Displaying publications 21 - 40 of 605 in total

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  1. Ramli SR, Neoh HM, Aziz MN, Hussin S
    Infect Dis Rep, 2012 Jan 2;4(1):e20.
    PMID: 24470927 DOI: 10.4081/idr.2012.e20
    In a 3-month study done in Hospital Kuala Lumpur (HKL), 7 out of 320 methicillin resistant Staphylococcus aureus isolates were confirmed as heterogeneous vancomycin intermediate S. aureus (hVISA) using the glycopeptide resistance detection e-test and population analysis, giving a prevalence rate of 2.19%. This is the first report of hVISA in Malaysia.
    Matched MeSH terms: Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus
  2. Sivaranjan K, Santhanalakshmi J, Panneer DS, Vivekananthan S, Sagadevan S, Johan MRB, et al.
    J Nanosci Nanotechnol, 2020 02 01;20(2):918-923.
    PMID: 31383087 DOI: 10.1166/jnn.2020.16895
    Herein, we report the facile synthesis of Iron oxide@Pt core-shell nanoparticles (NPs) by facile two step synthesis process. The first step follows the growth of iron oxide nanoparticle by thermal decomposition process while the second step deals with the formation of iron oxide@Pt core-shell nanoparticles by the chemical reduction method. The synthesized core-shell nanoparticles were characterized by several techniques and used for the catalytic reductive translation of Cr(VI) to Cr(III) in the presence of formic acid by a UV-vis spectrophotometer. The UV photo-spectrometer analysis confirmed the conversion efficiency from 12% to as high as 98.8% at the end of 30 minutes. Thus, the presence of Iron oxide @Pt core-shell nanoparticles (NPs) can be effectively used as a catalyst for the reducion of Cr(VI) to Cr(III) ions. Additionally, antibacterial studies were performed for the prepared core-shell nanoparticles against two bacterial strains, i.e., gram (+ve) Staphylococcus Aureus (S. Aureus) and gram (-ve) Escherichia Coli (E. Coli).
    Matched MeSH terms: Staphylococcus aureus*
  3. Lee WH, Rohanizadeh R, Loo CY
    Colloids Surf B Biointerfaces, 2021 Oct;206:111938.
    PMID: 34198233 DOI: 10.1016/j.colsurfb.2021.111938
    This study developed a novel bioactive bone substitute (hydroxyapatite, HA) with improved anti-biofilm activity by functionalizing with curcumin (anti-biofilm compound) which provide sufficient flux of curcumin concentration for 14 days. The released curcumin acts to inhibit biofilm formation and control the number of viable planktonic cells simultaneously. To prepare curcumin-functionalized HA, different concentrations of curcumin (up to 3% w/v) were added simultaneously during the precipitation process of HA. The highest loading (50 mg/g HA) of curcumin onto HA was achieved with 2% w/v of curcumin. Physicochemical characterizations of curcumin-functionalized HA composites revealed that curcumin was successfully incorporated onto HA. Curcumin was sustainably released over 14 days, while higher curcumin release was observed in acidic condition (pH 4.4) compared to physiological (pH 7.4). The cytotoxicity assays revealed that no significant difference on bone cells growth on curcumin-functionalized HA and non-functionalized HA. Curcumin-functionalized HA was effective to inhibit bacterial cell attachment and subsequent biofilm maturation stages. The anti-biofilm effect was stronger against Staphylococcus aureus compared to Pseudomonas aeruginosa. The curcumin-functionalized HA composite significantly delayed the maturation of S. aureus compared to non-functionalized HA in which microcolonies of cells only begin to appear at 96 h. Up to 3.0 log reduction in colony forming unit (CFU)/mL of planktonic cells was noted at 24 h of incubation for both microorganisms. Thus, in this study we have suggested that curcumin loaded HA could be an alternative antimicrobial agent to control the risk of infections in post-surgical implants.
    Matched MeSH terms: Staphylococcus aureus*
  4. Mohd Zain Z, Johari MF, Mohd Husin NS, Rozman NS, Ab Rashid A, Bahanuddin L, et al.
    MyJurnal
    Introduction: To determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage and detection of S. aureus leukotoxins among medical students of Universiti Teknologi MARA. Methods: Both sides of the anterior nares of 136 volunteers, comprising 68 preclinical and 68 clinical medical students, were swabbed and immediately cultured onto mannitol salt agar for growth of S. aureus. Standard microbiological techniques were conducted to identify and confirm the S. aureus colonies and susceptibility test against oxacillin were conducted by using Kirby-Bauer method to determine their resistance to methicillin. Polymerase chain reaction was performed for detection of leukotoxins, i.e., Panton-Valentine Leukocidin (PVL) and -haemolysin genes. Results: Nineteen students (14%) consisting of 10 preclinical (14.7%) and 9 clinical (13.2%) were nasal carriers of S. aureus. However, none of the S. aureus isolates were MRSA. No PVL gene was detected but eight of them were positive for -haemolysin gene. Conclusion: There were no MRSA nasal carriers among the medical students, but a low prevalence of S. aureus nasal carriers was detected. These carriers do not pose as high risk because none of the strains of S. aureus possess both the -haemolysin toxin and the PVL toxin that are associated with tissue necrosis.
    Matched MeSH terms: Staphylococcus aureus*
  5. Bitrus AA, Zunita Z, Khairani-Bejo S, Othman S, Ahmad Nadzir NA
    Microb Pathog, 2018 Oct;123:323-329.
    PMID: 30053600 DOI: 10.1016/j.micpath.2018.07.033
    This study was designed to screen for SCCmec types and to characterize the attachment site (attB) and universal insertion site (orfX) of SCCmec in a collection of 27 isolates (n = 11) methicillin resistant S. aureus and (n = 16) methicillin susceptible S. aureus isolates in Malaysia. Screening of SCCmec types and characterization of the attachment site was carried out using PCR amplification and Sanger's sequencing method. The result showed that a large proportion of the MRSA isolates carried SCCmec type III 7/11 (63%). Three isolates 3/11 (27%) and 1/11 (9.0%) carried SCCmec type II and IVd respectively. Amplification of the universal insertion site of the SCCmec (orfX) and attachment site (attB) showed that all 16 S. aureus isolates were positive for the orfX gene, while only 7 were positive for the attB gene. Phylogenetic diversity showed that the isolates clustered around strains with features similar to a community acquired MRSA. In conclusion, a high carriage rate of SCCmec type III was observed. The result also showed that all the S. aureus isolates have the orfX structure; however, not all isolates possesses the attB site on the 3' end of the orfX region.
    Matched MeSH terms: Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus
  6. Faizah, M. H., Anisah, N., Yusof, S., Noraina, A. R., Adibah, M. R.
    Medicine & Health, 2017;12(2):286-292.
    MyJurnal
    Acanthamoeba spp. merupakan ameba hidup bebas yang biasa ditemui
    di persekitaran. Ia merupakan agen penyebab keratitis Acanthamoeba (AK)
    dan ensefalitis ameba bergranuloma (GAE). Ameba ini juga mampu menjadi
    perumah kepada pelbagai bakteria termasuklah yang bersifat patogenik seperti
    Mycobacterium, Legionella dan Staphylococcus aureus rintang metisilin (MRSA).
    Berdasarkan maklumat ini, satu kajian dijalankan untuk mengesan kehadiran tiga
    bakteria endosimbion berkepentingan perubatan di dalam Acanthamoeba spp. yang
    telah dipencilkan dari bolong penghawa dingin yang terdapat di wad and dewan
    bedah di Pusat Perubatan Universiti Kebangsaan Malaysia. Kehadiran bakteria
    endosimbion ini disaring menggunakan pasangan primer khusus bagi setiap genus
    menggunakan reaksi rantai polimerase (PCR) konvensional dan disahkan dengan
    analisis penjujukan. Dua puluh sembilan (80.56%) pencilan Acanthamoeba spp.
    didapati mengandungi bakteria endosimbion patogenik yang disasarkan dengan
    sekurang-kurangnya satu genus bakteria bagi setiap pencilan. Mycobacterium
    (82.76 %) adalah bakteria yang paling banyak dikesan, diikuti dengan Legionella sp.
    (65.52 %) dan Pseudomonas spp. (62.07 %). Tiada bakteria MRSA dikesan daripada
    mana-mana pencilan dalam kajian ini. Dua endosimbion Mycobacterium yang
    dikenalpasti telah dikelompokkan ke dalam strain Mycobacterium tuberculosis.
    Kami membuat kesimpulan bahawa, kebanyakan Acanthamoeba berpotensi untuk
    menjadi perumah bagi pelbagai bakteria patogenik, namun implikasi interaksi ini
    terhadap patogenisiti kedua-dua organisma masih kurang jelas dan memerlukan
    penyelidikan yang lebih lanjut.
    Matched MeSH terms: Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus
  7. Wan Omar WH, Mahyudin NA, Azmi NN, Mahmud Ab Rashid NK, Ismail R, Mohd Yusoff MHY, et al.
    Int J Food Microbiol, 2023 Jun 02;394:110184.
    PMID: 36996693 DOI: 10.1016/j.ijfoodmicro.2023.110184
    Staphylococcus aureus and Salmonella Typhimurium have a propensity to develop biofilms on food contact surfaces, such as stainless-steel, that persist despite rigorous cleaning and sanitizing procedures. Since both bacterial species pose a significant public health risk within the food chain, improved anti-biofilm measures are needed. This study examined the potential of clays as antibacterial and anti-biofilm agents against these two pathogens on appropriate contact surfaces. Natural soil was processed to yield leachates and suspensions of both untreated and treated clays. Soil particle size, pH, cation-exchange capacity, and metal ions were characterized to assess their importance in bacterial killing. Initial antibacterial screening was performed on nine distinct types of natural Malaysian soil using a disk diffusion assay. Untreated leachate from Kuala Gula and Kuala Kangsar clays were found to inhibit S. aureus (7.75 ± 0.25 mm) and Salmonella Typhimurium (11.85 ± 1.63 mm), respectively. The treated Kuala Gula suspension (50.0 and 25.0 %) reduced S. aureus biofilms by 4.4 and 4.2 log at 24 and 6 h, respectively, while treated Kuala Kangsar suspension (12.5 %) by a 4.16 log reduction at 6 h. Although less effective, the treated Kuala Gula leachate (50.0 %) was effective in removing Salmonella Typhimurium biofilm with a decrease of >3 log in 24 h. In contrast to Kuala Kangsar clays, the treated Kuala Gula clays contained a much higher soluble metal content, especially Al (301.05 ± 0.45 ppm), Fe (691.83 ± 4.80 ppm) and Mg (88.44 ± 0.47 ppm). Elimination of S. aureus biofilms correlated with the presence of Fe, Cu, Pb, Ni, Mn and Zn irrespective of the pH of the leachate. Our findings demonstrate that a treated suspension is the most effective for eradication of S. aureus biofilms with a potential as a sanitizer-tolerant, natural antibacterial against biofilms for applications in the food industry.
    Matched MeSH terms: Staphylococcus aureus*
  8. Ismaeil R, Nahas ARF, Kamarudin NB, Abubakar U, Mat-Nor MB, Mohamed MHN
    BMC Infect Dis, 2023 Nov 09;23(1):779.
    PMID: 37946158 DOI: 10.1186/s12879-023-08770-3
    BACKGROUND: Infection prevention measures are the gold standard for preventing the spread of hospital-acquired infections (HAIs). COVID-19 pandemic caused major disruptions in infection prevention measures, and this has implications on the rate of HAIs. This study assessed the impact of COVID-19 pandemic on the rate and the types of HAIs at Sultan Ahmed Shah Hospital.

    METHOD: This is a retrospective cohort study that compared the rate of HAIs from April to October 2019 (pre COVID period) and April to October 2020 (during COVID period). Data was collected through the review of patients' electronic medical records.

    RESULTS: There were a total of 578 patients included in the selected wards during the pre- and during the pandemic. Thirty-nine episodes (12.1%) of HAIs were report in the pre COVID period and 29 (11.3%) during COVID-19. In both periods, hospital-acquired pneumonia (HAP) was the most frequent HAI among the patients. There was a rise in catheter-associated bloodstream infections (CLABSI) (0.8%) and ventilator associated pneumonia (VAP) (1.1%) during the COVID-19 period. The most common bacteria were methicillin-resistant Staphylococcus aureus (MRSA) (28.2%) and Enterococcus faecalis (17.9%) in the Pre COVID-19 period, and Pseudomonas aeruginosa (27.6%) and Stenotrophomonas maltophilia (6.9%) during COVID-19.

    CONCLUSION: Our research concluded that the rates of HAIs during the COVID-19 pandemic were not significantly impacted by the improved in-hospital infection prevention efforts to control the pandemic. There is need for further efforts to promote adherence to preventive practices.

    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus*
  9. Zhong W, Tang M, Xie Y, Huang X, Liu Y
    Foodborne Pathog Dis, 2023 Jul;20(7):294-302.
    PMID: 37347934 DOI: 10.1089/fpd.2022.0085
    Staphylococcus aureus can cause bacterial food intoxication and seriously affect human health. Tea polyphenols (TP) are a kind of natural, safe, and broad-spectrum bacteriostatic substances, with a wide range of bacteriostatic effects. In the study, we explored the possible bacteriostatic mode of TP. The minimum inhibitory concentration of TP against S. aureus was 64 μg/mL. Protein, DNA, and K+ leak experiments, fluorescence microscopy, and transmission electron microscopy suggested that TP disrupt cell membranes, leading to intracellular component loss. By studying the effect of TP on the toxicity of S. aureus, it was found that the expression levels of two toxin genes, coa and spa, were downregulated by 2.37 and 32.6, respectively. Furthermore, after treatment with TP, a large number of reactive oxygen species (ROS) were propagated and released, leading to oxidative stress in cells. We speculated that the bacteriostatic mechanism of TP may be through the destruction of the cell membrane and ROS-mediated oxidative stress. Meanwhile, the hemolysis activity proved the safety of TP. Our results suggested that TP may be a potential antimicrobial agent for food.
    Matched MeSH terms: Staphylococcus aureus*
  10. Ghimire L, Banjara MR, Abdulla AM
    J Nepal Health Res Counc, 2024 Mar 31;21(4):616-622.
    PMID: 38616592 DOI: 10.33314/jnhrc.v21i4.4861
    BACKGROUND: Staphylococcus aureus (S.aureus) is an emerging antibiotic resistant bacterium responsible for various infections in human. Resistance to methicillin and vancomycin are of prime concern in S. aureus. The study aims to determine the minimum inhibitory concentration (MIC) of Vancomycin and evaluate the existence of mecA and vanA genes, associated with antibiotic resistance.

    METHODS: Clinical specimens from three Kathmandu hospitals were processed and S. aureus was identified using conventional microbiological procedures. MRSA was phenotypically identified with cefoxitin (30µg) disc diffusion, while vancomycin susceptibility was assessed using the Ezy MICTM stripes. The mecA and vanA genes were detected by polymerase chain reaction (PCR).

    RESULTS: Out of 266 S. aureus samples from various clinical specimen subjected for analysis, 77 (28.9%) were found methicillin-resistant (MRSA) and 10 (3.8%) were observed vancomycin-resistant (VRSA). Vancomycin resistant isolates showed a significant correlation between resistance to ampicillin, chloramphenicol, and cefoxitin. The mecA gene was found in 39 of the MRSA isolates, having 50.64% of MRSA cases, while the vanA gene was detected in 4 of the VRSA cases, constituting 40% of VRSA occurrences.

    CONCLUSIONS: The strains with higher vancomycin minimum inhibitory concentration values (≥ 1.5 μg/ml) displayed increased resistance rates to various antibiotics compared to strains with lower minimum inhibitory concentration values (< 1.5 μg/ml). The presence of vanA genes was strongly associated (100%) with vancomycin resistance, while the 10.3% mecA gene was identified from MRSA having resistance towards vancomycin also.

    Matched MeSH terms: Staphylococcus aureus/genetics
  11. Lee KG, Cheng MO
    Med J Malaysia, 2012 Oct;67(5):529.
    PMID: 23770874 MyJurnal
    Varicella-zoster (chickenpox) infection is a common infectious disease and generally considered to be selflimiting. However, severe bacterial complications associated with the disease have been reported. We describe a case of varicella-zoster infection with secondary Staphylococcus aureus bacteremia, preseptal orbital cellulitis and extensive facial abscesses. She was aggressively treated with intravenous antibiotics and repeated surgical drainage, and eventually made good recovery.
    Matched MeSH terms: Staphylococcus aureus
  12. Sabet NS, Subramaniam G, Navaratnam P, Sekaran SD
    Diagn Microbiol Infect Dis, 2006 Sep;56(1):13-8.
    PMID: 16650954
    For rapid identification of methicillin-resistant Staphylococcus aureus, molecular methods are generally targeting mecA and species-specific genes. Sa442 DNA fragment is a popular species-specific target. However, recently, there have been few reports on S. aureus isolates that are negative for Sa442 fragment; therefore, use of single gene or DNA-fragment-specific polymerase chain reaction (PCR) for identification of microbial isolate may result in misidentification. This study includes CoA gene in parallel with Sa442 marker for identification of S. aureus. This further improves the specificity of the assay by checking for 2 determinants simultaneously for the identification of S. aureus and can prevent misidentification of S. aureus isolates lacking Sa442 DNA fragment. In this study, the newly developed triplex real-time PCR assay was compared with a quadruplex conventional gel-based PCR assay using the same primer sets in both assays. The dual-labeled TaqMan probes (ProOligo, France) for these primers were specifically designed and used in a real-time PCR assay. The clinical isolates (n = 152) were subjected to both PCR assays. The results obtained from both assays proved that the primer and probe sets were 100% sensitive and 100% specific for identification of S. aureus and detection of methicillin resistance. This triplex real-time PCR assay represents a rapid and powerful method for S. aureus identification and detection of methicillin resistance.
    Matched MeSH terms: Staphylococcus aureus/drug effects; Staphylococcus aureus/genetics*; Staphylococcus aureus/isolation & purification
  13. Zarizal S, Yeo CC, Faizal GM, Chew CH, Zakaria ZA, Jamil Al-Obaidi MM, et al.
    Trop Med Int Health, 2018 08;23(8):905-913.
    PMID: 29873865 DOI: 10.1111/tmi.13090
    BACKGROUND: This study aimed to profile the antimicrobial susceptibility and presence of resistance and virulence genes of methicillin-susceptible Staphylococcus aureus (MSSA) and MRSA nasal carriage, by means of genotypic analyses, in students of a tertiary institution in the state of Terengganu, east coast of Malaysia.

    METHODS: A total of 370 agricultural biotechnology students from Universiti Sultan Zainal Abidin in Besut, Terengganu, were enrolled in this study. Antimicrobial susceptibility profiles were evaluated by standard methods. PCR detection of resistance and virulence genes was performed on S. aureus that were methicillin-resistant, macrolide-lincosamide-streptogramin B (MLSB )-positive phenotype and/or positive for the leukocidin (pvl) gene followed by staphylococcal cassette chromosome mec (SCCmec), staphylococcal protein A (spa) and accessory gene regulator (agr) typing.

    RESULTS: One hundred and nineteen of 370 students carried S. aureus (32%); 18 of the isolates were MRSA (15%). Erythromycin resistance was detected in 20% (24/119) of which 15% (18/119) were MRSA and 5% (6/119) MSSA. Among the 24 erythromycin-resistant isolates, D-test was positive in 29% (7/24) displaying inducible MLSB , whereas the remaining 71% (17/24) showed constitutive MLSB phenotypes. Nine (7.6%) of 119 isolates were pvl positive: 44% MRSA (4/9) and 56% MSSA (5/9). Staphylococcal surface protein sasX gene was present in 92% of MRSA and 8% of MSSA isolates. The majority of MRSA isolates were agr type I (15/18; 83%). Five spa types identified with spa t037 were predominant, followed by spa types (t304 and t8696) as newly reported Malaysian MRSA in a community setting.

    CONCLUSION: The presence of MRSA with SCCmec of hospital-associated features and globally recognised spa types in community setting is worrisome. Furthermore, the presence of MLSB strains among multidrug-resistant (MDR) S. aureus with sasX as well as pvl-positive isolates highlights the potential risk of a community setting in facilitating the dissemination of both virulence and resistance determinants.

    Matched MeSH terms: Staphylococcus aureus/isolation & purification*; Methicillin-Resistant Staphylococcus aureus/isolation & purification*
  14. Tham HY, Song AA, Yusoff K, Tan GH
    Biotechniques, 2020 09;69(3):161-170.
    PMID: 32787565 DOI: 10.2144/btn-2020-0034
    Endolysins have been studied intensively as an alternative to antibiotics. In this study, endolysin derived from a phage which infects methicillin-resistant Staphylococcus aureus (MRSA) was cloned and expressed in Escherichia coli pET28a. Initially, the endolysin was cloned using BamHI/XhoI, resulting in expression of a recombinant endolysin which was expressed in inclusion bodies. While solubilization was successful, the protein remained nonfunctional. Recloning the endolysin using NcoI/XhoI resulted in expression of soluble and functional proteins at 18°C. The endolysin was able to form halo zones on MRSA plates and showed a reduction in turbidity of MRSA growth. Therefore, cloning strategies should be chosen carefully even in an established expression system as they could greatly affect the functionality of the expressed protein.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/genetics*; Methicillin-Resistant Staphylococcus aureus/growth & development; Methicillin-Resistant Staphylococcus aureus/pathogenicity
  15. Soo Yean CY, Selva Raju K, Xavier R, Subramaniam S, Gopinath SC, Chinni SV
    PLoS One, 2016;11(7):e0158736.
    PMID: 27367909 DOI: 10.1371/journal.pone.0158736
    Non-protein coding RNA (npcRNA) is a functional RNA molecule that is not translated into a protein. Bacterial npcRNAs are structurally diversified molecules, typically 50-200 nucleotides in length. They play a crucial physiological role in cellular networking, including stress responses, replication and bacterial virulence. In this study, by using an identified npcRNA gene (Sau-02) in Methicillin-resistant Staphylococcus aureus (MRSA), we identified the Gram-positive bacteria S. aureus. A Sau-02-mediated monoplex Polymerase Chain Reaction (PCR) assay was designed that displayed high sensitivity and specificity. Fourteen different bacteria and 18 S. aureus strains were tested, and the results showed that the Sau-02 gene is specific to S. aureus. The detection limit was tested against genomic DNA from MRSA and was found to be ~10 genome copies. Further, the detection was extended to whole-cell MRSA detection, and we reached the detection limit with two bacteria. The monoplex PCR assay demonstrated in this study is a novel detection method that can replicate other npcRNA-mediated detection assays.
    Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/cytology; Methicillin-Resistant Staphylococcus aureus/genetics*; Methicillin-Resistant Staphylococcus aureus/isolation & purification*
  16. Chua HP, Aminah Abdullah
    Sains Malaysiana, 2011;40:1123-1127.
    Kajian keberkesanan sifat antimikrob ekstrak kacangma dijalankan menggunakan ujian resapan cakera dan ujian perencatan langsung. Hasil menunjukkan ekstrak etanol dengan kepekatan 50 dan 100 mg/mL merencat Staphylococcus aureus. Bagi ekstrak air, kepekatan 10, 25, 50 dan 100 mg/mL merencat Aspergillus niger, 25, 50 dan 100 mg/mL dapat merencat Saccharomyces cerevisae dan kepekatan 100 mg/mL dapat merencat Staphylococcus aureus. Perlakuan suhu yang berbeza ke atas ekstrak dalam ujian perencatan langsung tidak menunjukkan sebarang perbezaan ke atas perencatan mikroorganisma yang dikaji.
    Matched MeSH terms: Staphylococcus aureus
  17. Shunmugaperumal T, Ramamurthy S
    Drug Dev Ind Pharm, 2012 Mar 12.
    PMID: 22409156 DOI: 10.3109/03639045.2012.665459
    Magnesium fluoride (MgF(2)) nanoparticles-stabilized oil-in-water nanosized emulsion was prepared and assessed for its antiadherent and antibiofilm activities over glass coupons against pathogenic microorganisms like Escherichia coli and Staphylococcus aureus.
    Matched MeSH terms: Staphylococcus aureus
  18. Chung PY, Khoo REY, Liew HS, Low ML
    Ann Clin Microbiol Antimicrob, 2021 Sep 24;20(1):67.
    PMID: 34560892 DOI: 10.1186/s12941-021-00473-4
    BACKGROUND: Methicillin-resistance S. aureus (MRSA) possesses the ability to resist multiple antibiotics and form biofilm. Currently, vancomycin remains the last drug of choice for treatment of MRSA infection. The emergence of vancomycin-resistant S. aureus (VRSA) has necessitated the development of new therapeutic agents against MRSA. In this study, the antimicrobial and antibiofilm activities of two copper-complexes derived from Schiff base (SBDs) were tested individually, and in combination with oxacillin (OXA) and vancomycin (VAN) against reference strains methicillin-susceptible and methicillin-resistant Staphylococcus aureus. The toxicity of the SBDs was also evaluated on a non-cancerous mammalian cell line.

    METHODS: The antimicrobial activity was tested against the planktonic S. aureus cells using the microdilution broth assay, while the antibiofilm activity were evaluated using the crystal violet and resazurin assays. The cytotoxicity of the SBDs was assessed on MRC5 (normal lung tissue), using the MTT assay.

    RESULTS: The individual SBDs showed significant reduction of biomass and metabolic activity in both S. aureus strains. Combinations of the SBDs with OXA and VAN were mainly additive against the planktonic cells and cells in the biofilm. Both the compounds showed moderate toxicity against the MRC5 cell line. The selectivity index suggested that the compounds were more cytotoxic to S. aureus than the normal cells.

    CONCLUSION: Both the SBD compounds demonstrated promising antimicrobial and antibiofilm activities and have the potential to be further developed as an antimicrobial agent against infections caused by MRSA.

    Matched MeSH terms: Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus/drug effects*; Methicillin-Resistant Staphylococcus aureus/isolation & purification
  19. Chong WX, Lai YX, Choudhury M, Amalraj FD
    J Prosthet Dent, 2022 Nov;128(5):1114-1120.
    PMID: 33685653 DOI: 10.1016/j.prosdent.2021.01.010
    STATEMENT OF PROBLEM: The presence of biofilms on maxillofacial silicone increases the risk of infections and reduces durability. Whether silver nanoparticles (AgNPs) with potent antimicrobial effects help reduce biofilm formation is unclear.

    PURPOSE: The purpose of this in vitro study was to assess the antimicrobial effect of sub 10-nm AgNPs in maxillofacial silicone against Staphylococcus aureus, Candida albicans, and mixed species biofilms containing both and to test the effectiveness of different AgNP concentrations against all 3 biofilms in vitro.

    MATERIAL AND METHODS: Silicone disks (M511; Technovent Ltd) containing 0.0% (control), 0.1%, and 0.5% AgNPs were fabricated and treated with S. aureus, C. albicans, and mixed species strains of both in 24-well culture plates containing appropriate media. Each well received a 0.1-mL aliquot of the standardized suspension of microorganisms. The plates were incubated for 21 consecutive days, and colony-forming units per milliliter (CFU/mL) were measured on the first, third, fifth, seventh, fifteenth, and twenty-first day with the Miles and Misra method. Data were analyzed by 2-way ANOVA and the paired t test to evaluate the relationship between AgNP concentration, microbial strain, and time (α=.05). Mean CFU/mL differences for each time and for each biofilm category were assessed by repeated measure ANOVA.

    RESULTS: AgNPs decreased the mean CFU/mL in both concentrations compared with the control. The 0.1% concentration showed sustained efficacy throughout the test, while the 0.5% concentration had high efficacy initially with a gradual decrease. However, the results were inconsistent for the mixed biofilm. The paired sample t test at day 3 and 15 and day 3 and 21 showed statistically significantly different results (P

    Matched MeSH terms: Staphylococcus aureus
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