Displaying publications 261 - 280 of 621 in total

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  1. Saleem S, Iqbal A, Hasnain S
    Trop Biomed, 2020 Jun 01;37(2):482-488.
    PMID: 33612817
    Bacterial mediated Silver nanoparticles is considered as an emerging Ecofriendly approach to eradicate human pathogens. This paper aims to provide the biological approach for the synthesis of silver nanoparticles from indigenously isolated bacteria. This study will be beneficial to control the nosocomial infections triggered by MRSA (Methicillin-resistant Staphylococcus aureus). The current study is the extracellular synthesis of silver nanoparticles by using the cell free filtrate of bacterial strains isolated from the soil. The optimization study was also carried out to obtain the maximum production of silver nanoparticles. Nanoparticles were confirmed and characterized by UV-Vis spectroscopy and Transmission Electron Microscopy (TEM) having the plasmon resonance peak between 420-450nm with 10-60nm in size range and most were spherical in shape. Synthesized silver nanoparticles showed a potential antibacterial activity against MRSA (Methicillin Resistant Staphylococcus aureus) in-vitro study. This is the green approach for the production of AgNPs, as there was no previous work done on the synthesis of silver nanoparticles by bacteria in this region of Southern Punjab, Pakistan and these nanoparticles can be used to treat nosocomial infection. These silver nanoparticles can be used in effective disease management as antimicrobial agent.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
  2. 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*
  3. Azmi NN, Mahyudin NA, Wan Omar WH, Mahmud Ab Rashid NK, Ishak CF, Abdullah AH, et al.
    Molecules, 2021 Dec 28;27(1).
    PMID: 35011396 DOI: 10.3390/molecules27010170
    Natural clays have recently been proven to possess antibacterial properties. Effective natural antimicrobial agents are needed to combat bacterial contamination on food contact surfaces, which are increasingly more prevalent in the food chain. This study sought to determine the antibacterial activity of clays against the food-borne pathogens Salmonella typhimurium ATCC 14028 and Staphylococcus aureus ATCC 13565. Soils were processed to yield leachates and suspensions from untreated and treated clays. Soil particle size, pH, cation-exchange capacity, metal composition and mineralogy were characterized. Antibacterial screening was performed on six Malaysian soils via the disc diffusion method. In addition, a time-kill assay was conducted on selected antibacterial clays after 6 h of exposure. The screening revealed that Munchong and Carey clays significantly inhibit Salmonella typhimurium (11.00 ± 0.71 mm) and S. aureus (7.63 ± 0.48 mm), respectively. Treated Carey clay leachate and suspension completely kill Salmonella typhimurium, while S. aureus viability is reduced (2 to 3 log10). The untreated Carey and all Munchong clays proved ineffective as antibacterials. XRD analysis confirmed the presence of pyrite and magnetite. Treated Carey clays had a higher soluble metal content compared to Munchong; namely Al (92.63 ± 2.18 mg/L), Fe (65.69 ± 3.09 mg/L) and Mg (88.48 ± 2.29 mg/L). Our results suggest that metal ion toxicity is responsible for the antibacterial activity of these clays.
    Matched MeSH terms: Staphylococcus aureus/drug effects*
  4. Hazni H, Ahmad N, Hitotsuyanagi Y, Takeya K, Choo CY
    Planta Med, 2008 Dec;74(15):1802-5.
    PMID: 18991205 DOI: 10.1055/s-0028-1088340
    The methanolic extract of the leaves of CASSIA ALATA was sequentially partitioned in increasing polarity to afford the hexane, chloroform, butanol and residual extract. Crude extracts were evaluated against MRSA using the agar well diffusion assay. The butanol and chloroform extracts both exhibited inhibition against MRSA with inhibition indexes of 1.03 +/- 0.16 and 0.78 +/- 0.07 at the concentration of 50 mg/mL. The butanol extracts were further purified using silica gel and reverse phase chromatography to afford kaempferol ( 1), kaempferol 3- O-beta-glucopyranoside ( 2), kaempferol 3- O-gentiobioside ( 3) and aloe emodin ( 4). The four constituents showed varying degrees of inhibition against MRSA. Both 1 and 4 exhibited MIC (50) values of 13.0 +/- 1.5 microg/mL and 12.0 +/- 1.5 microg/mL, respectively. The kaempferol glycosides 2 and 3 were less active with MIC (50) values of 83.0 +/- 0.9 microg/mL and 560.0 +/- 1.2 microg/mL, respectively. A free hydroxyl group at C-3 of the flavonol structure is a structural requirement for the inhibition of MRSA.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
  5. Anita Lett J, Sagadevan S, Léonard E, Fatimah I, Motalib Hossain MA, Mohammad F, et al.
    Artif Organs, 2021 Dec;45(12):1501-1512.
    PMID: 34309044 DOI: 10.1111/aor.14045
    The primary role of bone tissue engineering is to reconcile the damaged bones and facilitate the speedy recovery of the injured bones. However, some of the investigated metallic implants suffer from stress-shielding, palpability, biocompatibility, etc. Consequently, the biodegradable scaffolds fabricated from polymers have gathered much attention from researchers and thus helped the tissue engineering sector by providing many alternative materials whose functionality is similar to that of natural bones. Herein, we present the fabrication and testing of a novel composite, magnesium (Mg)-doped hydroxyapatite (HAp) glazed onto polylactic acid (PLA) scaffolds where polyvinyl alcohol (PVA) used as a binder. For the composite formation, Creality Ender-3 pro High Precision 3D Printer with Shape tool 3D Technology on an FSD machine operated by Catia design software was employed. The composite has been characterized for the crystallinity (XRD), surface functionality (FTIR), morphology (FESEM), biocompatibility (hemolytic and protein absorption), and mechanical properties (stress-strain and maximum compressive strength). The powder XRD analysis confirmed the semicrystalline nature and intact structure of HAp even after doping with Mg, while FTIR studies for the successful formation of Mg-HAp/PVA@PLA composite. The FESEM provided analysis indicated for the 3D porous architecture and well-defined morphology to efficiently transport the nutrients, and the biocompatibility studies are supporting that the composite for blood compatible with the surface being suitable enough for the protein absorption. Finally, the composite's antibacterial activity (against Staphylococcus aureus and Escherichia coli) and the test of mechanical properties supported for the enhanced inhibition of active growth of microorganisms and maximum compressive strength, respectively. Based on the research outcomes of biocompatibility, antibacterial activity, and mechanical resistance, the fabricated Mg-HAp/PVA@PLA composite suits well as a promising biomaterial platform for orthopedic applications by functioning towards the open reduction internal fixation of bone fractures and internal repairs.
    Matched MeSH terms: Staphylococcus aureus/drug effects
  6. Mohd-Zain Z, Mohd-Nawi SFA, Adnan A, Kumar S
    Malays J Pathol, 2017 Aug;39(2):115-122.
    PMID: 28866692 MyJurnal
    BACKGROUND: HIV-infected patients pose a high risk of contracting skin and soft tissue infections caused by Staphylococcus aureus. Those who are colonized with methicillin-resistant S. aureus (MRSA) that carry Panton-Valentine leukocidin (PVL) are predisposed to severe infections that could lead to necrotic skin infections. However the association of S. aureus specifically methicillin sensitive S. aureus carrying PVL gene in HIV patients has not been widely reported. Here, we study the prevalence and the molecular epidemiology of PVL-producing S. aureus in HIV-infected patients.

    METHODS: Swabs from four body sites of 129 HIV-infected patients were cultured for S. aureus and identified by standard microbiological procedures. The isolates were subjected to antimicrobial susceptibility testing by disk diffusion against penicillin, erythromycin, clindamycin, and cotrimoxazole. PCR was used to detect the PVL gene and genetic relationship between the isolates was determined by using pulse field gel electrophoresis.

    RESULTS: A total of 51 isolates of S. aureus were obtained from 40 (31%) of the patients. The majority (43.1%) of the isolates were obtained from the anterior nares. Thirteen (25.5%) of all the isolates were resistant to more than one category of antibiotics, with one isolate identified as MRSA. Thirty-eight (74.5%) isolates (including the MRSA isolate) carried PVL gene where the majority (44.7%) of these isolates were from the anterior nares. A dendogram revealed that the isolates were genetically diverse with 37 distinct pulsotypes clustered in 11 groups.

    CONCLUSION: S. aureus obtained from multiple sites of the HIV patients were genetically diverse without any clonality observed.

    Matched MeSH terms: Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus
  7. Kong C, Chee CF, Richter K, Thomas N, Abd Rahman N, Nathan S
    Sci Rep, 2018 02 09;8(1):2758.
    PMID: 29426873 DOI: 10.1038/s41598-018-21141-2
    Staphylococcus aureus is a major cause of nosocomial infections and secretes a diverse spectrum of virulence determinants as well as forms biofilm. The emergence of antibiotic-resistant S. aureus highlights the need for alternative forms of therapeutics other than conventional antibiotics. One route to meet this need is screening small molecule derivatives for potential anti-infective activity. Using a previously optimized C. elegans - S. aureus small molecule screen, we identified a benzimidazole derivative, UM-C162, which rescued nematodes from a S. aureus infection. UM-C162 prevented the formation of biofilm in a dose-dependent manner without interfering with bacterial viability. To examine the effect of UM-C162 on the expression of S. aureus virulence genes, a genome-wide transcriptome analysis was performed on UM-C162-treated pathogen. Our data indicated that the genes associated with biofilm formation, particularly those involved in bacterial attachment, were suppressed in UM-C162-treated bacteria. Additionally, a set of genes encoding vital S. aureus virulence factors were also down-regulated in the presence of UM-C162. Further biochemical analysis validated that UM-C162-mediated disruption of S. aureus hemolysins, proteases and clumping factors production. Collectively, our findings propose that UM-C162 is a promising compound that can be further developed as an anti-virulence agent to control S. aureus infections.
    Matched MeSH terms: Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus
  8. Phoon HYP, Hussin H, Hussain BM, Lim SY, Woon JJ, Er YX, et al.
    J Glob Antimicrob Resist, 2018 09;14:132-140.
    PMID: 29540306 DOI: 10.1016/j.jgar.2018.02.022
    OBJECTIVES: Hospital environments are potential reservoirs of bacteria associated with nosocomial infections. In this study, the distribution of cultivable environmental bacteria of clinical importance from a Malaysian tertiary hospital was determined and their resistotypes and genotypes were investigated.

    METHODS: Swab and fluid samples (n=358) from healthcare workers' hands, frequently touched surfaces, medical equipment, patients' immediate surroundings, ward sinks and toilets, and solutions or fluids of 12 selected wards were collected. Biochemical tests, PCR and 16S rRNA sequencing were used for identification following isolation from CHROMagar™ Orientation medium. Clinically important bacteria such as Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter spp., Pseudomonas aeruginosa and Enterobacter spp. were further characterised by disc diffusion method and rep-PCR.

    RESULTS: The 24 Gram-negative and 19 Gram-positive bacteria species identified were widely distributed in the hospital environment. Staphylococci were predominant, followed by Bacillus spp. and P. aeruginosa. Frequently touched surfaces, medical equipment, and ward sinks and toilets were the top three sources of bacterial species. Nine S. aureus, four Acinetobacter spp., one K. pneumoniae and one Enterobacter spp. were multidrug-resistant (MDR). The ESKAPE organisms were genetically diverse and widely dispersed across the hospital wards. A MDR MRSA clone was detected in a surgical ward isolation room.

    CONCLUSION: The large variety of cultivable, clinically important bacteria, especially the genetically related MDR S. aureus, K. pneumoniae, Acinetobacter spp. and Enterobacter spp., from various sampling sites indicated that the surfaces and fomites in the hospital were potential exogenous sources of nosocomial infection in the hospital.

    Matched MeSH terms: Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus
  9. Bo ZM, Tan WK, Chong CSC, Lye MS, Parmasivam S, Pang ST, et al.
    PLoS One, 2022;17(11):e0277802.
    PMID: 36395327 DOI: 10.1371/journal.pone.0277802
    Acute pharyngitis (AP) is a common reason for private primary care consultations, thus providing an avenue for widespread antibiotic intake among the community. However, there is limited data on the antibiotic prescription appropriateness and resistance information in the Malaysian private primary care setting, therefore, this study aimed to investigate the prevalence of isolated viruses and bacteria, antibiotic resistance patterns, antibiotic prescription patterns and appropriateness by general practitioners (GPs) and factors affecting antibiotic resistance and antibiotic prescription patterns. To investigate, a cross-sectional study was conducted among 205 patients presenting with AP symptoms at private primary care clinics in central Malaysia from 3rd January 2016 to 30th November 2016. Throat swabs were collected from 205 AP patients for two purposes: (i) the detection of four common respiratory viruses associated with AP via reverse-transcription real-time PCR (qRT-PCR); and (ii) bacterial identification using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). Bacterial isolates were then subjected to antibiotic susceptibility screening and McIsaac scoring was calculated post-prescription based on GP selection of criteria. Generalized estimating equations analysis with multiple logistic regression was conducted to identify factors associated with presence of virus and antibiotic prescription. The results showed that 95.1% (195/205) of patients had at least one of the four viruses, with rhinovirus (88.5%) being the most prevalent, followed by adenovirus (74.9%), influenza A virus (4.6%) and enterovirus (2.1%). A total of 862 non-repetitive colonies were isolated from the culture of throat swabs from 205 patients who were positive for bacteria. From a total of 22 genera, Streptococcus constitutes the most prevalent bacteria genus (40.9%), followed by Neisseria (20%), Rothia (13.0%), Staphylococcus (11%) and Klebsiella (4.9%). Only 5 patients carried group A beta-hemolytic streptococci (GABHS). We also report the presence of vancomycin-resistant S. aureus or VRSA (n = 9, 10.1%) among which one isolate is a multidrug-resistant methicillin-resistant S. aureus (MDR-MRSA), while 54.1% (n = 111) were found to carry at least one antibiotic-resistant bacteria species. Application of the McIsaac scoring system indicated that 87.8% (n = 180) of patients should not be prescribed antibiotics as the majority of AP patients in this study had viral pharyngitis. The antibiotic prescription appropriateness by applying post-prescription McIsaac scoring was able to rule out GABHS pharyngitis in this sample with a GABHS culture-positive sensitivity of 40% (n = 2/5) and specificity of 90% (180/200). In conclusion, antibiotic-resistant throat isolates and over-prescription of antibiotics were observed and McIsaac scoring system is effective in guiding GPs to determine occurrences of viral pharyngitis to reduce unnecessary antibiotic prescription.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus*
  10. Abubakar U, Al-Anazi M, Alanazi Z, Rodríguez-Baño J
    J Infect Public Health, 2023 Mar;16(3):320-331.
    PMID: 36657243 DOI: 10.1016/j.jiph.2022.12.022
    BACKGROUND: There is paucity of data describing the impact of COVID-19 pandemic on antimicrobial resistance. This review evaluated the changes in the rate of multidrug resistant gram negative and gram positive bacteria during the COVID-19 pandemic.

    METHODS: A search was conducted in PubMed, Science Direct, and Google Scholar databases to identify eligible studies. Studies that reported the impact of COVID-19 pandemic on carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Enterobacteriaceae (CRE), extended-spectrum beta-lactamase inhibitor (ESBL)-producing Enterobacteriaceae, vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA) and carbapenem-resistant Pseudomonas aeruginosa (CPE) were selected. Studies published in English language from the start of COVID-19 pandemic to July 2022 were considered for inclusion.

    RESULTS: Thirty eligible studies were selected and most of them were from Italy (n = 8), Turkey (n = 3) and Brazil (n = 3). The results indicated changes in the rate of multidrug resistant bacteria, and the changes varied between the studies. Most studies (54.5%) reported increase in MRSA infection/colonization during the pandemic, and the increase ranged from 4.6 to 170.6%. Five studies (55.6%) reported a 6.8-65.1% increase in VRE infection/colonization during the pandemic. A 2.4-58.2% decrease in ESBL E. coli and a 1.8-13.3% reduction in ESBL Klebsiella pneumoniae was observed during the pandemic. For CRAB, most studies (58.3%) reported 1.5-621.6% increase in infection/colonization during the pandemic. Overall, studies showed increase in the rate of CRE infection/colonization during the pandemic. There was a reduction in carbapenem-resistant E. coli during COVID-19 pandemic, and an increase in carbapenem-resistant K. pneumoniae. Most studies (55.6%) showed 10.4 - 40.9% reduction in the rate of CRPA infection during the pandemic.

    CONCLUSION: There is an increase in the rate of multidrug resistant gram positive and gram negative bacteria during the COVID-19 pandemic. However, the rate of ESBL-producing Enterobacteriaceae and CRPA has decrease during the pandemic. Both infection prevention and control strategies and antimicrobial stewardship should be strengthen to address the increasing rate of multidrug resistant gram positive and gram negative bacteria.

    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus*
  11. Norazah A, Liew SM, Kamel AG, Koh YT, Lim VK
    Singapore Med J, 2001 Jan;42(1):15-9.
    PMID: 11361232
    To determine and compare the pulsed-field gel electrophoresis (PFGE) patterns of endemic MRSA strains in 2 major Malaysian hospitals and to compare the PFGE patterns with antibiotypes of the strains studied.
    Matched MeSH terms: Staphylococcus aureus/genetics*
  12. Loganathan A, Arumainathan UD, Raman R
    Singapore Med J, 2006 Apr;47(4):271-5.
    PMID: 16572236
    Diagnosis and treatment of acute tonsillitis are one of the most common problems seen at an otorhinolaryngology clinic in both adult and paediatric populations. Much has been written about bacteriology of recurrent tonsillitis but it remains a controversial topic. Despite the fact that tonsillitis is so common, consensus seems to be lacking as to the main causative organism and the differences between children and adults. The tonsillar core bacteriology of 233 patients with recurrent tonsillitis who underwent tonsillectomy from January 2000 to June 2003 is presented.
    Study site: inpatients, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
    Matched MeSH terms: Staphylococcus aureus/isolation & purification*
  13. Tan KW, Tay L, Lim SH
    Singapore Med J, 1994 Jun;35(3):277-82.
    PMID: 7997904
    Methicillin resistant Staphylococcus aureus (MRSA) is a major infection control problem in many countries. There have been many reports of outbreaks in neonatal nurseries including, in our part of the world, Australia, Hong Kong and Malaysia. A recent outbreak of MRSA in the neonatal intensive care unit in the Kandang Kerbau Hospital, Singapore, presented us with the opportunity to study the clinical characteristics of the outbreak and the effects of infection control measures. Neonates admitted to the neonatal intensive care unit were studied over a 20-month period. They were all screened for nasal colonisation on admission and weekly thereafter. Infections were documented. Over this period there were altogether 2,576 admissions of which 85 infants had nasal colonisation with MRSA (3.3%) and 28 developed infections (1%). Although the majority of infants colonised by MRSA suffered no ill effects, 3 had septicaemia and 2 had septicaemia with osteomyelitis. There were no deaths. Standard infection control measures with barrier nursing and the use of mupirocin nasal ointment were ineffective, and control was achieved only after strict cohorting together with the use of mupirocin was instituted. This was done without additional costs to the department and without additional nurses or doctors.
    Matched MeSH terms: Staphylococcus aureus/drug effects*
  14. Puthucheary SD, Lim CT, Parasakthi N, Tan A, Lam KL
    Singapore Med J, 1987 Oct;28(5):456-8.
    PMID: 3433116
    Matched MeSH terms: Staphylococcus aureus/drug effects*
  15. Lim VKE, Zulkifli HI
    Singapore Med J, 1987 Apr;28(2):176-9.
    PMID: 3629274
    Methicillin resistant Siaphylococcus aureus Is a common isolate from clinical specimens obtained from babies at the special care nursery of the Kuala Lumpur Maternity Hospital. Major Infections due to this organism were, however uncommon and the organism had in the majority of cases been present as a coloniser or as a cause of superficial infection. Netilmicin is a valuable antibiotic in the treatment of the severe infections.
    Matched MeSH terms: Staphylococcus aureus/drug effects
  16. Goh ZNL, Chung PY
    J Hosp Infect, 2019 Apr;101(4):482-483.
    PMID: 30711530 DOI: 10.1016/j.jhin.2019.01.022
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/isolation & purification*
  17. Anggraeni VS, Lee HC, Goh PS, Sutrisna PD, Chan EWC, Wong CW
    Biofouling, 2024;40(5-6):348-365.
    PMID: 38836472 DOI: 10.1080/08927014.2024.2357309
    Our research focuses on developing environmentally friendly biodegradable ultrafiltration (UF) membranes for small-scale water purification in areas lacking infrastructure or during emergencies. To address biofouling challenges without resorting to harmful chemicals, we incorporate bio-based extracts, such as methyl gallate from A. occidentale leaves, a Malaysian ulam herb, known for its quorum sensing inhibition (QSI) properties. The methyl gallate enriched extract was purified by solvent partitioning and integrated into cellulose-based UF membranes (0 to 7.5% w w-1) through phase inversion technique. The resulting membranes exhibited enhanced anti-organic fouling and anti-biofouling properties, with flux recovery ratio (FRR) of 87.84 ± 2.00% against bovine serum albumin and FRRs of 76.67 ± 1.89% and 69.57 ± 1.77% against E. coli and S. aureus, respectively. The CA/MG-5 membrane showed a 224% improvement in pure water flux (PWF) compared to the neat CA membrane. Our innovative approach significantly improves PWF, presenting an environmentally friendly method for biofouling prevention in UF membrane applications.
    Matched MeSH terms: Staphylococcus aureus/drug effects
  18. Matejczyk M, Ofman P, Juszczuk-Kubiak E, Świsłocka R, Shing WL, Kesari KK, et al.
    Ecotoxicol Environ Saf, 2024 Jun 01;277:116383.
    PMID: 38663192 DOI: 10.1016/j.ecoenv.2024.116383
    Vanillic acid (4-hydroxy-3-methoxybenzoic acid) (VA) is a natural benzoic acid derivative commonly found in herbs, rice, maize, and some fruits and vegetables. However, due to the wide use of VA in various industrial sectors, its presence in the environment might harm living organisms. This study evaluated the toxicity of VA and its isomers, iso-VA and orto-VA. Firstly, the antimicrobial effect of VA and its isomers iso-VA and orto-VA (in doses of 1000; 100, 10, 1; 0.1; 0.01 mg/L) against Escherichia coli, Sarcina spp., Enterobacter homaechei, Staphylococcus aureus and Candida albicans were identified. The toxic effect and protein degradation potential of VA and its isomers were determined using E. coli grpE:luxCDABE and lac:luxCDABE biosensor strains. However, the genotoxicity and oxidative stress generation were assessed with the E. coli recA:luxCDABE biosensor and E. coli strain. The results showed that VA, iso-VA, and orto-VA exhibited antimicrobial activity against all tested bacterial strains. However, VA's antimicrobial effect differed from iso-VA and orto-VA. Similar toxic, genotoxic, and oxidative stress-inducing effects were observed for VA and its isomers. Each compound exhibited toxicity, cellular protein degradation, and genotoxic activity against E. coli grpE:luxCDABE, E. coli lac:luxCDABE, and E. coli recA:luxCDABE strains. Analysis of reactive oxygen species (ROS) generation within E. coli cells highlighted oxidative stress as a contributing factor to the toxicity and genotoxicity of VA and its isomers. While the findings suggest potential applications of VA compounds as food preservatives, their presence in the environment raises concerns regarding the risks posed to living organisms due to their toxic and genotoxic characteristics.
    Matched MeSH terms: Staphylococcus aureus/drug effects
  19. Wu XY, Zhao ZY, Osman EEA, Wang XJ, Choo YM, Benjamin MM, et al.
    Bioorg Chem, 2024 Feb;143:107103.
    PMID: 38211549 DOI: 10.1016/j.bioorg.2024.107103
    Three undescribed (1-3) and nine known (4-12) platanosides were isolated and characterized from a bioactive extract of the May leaves of Platanus × acerifolia that initially showed inhibition against Staphylococcus aureus. Targeted compound mining was guided by an LC-MS/MS-based molecular ion networking (MoIN) strategy combined with conventional isolation procedures from a unique geographic location. The novel structures were mainly determined by 2D NMR and computational (NMR/ECD calculations) methods. Compound 1 is a rare acylated kaempferol rhamnoside possessing a truxinate unit. 6 (Z,E-platanoside) and 7 (E,E-platanoside) were confirmed to have remarkable inhibitory effects against both methicillin-resistant S. aureus (MIC: ≤ 16 μg/mL) and glycopeptide-resistant Enterococcus faecium (MIC: ≤ 1 μg/mL). These platanosides were subjected to docking analyses against FabI (enoyl-ACP reductase) and PBP1/2 (penicillin binding protein), both of which are pivotal enzymes governing bacterial growth but not found in the human host. The results showed that 6 and 7 displayed superior binding affinities towards FabI and PBP2. Moreover, surface plasmon resonance studies on the interaction of 1/7 and FabI revealed that 7 has a higher affinity (KD = 1.72 μM), which further supports the above in vitro data and is thus expected to be a novel anti-antibacterial drug lead.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus*
  20. Hairil Anuar AH, Abd Ghafar SA, Hanafiah RM, Lim V, Mohd Pazli NFA
    Int J Nanomedicine, 2024;19:1339-1350.
    PMID: 38348172 DOI: 10.2147/IJN.S431499
    INTRODUCTION: This study aimed to characterize silver nanoparticles-kaempferol (AgNP-K) and its antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA). Green synthesis method was used to synthesize AgNP-K under the influence of temperature and different ratios of silver nitrate (AgNO3 and kaempferol).

    METHODS: AgNP-K 1:1 was synthesized with 1 mM kaempferol, whereas AgNP-K 1:2 with 2 mM kaempferol. The characterization of AgNP-K 1:1 and AgNP-K 1:2 was performed using UV-visible spectroscopy (UV-Vis), Zetasizer, transmission electron microscopy (TEM), scanning electron microscopy-dispersive X-ray spectrometer (SEM-EDX), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The antibacterial activities of five samples (AgNP-K 1:1, AgNP-K 1:2, commercial AgNPs, kaempferol, and vancomycin) at different concentrations (1.25, 2.5, 5, and 10 mg/mL) against MRSA were determined via disc diffusion assay (DDA), minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) assay, and time-kill assay.

    RESULTS: The presence of a dark brown colour in the solution indicated the formation of AgNP-K. The UV-visible absorption spectrum of the synthesized AgNP-K exhibited a broad peak at 447 nm. TEM, Zetasizer, and SEM-EDX results showed that the morphology and size of AgNP-K were nearly spherical in shape with 16.963 ± 6.0465 nm in size. XRD analysis confirmed that AgNP-K had a crystalline phase structure, while FTIR showed the absence of (-OH) group, indicating that kaempferol was successfully incorporated with silver. In DDA analysis, AgNP-K showed the largest inhibition zone (16.67 ± 1.19 mm) against MRSA as compared to kaempferol and commercial AgNPs. The MIC and MBC values for AgNP-K against MRSA were 1.25 and 2.50 mg/mL, respectively. The time-kill assay results showed that AgNP-K displayed bacteriostatic activity against MRSA. AgNP-K exhibited better antibacterial activity against MRSA when compared to commercial AgNPs or kaempferol alone.

    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus*
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