Displaying publications 1 - 20 of 58 in total

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  1. Forde BM, Phan MD, Gawthorne JA, Ashcroft MM, Stanton-Cook M, Sarkar S, et al.
    mBio, 2015 Nov 17;6(6):e01602-15.
    PMID: 26578678 DOI: 10.1128/mBio.01602-15
    Escherichia coli sequence type 131 (ST131) is a clone of uropathogenic E. coli that has emerged rapidly and disseminated globally in both clinical and community settings. Members of the ST131 lineage from across the globe have been comprehensively characterized in terms of antibiotic resistance, virulence potential, and pathogenicity, but to date nothing is known about the methylome of these important human pathogens. Here we used single-molecule real-time (SMRT) PacBio sequencing to determine the methylome of E. coli EC958, the most-well-characterized completely sequenced ST131 strain. Our analysis of 52,081 methylated adenines in the genome of EC958 discovered three (m6)A methylation motifs that have not been described previously. Subsequent SMRT sequencing of isogenic knockout mutants identified the two type I methyltransferases (MTases) and one type IIG MTase responsible for (m6)A methylation of novel recognition sites. Although both type I sites were rare, the type IIG sites accounted for more than 12% of all methylated adenines in EC958. Analysis of the distribution of MTase genes across 95 ST131 genomes revealed their prevalence is highly conserved within the ST131 lineage, with most variation due to the presence or absence of mobile genetic elements on which individual MTase genes are located.

    IMPORTANCE: DNA modification plays a crucial role in bacterial regulation. Despite several examples demonstrating the role of methyltransferase (MTase) enzymes in bacterial virulence, investigation of this phenomenon on a whole-genome scale has remained elusive until now. Here we used single-molecule real-time (SMRT) sequencing to determine the first complete methylome of a strain from the multidrug-resistant E. coli sequence type 131 (ST131) lineage. By interrogating the methylome computationally and with further SMRT sequencing of isogenic mutants representing previously uncharacterized MTase genes, we defined the target sequences of three novel ST131-specific MTases and determined the genomic distribution of all MTase target sequences. Using a large collection of 95 previously sequenced ST131 genomes, we identified mobile genetic elements as a major factor driving diversity in DNA methylation patterns. Overall, our analysis highlights the potential for DNA methylation to dramatically influence gene regulation at the transcriptional level within a well-defined E. coli clone.

    Matched MeSH terms: Escherichia coli Infections/microbiology; Escherichia coli Infections/epidemiology
  2. Nhu NTK, Phan MD, Peters KM, Lo AW, Forde BM, Min Chong T, et al.
    mBio, 2018 08 21;9(4).
    PMID: 30131362 DOI: 10.1128/mBio.01462-18
    Curli are bacterial surface-associated amyloid fibers that bind to the dye Congo red (CR) and facilitate uropathogenic Escherichia coli (UPEC) biofilm formation and protection against host innate defenses. Here we sequenced the genome of the curli-producing UPEC pyelonephritis strain MS7163 and showed it belongs to the highly virulent O45:K1:H7 neonatal meningitis-associated clone. MS7163 produced curli at human physiological temperature, and this correlated with biofilm growth, resistance of sessile cells to the human cationic peptide cathelicidin, and enhanced colonization of the mouse bladder. We devised a forward genetic screen using CR staining as a proxy for curli production and identified 41 genes that were required for optimal CR binding, of which 19 genes were essential for curli synthesis. Ten of these genes were novel or poorly characterized with respect to curli synthesis and included genes involved in purine de novo biosynthesis, a regulator that controls the Rcs phosphorelay system, and a novel repressor of curli production (referred to as rcpA). The involvement of these genes in curli production was confirmed by the construction of defined mutants and their complementation. The mutants did not express the curli major subunit CsgA and failed to produce curli based on CR binding. Mutation of purF (the first gene in the purine biosynthesis pathway) and rcpA also led to attenuated colonization of the mouse bladder. Overall, this work has provided new insight into the regulation of curli and the role of these amyloid fibers in UPEC biofilm formation and pathogenesis.IMPORTANCE Uropathogenic Escherichia coli (UPEC) strains are the most common cause of urinary tract infection, a disease increasingly associated with escalating antibiotic resistance. UPEC strains possess multiple surface-associated factors that enable their colonization of the urinary tract, including fimbriae, curli, and autotransporters. Curli are extracellular amyloid fibers that enhance UPEC virulence and promote biofilm formation. Here we examined the function and regulation of curli in a UPEC pyelonephritis strain belonging to the highly virulent O45:K1:H7 neonatal meningitis-associated clone. Curli expression at human physiological temperature led to increased biofilm formation, resistance of sessile cells to the human cationic peptide LL-37, and enhanced bladder colonization. Using a comprehensive genetic screen, we identified multiple genes involved in curli production, including several that were novel or poorly characterized with respect to curli synthesis. In total, this study demonstrates an important role for curli as a UPEC virulence factor that promotes biofilm formation, resistance, and pathogenesis.
    Matched MeSH terms: Escherichia coli Infections/microbiology
  3. Son R, Ansary A, Rusul G, Karim MI
    World J Microbiol Biotechnol, 1996 May;12(3):243-6.
    PMID: 24415231 DOI: 10.1007/BF00360921
    Three strains of verotoxin-producing Escherichia coli isolated from patients with haemorrhagic colitis harboured plasmids ranging in size from 2.7 kb to 91.2 kb. Those plasmids ranging from 2.7 kb to 6.8 kb hybridized to Shiga-like toxin I and Shiga-like toxin II gene probes.
    Matched MeSH terms: Escherichia coli Infections
  4. Ahmad KA, Mohanmmed AS, Abas F, Chin SC
    Virol Sin, 2015 Feb;30(1):73-5.
    PMID: 25662886 DOI: 10.1007/s12250-014-3541-8
    Matched MeSH terms: Escherichia coli Infections/microbiology*
  5. Borkataki S, Katoch R, Goswami P, Bhat A, Chakraborty D
    Trop Biomed, 2021 Mar 01;38(1):86-93.
    PMID: 33797529 DOI: 10.47665/tb.38.1.015
    The study was aimed to evaluate the effectiveness of maggot therapy in healing of cutaneous infected wound in streptozotocin (STZ) induced diabetic Wistar rat. For live maggots, the sterilized eggs of Lucilia sericata were obtained from colonies established in laboratory. Diabetes model was established in 48 male Wister rat by intra-peritoneal injection of STZ at the dose of 60 mg/kg body-weight. Cutaneous wounds exposed with mixed colonies of bacteria like Staphylococcus aureus, E. coli and Pseudomonas aeruginosa were prepared in all rat. The animals equally divided in 4 groups with 12 rats each being presented as treatment group of control, antibiotic, maggot and maggot with antibiotic in combination. All treatments were done once and hold for 24 hours. Wound kinetics and bacterial bio burden were measured at weekly interval to till complete healing. Significant reduction in wound area with maximum contraction was found (>95%) in maggot treated group when compared to antibiotic treated (79%) and control (72%). In maggot as well as maggot and antibiotic in combination group showed early elimination of bacterial bio-burden 7.88±0.03log CFU/ml to 1.12±0.65log CFU/ml and 7.86±0.04) log CFU/ml to 1.54±0.52log CFU/ml respectively in three weeks of time. Early healing indication was also experienced on histomorphological examination of wounded tissue of maggot treated groups by early and better epithelialization, collagenation and neovascularization with complete healing of wound in three weeks in comparison to antibiotic and control respectively. However, the present study did not show any difference in healing of wound with use of maggot alone or in antibiotic combination. Live maggot of Lucilia sericata effectively lower bacterial bioburden and and accelerate healing of infected cutaneous wound in diabetic conditions.
    Matched MeSH terms: Escherichia coli Infections/therapy
  6. Teh CS, Chua KH, Lim YA, Lee SC, Thong KL
    ScientificWorldJournal, 2014;2014:457839.
    PMID: 24967435 DOI: 10.1155/2014/457839
    We have successfully developed a Loop-mediated isothermal amplification (LAMP) assay that could specifically detect generic Escherichia coli (E. coli). This assay was tested on 85 bacterial strains and successfully identified 54 E. coli strains (average threshold time, Tt = 21.26). The sensitivity of this assay was evaluated on serial dilutions of bacterial cultures and spiked faeces. The assay could detect 10(2) CFU/mL for bacterial culture with Tt = 33.30 while the detection limit for spiked faeces was 10(3) CFU/mL (Tt = 31.12). We have also detected 46 generic E. coli from 50 faecal samples obtained from indigenous individuals with 16% of the positive samples being verocytotoxin-producing E. coli (VTEC) positive. VT1/VT2 allele was present in one faecal sample while the ratio of VT1 to VT2 was 6 : 1. Overall, our study had demonstrated high risk of VTEC infection among the indigenous community and most of the asymptomatic infection occurred among those aged below 15 years. The role of asymptomatic human carriers as a source of dissemination should not be underestimated. Large scale screening of the VTEC infection among indigenous populations and the potential contamination sources will be possible and easy with the aid of this newly developed rapid and simple LAMP assay.
    Matched MeSH terms: Escherichia coli Infections/diagnosis; Escherichia coli Infections/microbiology*
  7. Samuel S, Vadivelu J, Parasakthi N
    PMID: 9322293
    Amongst 107 diarrheal cases studied a bacterial agent was isolated from 71 (66%) cases of which 60 (85%) were due to a single agent and the remaining 11 (15%) were of mixed infections. Enterotoxigenic Escherichia coli (ETEC) was isolated from 65 cases. Other pathogens isolated included Salmonella spp, Shigella spp and rotavirus. There was a higher isolation rate of ETEC from females and rotavirus from males. The infection rate was found to higher for the 0-2 year age group as compared to the 3-5 year age group. Amongst the ETEC isolated the STa 2 toxotype was the predominant type.
    Matched MeSH terms: Escherichia coli Infections/diagnosis; Escherichia coli Infections/microbiology*; Escherichia coli Infections/epidemiology
  8. Koh CL, Kok CH
    PMID: 6377513
    Fifteen independent E. coli strains of avian, bovine and porcine origin in Peninsular Malaysia were tested for antibiotic resistance and conjugative R plasmids. Eight (53%) isolates were found to be antibiotic resistant. Among them, 37.5% were mono-resistant and 62.5% were resistant to three or more antibiotics, i.e., multi-resistant. All of them were resistant to Tc and sensitive to Gm and Nx. Three of the eight antibiotic resistant strains were able to transfer all or part of their resistance to an E. coli K12 recipient by conjugation. The transfer frequencies of Km, Sm and Tc resistance of the three donors varied between 4.5 X 10(-8) to 6.8 X 10(-7). Analysis of the plasmid profiles of all the three donors and their respective transconjugants after agarose gel electrophoresis provided conclusive evidence that the transferable resistance traits were plasmid-mediated.
    Matched MeSH terms: Escherichia coli Infections/drug therapy
  9. Wan KF, Radu S, Cheah YK, Benjamin PG, Ling CM, Hon SF, et al.
    PMID: 15115139
    Enteropathogenic Escherichia coli (EPEC) is a leading cause of diarrhea among infants in developing countries. A total of 38 EPEC isolates, obtained from diarrhea patients of Hospital Miri, Sarawak, were investigated through plasmid profile, antibiotic resistance and randomly amplified polymorphic DNA (RAPD) analysis. From the 8 types of antibiotics used, all isolates were 100% resistant to furoxime, cephalothin and sulphamethoxazole and showed high multiple antibiotic resistant (MAR) indexes, ranging from 0.5 to 1.0. In plasmid profiling, 22 isolates (58%) showed the presence of one or more plasmids in the range 1.0 to 30.9 mDa. The dendrogram obtained from the results of the RAPD-PCR discriminated the isolates into 30 single isolates and 3 clusters at the level of 40% similarity. The EPEC isolates were highly diverse, as shown by their differing plasmid profiles, antibiotic resistance patterns and RAPD profiles.
    Matched MeSH terms: Escherichia coli Infections/microbiology*; Escherichia coli Infections/epidemiology
  10. Jegathesan M, Singh RB, Kanaganayagy M, Soon LE
    PMID: 1096307
    Matched MeSH terms: Escherichia coli Infections/microbiology*; Escherichia coli Infections/epidemiology
  11. Wameadesa N, Sae-lim A, Hayeebilan F, Rattanachuay P, Sukhumungoon P
    PMID: 29642296
    Local Thai and imported Malaysian beef in southern Thailand area carry
    several Shiga toxin-producing Escherichia coli (STEC) serotypes. STEC O104 is an
    important pathogen capable of causing outbreaks with considerable morbidity
    and mortality. This study investigated the presence of E. coli O104 from local Thai
    and imported Malaysian beef obtained from markets in Hat Yai City, Songkhla
    Province during August 2015 - February 2016. Thirty-one E. coli O104 strains
    were isolated from 12 beef samples (16% and 23% Thai and imported Malaysian,
    respectively). Thirty strains possessed aggA (coding for a major component of
    AAF/I fimbriae), a gene associated with enteroaggregative E. coli (EAEC) pathotype,
    and all strains carried fimH (encoding Type 1 fimbriae). Thirty strains
    belonged to phylogenetic group B1 and one strain (from Malaysian beef) to group
    A. Agglutination of yeast cells was observed among 29 E. coli O104 strains. Investigation
    of stx2 phage occupancy loci demonstrated that sbcB was occupied in 12
    strains. Antimicrobial susceptibility assay revealed that 7 strains were resistant
    to at least one antimicrobial agent and two were multi-drug resistant. One strain
    carried extended spectrum β-lactamase gene blaCTX-M and three carried blaTEM. PFGE-generated DNA profiling showed identical DNA pattern between that of
    one EAEC O104 strain from Thai beef and another from Malaysian beef, indicating
    that these two strains originated from the same clone. This is the first report
    in Thailand describing the presence of EAEC O104 from both Thai and imported
    Malaysian beef and their transfer between both countries. Thorough surveillance
    of this pathogen in fresh meats and vegetables should help to prevent any possible
    outbreak of E. coli O104.
    Matched MeSH terms: Escherichia coli Infections/microbiology; Escherichia coli Infections/epidemiology*
  12. Wong AC, Chan LG
    Med J Malaysia, 2014 Oct;69(5):229-30.
    PMID: 25638238 MyJurnal
    We report a case of neonatal Bartter syndrome in a 31 weeks premature baby girl with antenatal unexplained polyhydramnios requiring amnioreduction. She presented with early onset E. coli septicaemia and severe dehydration leading to pre-renal renal impairment which obscure the typical biochemical changes of hypokalaemic hypochloraemic metabolic alkalosis.
    Matched MeSH terms: Escherichia coli Infections
  13. Tang ML, Lee SC, Phoon MP
    Med J Malaysia, 2011 Dec;66(5):501-3.
    PMID: 22390112
    A 10 year-old Iban girl presented with severe odynophagia for 4 days and subcutaneous emphysema. Clinically, her neck was tender with crepitus. Lateral neck radiograph showed multiple linear radiolucent shadows at retropharyngeal space. Flexible nasopharyngolaryngoscope revealed a tunnel behind upper oesophagus with slough and there was pooling of saliva at pyriform sinus. Feeding via nasogastric tube was started and empirical treatment for fungal and bacterial infection was commenced. Subsequent computed tomography of neck and thorax showed a 15-long blind tract at subglottic region posterior to oesophagus (prevertebral region), extending to superior mediastinum just before carina at T3/T4 level, represent abscess. Hourly suctioning of the remaining abscess in the blind tract with 10ml-syringe was done.
    Matched MeSH terms: Escherichia coli Infections/diagnosis; Escherichia coli Infections/therapy*
  14. Tan TL, Lee LY, Lim WC
    Med J Malaysia, 2018 12;73(6):427-429.
    PMID: 30647223
    The occurrence of Leptospirosis and Escherichia coli coinfection in the post-partum period is a novel case. This report illustrated a previously well woman from a suburban area presented with acute neurological deterioration following a two days history of fever during her puerperal period. Early interventions with fluids, broad spectrum antibiotics and intensive supportive care were given. Despite that, she deteriorated rapidly and developed pulmonary hemorrhage, disseminated intravascular coagulopathy, and multi-organ failure. She succumbed within 12 hours of admission. The knowledge about such fatal co-infections should be disseminated to medical practitioners encountering Leptospirosis infection and general public.
    Matched MeSH terms: Escherichia coli Infections/complications*; Escherichia coli Infections/microbiology
  15. Jegathesan M, Singh RB, Kanaganayagi M, Soon LE
    Med J Malaysia, 1976 Sep;31(1):46-56.
    PMID: 799233
    Matched MeSH terms: Escherichia coli Infections/complications
  16. Shunmugam P, Kanapathy S, Chan SE, Singh KK
    Braz J Infect Dis, 2012 Nov-Dec;16(6):603-4.
    PMID: 23158263 DOI: 10.1016/j.bjid.2012.07.005
    Matched MeSH terms: Escherichia coli Infections/epidemiology*
  17. Iyer L, Vadivelu J, Parasakthi N
    Singapore Med J, 1995 Oct;36(5):495-7.
    PMID: 8882532
    The production of heat-labile (LT) and heat-stable (ST) enterotoxins, colonisation factor antigens (CFAs) and haemagglutinins was investigated amongst 310 Escherichia coli (E. coli) isolates obtained from 62 children under the age of five, with diarrhoea. Twenty-one isolates were found to produce enterotoxins, of which fifteen (71%) isolates produced ST only, 2 (10%) produced LT only and 4 (19%) produced both LT and ST. However, none of the isolates demonstrated any of the common CFAs identified to date, but 8 out of the 21 isolates demonstrated haemagglutination with rabbit, sheep or human group A erythrocytes, suggesting the presence of putative CFAs, yet unidentified.
    Matched MeSH terms: Escherichia coli Infections/immunology*
  18. Chen SL, Ding Y, Apisarnthanarak A, Kalimuddin S, Archuleta S, Omar SFS, et al.
    Sci Rep, 2019 09 13;9(1):13245.
    PMID: 31519972 DOI: 10.1038/s41598-019-49467-5
    The ST131 multilocus sequence type (MLST) of Escherichia coli is a globally successful pathogen whose dissemination is increasing rates of antibiotic resistance. Numerous global surveys have demonstrated the pervasiveness of this clone; in some regions ST131 accounts for up to 30% of all E. coli isolates. However, many regions are underrepresented in these published surveys, including Africa, South America, and Asia. We collected consecutive bloodstream E. coli isolates from three countries in Southeast Asia; ST131 was the most common MLST type. As in other studies, the C2/H30Rx clade accounted for the majority of ST131 strains. Clinical risk factors were similar to other reported studies. However, we found that nearly all of the C2 strains in this study were closely related, forming what we denote the SEA-C2 clone. The SEA-C2 clone is enriched for strains from Asia, particularly Southeast Asia and Singapore. The SEA-C2 clone accounts for all of the excess resistance and virulence of ST131 relative to non-ST131 E. coli. The SEA-C2 strains appear to be locally circulating and dominant in Southeast Asia, despite the intuition that high international connectivity and travel would enable frequent opportunities for other strains to establish themselves.
    Matched MeSH terms: Escherichia coli Infections/drug therapy; Escherichia coli Infections/genetics; Escherichia coli Infections/microbiology; Escherichia coli Infections/epidemiology*
  19. Anwar A, Masri A, Rao K, Rajendran K, Khan NA, Shah MR, et al.
    Sci Rep, 2019 02 28;9(1):3122.
    PMID: 30816269 DOI: 10.1038/s41598-019-39528-0
    Herein, we report green synthesized nanoparticles based on stabilization by plant gums, loaded with citrus fruits flavonoids Hesperidin (HDN) and Naringin (NRG) as novel antimicrobial agents against brain-eating amoebae and multi-drug resistant bacteria. Nanoparticles were thoroughly characterized by using zetasizer, zeta potential, atomic force microscopy, ultravoilet-visible and Fourier transform-infrared spectroscopic techniques. The size of these spherical nanoparticles was found to be in the range of 100-225 nm. The antiamoebic effects of these green synthesized Silver and Gold nanoparticles loaded with HDN and NRG were tested against Acanthamoeba castellanii and Naegleria fowleri, while antibacterial effects were evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and neuropathogenic Escherichia coli K1. Amoebicidal assays revealed that HDN loaded Silver nanoparticles stabilized by gum acacia (GA-AgNPs-HDN) quantitatively abolished amoeba viability by 100%, while NRG loaded Gold nanoparticles stabilized by gum tragacanth (GT-AuNPs-NRG) significantly reduced the viability of A. castellanii and N. fowleri at 50 µg per mL. Furthermore, these nanoparticles inhibited the encystation and excystation by more than 85%, as well as GA-AgNPs-HDN only completely obliterated amoeba-mediated host cells cytopathogenicity. Whereas, GA-AgNPs-HDN exhibited significant bactericidal effects against MRSA and E. coli K1 and reduced bacterial-mediated host cells cytotoxicity. Notably, when tested against human cells, these nanoparticles showed minimal (23%) cytotoxicity at even higher concentration of 100 µg per mL as compared to 50 µg per mL used for antimicrobial assays. Hence, these novel nanoparticles formulations hold potential as therapeutic agents against infections caused by brain-eating amoebae, as well as multi-drug resistant bacteria, and recommend a step forward in drug development.
    Matched MeSH terms: Escherichia coli Infections/drug therapy
  20. Lau GL, Sieo CC, Tan WS, Hair-Bejo M, Jalila A, Ho YW
    Poult Sci, 2010 Dec;89(12):2589-96.
    PMID: 21076096 DOI: 10.3382/ps.2010-00904
    The efficacy of bacteriophage EC1, a lytic bacteriophage, against Escherichia coli O78:K80, which causes colibacillosis in poultry, was determined in the present study. A total of 480 one-day-old birds were randomly assigned to 4 treatments groups, each with 4 pens of 30 birds. Birds from the control groups (groups I and II) received PBS (pH 7.4) or 10(10) pfu of bacteriophage EC1, respectively. Group III consisted of birds challenged with 10(8) cfu of E. coli O78:K80 and treated with 10(10) pfu of bacteriophage EC1 at 2 h postinfection, whereas birds from group IV were challenged with 10(8) cfu of E. coli O78:K80 only. All the materials were introduced into the birds by intratracheal inoculation. Based on the results of the present study, the infection was found to be less severe in the treated E. coli-challenged group. Mean total viable cell counts of E. coli identified on eosin methylene blue agar (designated EMB + E. coli) in the lungs were significantly lower in treated, E. coli-challenged birds than in untreated, E. coli-challenged birds on d 1 and 2 postinfection. The EMB + E. coli isolation frequency was also lower in treated birds; no E. coli was detectable in blood samples on any sampling day, and E. coli were isolated only in the liver, heart, and spleen of treated chickens at a ratio of 2/6, 1/6, and 3/6, respectively, at d 1 postinfection. The BW of birds from the E. coli-challenged group treated with bacteriophage EC1 were not significantly different from those of birds from both control groups but were 15.4% higher than those of the untreated, E. coli-challenged group on d 21 postinfection. The total mortality rate of birds during the 3-wk experimental period decreased from 83.3% in the untreated, E. coli-challenged birds (group IV) to 13.3% in birds treated with bacteriophage EC1 (group III). These results suggest that bacteriophage EC1 is effective in vivo and could be used to treat colibacillosis in chickens.
    Matched MeSH terms: Escherichia coli Infections/pathology; Escherichia coli Infections/therapy; Escherichia coli Infections/transmission; Escherichia coli Infections/veterinary*
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