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Fulltext Evaluation of in-vitro antioxidant and antibacterial properties of Commelina nudiflora L. extracts prepared by different polar solvents

Kuppusamy P, Yusoff MM, Parine NR, Govindan N

Saudi J Biol Sci, 2015 May;22(3):293-301.
PMID: 25972750 DOI: 10.1016/j.sjbs.2014.09.016

The study explored on the commonly available weed plant Commelina nudiflora which has potential in-vitro antioxidant and antimicrobial activity. The different polar solvents such as ethanol, chloroform, dichloromethane, hexane and aqueous were used for the soxhlet extraction. The extracts were identified pharmacologically as important bioactive compounds and their potential free radical scavenging activities, and antimicrobial properties were studied. C. nudiflora extracts were monitored on their in-vitro antioxidant ability by DPPH and ABTS radical scavenging assay. Aqueous extract shows significant free radical scavenging activity of 63.4 mg/GAE and 49.10 mg/g in DPPH and ABTS respectively. Furthermore, the aqueous crude extract was used in antibacterial studies, which shows the highest inhibitory activity against Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among all the extracts, aqueous extract of C. nudiflora has significant control over free radical scavenging activity and inhibition of the growth of food pathogenic bacteria. Also, the aqueous extract contains abundance of phenolics and flavonoids higher than other extracts. This study explored weed plant C. nudiflora as a potential source of antioxidant and antibacterial efficacy and identified various therapeutic value bioactive compounds from GC-MS analysis.

Matched MeSH terms: Escherichia coli
Fulltext Unravelling the genome of long chain N-acylhomoserine lactone-producing Acinetobacter sp. strain GG2 and identification of its quorum sensing synthase gene

How KY, Hong KW, Sam CK, Koh CL, Yin WF, Chan KG

Front Microbiol, 2015;6:240.
PMID: 25926817 DOI: 10.3389/fmicb.2015.00240

Myriad proteobacteria use N-acyl homoserine lactone (AHL) molecules as quorum sensing (QS) signals to regulate different physiological functions, including virulence, antibiotic production, and biofilm formation. Many of these proteobacteria possess LuxI/LuxR system as the QS mechanism. Recently, we reported the 3.89 Mb genome of Acinetobacter sp. strain GG2. In this work, the genome of this long chain AHL-producing bacterium was unravelled which led to the molecular characterization of luxI homologue, designated as aciI. This 552 bp gene was cloned and overexpressed in Escherichia coli BL21(DE3). The purified protein was ∼20.5 kDa and is highly similar to several autoinducer proteins of LuxI family among Acinetobacter species. To verify the AHL synthesis activity of this protein, high-resolution liquid chromatography-mass spectrometry analysis revealed the production of 3-oxo-dodecanoyl-homoserine lactone and 3-hydroxy-dodecanoyl-homoserine lactone from induced E. coli harboring the recombinant AciI. Our data show for the first time, the cloning and characterization of the luxI homologue from Acinetobacter sp. strain GG2, and confirmation of its AHLs production. These data are of great significance as the annotated genome of strain GG2 has provided a valuable insight in the study of autoinducer molecules and its roles in QS mechanism of the bacterium.

Matched MeSH terms: Escherichia coli
In silico deletion of PtsG gene in Escherichia coli genome-scale model predicts increased succinate production from glycerol

Mienda BS, Shamsir MS

J Biomol Struct Dyn, 2015;33(11):2380-9.
PMID: 25921851 DOI: 10.1080/07391102.2015.1036461

Systems metabolic engineering and in silico analyses are necessary to study gene knockout candidate for enhanced succinic acid production by Escherichia coli. Metabolically engineered E. coli has been reported to produce succinate from glucose and glycerol. However, investigation on in silico deletion of ptsG/b1101 gene in E. coli from glycerol using minimization of metabolic adjustment algorithm with the OptFlux software platform has not yet been elucidated. Herein we report what is to our knowledge the first direct predicted increase in succinate production following in silico deletion of the ptsG gene in E. coli GEM from glycerol with the OptFlux software platform. The result indicates that the deletion of this gene in E. coli GEM predicts increased succinate production that is 20% higher than the wild-type control model. Hence, the mutant model maintained a growth rate that is 77% of the wild-type parent model. It was established that knocking out of the ptsG/b1101 gene in E. coli using glucose as substrate enhanced succinate production, but the exact mechanism of this effect is still obscure. This study informs other studies that the deletion of ptsG/b1101 gene in E. coli GEM predicted increased succinate production, enabling a model-driven experimental inquiry and/or novel biological discovery on the underground metabolic role of this gene in E. coli central metabolism in relation to increasing succinate production when glycerol is the substrate.

Matched MeSH terms: Escherichia coli
Fulltext Comparable outcomes for β-lactam/β-lactamase inhibitor combinations and carbapenems in definitive treatment of bloodstream infections caused by cefotaxime-resistant Escherichia coli or Klebsiella pneumoniae

Harris PN, Yin M, Jureen R, Chew J, Ali J, Paynter S, et al.

Antimicrob Resist Infect Control, 2015;4:14.
PMID: 25932324 DOI: 10.1186/s13756-015-0055-6

Extended-spectrum β-lactamase (ESBL) producing Enterobacteriaceae are often susceptible in vitro to β-lactam/β-lactamase inhibitor (BLBLI) combination antibiotics, but their use has been limited by concerns of clinical inefficacy. We aimed to compare outcomes between patients treated with BLBLIs and carbapenems for bloodstream infection (BSI) caused by cefotaxime non-susceptible (likely ESBL- or AmpC β-lactamase-producing) Escherichia coli and Klebsiella pneumoniae.

Matched MeSH terms: Escherichia coli
Survey of plasmids and resistance factors among veterinary isolates of Salmonella enteritidis in Malaysia

Son R, Ansary A, Salmah I, Maznah A

World J Microbiol Biotechnol, 1995 May;11(3):315-8.
PMID: 24414656 DOI: 10.1007/BF00367107

Thirty-five veterinary isolates of Salmonella enteritidis were characterized by their susceptibility to 10 antimicrobial agents and by their plasmid profiles on agarose gel electrophoresis. All were susceptible to carbenicillin, chloramphenicol and nalidixic acid but 89% were resistant to tetracycline. When examined, 91% of the isolates harboured plasmids, with sizes ranging from 9.8 to 60 MDa. However, it was only possible to associate the presence of plasmids with tetracycline resistance; plasmids occurring in 90% of the tetracycline-resistant isolates. In conjugation experiments, with Escherichia coli K12 Nal(r) as recipient, the tetracycline resistance in three selected S. enteritidis isolates was observed to transfer at frequencies of 3.0×10(-3) to 1.0×10(-2)/donor cell. The concomitant transfer of a 56-MDa or 60-MDa plasmid in these three S. enteritidis isolates was also detected.

Matched MeSH terms: Escherichia coli K12
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
Antibiotic resistance patterns in nosocomial gram-negative bacterial infections in units with heavy antibiotic usage

Ariffin H, Navaratnam P, Kee TK, Balan G

J Trop Pediatr, 2004 Feb;50(1):26-31.
PMID: 14984166

The pattern of antibiotic resistance amongst gram-negative bacteria (GNB) in paediatric units, which have heavy empirical usage of broad-spectrum antibiotics, was studied prospectively over a 6-month period. A total of 200 consecutive, non-duplicate gram-negative isolates were obtained from 109 patients admitted to intensive care and oncology units in two hospitals. The commonest isolates were Klebsiella spp (36.5 per cent) and Pseudomonas (20.0 per cent). The isolates showed lower susceptibility rates to the third-generation cephalosporins (47-62 per cent) compared with cefepime (91 per cent), imipenem (90 per cent) and ciprofloxacin (99 per cent). Fifty-four (52.8 per cent) Klebsiella and Escherichia coli isolates were determined to be extended-spectrum beta-lactamase (ESBL) producing strains. Antibiotics found to be effective against ESBL-producers were imipenem and ciprofloxacin. The high resistance rate amongst GNB to third-generation cephalosporins is a likely consequence of heavy empirical usage of this group of antibiotics. The carbapenems and quinolones remain useful agents in the management of patients admitted to these units.

Matched MeSH terms: Escherichia coli/drug effects; Escherichia coli/enzymology; Escherichia coli/isolation & purification
Fulltext Identification of salmonella and other pathogenic bacteria in pet red-eared sliders, trachemys scripta elegans, from pet shops in the Klang valley

Selvarajah, G.T., Khairani-Bejo, S.

Jurnal Veterinar Malaysia, 2019;31(2):23-27.
MyJurnal

Bacteriological isolation and identification were performed on 60 cloacal swabs and 15 aquarium water samples of pet red-eared sliders (Trachemys scripta elegans) obtained from aquarium shops in the Klang Valley, Central Peninsula Malaysia. The most common bacteria isolated was Aeromonas spp., which was present in both cloacal swabs (70%) and aquarium water (86.7%). Klebsiella spp. (50%), Escherichia coli (33.3%), Yersinia spp. (16.7%) and Salmonella spp. (15%) obtained form cloacal swabs were identified as pathogenic to both humans and animals. Salmonella spp. were isolated from both cloacal swabs and aquarium water. The Salmonella serotypes identified were S. tennessee, S. typhimurium, S. brezany, S. pomona, S. corvallis and S. schwarzengrund. Bacterial infections in humans associated with handling exotic pets directly or indirectly in contact with aquarium water have been described regularly, hence the zoonotic significance of owning a turtle infected with Salmonella spp. or any pathogenic bacteria therefore cannot be ignored.

Matched MeSH terms: Escherichia coli
Fulltext The antibacterial and antibiofilm activity of aqueous oil palm (Elaeis guineensis) leaf extracts against Staphylococcus aureus

Nur Fatihah Nordin, Hasnah Begum Said Gulam Khan, Kazi Ahsan Jamil, Nurul ‘Izzah Mohd Sarmin

Malaysian Journal of Medicine and Health Sciences, 2019;15(108):34-34.
MyJurnal

Introduction:Staphylococcus aureus is a Gram-positive staphylococci that form biofilms. Bacteria that dwell in bio-films tend to be highly resistant towards the action of antibiotics. S. aureus is a main cause of infections in the oral cavity such as angular cheilitis, endodontic infections, osteomyelitis of the jaw, parotitis and oral mucositis. Previous studies reported that S. aureus also spread to the other parts of the body through the circulatory system, which may lead to chronic infections. Hence the search for new antibacterial agents remains high and needs urgent attention to treat this problem. Plants offer a rich source of antimicrobial agents and bioactive compounds. In this study, aque-ous oil palm leaf extracts (OPLE) has been used as an alternative antibacterial agent against oral infections mainly caused by Staphylococcus aureus. Many studies report the potential use of oil palm leaf extracts in treating bacterial infections such as Escherichia coli, Salmonella sp., Staphylococcus aureus (isolated from other part of the body), Pseudomonas aeruginosa and Bacillus sp. Although previous studies have documented the antimicrobial properties of oil palm leaf extracts, to date no study has been reported on the effect of oil palm leaf extract on oral microbes. Methods: The agar diffusion method, minimum inhibitory concentration (MIC) and minimal bactericidal concen-tration (MBC) assay were conducted in order to observe the antibacterial activity of aqueous oil palm leaf extract. The crystal violet assay was used to determine the anti-biofilm activity of the extracts. Chlorhexidine and deionised distilled water were used as the positive and negative control respectively. For agar diffusion method, the diameter of inhibition zone was measured. Results: The inhibition zone of the tested bacteria was observed between 0-20mm. The MIC and MBC assay were used to know the lowest concentrations of the extract that inhibit the growth and killed the tested bacteria respectively. The MIC and MBC values for the tested bacteria were observed between 0-7.813mg/mL. While for anti-biofilm assays, OPLE aqueous extract acts as a potent anti-biofilm agent with dual actions, pre-venting and eradicating the biofilm of the tested bacteria. Conclusion: In conclusion, the tested plant extracts could serve as alternative natural antibacterial and anti-biofilm agent against oral infections.

Matched MeSH terms: Escherichia coli
Fulltext Development of Polyvinylidene Fluoride Membrane by Incorporating Bio-Based Ginger Extract as Additive

Fahrina A, Arahman N, Mulyati S, Aprilia S, Mat Nawi NI, Aqsha A, et al.

Polymers (Basel), 2020 Sep 03;12(9).
PMID: 32899138 DOI: 10.3390/polym12092003

Biofouling on the membrane surface leads to performance deficiencies in membrane filtration. In this study, the application of ginger extract as a bio-based additive to enhance membrane antibiofouling properties was investigated. The extract was dispersed in a dimethyl acetamide (DMAc) solvent together with polyvinylidene fluoride (PVDF) to enhance biofouling resistance of the resulting membrane due to its antibiotic property. The concentrations of the ginger extract in the dope solution were varied in the range of 0-0.1 wt %. The antibacterial property of the resulting membranes was assessed using the Kirby Bauer disc diffusion method. The results show an inhibition zone formed around the PVDF/ginger membrane against Escherichia coli and Staphylococcus aureus demonstrating the efficacy of the residual ginger extract in the membrane matrix to impose the antibiofouling property. The addition of the ginger extract also enhanced the hydrophilicity in the membrane surface by lowering the contact angle from 93° to 85°, which was in good agreement with the increase in the pure water flux of up to 62%.

Matched MeSH terms: Escherichia coli
Fulltext Dual bioactivities of laurus nobilis essential oil

Nur Afiqah Saparin, Mohd Muzamir Mahat, Muhd Fauzi Safian, Shahrul Hisham Zainal Ariffin, Nor Azah Mohamad Ali, Zaidah Zainal Ariffin

Science Letters, 2020;14(1):62-67.
MyJurnal

The evolution of cosmetic products results in the growing demands for cosmetics that are preservatives free. Plant essential oils were found to be a promising antimicrobial and also antioxidant agent. In this study, Cymbopogon citratus (lemongrass), Laurus nobilis (bay leaf) and Backhousia citriodora (lemon myrtle) essential oils were selected and evaluated for their antimicrobial properties. It was found that Laurus nobilis exhibited strong antimicrobial activity against the selected bacteria Streptococcus saprophyticus (ATCC 49619), Streptococcus aureus (ATCC 22923), Streptococcus pyogenes (ATCC 29436), Pseudomonas aeruginosa (ATCC 13048), Klebsiella pneumoniae (ATCC 700603), Escherichia coli (ATCC 22922) with MIC ranging between 7.8 ug/mL to 250 μg/mL. The antioxidant activity of selected essential oils was determined by antioxidant assays which were 1,1-Diphenyl-2-picrylhydrazyl assay (DPPH), determination of ferric reducing antioxidant power assay (FRAP) and β-Carotene/linoleic acid bleaching assay. Backhousia citriodora and Laurus nobilis showed the highest antioxidant activity.
n-Octanal and β-Selinene were identified to be the major components with peak area of 26.37 % and 13.92 % respectively in secondary metabolites analysis by Gas Chromatography-Mass Spectrometry (GCMS).

Matched MeSH terms: Escherichia coli
Fulltext Survival study and haemolysin activity of Escherichia coli in raw and pasteurized milk produced in Negeri Sembilan

Farra Amira Mohamed, Aimi Nadia Ramli,, Noorlis Ahmad

Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2020;8(1):66-77.
MyJurnal

Demand for milk has increased in Malaysia due to the increased in awareness of healthy foods consumption.
Hence, research of milk is crucial to ensure that it is not contaminated with Escherichia coli. This study
evaluated the survival of Escherichia coli at different temperature and haemolysin activity of Escherichia
coli on blood agar. A total of 8 samples of raw fresh and pasteurized milk were collected from nearby farm
and market in Negeri Sembilan, Malaysia. After an overnight exposure to four different temperatures of
0
0C, 280C, 350C and 450C, the bacteriological test of milk was evaluated for the presence of Escherichia
coli. Overall, all raw fresh milk sampled exceeded the acceptable limit of bacterial count of 1 x 105 CFU/ml.
Raw fresh milk recorded the highest count at 35oC with 4.4 x 107 CFU/ml and the lowest at 0oC with 8.3 x
104 CFU/ml. The presence of Escherichia coli was detected in 7/20(35%) of the total raw fresh milk
samples. All pasteurized milk showed no presence of Escherichia coli due to the effectiveness of heat
treatment. Haemolysin test showed no haemolytic activity. Milk contaminated with Escherichia coli can
cause diarrheal, gastrointestinal diseases and urinary infection. Hence, it is important to study the survival
rate of Escherichia coli and its pathogenicity in milk to ensure public safety.

Matched MeSH terms: Escherichia coli
Dissection of synechococcus rubisco large subunit sections involved in holoenzyme formation in escherichia coli by combinatorial section swapping and sequence analyses

Yee Hung Yeap, Teng Wei Koay, Boon Hoe Lim

Sains Malaysiana, 2018;47:2269-2289.

Engineering the CO2
-fixing enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) to improve photosynthesis
has long been sought. Rubisco large subunits (RbcL) are highly-conserved but because of certain undefined sequence
differences, plant Rubisco research cannot fully utilise the robust heterologous Escherichia coli expression system and its
GroEL folding machinery. Previously, a series of chimeric cyanobacteria Synechococcus elongatus Rubisco, incorporated
with sequences from the green alga Chlamydomonas reinhardtii, were expressed in E. coli; differences in RbcL sections
essential for holoenzyme formation were pinpointed. In this study, the remaining sections, presumably not crucial for
holoenzyme formation and also the small subunit (RbcS), are substituted to further ascertain the possible destabilising
effects of multiple section mutations. To that end, combinations of Synechococcus RbcL Sections 1 (residues 1-47), 2
(residues 48-97), 5 (residues 198-247) and 10 (residues 448-472), and RbcS, were swapped with collinear Chlamydomonas
sections and expressed in E. coli. Interestingly, only the chimera with Sections 1 and 2 together produces holoenzyme and
an interaction network of complementing amino acid changes is delineated by crystal structure analysis. Furthermore,
sequence-based analysis also highlighted possible GroEL binding site differences between the two RbcLs.

Matched MeSH terms: Escherichia coli
Fulltext Synthesis, characterization and application of gelatin-carboxymethyl cellulose blend films for preservation of cherry tomatoes and grapes

Samsi MS, Kamari A, Din SM, Lazar G

J Food Sci Technol, 2019 Jun;56(6):3099-3108.
PMID: 31205364 DOI: 10.1007/s13197-019-03809-3

In the present study, gelatin-carboxymethyl cellulose blend film was synthesized, characterized and applied for the first time to preserve cherry tomatoes (Solanum lycopersicum var. cerasiforme) and grapes (Vitis vinifera). Gelatin (Gel) film forming solution was incorporated with carboxymethyl cellulose (CMC) at three volume per volume (Gel:CMC) ratios, namely 75:25, 50:50 and 25:75. CMC treatment has improved the transparency, tensile strength (TS), elongation at break (EAB), water vapor permeability and oxygen permeability of gelatin films. A pronounced effect was obtained for 25Gel:75CMC film. The TS and EAB values were increased from 25.98 MPa and 2.34% (100Gel:0CMC) to 37.54 MPa and 4.41% (25Gel:75CMC), respectively. A significant improvement in antimicrobial property of gelatin films against two food pathogens, namely Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was obtained in the presence of CMC. The effectiveness of gelatin-CMC blend films to extend the shelf life of agricultural products was evaluated in a 14-day preservation study. The gelatin-CMC films were successfully controlled the weight loss and browning index of the fruits up to 50.41% and 31.34%, respectively. Overall, gelatin-CMC film is an environmental friendly film for food preservation.

Matched MeSH terms: Escherichia coli
Fulltext Chemical composition, antioxidant and antimicrobial potential of essential oils from different parts of Daphne mucronata Royle

Ashraf I, Zubair M, Rizwan K, Rasool N, Jamil M, Khan SA, et al.

Chem Cent J, 2018 Dec 17;12(1):135.
PMID: 30556121 DOI: 10.1186/s13065-018-0495-1

This research work was executed to determine chemical composition, anti-oxidant and anti-microbial potential of the essential oils extracted from the leaves and stem of Daphne mucronata Royle. From leaves and stem oils fifty-one different constituents were identified through GC/MS examination. The antioxidant potential evaluated through DPPH free radical scavenging activity and %-inhibition of peroxidation in linoleic acid system. The stem's essential oil showed the good antioxidant activity as compared to leaves essential oil. Results of Antimicrobial activity revealed that both stem and leaves oils showed strong activity against Candida albicans with large inhibition zone (22.2 ± 0.01, 18.9 ± 0.20 mm) and lowest MIC values (0.98 ± 0.005, 2.44 ± 0.002 mg/mL) respectively. Leaves essential was also active against Escherichia coli with inhibition zone of 8.88 ± 0.01 mm and MIC values of 11.2 ± 0.40 mg/mL. These results suggested that the plant's essential oils would be a potential cradle for the natural product based antimicrobial as well as antioxidant agents.

Matched MeSH terms: Escherichia coli
Design, Synthesis and Therapeutic Potential of Some 6, 6'-(1,4- phenylene)bis(4-(4-bromophenyl)pyrimidin-2-amine)analogues

Kumar S, Narasimhan B, Lim SM, Ramasamy K, Mani V, Shah SAA

Mini Rev Med Chem, 2019;19(7):609-621.
PMID: 30526456 DOI: 10.2174/1389557519666181210162413

BACKGROUND: A series of 6, 6'-(1,4-phenylene)bis(4-(4-bromophenyl)pyrimidin-2-amine) derivatives has been synthesized by Claisen-Schmidt condensation and its chemical structures was confirmed by FT-IR, 1H/13C-NMR spectral and elemental analyses. The molecular docking study was carried out to find the interaction between active bis-pyrimidine compounds with CDK-8 protein. The in vitro antimicrobial potential of the synthesized compounds was determined against Gram-positive and Gram-negative bacterial species as well fungal species by tube dilution technique. Antimicrobial results indicated that compound 11y was found to be most potent one against E. coli (MICec = 0.67 µmol/mL) and C. albicans (MICca = 0.17 µmol/mL) and its activity was comparable to norfloxacin (MIC = 0.47 µmol/mL) and fluconazole (MIC = 0.50 µmol/mL), respectively.
CONCLUSION: Anticancer screening of the synthesized compounds using Sulforhodamine B (SRB) assay demonstrated that compounds 2y (IC50 = 0.01 µmol/mL) and 4y (IC50= 0.02 µmol/mL) have high antiproliferative potential against human colorectal carcinoma cancer cell line than the reference drug (5- fluorouracil) and these compounds also showed best dock score with better potency within the ATP binding pocket and may also be used lead for rational drug designing.

Matched MeSH terms: Escherichia coli/drug effects; Escherichia coli Infections/drug therapy
Antibacterial activity of quaternized chitosan modified nanofiber membrane

Cheah WY, Show PL, Ng IS, Lin GY, Chiu CY, Chang YK

Int J Biol Macromol, 2019 Apr 01;126:569-577.
PMID: 30584947 DOI: 10.1016/j.ijbiomac.2018.12.193

The electrospinning PAN nanofiber membrane (P-CN) was hydrolysed to convert carboxylic groups as reaction sites and covalently graft chitosan molecule. The chitosan derivatives with quaternary ammonium groups exerted greater efficiency against bacteria as compared to pure chitosan. Hence, the chitosan modified membrane (P-CS), can be functionalized with quaternary amine (i.e., glycidyl trimethyl ammonium chloride, GTMAC) to form quaternized chitosan nanofiber membrane (designated as P-HTCC) under various conditions (acidic, neutral, and alkaline). N-quaternized derivatives of chitosan modified membrane (N-HTCC) showed 72% and 60% degree of quaternization (DQ) under acidic and neutral conditions, respectively. Under alkaline condition, additional quaternization of N, O-HTCC via its amino and hydroxyl groups, has improved up to 90% DQ of the chitosan. The antibacterial activity of the quaternized chitosan modified membrane prepared from acetic acid medium is stronger than that prepared from water and alkaline media. Also, antibacterial activity of quaternized chitosan is stronger than chitosan modified membrane against E. coli. The microbiological assessments showed that the water-stable P-HTCC nanofiber membrane under modification in acidic medium exerted antibacterial activity up to 99.95% against E. coli. Therefore, the P-HTCC membrane exhibited high potential to be integrated into microfiltration membrane to effectively disinfect E. coli.

Matched MeSH terms: Escherichia coli
Molecular detection of Enterobacteriaceae isolates producing blaOXA-48 and blaOXA-181 genes: A single centre study

Heng PY, Sulong A, Ali UKS, Wong KK

Malays J Pathol, 2019 Aug;41(2):139-148.
PMID: 31427549

INTRODUCTION: OXA-48, a carbapenem-hydrolysing class D β-lactamase, and its variant, OXA-181, are increasingly reported worldwide. This study aimed to describe the prevalence and distribution of OXA-48 and OXA-181 carbapenem-resistant Enterobacteriaceae (CRE) in a tertiary medical centre in Malaysia.
MATERIALS & METHODS: A total of 13,098 Enterobacteriaceae isolates from various clinical samples were sent to our laboratory between January 2011 and December 2012. Of these, 90 demonstrated reduced susceptibility to at least one carbapenem and were included in this study. Only 88 isolates were successfully subcultured on blood agar (BA). Another 2 isolates failed to grow and were excluded. Of the 88, 2 isolates had the same identification number (repetitive isolates); therefore, 1 isolate was excluded from further analyses. Only 87 isolates were subjected to molecular detection of the blaOXA-48 and blaOXA-181 genes by polymerase chain reaction.
RESULTS: Eighty-seven non-repetitive isolates grew following subculture on BA. Of these, 9 (10.34%) were positive for OXA-48 (7 Klebsiella pneumoniae, 2 Escherichia coli). Each isolate originated from different patients. All patients had a history of treatment with at least one cephalosporin and/or carbapenem prior to the isolation of OXA-48 CRE. OXA-181 was detected in one (1.15%) out of the 87 isolates; CONCLUSIONS: The prevalence of OXA-48 and OXA-181 CRE among all Enterobacteriaceae isolates in our institution is 0.069% and 0.008%, respectively. Nevertheless, our findings suggest that OXA-48 and OXA-181 carbapenemases appear to be important and possibly under-recognised causes of carbapenem resistance in Malaysia.

Matched MeSH terms: Escherichia coli
Fulltext Antibacterial activity of ethanolic Piper cubeba L. extract against Escherichia coli and its effect on microbiological quality of raw chicken meat during storage

Fazly Ann, Z., Rukayadi, Y.

International Food Research Journal, 2019;26(3):933-944.
MyJurnal

Piper cubeba L. is traditionally recognised as flavouring ingredient in various types of foods and has been used to marinate meat. Scientifically, it has been reported to possess various valuable nutritional and pharmacological properties including antimicrobial potential. The aim of the present work was to determine the antibacterial activity of ethanolic P. cubeba L. extract against Escherichia coli and its effect on the microbiological quality of raw chicken meat during storage. Disc diffusion assay was done and resulted in 8.40 ± 0.10 mm of inhibition zone. The bacteriostatic and bactericidal effects of the extract were determined at 0.63 ± 0.00 mg/mL and 1.25 ± 0.00 mg/mL of concentration by MIC and MBC methods, respectively. The killing time was recorded at 2 × MIC (1.25 mg/mL) for 4 h. The application of the extract on chicken meat samples showed reduction in TPC and E. coli count with the observed optimum condition at 5.00% concentration stored at -18°C for 14 days based on the consistent reduction. Sensory attributes acceptability evaluation by 9-point hedonic scale showed acceptable score for colour, odour, texture and overall acceptability of the treated raw chicken meat samples. The findings implies that P. cubeba L. can be listed as one of the alternatives to reduce the bacterial load of raw chicken meat prior to cooking which is very important in ensuring food safety as well as reducing the occurrence of foodborne poisoning associated with chicken meat.

Matched MeSH terms: Escherichia coli
Fulltext Safely Dissolvable and Healable Active Packaging Films Based on Alginate and Pectin

Makaremi M, Yousefi H, Cavallaro G, Lazzara G, Goh CBS, Lee SM, et al.

Polymers (Basel), 2019 Sep 29;11(10).
PMID: 31569482 DOI: 10.3390/polym11101594

Extensive usage of long-lasting petroleum based plastics for short-lived application such as packaging has raised concerns regarding their role in environmental pollution. In this research, we have developed active, healable, and safely dissolvable alginate-pectin based biocomposites that have potential applications in food packaging. The morphological study revealed the rough surface of these biocomposite films. Tensile properties indicated that the fabricated samples have mechanical properties in the range of commercially available packaging films while possessing excellent healing efficiency. Biocomposite films exhibited higher hydrophobicity properties compared to neat alginate films. Thermal analysis indicated that crosslinked biocomposite samples possess higher thermal stability in temperatures below 120 °C, while antibacterial analysis against E. coli and S. aureus revealed the antibacterial properties of the prepared samples against different bacteria. The fabricated biodegradable multi-functional biocomposite films possess various imperative properties, making them ideal for utilization as packaging material.

Matched MeSH terms: Escherichia coli

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