Displaying publications 1 - 20 of 138 in total

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  1. Wong JS, Mohd Azri ZA, Subramaniam G, Ho SE, Palasubramaniam S, Navaratnam P
    Malays J Pathol, 2003 Dec;25(2):113-9.
    PMID: 16196367
    beta-Lactamases have been identified as the major cause of antimicrobial resistance to beta-lactam antibiotics in Escherichia coli. The activities of ampicillin-sulbactam and amoxicillin-clavulanate as well as a range of beta-lactam antibiotics were studied with 87 clinical E. coli isolates from patients of the University Malaya Medical Center using the disc diffusion technique. Susceptible, intermediate and resistant categories were established based on the diameter of zones of inhibition set by the National Committee for Clinical Laboratory Standards (NCCLS). The isolates were then classified into 6 phenotypes according to the criteria stated in the methodology: S (susceptible to all beta-lactams); TL (resistant to aminopenicillins; amoxicillin-clavulanate susceptible and susceptible or intermediate to ampicillin-sulbactam); TI (resistant to aminopenicillins and ampicillin-sulbactam; susceptible to amoxicilin-clavulanate); TH-IRT (resistant to aminopenicillins; intermediate or resistant to amoxicillin-clavulanate; resistant to ampicillin-sulbactam); ESBL (resistant to aminopenicillins and oxyimino cephalosporins; positive results with the double-disc diffusion test); and CP (resistant to aminopenicillins, beta-lactam-beta-lactamase inhibitor combinations, oxyimino cephalosporins and cephamycins). Results showed that the TL phenotype was the commonest (40.2% of the isolates) followed by S (31%), TH-IRT (16.1%), ESBL and CP (3.4% each) and TI (2.3%). One isolate showed both ESBL and CP phenotypes while two isolates were classified as inconclusive. Representatives from each phenotype were further analysed for the presence of beta-lactamases which revealed a predominance of TEM and SHV enzyme producers. PCR-SSCP analysis of the SHV gene from all the ESBL and CP isolates revealed the predominance of SHV 5-type enzyme which was concurrent with our previous studies.
    Matched MeSH terms: Escherichia coli/drug effects*
  2. Gondos AS, Al-Moyed KA, Al-Robasi AB, Al-Shamahy HA, Alyousefi NA
    PLoS One, 2015;10(12):e0144266.
    PMID: 26657128 DOI: 10.1371/journal.pone.0144266
    Urinary tract infection (UTI) is the most common complication following kidney transplantation (KT), which could result in losing the graft. This study aims to identify the prevalence of bacterial UTI among KT recipients in Yemen and to determine the predisposing factors associated with post renal transplantation UTI. A cross sectional study included of 150 patients, who underwent KT was conducted between June 2010 and January 2011. A Morning mid-stream urine specimen was collected for culture and antibiotic susceptibility test from each recipient. Bacterial UTI was found in 50 patients (33.3%). The prevalence among females 40.3% was higher than males 29%. The UTI was higher in the age group between 41-50 years with a percentage of 28% and this result was statistically significant. Predisposing factors as diabetes mellitus, vesicoureteral reflux, neurogenic bladder and polycystic kidney showed significant association. High relative risks were found for polycystic kidney = 13.5 and neurogenic bladder = 13.5. The most prevalent bacteria to cause UTI was Escherichia coli represent 44%, followed by Staphylococcus saprophyticus 34%. Amikacin was the most effective antibiotic against gram-negative isolates while Ciprofloxacin was the most effective antibiotic against Staphylococcus saprophyticus. In conclusion, there is high prevalence of bacterial UTI among KT recipients in Yemen. Diabetes mellitus, vesicoureteral reflux, neurogenic bladder, polycystic kidney and calculi were the main predisposing factors.
    Matched MeSH terms: Escherichia coli/drug effects
  3. Ishii T, Kamada T, Vairappan CS
    J Asian Nat Prod Res, 2016 May;18(5):415-22.
    PMID: 26983053 DOI: 10.1080/10286020.2016.1145670
    Three new cembranoid diterpenes, 10-hydroxy-nephthenol acetate (1), 7,8-epoxy-10-hydroxy-nephthenol acetate (2), and 6-acetoxy-7,8-epoxy-10-hydroxy-nephthenol acetate (3), along with a known compound, 6-acetoxy-7,8-epoxy-nephthenol acetate (4), were isolated from the Bornean soft coral Nephthea sp. Antibacterial and anticancer activities were exhibited by compounds 1 and 2 against Staphylococcus aureus (ATCC 6538)/Escherichia coli (ATCC 13311) and Hela/MCF-7, respectively.
    Matched MeSH terms: Escherichia coli/drug effects
  4. Al-Qaim FF, Mussa ZH, Yuzir A, Latip J, Othman MR
    J Environ Sci (China), 2018 Dec;74:134-146.
    PMID: 30340667 DOI: 10.1016/j.jes.2018.02.019
    Prazosin (PRZ) and levonorgestrel (LNG) are widely used as an anti-disease drugs due to their biological activity in the human body. The frequent detection of these compounds in water samples requires alternative technologies for the removal of both compounds. After electrochemical degradation of PRZ and LNG, the parent compounds could be completely removed after treatment, but the identification and characterization of by-products are necessary as well. In this study, the effects of NaCl concentration and applied voltage were investigated during the electrochemical degradation process. The results revealed that the increase of NaCl concentration and applied voltage could promote the generation of hypochlorite OCl- and then enhance the degradation of PRZ and LNG. After initial study, 6V and 0.2g NaCl were selected for further experiments (96% and 99% removal of PRZ and LNG after 40min, respectively). Energy consumption was also evaluated and calculated for PRZ and LNG at 3, 6 and 8V. Solid phase extraction (SPE) method plays an important role in enhancing the detection limit of by-products. Furthermore, characterization and identification of chlorinated and non-chlorinated by-products were conducted using an accurate liquid chromatography-time of flight/mass spectrometry LC-TOF/MS instrument. The monitoring of products during the electrochemical degradation process was performed at 6V and 0.2g NaCl in a 50mL solution. The results indicated that two chlorinated products were formed during the electrochemical process. The toxicity of by-products toward E. coli bacteria was investigated at 37°C and 20hr incubation time.
    Matched MeSH terms: Escherichia coli/drug effects
  5. Ramli NS, Eng Guan C, Nathan S, Vadivelu J
    PLoS One, 2012;7(9):e44104.
    PMID: 22970167 DOI: 10.1371/journal.pone.0044104
    Burkholderia pseudomallei, a Gram-negative saprophytic bacterium, is the causative agent of the potentially fatal melioidosis disease in humans. In this study, environmental parameters including temperature, nutrient content, pH and the presence of glucose were shown to play a role in in vitro biofilm formation by 28 B. pseudomallei clinical isolates, including four isolates with large colony variants (LCVs) and small colony variants (SCVs) morphotypes. Enhanced biofilm formation was observed when the isolates were tested in LB medium, at 30 °C, at pH 7.2, and in the presence of as little as 2 mM glucose respectively. It was also shown that all SVCs displayed significantly greater capacity to form biofilms than the corresponding LCVs when cultured in LB at 37 °C. In addition, octanoyl-homoserine lactone (C(8)-HSL), a quorum sensing molecule, was identified by mass spectrometry analysis in bacterial isolates referred to as LCV CTH, LCV VIT, SCV TOM, SCV CTH, 1 and 3, and the presence of other AHL's with higher masses; decanoyl-homoserine lactone (C(10)-HSL) and dodecanoyl-homoserine lactone (C(12)-HSL) were also found in all tested strain in this study. Last but not least, we had successfully acquired two Bacillus sp. soil isolates, termed KW and SA respectively, which possessed strong AHLs degradation activity. Biofilm formation of B. pseudomallei isolates was significantly decreased after treated with culture supernatants of KW and SA strains, demonstrating that AHLs may play a role in B. pseudomallei biofilm formation.
    Matched MeSH terms: Escherichia coli/drug effects
  6. Forde BM, Ben Zakour NL, Stanton-Cook M, Phan MD, Totsika M, Peters KM, et al.
    PLoS One, 2014;9(8):e104400.
    PMID: 25126841 DOI: 10.1371/journal.pone.0104400
    Escherichia coli ST131 is now recognised as a leading contributor to urinary tract and bloodstream infections in both community and clinical settings. Here we present the complete, annotated genome of E. coli EC958, which was isolated from the urine of a patient presenting with a urinary tract infection in the Northwest region of England and represents the most well characterised ST131 strain. Sequencing was carried out using the Pacific Biosciences platform, which provided sufficient depth and read-length to produce a complete genome without the need for other technologies. The discovery of spurious contigs within the assembly that correspond to site-specific inversions in the tail fibre regions of prophages demonstrates the potential for this technology to reveal dynamic evolutionary mechanisms. E. coli EC958 belongs to the major subgroup of ST131 strains that produce the CTX-M-15 extended spectrum β-lactamase, are fluoroquinolone resistant and encode the fimH30 type 1 fimbrial adhesin. This subgroup includes the Indian strain NA114 and the North American strain JJ1886. A comparison of the genomes of EC958, JJ1886 and NA114 revealed that differences in the arrangement of genomic islands, prophages and other repetitive elements in the NA114 genome are not biologically relevant and are due to misassembly. The availability of a high quality uropathogenic E. coli ST131 genome provides a reference for understanding this multidrug resistant pathogen and will facilitate novel functional, comparative and clinical studies of the E. coli ST131 clonal lineage.
    Matched MeSH terms: Escherichia coli/drug effects
  7. Ur-Rehman A, Khan SG, Naqvi SAR, Ahmad M, Akhtar N, Bokhari TH, et al.
    Pak J Pharm Sci, 2021 Jan;34(1(Special)):441-446.
    PMID: 34275792
    A series of new derivatives of 4-(2-chloroethyl)morpholine hydrochloride (5) were efficiently synthesized. Briefly, different aromatic organic acids (1a-f) were refluxed to acquire respective esters (2a-f) using conc. H2SO4 as catalyst. The esters were subjected to nucleophillic substitution by monohydrated hydrazine to acquire hydrazides (3a-f). The hydrazides were cyclized with CS2 in the presence of KOH to yield corresponding oxadiazoles (4a-f). Finally, the derivatives, 6a-f, were prepared by reacting oxadiazoles (4a-f) with 5 using NaH as activator. Structures of all the derivatives were elucidated through 1D-NMR EI-MS and IR spectral data. All these molecules were subjected to antibacterial and hemolytic activities and showed good antibacterial and hemolytic potential relative to the reference standards.
    Matched MeSH terms: Escherichia coli/drug effects
  8. Rehman A, Siddiqa A, Abbasi MA, Siddiqui SZ, Khan SG, Rasool S, et al.
    Pak J Pharm Sci, 2018 Sep;31(5):1783-1790.
    PMID: 30150171
    A number of novel 5-substituted-2-((6-bromo-3,4-methylenedioxybenzyl)thio)-1,3,4-Oxadiazole derivatives (6a-l) have been synthesized to evaluate their antibacterial activity. Using aryl/aralkyl carboxylic acids (1a-l) as precursors, 5-substituted-1,3,4-Oxadiazol-2-thiols (4a-l) were yielded in good amounts. The derivatives, 4a-l, were subjected to electrophilic substitution reaction on stirring with 6-bromo-3,4-methylenedioxybenzyl chloride (5) in DMF to synthesize the required compounds. All the synthesized molecules were well characterized by IR, 1H-NMR, 13C-NMR and EIMS spectral data and evaluated for antibacterial activity against some bacterial strains of Gram-bacteria. The molecule, 6d, demonstrated the best activity among all the synthesized molecules exhibiting weak to moderate inhibition potential.
    Matched MeSH terms: Escherichia coli/drug effects
  9. Talari MK, Abdul Majeed AB, Tripathi DK, Tripathy M
    Chem Pharm Bull (Tokyo), 2012;60(7):818-24.
    PMID: 22790812
    The application of nanomaterials has gained considerable momentum in various fields in recent years due to their high reactivity, excellent surface properties and quantum effects in the nanometer range. The properties of zinc oxide (ZnO) vary with its crystallite size or particle size and often nanocrystalline ZnO is seen to exhibit superior physical and chemical properties due to their higher surface area and modified electronic structure. ZnO nanoparticles are reported to exhibit strong bacterial inhibiting activity and silver (Ag) has been extensively used for its antimicrobial properties since ages. In this study, Ag doped ZnO nanoparticles were synthesized by mechanochemical processing in a high energy ball mill and investigated for antimicrobial activity. The nanocrystalline nature of zinc oxide was established by X-ray diffraction (XRD) studies. It is seen from the XRD data obtained from the samples, that crystallite size of the zinc oxide nanoparticles is seen to decrease with increasing Ag addition. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) data also supported the nanoparticle formation during the synthesis. The doped nanoparticles were subjected to antimicrobial investigation and found that both increase in Ag content and decrease in particle size contributed significantly towards antimicrobial efficiency. It was also observed that Ag doped ZnO nanoparticles possess enhanced antimicrobial potential than that of virgin ZnO against the studied microorganisms of Escherichia coli and Staphylococcus aureus.
    Matched MeSH terms: Escherichia coli/drug effects
  10. Lah NAC, Gray R, Trigueros S
    Microb Cell Fact, 2021 Feb 17;20(1):46.
    PMID: 33596912 DOI: 10.1186/s12934-020-01478-y
    With the long-term goal of developing an ultra-sensitive microcantilever-based biosensor for versatile biomarker detection, new controlled bioreceptor-analytes systems are being explored to overcome the disadvantages of conventional ones. Gold (Au) microwires have been used as a probe to overcome the tolerance problem that occurs in response to changes in environmental conditions. However, the cytotoxicity of Au microwires is still unclear. Here, we examined the cytotoxicity of Au microwires systems using both commercial and as-synthesised Au microwires. In vitro experiments show that commercial Au microwires with an average quoted length of 5.6 µm are highly toxic against Gram-negative Escherichia coli (E. coli) at 50 µg/mL. However, this toxicity is due to the presence of CTAB surfactant not by the microwires. Conversely, the as-synthesised Au microwires show non-cytotoxicity even at the maximum viable concentration (330 µg/mL). These findings may lead to the development of potentially life-saving cytotoxicity-free biosensors for an early diagnostic of potential diseases.
    Matched MeSH terms: Escherichia coli/drug effects*
  11. Boldbaatar D, Gunasekera S, El-Seedi HR, Göransson U
    J Nat Prod, 2015 Nov 25;78(11):2545-51.
    PMID: 26509914 DOI: 10.1021/acs.jnatprod.5b00463
    The Ricinus communis biomarker peptides RCB-1 to -3 comprise homologous sequences of 19 (RCB-1) or 18 (RCB-2 and -3) amino acid residues. They all include four cysteine moieties, which form two disulfide bonds. However, neither the 3D structure nor the biological activity of any of these peptides is known. The synthesis of RCB-1, using microwave-assisted, Fmoc-based solid-phase peptide synthesis, and a method for its oxidative folding are reported. The tertiary structure of RCB-1, subsequently established using solution-state NMR, reveals a twisted loop fold with antiparallel β-sheets reinforced by the two disulfide bonds. Moreover, RCB-1 was tested for antibacterial, antifungal, and cytotoxic activity, as well as in a serum stability assay, in which it proved to be remarkably stable.
    Matched MeSH terms: Escherichia coli/drug effects
  12. Abbasi MA, Zeb A, Rehman A, Siddiqui SZ, Shah SAA, Shahid M, et al.
    Pak J Pharm Sci, 2020 Jan;33(1):41-47.
    PMID: 32122829
    The current research was commenced by reaction of 1,4-benzodioxane-6-amine (1) with 4-nitrobenzenesulfonyl chloride (2) in the presence of aqueous base under dynamic pH control at 9 to yield N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamide (3) which was further reacted with a series of alkyl/aralkyl halides (4a-i) in polar aprotic solvent using catalytic amount of lithium hydride which acts as base to afford some new N-alkyl/aralkyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamides (5a-i). The projected structures of all the synthesized derivatives were characterized by contemporary techniques i.e., IR, 1H-NMR and EIMS. The biofilm Inhibitory action of all synthesized molecules was carried out against Escherichia coli and Bacillus subtilis. It was inferred from their results that 5f and 5e exhibited suitable inhibitory action against the biofilms of these bacterial strains. Moreover, their cytotoxicity was also checked and it was concluded that these synthesized molecules displayed docile cytotoxicity.
    Matched MeSH terms: Escherichia coli/drug effects
  13. Abbasi MA, Fatima Z, Rehman AU, Siddiqui SZ, Ali Shah SA, Shahid M, et al.
    Pak J Pharm Sci, 2019 Sep;32(5):1957-1964.
    PMID: 31813858
    The present study comprises the synthesis of a new series of benzenesulfonamides derived from N-sulfonation of 2-(4-methoxyphenyl)-1-ethanamine (1). The synthesis was initiated by the reaction of 2-(4-methoxyphenyl)-1-ethanamine (1) with benzenesulfonyl chloride (2), to yield N-(4-methoxyphenethyl)benzenesulfonamide (3). This parent molecule 3 was subsequently treated with various alkyl/aralkyl halides (4a-j) in N,N-dimethylformamide (DMF) and in the presence of a weak base lithium hydride (LiH) to obtain various N-(alkyl/aralkyl)-N-(4-methoxyphenethyl) benzenesulfonamides (5a-j). The characterization of these derivatives was carried out by spectroscopic techniques like IR, 1H-NMR, and 13C-NMR. Elemental analysis also supported this data. The biofilm inhibitory action of all the synthesized compounds was carried out on Escherichia coli and some of the compounds were identified to be very suitable inhibitors of this bacterial strain. Furthermore, the molecules were also tested for their cytotoxicity behavior to assess their utility as less cytotoxic therapeutic agents.
    Matched MeSH terms: Escherichia coli/drug effects*
  14. Shameli K, Ahmad MB, Zargar M, Yunus WM, Rustaiyan A, Ibrahim NA
    Int J Nanomedicine, 2011;6:581-90.
    PMID: 21674015 DOI: 10.2147/IJN.S17112
    Silver nanoparticles (Ag NPs) were synthesized by the chemical reducing method in the external and interlamellar space of montmorillonite (MMT) as a solid support at room temperature. AgNO(3) and NaBH(4) were used as a silver precursor and reducing agent, respectively. The most favorable experimental conditions for synthesizing Ag NPs in the MMT are described in terms of the initial concentration of AgNO(3). The interlamellar space limits changed little (d-spacing = 1.24-1.47 nm); therefore, Ag NPs formed on the MMT suspension with d-average = 4.19-8.53 nm diameter. The Ag/MMT nanocomposites (NCs), formed from AgNO(3)/MMT suspension, were characterizations with different instruments, for example UV-visible, PXRD, TEM, SEM, EDXRF, FT-IR, and ICP-OES analyzer. The antibacterial activity of different sizes of Ag NPs in MMT were investigated against Gram-positive, ie, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) and Gram-negative bacteria, ie, Escherichia coli, Escherichia coli O157:H7, and Klebsiella pneumoniae, by the disk diffusion method using Mueller-Hinton agar (MHA). The smaller Ag NPs were found to have significantly higher antibacterial activity. These results showed that Ag NPs can be used as effective growth inhibitors in different biological systems, making them applicable to medical applications.
    Matched MeSH terms: Escherichia coli/drug effects
  15. Nazir M, Abbasi MA, Aziz-Ur-Rehman -, Siddiqui SZ, Ali Shah SA, Shahid M, et al.
    Pak J Pharm Sci, 2019 Nov;32(6):2585-2597.
    PMID: 31969290
    In the study presented here, the nucleophilic substitution reaction of 5-[3-(1H-indol-3-yl)propyl]-1,3,4-oxadiazol-2-ylhydrosulfide was carried out with different alkyl/aralkyl halides (5a-r) to form its different S-substituted derivatives (6a-r), as depicted in scheme 1. The structural confirmation of all the synthesized compounds was done by IR, 1H-NMR, 13C-NMR and CHN analysis data. Bacterial biofilm inhibitory activity of all the synthesized compounds was carried out against Bacillus subtilis and Escherichia coli. The anticancer activity of these molecules was ascertained using anti-proliferation (SRB) assay on HCT 116 Colon Cancer Cell lines while the cytotoxicity of these molecules was profiled for their haemolytic potential. From this investigation it was rational that most of the compounds exhibited suitable antibacterial and anticancer potential along with a temperate cytotoxicity.
    Matched MeSH terms: Escherichia coli/drug effects
  16. Ngaini Z, Mortadza NA
    Nat Prod Res, 2019 Dec;33(24):3507-3514.
    PMID: 29911437 DOI: 10.1080/14786419.2018.1486310
    Chemical modification of medicines from natural product-based molecules has become of interest in recent years. In this study, a series of halogenated azo derivatives 1a-d were synthesised via coupling reaction, followed by Steglich esterification with aspirin (a natural product derivative) to form azo derivatives 2a-d. While, halogenated azo-aspirin 3a-d were synthesised via direct coupling reaction of aspirin and diazonium salt. Bacteriostatic activity was demonstrated against E. coli and S. aureus via turbidimetric kinetic method. Compound 3a-d showed excellent antibacterial activities against E. coli (MIC 75-94 ppm) and S. aureus (MIC 64-89 ppm) compared to ampicillin (MIC 93 and 124 ppm respectively), followed by 1a-d and 2a-d. The presence of reactive groups of -OH, N=N, C=O and halogens significantly contribute excellent interaction towards E. coli and S. aureus. Molecular dockings analysis of 3a against MIaC protein showed binding free energy of -7.2 kcal/mol (E. coli) and -6.6 kcal/mol (S. aureus).
    Matched MeSH terms: Escherichia coli/drug effects
  17. Anwar A, Khalid S, Perveen S, Ahmed S, Siddiqui R, Khan NA, et al.
    J Nanobiotechnology, 2018 Jan 29;16(1):6.
    PMID: 29378569 DOI: 10.1186/s12951-017-0332-z
    BACKGROUND: Gold nanoparticles are useful candidate for drug delivery applications and are associated with enhancement in the bioavailability of coated drugs and/or therapeutic agent. Since, heterocyclic compounds are known to exhibit antimicrobial potential against variety of pathogens, we designed this study to evaluate the antibacterial effects of gold nanoparticles conjugation with new synthesized cationic ligand; 4-Dimethyl aminopyridinium propylthioacetate (DMAP-PTA) in comparison with pure compound and antibiotic drug Pefloxacin. Antibacterial activity of DMAP-PTA coated gold nanoparticles was investigated against a fecal strain of E. coli (ATCC 8739).

    RESULTS: A new dimethyl aminopyridine based stabilizing agent named as DMAP-PTA was synthesized and used for stabilization of gold nanoparticles. Gold nanoparticles coated with DMAP-PTA abbreviated as DMAP-PTA-AuNPs were thoroughly characterized by UV-visible, FT-IR spectroscopic methods and transmission electron microscope before biological assay. DMAP-PTA, DMAP-PTA-AuNPs and Pefloxacin were examined for their antibacterial potential against E. coli, and the minimum inhibitory concentration (MIC) was determined to be 300, 200 and 50 µg/mL respectively. Gold nanoparticles conjugation was found to significantly enhance the antibacterial activity of DMAP-PTA as compared to pure compound. Moreover, effects of DMAP-PTA-AuNPs on the antibacterial potential of Pefloxacin was also evaluated by combination therapy of 1:1 mixture of DMAP-PTA-AuNPs and Pefloxacin against E. coli in a wide range of concentrations from 5 to 300 µg/mL. The MIC of Pefloxacin + DMAP-PTA-AuNPs mixture was found to be 25 µg/mL as compared to Pefloxacin alone (50 µg/mL), which clearly indicates that DMAP-PTA-AuNPs increased the potency of Pefloxacin. AFM analysis was also carried out to show morphological changes occur in bacteria before and after treatment of test samples. Furthermore, DMAP-PTA-AuNPs showed high selectivity towards Pefloxacin in spectrophotometric drug recognition studies which offers tremendous potential for analytical applications.

    CONCLUSIONS: Gold nanoparticles conjugation was shown to enhance the antibacterial efficacy of DMAP-PTA ligand, while DMAP-PTA-AuNPs also induced synergistic effects on the potency of Pefloxacin against E. coli. DMAP-PTA-AuNPs were also developed as Pefloxacin probes in recognizing the drug in blood and water samples in the presence of other drugs.

    Matched MeSH terms: Escherichia coli/drug effects
  18. Shameli K, Bin Ahmad M, Zargar M, Yunus WM, Ibrahim NA, Shabanzadeh P, et al.
    Int J Nanomedicine, 2011;6:271-84.
    PMID: 21499424 DOI: 10.2147/IJN.S16043
    Silver nanoparticles (AgNPs) of a small size were successfully synthesized using the wet chemical reduction method into the lamellar space layer of montmorillonite/chitosan (MMT/Cts) as an organomodified mineral solid support in the absence of any heat treatment. AgNO3, MMT, Cts, and NaBH4 were used as the silver precursor, the solid support, the natural polymeric stabilizer, and the chemical reduction agent, respectively. MMT was suspended in aqueous AgNO3/Cts solution. The interlamellar space limits were changed (d-spacing = 1.24-1.54 nm); therefore, AgNPs formed on the interlayer and external surface of MMT/Cts with d-average = 6.28-9.84 nm diameter. Characterizations were done using different methods, ie, ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence spectrometry, and Fourier transform infrared spectroscopy. Silver/montmorillonite/chitosan bionanocomposite (Ag/MMT/Cts BNC) systems were examined. The antibacterial activity of AgNPs in MMT/Cts was investigated against Gram-positive bacteria, ie, Staphylococcus aureus and methicillin-resistant S. aureus and Gram-negative bacteria, ie, Escherichia coli, E. coli O157:H7, and Pseudomonas aeruginosa by the disc diffusion method using Mueller Hinton agar at different sizes of AgNPs. All of the synthesized Ag/MMT/Cts BNCs were found to have high antibacterial activity. These results show that Ag/MMT/Cts BNCs can be useful in different biological research and biomedical applications, including surgical devices and drug delivery vehicles.
    Matched MeSH terms: Escherichia coli/drug effects
  19. Ngaini Z, Fadzillah SM, Hussain H
    Nat Prod Res, 2012;26(10):892-902.
    PMID: 21678160 DOI: 10.1080/14786419.2010.502896
    A series of (E)-1-(4-alkyloxyphenyl)-3-(hydroxyphenyl)-prop-2-en-1-one have been successfully synthesised via Claisen-Schmidt condensation. The synthesised chalcone derivatives consisted of hydroxyl groups at either ortho, meta or para position and differed in the length of the alkyl groups, C (n) H(2) (n) (+1,) where n = 6, 10, 12 and 14. The structures of all compounds were defined by elemental analysis, IR, (1)H- and (13)C-NMR. The antimicrobial studies were carried out against wild-type Escherichia coli American Type Culture Collection 8739 to evaluate the effect of the hydroxyl and the alkyl groups of the synthesised chalcones. All the synthesised compounds have shown significant antimicrobial activities. The optimum inhibition was dependent on the position of the hydroxyl group as well as the length of the alkyl chains.
    Matched MeSH terms: Escherichia coli/drug effects
  20. Wan-Hamat H, Lani MN, Hamzah Y, Alias R, Hassan Z, Mahat NA
    Trop Biomed, 2020 Mar 01;37(1):103-115.
    PMID: 33612722
    The microbiological quality of thirty ready-to-eat (RTE) keropok lekor (a sausage shape Malaysian fish product) was evaluated in comparison to microbiological guidelines for ready to eat foods. The two E. coli isolates were subjected to DNA sequencing, identified and tested for their resistance towards fifteen different antibiotics. The survival and growth of the isolated E. coli strains inoculated in keropok lekor at atmospheric air and vacuum packaging were also evaluated. Results revealed that four samples (13.33%) contained Enterobacteriaceae counts that exceeded the recommended allowable counts of 4.0 log10 CFU/g. Unsatisfactory level of coliforms (< 1.7 log10 CFU/g) was also observed in ten of the samples; two of which contained E. coli (2.1 ± 0.17 and 3.7 ± 0.02 log10 CFU/g), suggesting of poor hygiene and sanitation practices. While the 'Possible E10' E. coli strain was observably resistant towards Nalidixic acid (30µg) alone, B10 E. coli isolate was worryingly resistant towards Ampicillin (10µg), Ceftazidime (30µg), Ciprofloxacin (5µg), Ceftriaxone (30µg), Nalidixic acid (30µg) and Tetracycline (30µg). This study also revealed that the growth and survival of the 'Possible E10' and B10 E. coli strains were not significantly affected by vacuum packaging when stored at both 4°C and 28°C. Therefore, intervention programmes to alert and educate smallmedium enterprisers (SMEs) of keropok lekor producers on food safety as well as potential health risks that can be associated due to inappropriate handling procedures of such product, merits consideration.
    Matched MeSH terms: Escherichia coli/drug effects*
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