Displaying publications 61 - 80 of 606 in total

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  1. Fulltext Preliminary Insight of Pyrrolylated-Chalcones as New Anti-Methicillin-Resistant Staphylococcus aureus (Anti-MRSA) Agents
    Gunasekharan M, Choi TI, Rukayadi Y, Mohammad Latif MA, Karunakaran T, Mohd Faudzi SM, et al.
    Molecules, 2021 Sep 01;26(17).
    PMID: 34500755 DOI: 10.3390/molecules26175314
    Bacterial infections are regarded as one of the leading causes of fatal morbidity and death in patients infected with diseases. The ability of microorganisms, particularly methicillin-resistant Staphylococcus aureus (MRSA), to develop resistance to current drugs has evoked the need for a continuous search for new drugs with better efficacies. Hence, a series of non-PAINS associated pyrrolylated-chalcones (1-15) were synthesized and evaluated for their potency against MRSA. The hydroxyl-containing compounds (8, 9, and 10) showed the most significant anti-MRSA efficiency, with the MIC and MBC values ranging from 0.08 to 0.70 mg/mL and 0.16 to 1.88 mg/mL, respectively. The time-kill curve and SEM analyses exhibited bacterial cell death within four hours after exposure to 9, suggesting its bactericidal properties. Furthermore, the docking simulation between 9 and penicillin-binding protein 2a (PBP2a, PDB ID: 6Q9N) suggests a relatively similar bonding interaction to the standard drug with a binding affinity score of -7.0 kcal/mol. Moreover, the zebrafish model showed no toxic effects in the normal embryonic development, blood vessel formation, and apoptosis when exposed to up to 40 µM of compound 9. The overall results suggest that the pyrrolylated-chalcones may be considered as a potential inhibitor in the design of new anti-MRSA agents.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
  2. Dye degradation, antibacterial and in-silico analysis of Mg/cellulose-doped ZnO nanoparticles
    Ikram M, Mahmood A, Haider A, Naz S, Ul-Hamid A, Nabgan W, et al.
    Int J Biol Macromol, 2021 Aug 31;185:153-164.
    PMID: 34157328 DOI: 10.1016/j.ijbiomac.2021.06.101
    Various concentrations of Mg into fixed amount of cellulose nanocrystals (CNC)-doped ZnO were synthesized using facile chemical precipitation. The aim of present study is to remove dye degradation of methylene blue (MB) and bactericidal behavior with synthesized product. Phase constitution, functional group analysis, optical behavior, elemental composition, morphology and microstructure were examined using XRD, FTIR, UV-Vis spectrophotometer, EDS and HR-TEM. Highly efficient photocatalytic performance was observed in basic medium (98%) relative to neutral (65%), and acidic (83%) was observed upon Mg and CNC co-doping. Significant bactericidal activity of doped ZnO nanoparticles depicted inhibition zones for G -ve and +ve bacteria ranging (2.20 - 4.25 mm) and (5.80-7.25 mm) for E. coli and (1.05 - 2.75 mm) and (2.80 - 4.75 mm) for S. aureus at low and high doses, respectively. Overall, doped nanostructures showed significant (P 
    Matched MeSH terms: Staphylococcus aureus/drug effects
  3. Fulltext Streptomyces sp.-A Treasure Trove of Weapons to Combat Methicillin-Resistant Staphylococcus aureus Biofilm Associated with Biomedical Devices
    Pusparajah P, Letchumanan V, Law JW, Ab Mutalib NS, Ong YS, Goh BH, et al.
    Int J Mol Sci, 2021 Aug 28;22(17).
    PMID: 34502269 DOI: 10.3390/ijms22179360
    Biofilms formed by methicillin-resistant S. aureus (MRSA) are among the most frequent causes of biomedical device-related infection, which are difficult to treat and are often persistent and recurrent. Thus, new and effective antibiofilm agents are urgently needed. In this article, we review the most relevant literature of the recent years reporting on promising anti-MRSA biofilm agents derived from the genus Streptomyces bacteria, and discuss the potential contribution of these newly reported antibiofilm compounds to the current strategies in preventing biofilm formation and eradicating pre-existing biofilms of the clinically important pathogen MRSA. Many efforts are evidenced to address biofilm-related infections, and some novel strategies have been developed and demonstrated encouraging results in preclinical studies. Nevertheless, more in vivo studies with appropriate biofilm models and well-designed multicenter clinical trials are needed to assess the prospects of these strategies.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*; Methicillin-Resistant Staphylococcus aureus/physiology
  4. Fulltext Enhancing recovery of bioactive compounds from Cosmos caudatus leaves via ultrasonic extraction
    Latiff NA, Ong PY, Abd Rashid SNA, Abdullah LC, Mohd Amin NA, Fauzi NAM
    Sci Rep, 2021 08 27;11(1):17297.
    PMID: 34453075 DOI: 10.1038/s41598-021-96623-x
    Cosmos caudatus (C. caudatus) is a medicinal plant that is high in bioactive compounds such as phenolics. In this study, an ultrasound extraction method was used to optimise the extraction of bioactive compounds from C. caudatus leaves. Response surface methodology (RSM) based on a Box-Behnken design (BBD) was applied to obtain the optimum extraction parameters which is solid-liquid ratio (10-30 g/mL), particle size (180-850 µm) and extraction time (20-30 min) for maximal quercitrin and total phenolic content (TPC) yields. Analysis of antimicrobial activity was performed against two human pathogenic microbes: Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) by the agar well diffusion method. The optimal ultrasonic extraction condition was as follow: solvent-liquid ratio of 1:28 (g/mL), particle size of 485 µm, and duration of 30 min, respectively. Remarkably, extraction using ultrasonic method had recovered more bioactive content and antioxidant activity than the Soxhlet method. The extract also exhibited good antimicrobial activities. Due to the above findings, the ultrasonic extraction was found to be suitable to improve recovery extraction of quercitrin and TPC from C. caudatus leaves. It also opens the possibility that the plant extract can be used for functional food and antimicrobial agents in various applications.
    Matched MeSH terms: Staphylococcus aureus/drug effects
  5. Fulltext Synthesis of silver nanoparticle-decorated hydroxyapatite nanocomposite with combined bioactivity and antibacterial properties
    Bee SL, Bustami Y, Ul-Hamid A, Lim K, Abdul Hamid ZA
    J Mater Sci Mater Med, 2021 Aug 23;32(9):106.
    PMID: 34426879 DOI: 10.1007/s10856-021-06590-y
    Combination of bioactive material such as hydroxyapatite (HAp) with antibacterial agents would have great potential to be used as bone implant materials to avert possible bacterial infection that can lead to implant-associated diseases. The present study aimed to develop an antibacterial silver nanoparticle-decorated hydroxyapatite (HAp/AgNPs) nanocomposite using chemical reduction and thermal calcination approaches. In this work, natural HAp that was extracted from chicken bone wastes is used as support matrix for the deposition of silver nanoparticles (AgNPs) to produce HAp/AgNPs nanocomposite. XRD, FESEM-EDX, HRTEM, and XPS analyses confirmed that spherical AgNPs were successfully synthesized and deposited on the surface of HAp particles, and the amount of AgNPs adhered on the HAp surface increased with increasing AgNO3 concentration used. The synthesized HAp/AgNPs nanocomposites demonstrated strong antibacterial activity against Staphylococcus aureus bacteria, where the antibacterial efficiency is relied on the amount and size of deposited AgNPs. In addition, the in vitro bioactivity examination in Hank's balanced salt solution showed that more apatite were grown on the surface of HAp/AgNPs nanocomposite when AgNO3 concentration used >1 wt.%. Such nanocomposite with enhanced bioactivity and antibacterial properties emerged as a promising biomaterial to be applied for dentistry and orthopedic implantology.
    Matched MeSH terms: Staphylococcus aureus/drug effects; Staphylococcus aureus/growth & development
  6. Synthesis of Capsaicin Loaded Silver Nanoparticles Using Green Approach and Its Anti-Bacterial Activity Against Human Pathogens
    Mahmood S, Mei TS, Yee WX, Hilles AR, Alelwani W, Bannunah AM
    J Biomed Nanotechnol, 2021 Aug 01;17(8):1612-1626.
    PMID: 34544538 DOI: 10.1166/jbn.2021.3122
    Nanotechnology is drawing attention nowadays due to its ability to regulate metals into nanosize, ultimately changing metal's physical, chemical, and optical properties. Silver nanoparticles are known for their potential impact as antimicrobial agents due to their inherent property penetrating the cell wall. The present study aimed to develop and statistically optimise using a novel combination of capsaicin loaded silver nanoparticles (AgCNPs) as an effective anti-bacterial agent to treat psoriasis using a green approach. Ascorbic acid was used as a reducing agent to fabricate silver nanoparticles. The formulation parameters optimisation was conducted using Box-Behnken Design (3×3 factorial design). The loading of capsaicin was confirmed by attenuated total reflectance-fourier transform infrared spectroscopy. Energy-dispersive X-ray spectroscopy-scanning electron microscopy (EDX-SEM) confirmed the existence of silver; net-like structure revealed in SEM and high-resolution transmission electron microscopy further confirmed the nano size of the formulation. Differential scanning calorimetry and X-ray diffraction demonstrated the capsaicin transformed into amorphous after encapsulated. An in-vitro microbial study showed that the 0.10 M formulation of AgCNPs exerted potent anti-bacterial activity, which can be considered an alternative anti-bacterial agent. It also displayed that the zone of inhibition was significantly high in gram-negative bacteria (E. coli) than gram-positive bacteria (S. aureus). Green synthesised AgCNPs showed highly significant anti-bacterial activity, which indicates that this formulation can be very promising for treating psoriasis.
    Matched MeSH terms: Staphylococcus aureus
  7. Epidemiology of bloodstream infections in the paediatric population in a Malaysian general hospital over a 2-year period
    Subramaniam K, Khaithir TMN, Ding CH, Che Hussin NS
    Malays J Pathol, 2021 Aug;43(2):291-301.
    PMID: 34448793
    BACKGROUND: Bloodstream infection (BSI) is a major cause of morbidity and mortality. The classification of infection into community-acquired, hospital-acquired, and healthcare-associated infection provides an educated guess on the possible aetiological agents and appropriate empirical antimicrobial therapy to be instituted. This study aims to determine the aetiological agents, the antimicrobial susceptibility patterns, and the classification of infections among the paediatric population.

    MATERIALS & METHODS: This study was conducted in Hospital Kuala Lumpur, Malaysia from January 2016 to December 2017. A total of 303 isolates were included in this study which was obtained from 238 patients. The patients' microbiological worksheets and medical notes were reviewed to determine the antimicrobial susceptibility patterns, demographic data, classification of infection, and outcome (survival versus death).

    RESULTS: Most of the patients were in the age group of one to less than five years old (41%) with 58% male and 85% Malay patients. Common causes of BSI were Staphylococcus aureus (17%), followed by Klebsiella pneumoniae (15%), Acinetobacter baumanii (10%), Pseudomonas aeruginosa (10%), and Escherichia coli (6%). Sixty percent of BSI episodes were caused by gram-negative bacteria, 34% by gram-positive bacteria, and 6% by fungi. Most of the infections were classified as hospital-acquired infections (72%), followed by healthcareassociated (20%) and community-acquired infections (8%). There were 33% of methicillin-resistant Staphylococcus aureus, 53% of extended-spectrum beta-lactamase (ESBL) producing Klebsiella pneumoniae, and 33% ESBL producing Escherichia coli. The overall case fatality rate (CFR) was 27% with the highest CFR caused by Serratia marcescens (53.3%).

    CONCLUSIONS: The majority of paediatric bloodstream infections are hospital-acquired. Improvement in prevention strategies and revisions in antibiotic policies are important to overcome it.

    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus
  8. Fulltext A scaffolded approach to unearth potential antibacterial components from epicarp of Malaysian Nephelium lappaceum L
    Asghar A, Tan YC, Zahoor M, Zainal Abidin SA, Yow YY, Khan E, et al.
    Sci Rep, 2021 Jul 05;11(1):13859.
    PMID: 34226594 DOI: 10.1038/s41598-021-92622-0
    The emergence and spread of antimicrobial resistance have been of serious concern to human health and the management of bacterial infectious diseases. Effective treatment of these diseases requires the development of novel therapeutics, preferably free of side effects. In this regard, natural products are frequently conceived to be potential alternative sources for novel antibacterial compounds. Herein, we have evaluated the antibacterial activity of the epicarp extracts of the Malaysian cultivar of yellow rambutan fruit (Nephelium lappaceum L.) against six pathogens namely, Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella enterica. Among a series of solvent extracts, fractions of ethyl acetate and acetone have revealed significant activity towards all tested strains. Chemical profiling of these fractions, via HPLC, LC-MS and GC-MS, has generated a library of potentially bioactive compounds. Downstream virtual screening, pharmacological prediction, and receptor-ligand molecular dynamics simulation have eventually unveiled novel potential antibacterial compounds, which can be extracted for medicinal use. We report compounds like catechin, eplerenone and oritin-4-beta-ol to be computationally inhibiting the ATP-binding domain of the chaperone, DnaK of P. aeruginosa and MRSA. Thus, our work follows the objective to propose new antimicrobials capable of perforating the barrier of resistance posed by both the gram positives and the negatives.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects; Methicillin-Resistant Staphylococcus aureus/pathogenicity
  9. Fulltext Green Synthesized Silver Nanoparticles Immobilized on Activated Carbon Nanoparticles: Antibacterial Activity Enhancement Study and Its Application on Textiles Fabrics
    Wibawa PJ, Nur M, Asy'ari M, Wijanarka W, Susanto H, Sutanto H, et al.
    Molecules, 2021 Jun 22;26(13).
    PMID: 34206375 DOI: 10.3390/molecules26133790
    This research aimed to enhance the antibacterial activity of silver nanoparticles (AgNPs) synthesized from silver nitrate (AgNO3) using aloe vera extract. It was performed by means of incorporating AgNPs on an activated carbon nanoparticle (ACNPs) under ultrasonic agitation (40 kHz, 2 × 50 watt) for 30 min in an aqueous colloidal medium. The successful AgNPs synthesis was clarified with both Ultraviolet-Visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectrophotometers. The successful AgNPs-ACNPs incorporation and its particle size analysis was performed using Transmission Electron Microscope (TEM). The brown color suspension generation and UV-Vis's spectra maximum wavelength at around 480 nm confirmed the existence of AgNPs. The particle sizes of the produced AgNPs were about 5 to 10 nm in the majority number, which collectively surrounded the aloe vera extract secondary metabolites formed core-shell like nanostructure of 8.20 ± 2.05 nm in average size, while ACNPs themselves were about 20.10 ± 1.52 nm in average size formed particles cluster, and 48.00 ± 8.37 nm in average size as stacking of other particles. The antibacterial activity of the synthesized AgNPs and AgNPs-immobilized ACNPs was 57.58% and 63.64%, respectively (for E. coli); 61.25%, and 93.49%, respectively (for S. aureus). In addition, when the AgNPs-immobilized ACNPs material was coated on the cotton and polyester fabrics, the antibacterial activity of the materials changed, becoming 19.23% (cotton; E. coli), 31.73% (polyester; E. coli), 13.36% (cotton; S. aureus), 21.15% (polyester; S. aureus).
    Matched MeSH terms: Staphylococcus aureus/growth & development*
  10. Antibacterial polyene-polyol macrolides and cyclic peptides from the marine-derived Streptomyces sp. MS110128
    Jiang L, Huang P, Ren B, Song Z, Zhu G, He W, et al.
    Appl Microbiol Biotechnol, 2021 Jun;105(12):4975-4986.
    PMID: 34146138 DOI: 10.1007/s00253-021-11226-w
    Marine microbes provide an important resource to discover new chemical compounds with biological activities beneficial to drug discovery. In our study, two new polyene macrolides, pyranpolyenolides A (1) and B (2), and one new natural cyclic peptide (9), together with two known polyenes (7 and 8) and three known cyclic peptides (10-12), were isolated from a culture of the marine Streptomyces sp. MS110128. In addition, four new polyene macrolides, pyranpolyenolides C-F (3-6), were identified as olefin geometric isomers that were most likely produced by photochemical conversion during the cultivation or isolation procedures. The pyranpolyenolides are 32-membered macrolides endowed with a conjugated tetraene and several pairs of 1,3-dihydroxyl groups. Pyranpolyenolides that contain a hydropyran group have not been previously reported. Four cyclic peptides (9-12) showed significant activities against Bacillus subtilis, Staphylococcus aureus, and methicillin-resistant S. aureus with supporting MIC values ranging from 0.025 to 1.25 μg/mL. These cyclic peptides containing piperazic moieties showed moderate activities with MIC values of 12.5 μg/mL against Bacille Calmette Guerin (BCG), an attenuated form of the bovine. Additionally, cyclic peptide 12 showed moderate antifungal activity against Candida albicans with an MIC value of 12.5 μg/mL. KEY POINTS: • Discovery of new polyenes and cyclic peptides from a marine-derived Actinomycete. • Cyclic peptides containing piperazic moieties exhibited good antibacterial activity.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus*
  11. Comparison of MALDI-TOF mass spectrometry with phenotypic methods for identification and characterization of Staphylococcus aureus causing mastitis
    Alharbi A, Al-Dubaib M, Elhassan MAS, Elbehiry A
    Trop Biomed, 2021 Jun 01;38(2):9-24.
    PMID: 33973568 DOI: 10.47665/tb.38.2.032
    The emergence of methicillin-resistant Staphylococcus aureus (MRSA) infection is one of the greatest threats to both animal and human health. Our investigation was aimed to identify and differentiate between MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) recovered from mastitic milk using MALDI-TOF mass spectrometry compared with phenotypic methods and studying their susceptibility to various antibiotics. Four hundred milk samples from mastitic animals (cows, sheep, goats, and dromedary camels) were investigated. Phenotypic identification of S. aureus was made through MASTASAPH Latex test, STAPH ID 32, and Vitek 2 system. The proteomic characterization of S. aureus was done by MBT. The Kirby Bauer method was accomplished to detect the resistance of S. aureus strains to antibiotics. The results of the MASTASAPH Latex test, revealed that 54 (46%) were recognized as S. aureus. All S. aureus isolates were identified by MBT with a score of more or equal 2.00. Several peaks were identified in the mass of 4590 Da, 4863 Da, and 4938 Da for MSSA and in the mass of 2636 Da and 3009 Da for MRSA. The MSP dendrogram demonstrated that the S. aureus isolates were classified into one group with a distance level of less or equal 400. The percentage of S. aureus resistance against carbenicillin, erythromycin and kanamycin was 94.4%, 38.88%, and 33.33%, respectively. In conclusion, S. aureus bacteria are among the key triggers for mastitis in Saudi Arabia. MBT is reported to be not only the rapid tool to identify S. aureus but also able to discriminate MRSA from MSSA.
    Matched MeSH terms: Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus
  12. Antimicrobial efficacy and activity of ethanolic extract of Piper betle L. on Staphylococcus aureus-infected wound in mice and clinical isolates of multiple drug-resistant bacterial pathogens
    Valle DLJ, Puzon JJM, Cabrera EC, Cena-Navarro RB, Rivera WL
    Trop Biomed, 2021 Jun 01;38(2):134-142.
    PMID: 34172702 DOI: 10.47665/tb.38.2.049
    This study aimed to determine the in vivo effectiveness of the ethanolic extract of Piper betle L. leaves against Staphylococcus aureus-infected wounds in mice and its antimicrobial properties on clinical isolates of multiple drug-resistant bacterial pathogens. Twenty mice were divided into four groups. Wounds were created in all mice under anesthesia by excision from the dorsal skin down to the subcutaneous fat and inoculating with S. aureus. After 24 h, the wound of each mouse was treated once daily by application of the respective cream. Group I was treated with mupirocin antibacterial cream; Group II received a cream base containing no active ingredient; Groups III and IV were treated with 2.5% and 5.0% concentrations of P. betle cream, respectively. Further, an in vitro study was performed by adding undiluted, 1:50 and 1:100 dilutions of the four studied creams in normal saline containing 1.5 × 108 CFU/mL of the following bacteria: antimicrobial-susceptible S. aureus, Escherichia coli, Pseudomonas aeruginosa, methicillin-resistant S. aureus, extended-spectrum β-lactamase-producing Escherichia coli, vancomycin-resistant Enterococcus, metallo-βlactamase-producing P. aeruginosa and carbapenem-resistant Klebsiella pneumoniae. The mice in Groups III and IV had significantly faster wound contraction and significantly shorter reepithelialization time than Group II (p < 0.05), which were not significantly different from Group I (p > 0.05). P. betle creams inhibited all studied bacterial strains at full concentration and at a dilution of 1:50. The inhibitory effect was more significant than Groups I and II (p < 0.05), except on S. aureus. Specifically, S. aureus inhibition was not significantly different for Groups III and IV (p > 0.05) when compared with Group I. Cream formulations derived from P. betle ethanolic extract have great potential as antimicrobial agents for the treatment of wound infection. Further clinical tests are recommended to determine the safety and efficacy of these formulations in other mammalian species.
    Matched MeSH terms: Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus/drug effects
  13. Fulltext Facile Synthesis and Characterization of Palm CNF-ZnO Nanocomposites with Antibacterial and Reinforcing Properties
    Supramaniam J, Low DYS, Wong SK, Tan LTH, Leo BF, Goh BH, et al.
    Int J Mol Sci, 2021 May 28;22(11).
    PMID: 34071337 DOI: 10.3390/ijms22115781
    Cellulose nanofibers (CNF) isolated from plant biomass have attracted considerable interests in polymer engineering. The limitations associated with CNF-based nanocomposites are often linked to the time-consuming preparation methods and lack of desired surface functionalities. Herein, we demonstrate the feasibility of preparing a multifunctional CNF-zinc oxide (CNF-ZnO) nanocomposite with dual antibacterial and reinforcing properties via a facile and efficient ultrasound route. We characterized and examined the antibacterial and mechanical reinforcement performances of our ultrasonically induced nanocomposite. Based on our electron microscopy analyses, the ZnO deposited onto the nanofibrous network had a flake-like morphology with particle sizes ranging between 21 to 34 nm. pH levels between 8-10 led to the formation of ultrafine ZnO particles with a uniform size distribution. The resultant CNF-ZnO composite showed improved thermal stability compared to pure CNF. The composite showed potent inhibitory activities against Gram-positive (methicillin-resistant Staphylococcus aureus (MRSA)) and Gram-negative Salmonella typhi (S. typhi) bacteria. A CNF-ZnO-reinforced natural rubber (NR/CNF-ZnO) composite film, which was produced via latex mixing and casting methods, exhibited up to 42% improvement in tensile strength compared with the neat NR. The findings of this study suggest that ultrasonically-synthesized palm CNF-ZnO nanocomposites could find potential applications in the biomedical field and in the development of high strength rubber composites.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects; Methicillin-Resistant Staphylococcus aureus/growth & development
  14. Fulltext Functional Properties of Antimicrobial Neem Leaves Extract Based Macroalgae Biofilms for Potential Use as Active Dry Packaging Applications
    Oyekanmi AA, Kumar USU, H P S AK, Olaiya NG, Amirul AA, Rahman AA, et al.
    Polymers (Basel), 2021 May 20;13(10).
    PMID: 34065404 DOI: 10.3390/polym13101664
    Antimicrobial irradiated seaweed-neem biocomposite films were synthesized in this study. The storage functional properties of the films were investigated. Characterization of the prepared films was conducted using SEM, FT-IR, contact angle, and antimicrobial test. The macroscopic and microscopic including the analysis of the functional group and the gas chromatography-mass spectrometry test revealed the main active constituents present in the neem extract, which was used an essential component of the fabricated films. Neem leaves' extracts with 5% w/w concentration were incorporated into the matrix of seaweed biopolymer and the seaweed-neem bio-composite film were irradiated with different dosages of gamma radiation (0.5, 1, 1.5, and 2 kGy). The tensile, thermal, and the antimicrobial properties of the films were studied. The results revealed that the irradiated films exhibited improved functional properties compared to the control film at 1.5 kGy radiation dosage. The tensile strength, tensile modulus, and toughness exhibited by the films increased, while the elongation of the irradiated bio-composite film decreased compared to the control film. The morphology of the irradiated films demonstrated a smoother surface compared to the control and provided surface intermolecular interaction of the neem-seaweed matrix. The film indicated an optimum storage stability under ambient conditions and demonstrated no significant changes in the visual appearance. However, an increase in the moisture content was exhibited by the film, and the hydrophobic properties was retained until nine months of the storage period. The study of the films antimicrobial activities against Staphylococcus aureus (SA), and Bacillus subtilis (BS) indicated improved resistance to bacterial activities after the incorporation of neem leaves extract and gamma irradiation. The fabricated irradiated seaweed-neem bio-composite film could be used as an excellent sustainable packaging material due to its effective storage stability.
    Matched MeSH terms: Staphylococcus aureus
  15. Fulltext Synthesis and characterizations iron oxide carbon nanotubes nanocomposite by laser ablation for anti-microbial applications
    Al-Salih M, Samsudin S, Arshad SS
    J Genet Eng Biotechnol, 2021 May 18;19(1):76.
    PMID: 34003402 DOI: 10.1186/s43141-021-00161-y
    BACKGROUND: Environmental contamination by microbes is a major public health concern. A damp environment is one of the potential sources for microbe proliferation. Smart synthesis nanocatalytic coatings on surfaces, food, and material from different pathogen bacteria can inhibit using the Fe3O4/CNTs as anti-microbial growth can effectively curb this growing threat. In this present work, the anti-microbial efficacy of synthesis of a compound nanoparticle-containing iron oxide-multi-walled carbon nanotube was combined by laser ablation PLAL and explored the anti-bacterial action of colloidal solution of Fe3O4/CNTs NPs that was evaluated against bacteria which is classified as gram-negative (Escherichia coli (E. coli), Klebsiella pneumonia (K. pneumonia), and also that is identified as gram-positive (Streptococcus pyogenes (S .pyogenes) and Staphylococcus aureus (S. aureus) under visible light irradiation.

    RESULTS: Doping of a minute fraction of iron(III) salt (0.5 mol%) in a volatile solvent (ethanol) was carried out via the sol-gel technique. Fe3O4 was further calcined at various temperatures (in the range of 500-700 °C) to evaluate the thermal stability of the Fe3O4 nanoporous oxidizer nanoparticles. The physicochemical properties of the samples were characterized through X-ray diffraction (XRD), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and UV-Visible spectroscopy techniques. XRD results revealed that the nanoparticles framework of Fe3O4 was maintained well up to 650 °C by the Fe dopant. UV-Vis results suggested that absorption property of combination Fe3O4/CNTs nanopowder by PLAL was enhanced and the band gap is reduced into 2.0 eV.

    CONCLUSIONS: Density functional theory (DFT) studies emphasize the introduction of Fe+ and Fe2+ ions by replacing other ions in the CNT lattice, therefore creating oxygen vacancies. These further promoted anti-microbial efficiency. A significantly high bacterial inactivation that indicates results was evaluated and that the mean estimations of restraint were determined from triple assessment in every appraisal at 400 ml which represent the best anti-bacterial action against gram-positive and gram-negative microbes.

    Matched MeSH terms: Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus
  16. Biocompatible chitin-encapsulated CdS quantum dots: Fabrication and antibacterial screening
    Lim MJ, Shahri NNM, Taha H, Mahadi AH, Kusrini E, Lim JW, et al.
    Carbohydr Polym, 2021 May 15;260:117806.
    PMID: 33712152 DOI: 10.1016/j.carbpol.2021.117806
    Chitin-encapsulated cadmium sulfide quantum dots (CdS@CTN QDs) were successfully synthesized from chitin and Cd(NO3)2 precursor using the colloidal chemistry method, toward the development of biocompatible and biodegradable QDs for biomedical applications. CdS@CTN QDs exhibited the nanocrystalline cubic CdS encapsulated by α-chitin. The average particle size of CdS@CTN QDs was estimated using empirical Henglein model to be 3.9 nm, while their crystallite size was predicted using Scherrer equation to be 4.3 nm, slightly larger compared to 3-mercaptopropionic acid-capped CdS QDs (3.2 and 3.6 nm, respectively). The mechanism of formation was interpreted based on the spectroscopic data and X-ray crystal structures of CdS@CTN QDs fabricated at different pH values and mass ratios of chitin to Cd(NO3)2 precursor. As an important step to explore potential biomolecular and biological applications of CdS@CTN QDs, their antibacterial activities were tested against four different bacterial strains; i.e. Escherichia coli, Bacillus subtillus, Staphylococcus aureus and Pseudomonas aeruginosa.
    Matched MeSH terms: Staphylococcus aureus
  17. Fulltext Gut Bacteria of Rattus rattus (Rat) Produce Broad-Spectrum Antibacterial Lipopeptides
    Akbar N, Siddiqui R, Iqbal M, Sagathevan K, Kim KS, Habib F, et al.
    ACS Omega, 2021 May 11;6(18):12261-12273.
    PMID: 34056379 DOI: 10.1021/acsomega.1c01137
    Among several animals, Rattus rattus (rat) lives in polluted environments and feeds on organic waste/small invertebrates, suggesting the presence of inherent mechanisms to thwart infections. In this study, we isolated gut bacteria of rats for their antibacterial activities. Using antibacterial assays, the findings showed that the conditioned media from selected bacteria exhibited bactericidal activities against Gram-negative (Escherichia coli K1, Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens, and Salmonella enterica) and Gram-positive (Bacillus cereus, methicillin-resistant Staphylococcus aureus, and Streptococcus pyogenes) pathogenic bacteria. The conditioned media retained their antibacterial properties upon heat treatment at boiling temperature for 10 min. Using MTT assays, the conditioned media showed minimal cytotoxic effects against human keratinocyte cells. Active conditioned media were subjected to tandem mass spectrometry, and the results showed that conditioned media from Bacillus subtilis produced a large repertoire of surfactin and iturin A (lipopeptides) molecules. To our knowledge, this is the first report of isolation of lipopeptides from bacteria isolated from the rat gut. In short, these findings are important and provide a platform to develop effective antibacterial drugs.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus
  18. Gelatin Hydrogels Loaded with Lactoferrin-Functionalized Bio-Nanosilver as a Potential Antibacterial and Anti-Biofilm Dressing for Infected Wounds: Synthesis, Characterization, and Deciphering of Cytotoxicity
    Suleman Ismail Abdalla S, Katas H, Chan JY, Ganasan P, Azmi F, Fauzi MB
    Mol Pharm, 2021 05 03;18(5):1956-1969.
    PMID: 33822631 DOI: 10.1021/acs.molpharmaceut.0c01033
    Gelatin hydrogels are attractive for wound applications owing to their well-defined structural, physical, and chemical properties as well as good cell adhesion and biocompatibility. This study aimed to develop gelatin hydrogels incorporated with bio-nanosilver functionalized with lactoferrin (Ag-LTF) as a dual-antimicrobial action dressing, to be used in treating infected wounds. The hydrogels were cross-linked using genipin prior to loading with Ag-LTF and characterized for their physical and swelling properties, rheology, polymer and actives interactions, and in vitro release of the actives. The hydrogel's anti-biofilm and antibacterial performances against S. aureus and P. aeruginosa as well as their cytotoxicity effects were assessed in vitro, including primary wound healing gene expression of human dermal fibroblasts (HDFs). The formulated hydrogels showed adequate release of AgNPs and LTF, with promising antimicrobial effects against both bacterial strains. The Ag-LTF-loaded hydrogel did not significantly interfere with the normal cellular functions as no alteration was detected for cell viability, migration rate, and expression of the target genes, suggesting the nontoxicity of Ag-LTF as well as the hydrogels. In conclusion, Ag-LTF-loaded genipin-cross-linked gelatin hydrogel was successfully synthesized as a new approach for fighting biofilms in infected wounds, which may be applied to accelerate healing of chronic wounds.
    Matched MeSH terms: Staphylococcus aureus/drug effects
  19. In vitro polymicrobial inter-kingdom three-species biofilm model: influence of hyphae on biofilm formation and bacterial physiology
    Ruiz-Sorribas A, Poilvache H, Kamarudin NHN, Braem A, Van Bambeke F
    Biofouling, 2021 05;37(5):481-493.
    PMID: 34225500 DOI: 10.1080/08927014.2021.1919301
    Biofilms are an important medical burden, notably for patients with orthopaedic device-related infections. When polymicrobial, these infections are more lethal and recalcitrant. Inter-kingdom biofilm infections are poorly understood and challenging to treat. Here, an in vitro three-species model including Staphylococcus aureus, Escherichia coli and Candida albicans was developed, to represent part of the diversity observed in orthopaedic infections or other clinical contexts. The importance of fungal hyphae for biofilm formation and virulence factor expression was explored. Two protocols were set up, allowing, or not, for hyphal formation. Culturable cells and biomass were characterised in both models, and biofilms were imaged in bright-field, confocal and electron microscopes. The expression of genes related to virulence, adhesion, exopolysaccharide synthesis and stress response was analysed in early-stage and mature biofilms. It was found that biofilms enriched in hyphae had larger biomass and showed higher expression levels of genes related to bacterial virulence or exopolysaccharides synthesis.
    Matched MeSH terms: Staphylococcus aureus
  20. Bacterial disinfection and cell assessment post ultraviolet-C LED exposure for wound treatment
    Sheikh J, Swee TT, Saidin S, Yahya AB, Malik SA, Yin JSS, et al.
    Med Biol Eng Comput, 2021 May;59(5):1055-1063.
    PMID: 33866479 DOI: 10.1007/s11517-021-02360-8
    Ultraviolet-C sourced LED (UVC-LED) has been widely used for disinfection purposes due to its germicidal spectrum. In this study, the efficiencies of UVC-LED for Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) disinfections were investigated at three exposure distances (1, 1.5, and 2 cm) and two exposure times (30 and 60 s). The respective bacterial inhibition zones were measured, followed by a morphological analysis under SEM. The viabilities of human skin fibroblast cells were further evaluated under the treatment of UVC-LED with the adoption of aforesaid exposure parameters. The inhibition zones were increased with the increment of exposure distances and times. The highest records of 5.40 ± 0.10 cm P. aeruginosa inhibition and 5.43 ± 0.11 cm S. aureus inhibition were observed at the UVC-LED distance of 2 cm and 60-s exposure. Bacterial physical damage with debris formation and reduction in size were visualized following the UVC-LED exposures. The cell viability percentages were in a range of 75.20-99.00% and 82-100.00% for the 30- and 60-s exposures, respectively. Thus, UVC-LED with 275-nm wavelength is capable in providing bacterial disinfection while maintaining accountable cell viability which is suitable to be adopted in wound treatment. Bacterial disinfection and human skin fibroblast cell assessment using UVC-LED.
    Matched MeSH terms: Staphylococcus aureus*
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