Displaying publications 1 - 20 of 219 in total

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  1. Fulltext Risk factors and spatial distribution of extended spectrum β-lactamase-producing- Escherichia coli at retail poultry meat markets in Malaysia: a cross-sectional study
    Aliyu AB, Saleha AA, Jalila A, Zunita Z
    BMC Public Health, 2016 08 02;16:699.
    PMID: 27484086 DOI: 10.1186/s12889-016-3377-2
    BACKGROUND: The significant role of retail poultry meat as an important exposure pathway for the acquisition and transmission of extended spectrum β-lactamase-producing Escherichia coli (ESBL-EC) into the human population warrants understanding concerning those operational practices associated with dissemination of ESBL-EC in poultry meat retailing. Hence, the objective of this study was to determine the prevalence, spatial distribution and potential risk factors associated with the dissemination of ESBL-EC in poultry meat retail at wet-markets in Selangor, Malaysia.

    METHODS: Poultry meat (breast, wing, thigh, and keel) as well as the contact surfaces of weighing scales and cutting boards were sampled to detect ESBL-EC by using culture and disk combination methods and polymerase chain reaction assays. Besides, questionnaire was used to obtain data and information pertaining to those operational practices that may possibly explain the occurrence of ESBL-EC. The data were analysed using logistic regression analysis at 95 % CI.

    RESULTS: The overall prevalence of ESBL-EC was 48.8 % (95 % CI, 42 - 55 %). Among the risk factors that were explored, type of countertop, sanitation of the stall environment, source of cleaning water, and type of cutting board were found to be significantly associated with the presence of ESBL-EC.

    CONCLUSIONS: Thus, in order to prevent or reduce the presence of ESBL-EC and other contaminants at the retail-outlet, there is a need to design a process control system based on the current prevailing practices in order to reduce cross contamination, as well as to improve food safety and consumer health.

    Matched MeSH terms: Escherichia coli/genetics
  2. Fulltext Molecular characterization of multi-drug resistant Escherichia coli isolates from tropical environments in Southeast Asia
    Hara H, Yusaimi YA, Zulkeflle SNM, Sugiura N, Iwamoto K, Goto M, et al.
    J Gen Appl Microbiol, 2019 Jan 24;64(6):284-292.
    PMID: 29877296 DOI: 10.2323/jgam.2018.02.003
    The emergence of antibiotic resistance among multidrug-resistant (MDR) microbes is of growing concern, and threatens public health globally. A total of 129 Escherichia coli isolates were recovered from lowland aqueous environments near hospitals and medical service centers in the vicinity of Kuala Lumpur, Malaysia. Among the eleven antibacterial agents tested, the isolates were highly resistant to trimethoprim-sulfamethoxazole (83.7%) and nalidixic acid (71.3%) and moderately resistant to ampicillin and chloramphenicol (66.7%), tetracycline (65.1%), fosfomycin (57.4%), cefotaxime (57.4%), and ciprofloxacin (57.4%), while low resistance levels were found with aminoglycosides (kanamycin, 22.5%; gentamicin, 21.7%). The presence of relevant resistance determinants was evaluated, and the genotypic resistance determinants were as follows: sulfonamides (sulI, sulII, and sulIII), trimethoprim (dfrA1 and dfrA5), quinolones (qnrS), β-lactams (ampC and blaCTX-M), chloramphenicol (cmlA1 and cat2), tetracycline (tetA and tetM), fosfomycin (fosA and fosA3), and aminoglycosides (aphA1 and aacC2). Our data suggest that multidrug-resistant E. coli strains are ubiquitous in the aquatic systems of tropical countries and indicate that hospital wastewater may contribute to this phenomenon.
    Matched MeSH terms: Escherichia coli/genetics*
  3. Molecular characterization and phylogeny of Shiga toxin-producing E. coli (STEC) from imported beef meat in Malaysia
    Abuelhassan NN, Mutalib SA, Gimba FI, Yusoff WM
    Environ Sci Pollut Res Int, 2016 Sep;23(17):17553-62.
    PMID: 27234829 DOI: 10.1007/s11356-016-6954-0
    This study aimed at determining the presence and characterization of Escherichia coli and Shiga toxin-producing E. coli (STEC) from imported frozen beef meats. Seventy-four (74) frozen imported beef meat samples from two countries, India (42 samples) and Australia (32 samples), were collected and tested for E. coli. These samples were purchased from the frozen meat sections of five different supermarkets in different locations in Selangor, Malaysia, from April 2012 to October 2014. A total of 222 E. coli strains were isolated from the meat samples; 126 strains were isolated from country A (India), and 96 E. coli strains were from country of origin B (Australia), respectively. A total of 70 E. coli strains were identified and characterized. All E. coli strains were isolated into Fluorocult medium and identified using API 20E kit. All selected E. coli strains were characterized for Shiga toxin genes (stx1 and stx2). All biochemically identified E. coli in this study were further subjected to molecular detection through polymerase chain reaction (PCR) amplification and characterization using 16S ribosomal RNA (rRNA) gene of Shiga toxin-producing E. coli. Of the 70 E. coli strains, 11 strains were positive for both Shiga toxin genes (stx1 and stx2) and 11 (11/70) strains were positive for stx1 gene, while 25 (25/70) strains were positive for stx2 gene. The analysis of 16S rRNA gene of all the E. coli isolates in this study was successfully sequenced and analyzed, and based on sequence data obtained, a phylogenetic tree of the 16S rRNA gene was performed using Clustal W programme in MEGA 6.06 software. Phylogenetic tree showed that the E. coli isolates in our study cluster with the strain of E. coli isolated in other countries, which further confirm that the isolates of E. coli in this study are similar to those obtained in other studies. As a result, all the strains obtained in this study proved to be a strain of pathogenic E. coli, which may cause a serious outbreak of food-borne disease. The isolation of pathogenic E. coli strains from the imported meat samples calls for prudent management of imported meats by the relevant authorities.
    Matched MeSH terms: Shiga-Toxigenic Escherichia coli/genetics*
  4. Newcastle disease virus nucleocapsid protein: self-assembly and length-determination domains
    Kho CL, Tan WS, Tey BT, Yusoff K
    J Gen Virol, 2003 Aug;84(Pt 8):2163-2168.
    PMID: 12867648 DOI: 10.1099/vir.0.19107-0
    The nucleocapsid protein (NP) of Newcastle disease virus expressed in E. coli assembled as ring- and herringbone-like particles. In order to identify the contiguous NP sequence essential for assembly of these particles, 11 N- or C-terminally deleted NP mutants were constructed and their ability to self-assemble was tested. The results indicate that a large part of the NP N-terminal end, encompassing amino acids 1 to 375, is required for proper folding to form a herringbone-like structure. In contrast, the C-terminal end covering amino acids 376 to 489 was dispensable for the formation of herringbone-like particles. A region located between amino acids 375 to 439 may play a role in regulating the length of the herringbone-like particles. Mutants with amino acid deletions further from the C-terminal end (84, 98, 109 and 114 amino acids) tended to form longer particles compared to mutants with shorter deletions (25 and 49 amino acids).
    Matched MeSH terms: Escherichia coli/genetics
  5. Cloning and expression of the nucleocapsid protein gene of nipah virus in different strains of Escherichia coli
    Ong ST, Tan WS, Hassan SS, Mohd Lila MA, Yusoff K
    J. Biochem. Mol. Biol. Biophys., 2002 Oct;6(5):347-50.
    PMID: 12385971
    The coding region of the nucleocapsid (N) gene was amplified from the viral RNA and inserted into the bacterial expression vector, pTrcHis2, for intracellular expression in three Escherichia coli strains: TOP 10, BL 21 and SG 935. The N protein was expressed as a fusion protein containing the myc epitope and His-tag at its C-terminal end. The amount of the fusion protein expressed in strain SG 935 was significantly higher than the other two strains, and was detected by the anti-myc antibody, anti-His and swine anti-NiV serum. Hence, the N(fus) protein produced in E. coli could serve as an alternative antigen for the detection of anti-NiV in swine.
    Matched MeSH terms: Escherichia coli/genetics
  6. Chimeric Newcastle disease virus nucleocapsid with parts of viral hemagglutinin-neuraminidase and fusion proteins
    Rabu A, Tan WS, Kho CL, Omar AR, Yusoff K
    Acta Virol., 2002;46(4):211-7.
    PMID: 12693857
    The nucleocapsid (NP) protein of Newcastle disease virus (NDV) self-assembled in Escherichia coli as ring-like and herringbone-like particles. Several chimeric NP proteins were constructed in which the antigenic regions of the hemagglutinin-neuraminidase (HN) and fusion (F) proteins of NDV, myc epitope, and six histidines (a hexa-His tag) were linked to the C-terminus of the NP monomer. These chimeric proteins were expressed efficiently in soluble form in E. coli as detected by Western blot analysis. Electron microscopy of the purified products revealed that they self-assembled into ring-like particles. These chimeric particles exhibited antigenicity of the myc epitope, suggesting that the foreign sequences were exposed on the surface of the particles. Chickens inoculated with the chimeric particles mounted an immune response against NDV, suggesting the possibility of use of the ring-like particle as a carrier of immunogens in subunit vaccines and immunological reagents.
    Matched MeSH terms: Escherichia coli/genetics
  7. Cloning and expression of the phosphoprotein gene of Newcastle disease virus in Escherichia coli
    Kho CL, Tan WS, Yusoff K
    J. Biochem. Mol. Biol. Biophys., 2002 Apr;6(2):117-21.
    PMID: 12186767
    The phosphoprotein (P) gene of a heat stable Newcastle disease virus (NDV) was cloned, sequenced and expressed in Escherichia coli. SDS-PAGE analysis of the recombinant P protein (395 amino acids) and a C-terminal extension derivative (424 amino acids), gave rise to two distinct protein bands with molecular masses of approximately 53-55 and 56-58 kDa, respectively, which are approximately 26-30% heavier than those calculated from the deduced amino acid sequences. The differences in molecular mass on SDS-PAGE are thought to be attributed to the acidic nature of the P protein (pI=6.27) and also the different degrees of phosphorylation in the prokaryotic cell. Amino acid sequence comparison of the P protein among the published NDV strains showed that they were highly conserved particularly at the putative phosphorylation sites.
    Matched MeSH terms: Escherichia coli/genetics
  8. Solubility, immunogenicity and physical properties of the nucleocapsid protein of Nipah virus produced in Escherichia coli
    Tan WS, Ong ST, Eshaghi M, Foo SS, Yusoff K
    J Med Virol, 2004 May;73(1):105-12.
    PMID: 15042656
    The nucleocapsid (N) protein of Nipah virus (NiV) can be produced in three Escherichia coli strains [TOP10, BL21(DE3) and SG935] under the control of trc promoter. However, most of the product existed in the form of insoluble inclusion bodies. There was no improvement in the solubility of the product when this protein was placed under the control of T7 promoter. However, the solubility of the N protein was significantly improved by lowering the growth temperature of E. coli BL21(DE3) cell cultures. Solubility analysis of N- and C-terminally deleted mutants revealed that the full-length N protein has the highest solubility. The soluble N protein could be purified efficiently by sucrose gradient centrifugation and nickel affinity chromatography. Electron microscopic analysis of the purified product revealed that the N protein assembled into herringbone-like particles of different lengths. The C-terminal end of the N protein contains the major antigenic region when probed with antisera from humans and pigs infected naturally.
    Matched MeSH terms: Escherichia coli/genetics
  9. Purification of the extra-cellular domain of Nipah virus glycoprotein produced in Escherichia coli and possible application in diagnosis
    Eshaghi M, Tan WS, Chin WK, Yusoff K
    J Biotechnol, 2005 Mar 30;116(3):221-6.
    PMID: 15707682
    The glycoprotein (G) of Nipah virus (NiV) is important for virus infectivity and induction of the protective immunity. In this study, the extra-cellular domain of NiV G protein was fused with hexahistidine residues at its N-terminal end and expressed in Escherichia coli. The expression under transcriptional regulation of T7 promoter yielded insoluble protein aggregates in the form of inclusion bodies. The inclusion bodies were solubilized with 8 M urea and the protein was purified to homogeneity under denaturing conditions using nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography. The denatured protein was renatured by gradual removal of the urea. Light scattering analysis of the purified protein showed primarily monodispersity. The purified protein showed significant reactivity with the antibodies present in the sera of NiV-infected swine, as demonstrated in Western blot analysis and enzyme-linked immunosorbent assay (ELISA). Taken together, the data indicate the potential usefulness of the purified G protein for structural or functional studies and the development of immunoassay for detection of the NiV antibodies.
    Matched MeSH terms: Escherichia coli/genetics*
  10. Inhibitory effects of a peptide-fusion protein (Latarcin-PAP1-Thanatin) against chikungunya virus
    Rothan HA, Bahrani H, Shankar EM, Rahman NA, Yusof R
    Antiviral Res, 2014 Aug;108:173-80.
    PMID: 24929084 DOI: 10.1016/j.antiviral.2014.05.019
    Chikungunya virus (CHIKV) outbreaks have led to a serious economic burden, as the available treatment strategies can only alleviate disease symptoms, and no effective therapeutics or vaccines are currently available for human use. Here, we report the use of a new cost-effective approach involving production of a recombinant antiviral peptide-fusion protein that is scalable for the treatment of CHIKV infection. A peptide-fusion recombinant protein LATA-PAP1-THAN that was generated by joining Latarcin (LATA) peptide with the N-terminus of the PAP1 antiviral protein, and the Thanatin (THAN) peptide to the C-terminus, was produced in Escherichia coli as inclusion bodies. The antiviral LATA-PAP1-THAN protein showed 89.0% reduction of viral plaque formation compared with PAP1 (46.0%), LATA (67.0%) or THAN (79.3%) peptides alone. The LATA-PAP1-THAN protein reduced the viral RNA load that was 0.89-fold compared with the untreated control cells. We also showed that PAP1 resulted in 0.44-fold reduction, and THAN and LATA resulting in 0.78-fold and 0.73-fold reductions, respectively. The LATA-PAP1-THAN protein inhibited CHIKV replication in the Vero cells at an EC50 of 11.2μg/ml, which is approximately half of the EC50 of PAP1 (23.7μg/ml) and protected the CHIKV-infected mice at the dose of 0.75mg/ml. We concluded that production of antiviral peptide-fusion protein in E. coli as inclusion bodies could accentuate antiviral activities, enhance cellular internalisation, and could reduce product toxicity to host cells and is scalable to epidemic response quantities.
    Matched MeSH terms: Escherichia coli/genetics
  11. Fulltext Antiviral cationic peptides as a strategy for innovation in global health therapeutics for dengue virus: high yield production of the biologically active recombinant plectasin peptide
    Rothan HA, Mohamed Z, Suhaeb AM, Rahman NA, Yusof R
    OMICS, 2013 Nov;17(11):560-7.
    PMID: 24044366 DOI: 10.1089/omi.2013.0056
    Dengue virus infects millions of people worldwide, and there is no vaccine or anti-dengue therapeutic available. Antimicrobial peptides have been shown to possess effective antiviral activity against various viruses. One of the main limitations of developing these peptides as potent antiviral drugs is the high cost of production. In this study, high yield production of biologically active plectasin peptide was inexpensively achieved by producing tandem plectasin peptides as inclusion bodies in E. coli. Antiviral activity of the recombinant peptide towards dengue serotype-2 NS2B-NS3 protease (DENV2 NS2B-NS3pro) was assessed as a target to inhibit dengue virus replication in Vero cells. Single units of recombinant plectasin were collected after applying consecutive steps of refolding, cleaving by Factor Xa, and nickel column purification to obtain recombinant proteins of high purity. The maximal nontoxic dose (MNTD) of the recombinant peptide against Vero cells was 20 μM (100 μg/mL). The reaction velocity of DENV2 NS2B-NS3pro decreased significantly after increasing concentrations of recombinant plectasin were applied to the reaction mixture. Plectasin peptide noncompetitively inhibited DENV2 NS2B-NS3pro at Ki value of 5.03 ± 0.98 μM. The percentage of viral inhibition was more than 80% at the MNTD value of plectasin. In this study, biologically active recombinant plectasin which was able to inhibit dengue protease and viral replication in Vero cells was successfully produced in E. coli in a time- and cost- effective method. These findings are potentially important in the development of potent therapeutics against dengue infection.
    Matched MeSH terms: Escherichia coli/genetics
  12. Fulltext Scalable Production of Recombinant Membrane Active Peptides and Its Potential as a Complementary Adjunct to Conventional Chemotherapeutics
    Rothan HA, Ambikabothy J, Abdulrahman AY, Bahrani H, Golpich M, Amini E, et al.
    PLoS One, 2015;10(9):e0139248.
    PMID: 26418816 DOI: 10.1371/journal.pone.0139248
    The production of short anticancer peptides in recombinant form is an alternative method for costly chemical manufacturing. However, the limitations of host toxicity, bioactivity and column purification have impaired production in mass quantities. In this study, short cationic peptides were produced in aggregated inclusion bodies by double fusion with a central protein that has anti-cancer activity. The anticancer peptides Tachiplicin I (TACH) and Latarcin 1 (LATA) were fused with the N- and C-terminus of the MAP30 protein, respectively. We successfully produced the recombinant TACH-MAP30-LATA protein and MAP30 alone in E. coli that represented 59% and 68% of the inclusion bodies. The purified form of the inclusion bodies was prepared by eliminating host cell proteins through multiple washing steps and semi-solubilization in alkaline buffer. The purified active protein was recovered by inclusive solubilization at pH 12.5 in the presence of 2 M urea and refolded in alkaline buffer containing oxides and reduced glutathione. The peptide-fusion protein showed lower CC50 values against cancer cells (HepG2, 0.35±0.1 μM and MCF-7, 0.58±0.1 μM) compared with normal cells (WRL68, 1.83±0.2 μM and ARPE19, 2.5±0.1 μM) with outstanding activity compared with its individual components. The presence of the short peptides facilitated the entry of the peptide fusion protein into cancer cells (1.8 to 2.2-fold) compared with MAP30 alone through direct interaction with the cell membrane. The cancer chemotherapy agent doxorubicin showed higher efficiency and selectivity against cancer cells in combination with the peptide- fusion protein. This study provides new data on the mass production of short anticancer peptides as inclusion bodies in E. coli by fusion with a central protein that has similar activity. The product was biologically active against cancer cells compared with normal cells and enhanced the activity and selective delivery of an anticancer chemotherapy agent.
    Matched MeSH terms: Escherichia coli/genetics
  13. Fulltext Fusion of protegrin-1 and plectasin to MAP30 shows significant inhibition activity against dengue virus replication
    Rothan HA, Bahrani H, Mohamed Z, Abd Rahman N, Yusof R
    PLoS One, 2014;9(4):e94561.
    PMID: 24722532 DOI: 10.1371/journal.pone.0094561
    Dengue virus (DENV) broadly disseminates in tropical and sub-tropical countries and there are no vaccine or anti-dengue drugs available. DENV outbreaks cause serious economic burden due to infection complications that requires special medical care and hospitalization. This study presents a new strategy for inexpensive production of anti-DENV peptide-fusion protein to prevent and/or treat DENV infection. Antiviral cationic peptides protegrin-1 (PG1) and plectasin (PLSN) were fused with MAP30 protein to produce recombinant antiviral peptide-fusion protein (PG1-MAP30-PLSN) as inclusion bodies in E. coli. High yield production of PG1-MAP30-PLSN protein was achieved by solubilization of inclusion bodies in alkaline buffer followed by the application of appropriate refolding techniques. Antiviral PG1-MAP30-PLSN protein considerably inhibited DENV protease (NS2B-NS3pro) with half-maximal inhibitory concentration (IC50) 0.5±0.1 μM. The real-time proliferation assay (RTCA) and the end-point proliferation assay (MTT assay) showed that the maximal-nontoxic dose of the peptide-fusion protein against Vero cells is approximately 0.67±0.2 μM. The cell-based assays showed considerable inhibition of the peptide-fusion protein against binding and proliferating stages of DENV2 into the target cells. The peptide-fusion protein protected DENV2-challeged mice with 100% of survival at the dose of 50 mg/kg. In conclusion, producing recombinant antiviral peptide-fusion protein by combining short antiviral peptide with a central protein owning similar activity could be useful to minimize the overall cost of short peptide production and take advantage of its synergistic antiviral activities.
    Matched MeSH terms: Escherichia coli/genetics
  14. Combination of essential oils and antibiotics reduce antibiotic resistance in plasmid-conferred multidrug resistant bacteria
    Yap PS, Lim SH, Hu CP, Yiap BC
    Phytomedicine, 2013 Jun 15;20(8-9):710-3.
    PMID: 23537749 DOI: 10.1016/j.phymed.2013.02.013
    In this study we investigated the relationship between several selected commercially available essential oils and beta-lactam antibiotics on their antibacterial effect against multidrug resistant bacteria. The antibacterial activity of essential oils and antibiotics was assessed using broth microdilution. The combined effects between essential oils of cinnamon bark, lavender, marjoram, tea tree, peppermint and ampicillin, piperacillin, cefazolin, cefuroxime, carbenicillin, ceftazidime, meropenem, were evaluated by means of the checkerboard method against beta-lactamase-producing Escherichia coli. In the latter assays, fractional inhibitory concentration (FIC) values were calculated to characterize interaction between the combinations. Substantial susceptibility of the bacteria toward natural antibiotics and a considerable reduction in the minimum inhibitory concentrations (MIC) of the antibiotics were noted in some paired combinations of antibiotics and essential oils. Out of 35 antibiotic-essential oil pairs tested, four of them showed synergistic effect (FIC≤0.5) and 31 pairs showed no interaction (FIC>0.5-4.0). The preliminary results obtained highlighted the occurrence of a pronounced synergistic relationship between piperacillin/cinnamon bark oil, piperacillin/lavender oil, piperacillin/peppermint oil as well as meropenem/peppermint oil against two of the three bacteria under study with a FIC index in the range 0.26-0.5. The finding highlighted the potential of peppermint, cinnamon bark and lavender essential oils being as antibiotic resistance modifying agent. Reduced usage of antibiotics could be employed as a treatment strategy to decrease the adverse effects and possibly to reverse the beta-lactam antibiotic resistance.
    Matched MeSH terms: Escherichia coli/genetics
  15. Heterologous expression of the tetracycline resistance gene tetX to enhance degradability and safety in doxycycline degradation
    Wen X, Huang J, Cao J, Xu J, Mi J, Wang Y, et al.
    Ecotoxicol Environ Saf, 2020 Mar 15;191:110214.
    PMID: 31968275 DOI: 10.1016/j.ecoenv.2020.110214
    Microbial remediation has the potential to inexpensively yet effectively decontaminate and restore contaminated environments, but the virulence of pathogens and risk of resistance gene transmission by microorganisms during antibiotic removal often limit its implementation. Here, a cloned tetX gene with clear evolutionary history was expressed to explore doxycycline (DOX) degradation and resistance variation during the degradation process. Phylogenetic analysis of tetX genes showed high similarity with those of pathogenic bacteria, such as Riemerella sp. and Acinetobacter sp. Successful tetX expression was performed in Escherichia coli and confirmed by SDS-PAGE and Western blot. Our results showed that 95.0 ± 1.0% of the DOX (50 mg/L) was degraded by the recombinant strain (ETD-1 with tetX) within 48 h, which was significantly higher than that for the control (38.9 ± 8.7%) and the empty plasmid bacteria (8.8 ± 5.1%) (P  0.05). The efficient and safe DOX-degrading capacity of the recombinant strain ETD-1 makes it valuable and promising for antibiotic removal in the environment.
    Matched MeSH terms: Escherichia coli/genetics
  16. Fulltext Four products from Escherichia coli pseudogenes increase hydrogen production
    Mohd Yusoff MZ, Hashiguchi Y, Maeda T, Wood TK
    Biochem Biophys Res Commun, 2013 Oct 4;439(4):576-9.
    PMID: 24025676 DOI: 10.1016/j.bbrc.2013.09.016
    Pseudogenes are considered to be nonfunctional genes that lack a physiological role. By screening 3985 Escherichia coli mutants using chemochromic membranes, we found four pseudogenes involved in hydrogen metabolism. Knockouts of pseudogenes ydfW and ypdJ had a defective hydrogen phenotype on glucose and formate, respectively. Also, the knockout of pseudogene yqiG formed hydrogen from formate but not from glucose. For the yqiG mutant, 100% hydrogen recovery was obtained by the complementation of YqiG via a plasmid. The knockout of pseudogene ylcE showed hydrogen deficiency in minimal media which suggested that the role of YlcE is associated with cell growth. Hence, the products of these four pseudogenes play an important physiological role in hydrogen production in E. coli.
    Matched MeSH terms: Escherichia coli/genetics
  17. Conjugal transfer of multiple antibiotic resistance from hospital isolates of Klebsiella to Escherichia coli
    Koh CL, Lim ME, Wong YH
    Southeast Asian J. Trop. Med. Public Health, 1983 Sep;14(3):336-40.
    PMID: 6362015
    Six independent isolates of Klebsiella from hospital environmental sources in Malaysia were found to be resistant to at least ampicillin, carbenicillin, cefoperazone, chloramphenicol, gentamicin and tetracycline. On the basis of their antibiograms, they were divided into four antibiogroups. They transferred all or part of their multiple antibiotic resistance traits to E. coli by conjugation. The results suggest that these Klebsiella strains harbour self-transmissible R plasmids. The significance of these findings are discussed.
    Matched MeSH terms: Escherichia coli/genetics*
  18. Fulltext Role of α-helical structure in organic solvent-activated homodimer of elastase strain K
    Rahman RN, Salleh AB, Basri M, Wong CF
    Int J Mol Sci, 2011;12(9):5797-814.
    PMID: 22016627 DOI: 10.3390/ijms12095797
    Recombinant elastase strain K overexpressed from E. coli KRX/pCon2(3) was purified to homogeneity by a combination of hydrophobic interaction chromatography and ion exchange chromatography, with a final yield of 48% and a 25-fold increase in specific activity. The purified protein had exhibited a first ever reported homodimer size of 65 kDa by SDS-PAGE and MALDI-TOF, a size which is totally distinct from that of typically reported 33 kDa monomer from P. aeruginosa. The organic solvent stability experiment had demonstrated a stability pattern which completely opposed the rules laid out in previous reports in which activity stability and enhancement were observed in hydrophilic organic solvents such as DMSO, methanol, ethanol and 1-propanol. The high stability and enhancement of the enzyme in hydrophilic solvents were explained from the view of alteration in secondary structures. Elastinolytic activation and stability were observed in 25 and 50% of methanol, respectively, despite slight reduction in α-helical structure caused upon the addition of the solvent. Further characterization experiments had postulated great stability and enhancement of elastase strain K in broad range of temperatures, pHs, metal ions, surfactants, denaturing agents and substrate specificity, indicating its potential application in detergent formulation.
    Matched MeSH terms: Escherichia coli/genetics
  19. Extraintestinal pathogenic Escherichia coli (ExPEC) of human and avian origin belonging to sequence type complex 95 (STC95) portray indistinguishable virulence features
    Nandanwar N, Janssen T, Kühl M, Ahmed N, Ewers C, Wieler LH
    Int J Med Microbiol, 2014 Oct;304(7):835-42.
    PMID: 25037925 DOI: 10.1016/j.ijmm.2014.06.009
    Extraintestinal pathogenic Escherichia coli (ExPEC) strains of certain genetic lineages are frequently implicated in a wide range of diseases in humans and birds. ExPEC strains belonging to the phylogenetic lineage/sequence type complex 95 (STC95) are one such prominent lineage that is commonly isolated from extraintestinal infections such as systemic disease in poultry and urinary tract infections (UTIs), neonatal meningitis and sepsis in humans. Several epidemiological studies have indicated that ST95 strains obtained from such infections may share similar virulence genes and other genomic features. However, data on their ability to establish infections in vivo as deduced from the manifestation of similar virulence phenotypes remain elusive. In the present study, 116 STC95 ExPEC isolates comprising 55 human and 61 avian strains, possessing similar virulence gene patterns, were characterized in vitro using adhesion, invasion, biofilm formation and serum bactericidal assays. Overall, STC95 strains from both groups, namely human and birds, were equally capable of adhering to and invading the two mammalian kidney cell lines. Similarly, these strains were able to form strong biofilms in M63 medium. Furthermore, they were equally resistant to the bactericidal activity of human and avian serum. Our cumulative data reinforce the understanding that ST95 strains from poultry present a potential zoonotic risk and therefore need a One Health strategy for a successfull intervention.
    Matched MeSH terms: Escherichia coli/genetics*
  20. Fulltext Novel Plasmid-Mediated Colistin Resistance Gene mcr-3 in Escherichia coli
    Yin W, Li H, Shen Y, Liu Z, Wang S, Shen Z, et al.
    mBio, 2017 06 27;8(3).
    PMID: 28655818 DOI: 10.1128/mBio.00543-17
    The mobile colistin resistance gene mcr-1 has attracted global attention, as it heralds the breach of polymyxins, one of the last-resort antibiotics for the treatment of severe clinical infections caused by multidrug-resistant Gram-negative bacteria. To date, six slightly different variants of mcr-1, and a second mobile colistin resistance gene, mcr-2, have been reported or annotated in the GenBank database. Here, we characterized a third mobile colistin resistance gene, mcr-3 The gene coexisted with 18 additional resistance determinants in the 261-kb IncHI2-type plasmid pWJ1 from porcine Escherichia colimcr-3 showed 45.0% and 47.0% nucleotide sequence identity to mcr-1 and mcr-2, respectively, while the deduced amino acid sequence of MCR-3 showed 99.8 to 100% and 75.6 to 94.8% identity to phosphoethanolamine transferases found in other Enterobacteriaceae species and in 10 Aeromonas species, respectively. pWJ1 was mobilized to an E. coli recipient by conjugation and contained a plasmid backbone similar to those of other mcr-1-carrying plasmids, such as pHNSHP45-2 from the original mcr-1-harboring E. coli strain. Moreover, a truncated transposon element, TnAs2, which was characterized only in Aeromonas salmonicida, was located upstream of mcr-3 in pWJ1. This ΔTnAs2-mcr-3 element was also identified in a shotgun genome sequence of a porcine E. coli isolate from Malaysia, a human Klebsiella pneumoniae isolate from Thailand, and a human Salmonella enterica serovar Typhimurium isolate from the United States. These results suggest the likelihood of a wide dissemination of the novel mobile colistin resistance gene mcr-3 among Enterobacteriaceae and aeromonads; the latter may act as a potential reservoir for mcr-3IMPORTANCE The emergence of the plasmid-mediated colistin resistance gene mcr-1 has attracted substantial attention worldwide. Here, we examined a colistin-resistant Escherichia coli isolate that was negative for both mcr-1 and mcr-2 and discovered a novel mobile colistin resistance gene, mcr-3 The amino acid sequence of MCR-3 aligned closely with phosphoethanolamine transferases from Enterobacteriaceae and Aeromonas species originating from both clinical infections and environmental samples collected in 12 countries on four continents. Due to the ubiquitous profile of aeromonads in the environment and the potential transfer of mcr-3 between Enterobacteriaceae and Aeromonas species, the wide spread of mcr-3 may be largely underestimated. As colistin has been and still is widely used in veterinary medicine and used at increasing frequencies in human medicine, the continuous monitoring of mobile colistin resistance determinants in colistin-resistant Gram-negative bacteria is imperative for understanding and tackling the dissemination of mcr genes in both the agricultural and health care sectors.
    Matched MeSH terms: Escherichia coli/genetics*
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