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  1. Fulltext 4'-O-substitutions determine selectivity of aminoglycoside antibiotics
    Perez-Fernandez D, Shcherbakov D, Matt T, Leong NC, Kudyba I, Duscha S, et al.
    Nat Commun, 2014;5:3112.
    PMID: 24473108 DOI: 10.1038/ncomms4112
    Clinical use of 2-deoxystreptamine aminoglycoside antibiotics, which target the bacterial ribosome, is compromised by adverse effects related to limited drug selectivity. Here we present a series of 4',6'-O-acetal and 4'-O-ether modifications on glucopyranosyl ring I of aminoglycosides. Chemical modifications were guided by measuring interactions between the compounds synthesized and ribosomes harbouring single point mutations in the drug-binding site, resulting in aminoglycosides that interact poorly with the drug-binding pocket of eukaryotic mitochondrial or cytosolic ribosomes. Yet, these compounds largely retain their inhibitory activity for bacterial ribosomes and show antibacterial activity. Our data indicate that 4'-O-substituted aminoglycosides possess increased selectivity towards bacterial ribosomes and little activity for any of the human drug-binding pockets.
    Matched MeSH terms: Escherichia coli/drug effects; Escherichia coli/isolation & purification
  2. A Comprehensive Review on L-Asparaginase and Its Applications
    Batool T, Makky EA, Jalal M, Yusoff MM
    Appl Biochem Biotechnol, 2016 Mar;178(5):900-23.
    PMID: 26547852 DOI: 10.1007/s12010-015-1917-3
    L-asparaginase (LA) catalyzes the degradation of asparagine, an essential amino acid for leukemic cells, into ammonia and aspartate. Owing to its ability to inhibit protein biosynthesis in lymphoblasts, LA is used to treat acute lymphoblastic leukemia (ALL). Different isozymes of this enzyme have been isolated from a wide range of organisms, including plants and terrestrial and marine microorganisms. Pieces of information about the three-dimensional structure of L-asparaginase from Escherichia coli and Erwinia sp. have identified residues that are essential for catalytic activity. This review catalogues the major sources of L-asparaginase, the methods of its production through the solid state (SSF) and submerged (SmF) fermentation, purification, and characterization as well as its biological roles. In the same breath, this article explores both the past and present applications of this important enzyme and discusses its future prospects.
    Matched MeSH terms: Escherichia coli
  3. Fulltext A Highly Sensitive Impedimetric DNA Biosensor Based on Hollow Silica Microspheres for Label-Free Determination of E. coli
    Yuhana Ariffin E, Heng LY, Tan LL, Abd Karim NH, Hasbullah SA
    Sensors (Basel), 2020 Feb 26;20(5).
    PMID: 32111092 DOI: 10.3390/s20051279
    A novel label-free electrochemical DNA biosensor was constructed for the determination of Escherichia coli bacteria in environmental water samples. The aminated DNA probe was immobilized onto hollow silica microspheres (HSMs) functionalized with 3-aminopropyltriethoxysilane and deposited onto a screen-printed electrode (SPE) carbon paste with supported gold nanoparticles (AuNPs). The biosensor was optimized for higher specificity and sensitivity. The label-free E. coli DNA biosensor exhibited a dynamic linear response range of 1 × 10-10 µM to 1 × 10-5 µM (R2 = 0.982), with a limit of detection at 1.95 × 10-15 µM, without a redox mediator. The sensitivity of the developed DNA biosensor was comparable to the non-complementary and single-base mismatched DNA. The DNA biosensor demonstrated a stable response up to 21 days of storage at 4 ℃ and pH 7. The DNA biosensor response was regenerable over three successive regeneration and rehybridization cycles.
    Matched MeSH terms: Escherichia coli/isolation & purification*
  4. A MALDI TOF MS-based minisequencing method for rapid detection of TEM-type extended-spectrum beta-lactamases in clinical strains of Enterobacteriaceae
    Ikryannikova LN, Shitikov EA, Zhivankova DG, Il'ina EN, Edelstein MV, Govorun VM
    J Microbiol Methods, 2008 Dec;75(3):385-91.
    PMID: 18694787 DOI: 10.1016/j.mimet.2008.07.005
    A minisequencing method based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) was developed for rapid identification of single nucleotide polymorphisms at bla(TEM) gene codons 104, 164 and 238 associated with extended-spectrum activity on TEM-type beta-lactamases. The method was validated by testing the Escherichia coli and Klebsiella pneumoniae strains possessing the known bla(TEM) gene sequences.
    Matched MeSH terms: Escherichia coli/genetics
  5. A PROspective study on the Usage patterns of Doripenem in the Asia-Pacific region (PROUD study)
    Mustafa M, Chan WM, Lee C, Harijanto E, Loo CM, Van Kinh N, et al.
    Int J Antimicrob Agents, 2014 Apr;43(4):353-60.
    PMID: 24636429 DOI: 10.1016/j.ijantimicag.2014.01.017
    Doripenem is approved in the Asia-Pacific (APAC) region for treating nosocomial pneumonia (NP) including ventilator-associated pneumonia (VAP), complicated intra-abdominal infections (cIAIs) and complicated urinary tract infections (cUTIs). Clinical usage of doripenem (500mg intravenously, infused over 1h or 4h every 8h for 5-14 days) in APAC was evaluated in a prospective, open-label, non-comparative, multicentre study of inpatients (≥18 years) with NP, VAP, cIAI or cUTI. A total of 216 [intention-to-treat (ITT)] patients received doripenem: 53 NP (24.5%); 77 VAP (35.6%); 67 cIAI (31.0%); and 19 cUTI (8.8%). Doripenem MIC90 values for Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae were 32, 32, 0.094 and 0.64μg/mL, respectively. Doripenem was used most commonly as monotherapy (86.6%) and as second-line therapy (62.0%). The clinical cure rate in clinically evaluable patients was 86.7% at the end of therapy (EOT) and 87.1% at test of cure (TOC) (7-14 days after EOT). In the ITT population, overall clinical cure rates were 66.2% at EOT and 56.5% at TOC. The median duration of hospital stay, intensive care unit (ICU) stay and mechanical ventilation was 20, 12 and 10 days, respectively. Of 146 discharged patients, 7 were re-admitted within 28 days of EOT; 1 VAP patient was re-admitted to the ICU. The all-cause mortality rate was 22.7% (49/216). The most common treatment-related adverse events were diarrhoea (1.4%) and vomiting (1.4%). Doripenem is a viable option for treating APAC patients with NP, VAP, cIAI or cUTI. [ClinicalTrials.gov: NCT 00986102].
    Matched MeSH terms: Escherichia coli/drug effects; Escherichia coli/pathogenicity; Escherichia coli Infections/drug therapy
  6. A Point Prevalence Study of the Use of Antibiotics in Six Tertiary Care Hospitals in the Kathmandu Valley, Nepal
    Jha N, Thapa B, Pathak SB, Pandey A, Pokhrel S, Shankar PR, et al.
    Kathmandu Univ Med J (KUMJ), 2022;20(79):351-358.
    PMID: 37042379
    Background Point prevalence survey (PPS) on antibiotic use developed by the WHO has already been used in many hospitals globally. Objective To obtain information on antibiotic prescribtion using point prevalence survey methodology in six private hospitals in the Kathmandu valley. Method This descriptive cross-sectional study was completed during 20th July to 28th July 2021 using point prevalence survey methodology. The study was conducted among inpatients admitted at or before 8:00 AM on the day of survey in various wards. Data was presented as frequencies and percentages. Result Maximum number of patients were above 60 years [34 (18.7%)]. Number of male and female participants were equal [91 (50%)]. Only one antibiotic was used in 81 patients (44.5%) followed by two antibiotics in 71 (39%) patients. Duration of prophylactic antibiotic use was one day in 66 (63.7%) patients. Blood, urine, sputum, and wound swabs were the common samples for culture. Cultures were positive for 17 (24.7%) samples. The common organisms isolated were E. Coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. Ceftriaxone was the most used antibiotic. Drug and therapeutics, infection control committee and pharmacovigilance activities were present in 3/6 (50%) study sites. Antimicrobial stewardship was present in 3/6 (50%) and microbiological services was present in all hospitals. Antibiotic formulary and antibiotic guideline were present in 4/6 sites and facilities to audit or review surgical antibiotic prophylaxis choice in 2/6 (33.3%) sites, facility to monitor antibiotic use in 4/6 (66.6%) and cumulative antibiotic susceptibility reports in 2/6 (33.3%) study sites. Conclusion Ceftriaxone was the most used antibiotic. E. Coli, Pseudomonas aeruginosa and Klebsiella pneumonia were the commonly isolated organisms. Not all parameters for infrastructure, policy and practice and monitoring and feedback were present at the study sites. KEY WORDS.
    Matched MeSH terms: Escherichia coli*
  7. Fulltext A comparative study on the expression, purification and functional characterization of human adiponectin in Pichia pastoris and Escherichia coli
    Rothan HA, Teh SH, Haron K, Mohamed Z
    Int J Mol Sci, 2012;13(3):3549-62.
    PMID: 22489167 DOI: 10.3390/ijms13033549
    Adiponectin is one of the most bioactive substances secreted by adipose tissue and is involved in the protection against metabolic syndrome, artherosclerosis and type II diabetes. Research into the use of adiponectin as a promising drug for metabolic syndromes requires production of this hormone in high quantities considering its molecular isoforms. The objective of this study is to produce recombinant human adiponectin by Pichia pastoris (P-ADP) as a cheap and convenient eukaryotic expression system for potential application in pharmaceutical therapy. For comparison, adiponectin was also expressed using the Escherichia coli (E-ADP) expression system. Adiponectin was constructed by overlap-extension PCR, and cloned in standard cloning vector and hosts. Recombinant expression vectors were cloned in the P. pastoris and E. coli host strains, respectively. SDS-PAGE and western blotting were used to detect and analyse expressed recombinant protein in both systems. Adiponectin was purified by affinity chromatography and quantified using the Bradford Assay. The results of this study indicated that P-ADP quantity (0.111 mg/mL) was higher than that of E-ADP (0.04 mg/mL) and both were produced in soluble form. However, P-ADP was able to form high molecular weights of adiponectin molecules, whilst E-ADP was not able to form isoforms higher than trimer. In addition, P-ADP was more active in lowering blood glucose compared with E-ADP. The two types of proteins were equally efficient and significantly decreased blood triglyceride and increased high density lipoprotein. We conclude that P. pastoris is able to produce high quantity of bioactive adiponectin for potential use in treatment of metabolic syndromes.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism*
  8. A comprehensive study on antidiabetic and antibacterial activities of ZnO nanoparticles biosynthesized using Silybum marianum L seed extract
    Mohammadi Arvanag F, Bayrami A, Habibi-Yangjeh A, Rahim Pouran S
    Mater Sci Eng C Mater Biol Appl, 2019 Apr;97:397-405.
    PMID: 30678925 DOI: 10.1016/j.msec.2018.12.058
    Green synthesis of ZnO nanoparticles (NPs) using the plants' extract and their potential application have driven a tremendous interest in recent years. This study reports a green microwave-assisted method for synthesis of ZnO NPs using Silybum marianum L. seed extract. Characteristics of the as-prepared sample was explored in terms of crystalline phase, morphology, composition, surface area, optical, and thermal properties. The particles of the biosynthesized sample (ZnO/extract) had smaller sizes than the chemically produced one (ZnO). The existence of biomolecules from Silybum marianum L seed extract linked to the ZnO/extract sample was approved by various analyses. The ZnO/extract sample was used for treating alloxan-induced diabetic rats and its efficiency was compared with ZnO, extract, and insulin treatments. For this purpose, the levels of blood glucose, insulin, total cholesterol, total triglyceride, and high-density lipoprotein were measured before and after treating with the studied treatment agents and compared with each other. Moreover, the antibacterial activities of both ZnO samples were investigated against E. coli to assess their potential antibacterial application. From the results, ZnO/extract NPs represented an outstanding performance in overcoming the diabetic disorders and good antibacterial activity against the studied bacteria.
    Matched MeSH terms: Escherichia coli/drug effects
  9. Fulltext A fascinating case of the ‘purple urine bag syndrome'
    Low, Qin Jian, Lim, Tzyy Hue, Teoh, Kuo Zhau, Siow, Garry Peir Woeei, Go, Zher Lin, Tee, Vern Jun, et al.
    Borneo Journal of Medical Sciences, 2018;12(3):59-62.
    MyJurnal
    Purple urine bag syndrome (PUBS) is a rare presentation of urinary tract infections (UTIs). It is commonly seen in constipated patients. There is a deep purple discoloration of contents of urine bag due to presence of indigo and indirubin pigments which are metabolites of tryptophan. We would like to describe an interesting case of purple urine bag syndrome of 88-year-old woman who presented with catheter-related urinary tract infection. She had low-grade fever and suprapubic discomfort for three days duration. She had increased white cell count and C-reactive peptide (CRP). Urinalysis showed protein 2+, nitrite and leucocyte esterase positive. Urine culture grew Escherichia coli and Klebsiella pneumoniae. She was treated with oral cefuroxime and recovered. This case report may be the first case of PUBS reported in this region.
    Matched MeSH terms: Escherichia coli
  10. A feasibility study for appraising recreational water quality in a Southeast Asian beach complex
    Appan A
    Environ Monit Assess, 1991 Oct;19(1-3):361-72.
    PMID: 24233953 DOI: 10.1007/BF00401325
    In a case study involving preliminary investigations for the feasibility of a beach resort complex in the west coast of Sarawak, Malaysia, since the acceptable quality of recreational water quality had not been specified, existing international standards and practices were reviewed to arrive at acceptable microbiological and physicochemical parametric levels. Water samples were collected on a weekly basis in the proposed beach complex at Tanjong Batu Coastal Reserve and also along the nearby Sungei Batang Kemena and its estuary. It was ascertained that the swimming water quality was acceptable in terms of faecal Coliforms, temperature, pH and dissolved oxygen. However E. Coli counts did indicate a potential risk of 1.68% for gastrointestinal illness and the ubiquitous presence of faecal Streptococci pointed to recent pollution of human or animal origin. Besides, grease and oil contents exceeded the WHO Guideline values. It was hence recommended that an appropriate sanitation or pollution survey should be carried out in the adjacent coastal catchment area and the beach. Also routine water sampling should be undertaken. Such action will help to pinpoint sources of pollution and lead to antipollution measures, thus helping to upgrade swimming water quality and establish swimming water quality standards.
    Matched MeSH terms: Escherichia coli
  11. 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*; Escherichia coli Proteins/genetics
  12. A functionally-distinct carboxylic acid reductase PcCAR4 unearthed from a repertoire of type IV CARs in the white-rot fungus Pycnoporus cinnabarinus
    Ling JG, Mansor MH, Abdul Murad AM, Mohd Khalid R, Quay DHX, Winkler M, et al.
    J Biotechnol, 2020 Jan 10;307:55-62.
    PMID: 31545972 DOI: 10.1016/j.jbiotec.2019.09.008
    Carboxylic acid reductases (CARs) are attracting burgeoning attention as biocatalysts for organic synthesis of aldehydes and their follow-up products from economic carboxylic acid precursors. The CAR enzyme class as a whole, however, is still poorly understood. To date, relatively few CAR sequences have been reported, especially from fungal sources. Here, we sought to increase the diversity of the CAR enzyme class. Six new CAR sequences from the white-rot fungus Pycnoporus cinnabarinus were identified from genome-wide mining. Genome and gene clustering analysis suggests that these PcCAR enzymes play different natural roles in Basidiomycete systems, compared to their type II Ascomycete counterparts. The cDNA sequences of all six Pccar genes were deduced and analysis of their corresponding amino acid sequence showed that they encode for proteins of similar properties that possess a conserved modular functional tri-domain arrangement. Phylogenetic analyses showed that all PcCAR enzymes cluster together with the other type IV CARs. One candidate, PcCAR4, was cloned and over-expressed recombinantly in Escherichia coli. Subsequent biotransformation-based screening with a panel of structurally-diverse carboxylic acid substrates suggest that PcCAR4 possessed a more pronounced substrate specificity compared to previously reported CARs, preferring to reduce sterically-rigid carboxylic acids such as benzoic acid. These findings thus present a new functionally-distinct member of the CAR enzyme class.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism
  13. Fulltext A high-throughput oxidative stress biosensor based on Escherichia coli roGFP2 cells immobilized in a k-carrageenan matrix
    Ooi L, Heng LY, Mori IC
    Sensors (Basel), 2015;15(2):2354-68.
    PMID: 25621608 DOI: 10.3390/s150202354
    Biosensors fabricated with whole-cell bacteria appear to be suitable for detecting bioavailability and toxicity effects of the chemical(s) of concern, but they are usually reported to have drawbacks like long response times (ranging from hours to days), narrow dynamic range and instability during long term storage. Our aim is to fabricate a sensitive whole-cell oxidative stress biosensor which has improved properties that address the mentioned weaknesses. In this paper, we report a novel high-throughput whole-cell biosensor fabricated by immobilizing roGFP2 expressing Escherichia coli cells in a k-carrageenan matrix, for the detection of oxidative stress challenged by metalloid compounds. The E. coli roGFP2 oxidative stress biosensor shows high sensitivity towards arsenite and selenite, with wide linear range and low detection limit (arsenite: 1.0 × 10(-3)-1.0 × 10(1) mg·L(-1), LOD: 2.0 × 10(-4) mg·L(-1); selenite: 1.0 × 10(-5)-1.0 × 10(2) mg·L(-1), LOD: 5.8 × 10(-6) mg·L(-1)), short response times (0-9 min), high stability and reproducibility. This research is expected to provide a new direction in performing high-throughput environmental toxicity screening with living bacterial cells which is capable of measuring the bioavailability and toxicity of environmental stressors in a friction of a second.
    Matched MeSH terms: Escherichia coli/chemistry
  14. A hybrid of ant colony optimization and minimization of metabolic adjustment to improve the production of succinic acid in Escherichia coli
    Chong SK, Mohamad MS, Mohamed Salleh AH, Choon YW, Chong CK, Deris S
    Comput Biol Med, 2014 Jun;49:74-82.
    PMID: 24763079 DOI: 10.1016/j.compbiomed.2014.03.011
    This paper presents a study on gene knockout strategies to identify candidate genes to be knocked out for improving the production of succinic acid in Escherichia coli. Succinic acid is widely used as a precursor for many chemicals, for example production of antibiotics, therapeutic proteins and food. However, the chemical syntheses of succinic acid using the traditional methods usually result in the production that is far below their theoretical maximums. In silico gene knockout strategies are commonly implemented to delete the gene in E. coli to overcome this problem. In this paper, a hybrid of Ant Colony Optimization (ACO) and Minimization of Metabolic Adjustment (MoMA) is proposed to identify gene knockout strategies to improve the production of succinic acid in E. coli. As a result, the hybrid algorithm generated a list of knockout genes, succinic acid production rate and growth rate for E. coli after gene knockout. The results of the hybrid algorithm were compared with the previous methods, OptKnock and MOMAKnock. It was found that the hybrid algorithm performed better than OptKnock and MOMAKnock in terms of the production rate. The information from the results produced from the hybrid algorithm can be used in wet laboratory experiments to increase the production of succinic acid in E. coli.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism*; Escherichia coli/physiology
  15. A hybrid of bees algorithm and flux balance analysis with OptKnock as a platform for in silico optimization of microbial strains
    Choon YW, Mohamad MS, Deris S, Illias RM, Chong CK, Chai LE
    Bioprocess Biosyst Eng, 2014 Mar;37(3):521-32.
    PMID: 23892659 DOI: 10.1007/s00449-013-1019-y
    Microbial strain optimization focuses on improving technological properties of the strain of microorganisms. However, the complexities of the metabolic networks, which lead to data ambiguity, often cause genetic modification on the desirable phenotypes difficult to predict. Furthermore, vast number of reactions in cellular metabolism lead to the combinatorial problem in obtaining optimal gene deletion strategy. Consequently, the computation time increases exponentially with the increase in the size of the problem. Hence, we propose an extension of a hybrid of Bees Algorithm and Flux Balance Analysis (BAFBA) by integrating OptKnock into BAFBA to validate the result. This paper presents a number of computational experiments to test on the performance and capability of BAFBA. Escherichia coli, Bacillus subtilis and Clostridium thermocellum are the model organisms in this paper. Also included is the identification of potential reactions to improve the production of succinic acid, lactic acid and ethanol, plus the discussion on the changes in the flux distribution of the predicted mutants. BAFBA shows potential in suggesting the non-intuitive gene knockout strategies and a low variability among the several runs. The results show that BAFBA is suitable, reliable and applicable in predicting optimal gene knockout strategy.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism*
  16. A microdevice for rapid, monoplex and colorimetric detection of foodborne pathogens using a centrifugal microfluidic platform
    Sayad A, Ibrahim F, Mukim Uddin S, Cho J, Madou M, Thong KL
    Biosens Bioelectron, 2018 Feb 15;100:96-104.
    PMID: 28869845 DOI: 10.1016/j.bios.2017.08.060
    Outbreaks of foodborne diseases have become a global health concern; hence, many improvements and developments have been made to reduce the risk of food contamination. We developed a centrifugal microfluidic automatic wireless endpoint detection system integrated with loop mediated isothermal amplification (LAMP) for monoplex pathogen detection. Six identical sets were designed on the microfluidic compact disc (CD) to perform 30 genetic analyses of three different species of foodborne pathogens. The consecutive loading, mixing, and aliquoting of the LAMP primers/reagents and DNA sample solutions were accomplished using an optimized square-wave microchannel, metering chambers and revulsion per minute (RPM) control. We tested 24 strains of pathogenic bacteria (Escherichia coli, Salmonella spp and Vibrio cholerae), with 8 strains of each bacterium, and performed DNA amplification on the microfluidic CD for 60min. Then, the amplicons of the LAMP reaction were detected using the calcein colorimetric method and further analysed via the developed electronic system interfaced with Bluetooth wireless technology to transmit the results to a smartphone. The system showed a limit of detection (LOD) of 3 × 10-5ngμL-1 DNA by analysing the colour change when tested with chicken meat spiked with the three pathogenic bacteria. Since the entire process was performed in a fully automated way and was easy to use, our microdevice is suitable for point-of-care (POC) testing with high simplicity, providing affordability and accessibility even to poor, resource-limited settings.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/isolation & purification*
  17. Fulltext A multicentre study to determine the in vitro efficacy of flomoxef against extended-spectrum beta-lactamase producing Escherichia coli in Malaysia
    Yap PSX, Chong CW, Ponnampalavanar S, Ramli R, Harun A, Tengku Jamaluddin TZM, et al.
    PeerJ, 2023;11:e16393.
    PMID: 38047021 DOI: 10.7717/peerj.16393
    BACKGROUND: The high burden of extended-spectrum beta-lactamase-producing (ESBL)-producing Enterobacterales worldwide, especially in the densely populated South East Asia poses a significant threat to the global transmission of antibiotic resistance. Molecular surveillance of ESBL-producing pathogens in this region is vital for understanding the local epidemiology, informing treatment choices, and addressing the regional and global implications of antibiotic resistance.

    METHODS: Therefore, an inventory surveillance of the ESBL-Escherichia coli (ESBL-EC) isolates responsible for infections in Malaysian hospitals was conducted. Additionally, the in vitro efficacy of flomoxef and other established antibiotics against ESBL-EC was evaluated.

    RESULTS: A total of 127 non-repetitive ESBL-EC strains isolated from clinical samples were collected during a multicentre study performed in five representative Malaysian hospitals. Of all the isolates, 33.9% were isolated from surgical site infections and 85.8% were hospital-acquired infections. High rates of resistance to cefotaxime (100%), cefepime (100%), aztreonam (100%) and trimethoprim-sulfamethoxazole (100%) were observed based on the broth microdilution test. Carbapenems remained the most effective antibiotics against the ESBL-EC, followed by flomoxef. Antibiotic resistance genes were identified by PCR. The blaCTX-M-1 was the most prevalent ESBL gene, with 28 isolates (22%) harbouring blaCTX-M-1 only, 27 isolates (21.3%) co-harbouring blaCTX-M-1 and blaTEM, and ten isolates (7.9%) co-harbouring blaCTX-M-1, blaTEM and blaSHV. A generalised linear model showed significant antibacterial activity of imipenem against different types of infection. Besides carbapenems, this study also demonstrated a satisfactory antibacterial activity of flomoxef (81.9%) on ESBL-EC, regardless of the types of ESBL genes.

    Matched MeSH terms: Escherichia coli/genetics
  18. A mutant L-asparaginase II signal peptide improves the secretion of recombinant cyclodextrin glucanotransferase and the viability of Escherichia coli
    Ismail NF, Hamdan S, Mahadi NM, Murad AM, Rabu A, Bakar FD, et al.
    Biotechnol Lett, 2011 May;33(5):999-1005.
    PMID: 21234789 DOI: 10.1007/s10529-011-0517-8
    L-Asparaginase II signal peptide was used for the secretion of recombinant cyclodextrin glucanotransferase (CGTase) into the periplasmic space of E. coli. Despite its predominant localisation in the periplasm, CGTase activity was also detected in the extracellular medium, followed by cell lysis. Five mutant signal peptides were constructed to improve the periplasmic levels of CGTase. N1R3 is a mutated signal peptide with the number of positively charged amino acid residues in the n-region increased to a net charge of +5. This mutant peptide produced a 1.7-fold enhancement of CGTase activity in the periplasm and significantly decreased cell lysis to 7.8% of the wild-type level. The formation of intracellular inclusion bodies was also reduced when this mutated signal peptide was used as judged by SDS-PAGE. Therefore, these results provide evidence of a cost-effective means of expression of recombinant proteins in E. coli.
    Matched MeSH terms: Escherichia coli/enzymology*; Escherichia coli/genetics; Escherichia coli/metabolism*
  19. A new cold-adapted, organic solvent stable lipase from mesophilic Staphylococcus epidermidis AT2
    Kamarudin NH, Rahman RN, Ali MS, Leow TC, Basri M, Salleh AB
    Protein J, 2014 Jun;33(3):296-307.
    PMID: 24777627 DOI: 10.1007/s10930-014-9560-3
    The gene encoding a cold-adapted, organic solvent stable lipase from a local soil-isolate, mesophilic Staphylococcus epidermidis AT2 was expressed in a prokaryotic system. A two-step purification of AT2 lipase was achieved using butyl sepharose and DEAE sepharose column chromatography. The final recovery and purification fold were 47.09 % and 3.45, respectively. The molecular mass of the purified lipase was estimated to be 43 kDa. AT2 lipase was found to be optimally active at pH 8 and stable at pH 6-9. Interestingly, this enzyme demonstrated remarkable stability at cold temperature (<30 °C) and exhibited optimal activity at a temperature of 25 °C. A significant enhancement of the lipolytic activity was observed in the presence of Ca(2+), Tween 60 and Tween 80. Phenylmethylsulfonylfluoride, a well known serine inhibitor did not cause complete inhibition of the enzymatic activity. AT2 lipase exhibited excellent preferences towards long chain triglycerides and natural oils. The lipolytic activity was stimulated by dimethylsulfoxide and diethyl ether, while more than 50 % of its activity was retained in methanol, ethanol, acetone, toluene, and n-hexane. Taken together, AT2 lipase revealed highly attractive biochemical properties especially because of its stability at low temperature and in organic solvents.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism
  20. Fulltext A planetary health model for reducing exposure to faecal contamination in urban informal settlements: Baseline findings from Makassar, Indonesia
    French MA, Fiona Barker S, Taruc RR, Ansariadi A, Duffy GA, Saifuddaolah M, et al.
    Environ Int, 2021 10;155:106679.
    PMID: 34126296 DOI: 10.1016/j.envint.2021.106679
    BACKGROUND: The intense interactions between people, animals and environmental systems in urban informal settlements compromise human and environmental health. Inadequate water and sanitation services, compounded by exposure to flooding and climate change risks, expose inhabitants to environmental contamination causing poor health and wellbeing and degrading ecosystems. However, the exact nature and full scope of risks and exposure pathways between human health and the environment in informal settlements are uncertain. Existing models are limited to microbiological linkages related to faecal-oral exposures at the individual level, and do not account for a broader range of human-environmental variables and interactions that affect population health and wellbeing.

    METHODS: We undertook a 12-month health and environmental assessment in 12 flood-prone informal settlements in Makassar, Indonesia. We obtained caregiver-reported health data, anthropometric measurements, stool and blood samples from children coli and nitrogen species was common. Most (79·5%) houses had an in-house toilet, but no houses were connected to a piped sewer network or safe, properly constructed septic tank. Median monthly settlement outdoor temperatures ranged from 26·2 °C to 29.3 °C, and were on average, 1·1 °C warmer inside houses than outside. Mosquito density varied over time, with Culex quinquefasciatus accounting for 94·7% of species. Framed by a planetary health lens, our model includes four thematic domains: (1) the physical/built environment; (2) the ecological environment; (3) human health; and (4) socio-economic wellbeing, and is structured at individual, household, settlement, and city/beyond spatial scales.

    CONCLUSIONS: Our planetary health model includes key risk factors and faecal-oral exposure pathways but extends beyond conventional microbiological faecal-oral enteropathogen exposure pathways to comprehensively account for a wider range of variables affecting health in urban informal settlements. It includes broader ecological interconnections and planetary health-related variables at the household, settlement and city levels. It proposes a composite framework of markers to assess water and sanitation challenges and flood risks in urban informal settlements for optimal design and monitoring of interventions.

    Matched MeSH terms: Escherichia coli*
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