; Escherichia coli O157/immunology; Escherichia coli O157/metabolism
  11. Fulltext Titanium Dioxide Nanoparticle-Based Interdigitated Electrodes: A Novel Current to Voltage DNA Biosensor Recognizes E. coli O157:H7
    Nadzirah Sh, Azizah N, Hashim U, Gopinath SC, Kashif M
    PLoS One, 2015;10(10):e0139766.
    PMID: 26445455 DOI: 10.1371/journal.pone.0139766
    Nanoparticle-mediated bio-sensing promoted the development of novel sensors in the front of medical diagnosis. In the present study, we have generated and examined the potential of titanium dioxide (TiO2) crystalline nanoparticles with aluminium interdigitated electrode biosensor to specifically detect single-stranded E.coli O157:H7 DNA. The performance of this novel DNA biosensor was measured the electrical current response using a picoammeter. The sensor surface was chemically functionalized with (3-aminopropyl) triethoxysilane (APTES) to provide contact between the organic and inorganic surfaces of a single-stranded DNA probe and TiO2 nanoparticles while maintaining the sensing system's physical characteristics. The complement of the target DNA of E. coli O157:H7 to the carboxylate-probe DNA could be translated into electrical signals and confirmed by the increased conductivity in the current-to-voltage curves. The specificity experiments indicate that the biosensor can discriminate between the complementary sequences from the base-mismatched and the non-complementary sequences. After duplex formation, the complementary target sequence can be quantified over a wide range with a detection limit of 1.0 x 10(-13)M. With target DNA from the lysed E. coli O157:H7, we could attain similar sensitivity. Stability of DNA immobilized surface was calculated with the relative standard deviation (4.6%), displayed the retaining with 99% of its original response current until 6 months. This high-performance interdigitated DNA biosensor with high sensitivity, stability and non-fouling on a novel sensing platform is suitable for a wide range of biomolecular interactive analyses.
    Matched MeSH terms: Escherichia coli O157/genetics*; Escherichia coli O157/isolation & purification*
  12. Fulltext Lateral flow assay strip for detection of Escherichia coli O157:H7
    Suria, M.S., Mohd Afendy, A.T, Noor Azlina, M., Zamri, I.
    International Food Research Journal, 2015;22(6):2587-2593.
    MyJurnal
    The use of polyclonal antibody (IgG) has recently been applied to the detection of bacteria. We developed a lateral flow assay (LFA) strip using a specific IgG in combination with colloidal gold on a nitrocellulose membrane. A conjugate, gold-anti Escherichia coli (E. coli) O157:H7 IgG was developed in this study for the detection of E. coli O157:H7 in food. The 40 nm in size of colloidal gold nanoparticles was used to conjugate the anti-E. coli O157:H7 IgG. The optimal concentration, 12.0 µg/ml of the anti-E. coli O157:H7 IgG was determined by standard curve generated in titration method. The serially diluted of E. coli O157:H7 was detected and clearly visualized on the LFA strip as low as 106 CFU/ml (result not shown). The IgG raised in rabbit have shown specific binding capacity against E. coli O157:H7. No other genus of bacteria, including Salmonella typhimurium, Listeria monocytogenes and Campylobacter jejuni reacted to the IgG. The LFA strip could also detect E. coli O157:H7 in different food samples matrices after 18 h-enrichment and this result were in accordance with the results of the polymerase chain reaction (PCR) and colony count.
    Matched MeSH terms: Escherichia coli O157
  13. Fulltext Molecular characterization of Escherichia coli isolated from different food sources
    Cheah, Y.K., Tay, L.W., Aida, A.A., Son, R., Nakaguchi, T., Nishibuchi, M.
    International Food Research Journal, 2015;22(1):31-40.
    MyJurnal
    Escherichia coli and Escherichia coli O157 were identified from “selom” (Oenanthe stolonifera), “pegaga” (Centella asiatica), beef, chicken, lamb, buffalo, “ulam Raja” (Cosmos caudatus) and “tenggek burung” (Euodia redlevi). The bacteria were recovered using chromagenic agar. Isolated Escherichia coli and Escherichia coli 0157 were further characterized by plasmid profiling and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). The virulence genes of the isolates (VT1, VT2, LT, ST, eaeA, inV) that produces pathogenic Escherichia coli and 16S rRNA gene were screened by a multiplex PCR assay. The plasmid profiling analysis showed that out of 176 isolates, only 103 isolates contained plasmids. ERIC-PCR analysis generated amplified products in the range of ~150 bp to > 1000 bp categorizing isolates into a total of 52 different profiles. Multiplex PCR showed that 20 (32.3%) of the isolates carried eaeA gene, 6 (9.7%) isolates possessed inV genes, only 1 (1.6%) have VT2 genes and 1 (1.6%) as well carried VT1 genes, 2 (3.2%) of the isolates harboured LT genes, and only 1 (1.6%) isolate possessed ST genes. There were no correlation between plasmid, ERIC-PCR and virulence genes profiles.
    Matched MeSH terms: Escherichia coli O157
  14. Fulltext Effect of lipase hydrolysis on the antibacterial activity of coconut oil, palm mesocarp oil and selected seed oils against several pathogenic bacteria
    Lee, S.T., Ariffin, A., Son R., Ghazali, H.M.
    International Food Research Journal, 2015;22(1):46-54.
    MyJurnal
    The antibacterial activity of solvent-extracted oil of noni (Morinda citrifolia L.), spinach (Spinacia oleracea L.), lady’s finger (Abelmoschus esculentus (L.) Moench), bitter gourd (Momordica charantia Linn.), and mustard (Brassica nigra L.) seed oils, and coconut (Cocos nucifera L.) oil, palm (Elaeis guineensis L.) mesocarp in hydrolyzed and unhydrolyzed form were determined in order to explore their potential usage as antibacterial agent. The hydrolysis process that was catalyzed by immobilized lipase of Rhizomucor miehei (RMIM) showed highest hydrolytic activity with 1.0 ml of added water volume except bitter gourd seed oil and palm mesocarp oil which has maximum hydrolytic activity with added water volume of 5 ml and 2.5 ml respectively. Before hydrolysis, all oil samples did not show inhibition ring zones (IRZ) on any of the tested bacteria strains (Salmonella typhimurium, Listeria monocytogenes and Escherichia coli O157:H7). Hydrolyzed lady’s finger and bitter gourd seed oil showed IRZ on all tested bacteria strains; hydrolyzed mustard seed oil on S. typhimurium and L. monocytogenes; hydrolyzed spinach seed oil and coconut oil on L. monocytogenes; hydrolyzed noni seed oil and palm mesocarp oil did not exhibit IRZ on any of the tested bacteria strains. Most of the hydrolyzed oil exhibit an inhibition activity that was different from their respective dominant fatty acids except noni seed oil and palm mesocarp oil.
    Matched MeSH terms: Escherichia coli O157
  15. Incidence of escherichia coli O157:H7 in Thailand
    Pharanai Sukhumungoon
    Sains Malaysiana, 2015;44:261-267.
    Enterohemorrhagic Escherichia coli (EHEC) especially serotype O157:H7 is one of the important food-borne pathogens because it is able to produce crucial toxins Shiga. However, the outbreak of this organism in Thailand has not been reported. Antibody to O157 antigen was detected in some Thai populations and Shiga toxin-producing E. coli were detected in low numbers of clinical specimens. Interestingly, some E. coli that showed positive to O157 fimbriae probe and lack of virulence gene were isolated from certain patients and one isolate of E. coli O157:H7 which possessed stx1, stx2v was detected in a normal child. In addition, the incidence of E. coli O157:H7 strains were monitored by the samples from cattle and retail beef in Thailand although their inability to produce toxins or produce in a low concentration was demonstrated. This review discusses the incidences of E. coli O157 in clinical and environmental samples of Thailand including the transmission possibility of this bacterium across the Thai border through food trade.
    Matched MeSH terms: Escherichia coli O157
  16. Escherichia coli strains expressing H12 antigens demonstrate an increased ability to attach to abiotic surfaces as compared with E. coli strains expressing H7 antigens
    Goulter RM, Taran E, Gentle IR, Gobius KS, Dykes GA
    Colloids Surf B Biointerfaces, 2014 Jul 1;119:90-8.
    PMID: 24880987 DOI: 10.1016/j.colsurfb.2014.04.003
    The role of Escherichia coli H antigens in hydrophobicity and attachment to glass, Teflon and stainless steel (SS) surfaces was investigated through construction of fliC knockout mutants in E. coli O157:H7, O1:H7 and O157:H12. Loss of FliC(H12) in E. coli O157:H12 decreased attachment to glass, Teflon and stainless steel surfaces (p<0.05). Complementing E. coli O157:H12 ΔfliC(H12) with cloned wildtype (wt) fliC(H12) restored attachment to wt levels. The loss of FliCH7 in E. coli O157:H7 and O1:H7 did not always alter attachment (p>0.05), but complementation with cloned fliC(H12), as opposed to cloned fliCH7, significantly increased attachment for both strains compared with wt counterparts (p<0.05). Hydrophobicity determined using bacterial adherence to hydrocarbons and contact angle measurements differed with fliC expression but was not correlated to the attachment to materials included in this study. Purified FliC was used to functionalise silicone nitride atomic force microscopy probes, which were used to measure adhesion forces between FliC and substrates. Although no significant difference in adhesion force was observed between FliC(H12) and FliCH7 probes, differences in force curves suggest different mechanism of attachment for FliC(H12) compared with FliCH7. These results indicate that E. coli strains expressing flagellar H12 antigens have an increased ability to attach to certain abiotic surfaces compared with E. coli strains expressing H7 antigens.
    Matched MeSH terms: Escherichia coli O157/genetics; Escherichia coli O157/metabolism; Escherichia coli O157/chemistry*
  17. Investigating to some microbial pollution parameters of seawater and mussels (mytilus galloprovincialis, Lamarck 1819) of Sіnop Black Sea Coastal Zone, Turkey
    Ismet Berber, Cumhur Avsar
    Sains Malaysiana, 2014;43:1835-1842.
    The presence of coliforms bacteria is one of the most prevalent problems in terms of public health in marine ecosystems over the world. In this study were investigated the physico-chemical properties of seawater and the numbers of total aerobic, total coliform, fecal coliform, E. coli O157:H7 and fecal streptococci in seawater and mussel samples collected from Sinop environs between May and October 2011. The microbiological analysis of seawater samples showed that the difference between total coliform, fecal coliform and fecal streptococci numbers (p<0.05) was significant for each station. However, the difference among total aerobic bacteria numbers for each stations (p>0.05) were not found significant. The difference between whole counting results for mussel samples taken from different sampling sites was not significant (p>0.05), too. Furthermore, the results of the screening assay for the presence of E. coli O157:H7 showed that the strain was not detected in neither seawater nor mussel samples. In conclusion, it was determined that fecal coliform and fecal streptococci counts in the seawater and mussel samples were higher than legal (Turkish Bathing Water and Quality of Fishery Products Regulation) limit values for some stations in Sinop coastal areas.
    Matched MeSH terms: Escherichia coli O157
  18. Fulltext Effects of thermosonication on the fate of Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice
    Kiang WS, Bhat R, Rosma A, Cheng LH
    Lett Appl Microbiol, 2013 Apr;56(4):251-7.
    PMID: 23278854 DOI: 10.1111/lam.12042
    In this study, the effects of thermosonication and thermal treatment on Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice were investigated at 50 and 60°C. Besides, nonlethal injury of Salm. Enteritidis after both treatments was also examined. The highest inactivation was attained with thermosonication at 60°C. The inactivation rate was different for both pathogens, and Salm. Enteritidis was found to be more sensitive to thermosonication than E. coli O157:H7. Salmonella Enteritidis was recovered in all treated samples, except those subjected to more than 5-min thermosonication at 60°C. It was found that the introduction of high-intensity ultrasound enhanced the inactivation of pathogens compared to thermal treatment alone. On the other hand, Salm. Enteritidis was detected in a number of samples following incubation in universal pre-enrichment broth, but no growth was detected after incubation in mango juice.
    Matched MeSH terms: Escherichia coli O157/physiology*
  19. Fulltext Multiplex Polymerase Chain Reaction (PCR) efficiency in detection of pathogenic Escherichia coli O157:H7
    Suria, M. S., Adlin Azlina, A. K., Mohd Afendy, A. T., Zamri, I.
    International Food Research Journal, 2013;20(6):3307-3311.
    MyJurnal
    Shiga toxin-producing E. coli (STEC) is an important foodborne pathogen causing diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome in humans. STEC is an implicated in the vast majority of outbreaks, widely via consumption of STEC contaminated beef, as important vehicle of transmission of this organism to human. The E. coli O157:H7 serotype is traditionally identified by serological identification of the somatic antigen (O157) and structural flagella (H7). In this study, the bacteria were identified as STEC serotype O157:H7 with three primer pairs that amplified fragments of secD, rfbE and fliC genes in PCR assays. These primer pairs specifically amplified different sizes of target genes: a 244bp region of the E. coli diagnostic marker gene (secD); a 317bp region of the O157 lipopolysacharide (LPS) gene (rfbE); and a 381bp region of the H7 flagellin gene (fliC). The singleplex, duplex and triplex PCR assay developed in this study have a sensitivity limit at 2.8 x 103, 2.8 x 105 and 2.8 x 107 CFU/ml of E. coli O157:H7, respectively. Sensitivity to detect trace amount of E. coli O157:H7 DNA was reduced as the number of primer used was increased for competing to the same DNA template.
    Matched MeSH terms: Escherichia coli O157
  20. Fulltext Quantitative detection and characterization of Shiga toxin-producing Escherichia coli O157 and non-O157 in raw vegetables by MPN-PCR in Malaysia
    Loo, Y. Y., Puspanadan, S., Goh, S. G., Kuan, C. H., Chang, W. S., Lye, Y. L., et al.
    International Food Research Journal, 2013;20(6):3313-3317.
    MyJurnal
    Foodborne diseases are mainly caused by bacterial contamination which can lead to severe diarrhea. This study aimed to detect the presence of Shiga toxin-Producing Escherichia coli O157, Escherichia coli non-O157 and virulence gene in raw vegetables. The samples were purchased from wet market and hypermarket in Selangor. The detections were carried out by using the combination methods of Most Probable Number-Polymerase Chain Reaction (MPNPCR). A total of 37(18.5%) samples were found to be contaminated by STEC. Out of these 37 isolates, four (10.8%) of the isolates were E. coli O157 while 33(89.2%) were E. coli nonO157. However, there was no E. coli O157:H7 detected in all the samples. The occurrence of Shiga toxin-Producing E. coli in edible raw vegetables samples suggests the importance of this pathogen in vegetables. Therefore, more studies are required to remove this pathogen from vegetables.
    Matched MeSH terms: Escherichia coli O157
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