Displaying publications 61 - 80 of 887 in total

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  1. Jamal F, Aziz AH, Shafie MS
    Med J Malaysia, 1982 Jun;37(2):128-31.
    PMID: 7132831
    Two hundred strains of Klebsiella species isolated from clinical specimens over a four-month period were biotyped as Klebsiella aerogenes (173 strains), Klebsiella ozaenae (15 strains), Klebsiella edwardsii (5 strains), Klebsiella atlantae (2 strains) and Klebsiella oxytoca (1 strain). Klebsiella aerogenes and Klebsiella ozaenae were more resistant towards antibiotics when compared with other species. Colonial morphology on eosin methylene blue agar (Oxoid) was not found useful for differentiations of Klebsiella biotypes.
    Matched MeSH terms: Microbial Sensitivity Tests
  2. Nur Fatihah Nordin, Hasnah Begum Said Gulam Khan, Kazi Ahsan Jamil, Nurul ‘Izzah Mohd Sarmin
    MyJurnal
    Introduction:Staphylococcus aureus is a Gram-positive staphylococci that form biofilms. Bacteria that dwell in bio-films tend to be highly resistant towards the action of antibiotics. S. aureus is a main cause of infections in the oral cavity such as angular cheilitis, endodontic infections, osteomyelitis of the jaw, parotitis and oral mucositis. Previous studies reported that S. aureus also spread to the other parts of the body through the circulatory system, which may lead to chronic infections. Hence the search for new antibacterial agents remains high and needs urgent attention to treat this problem. Plants offer a rich source of antimicrobial agents and bioactive compounds. In this study, aque-ous oil palm leaf extracts (OPLE) has been used as an alternative antibacterial agent against oral infections mainly caused by Staphylococcus aureus. Many studies report the potential use of oil palm leaf extracts in treating bacterial infections such as Escherichia coli, Salmonella sp., Staphylococcus aureus (isolated from other part of the body), Pseudomonas aeruginosa and Bacillus sp. Although previous studies have documented the antimicrobial properties of oil palm leaf extracts, to date no study has been reported on the effect of oil palm leaf extract on oral microbes. Methods: The agar diffusion method, minimum inhibitory concentration (MIC) and minimal bactericidal concen-tration (MBC) assay were conducted in order to observe the antibacterial activity of aqueous oil palm leaf extract. The crystal violet assay was used to determine the anti-biofilm activity of the extracts. Chlorhexidine and deionised distilled water were used as the positive and negative control respectively. For agar diffusion method, the diameter of inhibition zone was measured. Results: The inhibition zone of the tested bacteria was observed between 0-20mm. The MIC and MBC assay were used to know the lowest concentrations of the extract that inhibit the growth and killed the tested bacteria respectively. The MIC and MBC values for the tested bacteria were observed between 0-7.813mg/mL. While for anti-biofilm assays, OPLE aqueous extract acts as a potent anti-biofilm agent with dual actions, pre-venting and eradicating the biofilm of the tested bacteria. Conclusion: In conclusion, the tested plant extracts could serve as alternative natural antibacterial and anti-biofilm agent against oral infections.
    Matched MeSH terms: Microbial Sensitivity Tests
  3. Siti Aisyah Abd Ghafar, Muhammad Fikhry Mohd Salehuddin,, Nur Syamimi Syuhada Che Awang, Rohazila Mohamad Hanafiah
    MyJurnal
    Introduction:Spilanthes acmella, also known as “subang nenek’, has been used traditionally in Malaysia to treat toothache. A previous study has shown Spilanthes acmella leaves extracts (SALE) inhibit Streptococcus mutans growth. Streptococcus mutans is commonly found in the human oral cavity and is the main contributor to tooth de-cay. There is no study on the antibacterial effects of Spilanthes acmella flower extracts (SAFE) against Streptococcus mutans reported to date. Therefore, the objective of this study is to investigate antibacterial properties of SAFE against S. mutans. Methods:S. mutans was subcultured in Muller Hinton (MH) broth and agar. Sequential extractions of S. acmella flowers were conducted using four different solvents with increasing polarity, [n- hexane, dichloromethane (DCM), acetone, methanol (MeoH)] and tested with different concentrations against S. mutans via the disc diffusion assay, minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Sodium fluoride (NaF) was used as a positive control while DMSO was used as a negative control. Results: The disc diffusion assay shows SAFE inhibited Streptococcus mutans growth. SAFE-DCM shows the greatest inhibition properties (12.33±2.30 mm) followed by SAFE-n-hexane (11.33±0.57 mm). Meanwhile, SAFE-Meoh and SAFE-acetone show no inhibition zone (6.00±0.001 mm). MIC value for SAFE-DCM and SAFE-n-hexane is 12.5 mg/mL respectively. Whereas, MBC value SAFE-DCM and SAFE-n-hexane is 50.0 mg/mL respectively. Conclusion: It can be concluded SAFE-DCM and SAFE-n-hexane possesses bactericidal properties against Streptococcus mutans.
    Matched MeSH terms: Microbial Sensitivity Tests
  4. Siti Radziah Ismail
    MyJurnal
    Introduction: Trigona thoracica propolis is known to have antimicrobial properties, however its
    antileptospiral properties and its synergistic effects with commonly prescribed antibiotics are scarcely
    documented. This study aimed to evaluate the antileptospiral properties of Trigona thoracica against
    pathogenic Leptospira species (spp.) and to study its synergistic effects with commonly prescribed
    antibiotics. Materials and Methods: The tested Leptospira serovars were Australis, Bataviae, Canicola and
    Javanica. Aqueous extract propolis (AEP) and ethanolic extracts propolis (EEP) were used. Broth dilution
    methods were used to determine the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal
    Concentration (MBC) and the synergistic effects between the propolis and the tested antibiotics. The
    synergistic effects was evaluated by using the fractional inhibitory concentration (FIC) index. Morphological
    changes of the treated Leptospira were observed under a Scanning Electron Microscope (SEM). Results: The
    AEP and EEP were found to have antileptospiral properties against the tested Leptospira spp. The synergy
    result showed that only combination of AEP and penicillin G against serovar Australis has demonstrated
    synergistic effect with the FIC index of 0.38. Morphological study using SEM showed significant structural
    changes of the treated Leptospira spp. Conclusions: The result suggests that Trigona thoracica propolis could
    potentially be used as either a complimentary or an alternative therapeutic agent against pathogenic
    Leptospira spp.
    Matched MeSH terms: Microbial Sensitivity Tests
  5. Normah Haron, Hanapi Mat Jusoh
    MyJurnal
    Gynura procumbens, commonly known as ‘sambung nyawa’ in Malaysia has been used
    traditionally as remedies for anti-inflammatory, anti-hyperlipidimic and anti-hyperglycemic. The
    purpose of the present study was to qualitatively evaluate the antimicrobial effects of Gynura procumbens extracts. effects of the sample were determined by disc diffusion method against two bacteria and two fungi namely E. coli, S. aureus, C. albicans and S. cerevisiae. The results showed that the acidic extract of G. procumbens has positive reactions towards E. coli, S. aureus and C. albicans with the presence of zone of inhibition at the concentration of 150 mg/mL. Following the positive reaction, the minimum inhibitory concentration (MIC) of the acidic extract was then evaluated by broth dilution method. The MIC of E. coli and S. aureus were determined at concentration 37.5 mg/mL and 75 mg/mL for C. albicans. It indicated that acidic extracts at lower concentration could inhibit the bacteria, but high concentration of extracts was required in the inhibition of the fungi. It can be concluded that, the present study proves that there is potential of antimicrobial effects in Gynura procumbens leaves extracts.
    Matched MeSH terms: Microbial Sensitivity Tests
  6. Sri Raja Rajeswari Mahalingam, Priya Madhavan, Chong, Pei Pei
    MyJurnal
    Introduction: One of the most common aetiology of opportunistic fungal infections in humans is Candida species. The virulence of Candida species is due to repertoire of factors, specifically, the ability to form biofilms. Medical devices such as intravenous catheters, prosthetic heart valves and surgical interventions provide pathogenic microorganisms with a surface to adhere to form biofilm. Fungi present as biofilms are often resistant to antifungal treatment because these biofilms offer a protective barrier that prohibits the drugs to get to the active site of the fungi. The objective of this study is to investigate the biofilm architecture of Candida rugosa (C.rugosa) at different developmental phases and to identify Sessile Minimum Inhibition Concentrations (SMICs) of amphotericin B, caspofungin, fluconazole, and voriconazole for the biofilm of C. rugosa. Methods: Confocal scanning laser microscopy (CSLM) and scanning electron microscopy (SEM) were used to visualize C. rugosa biofilms at different developmental phases. The antifungal susceptibility test was performed using serial doubling dilution. The growth kinetics of Candida biofilms was quantified using XTT reduction assay and crystal violet assay. Results: From the antifungal susceptibility test, the biofilms had SMIC of >16μg/mL for amphotericin B, 6µg/mL for caspofungin, >64μg/mL for fluconazole and >16μg/ mL for voriconazole. From the SEM micrographs, C. rugosa biofilm have a structure composed of an adherent yeast cells and blastopores with hyphal elements. There were significant alterations in the morphology after exposure to antifungal agents. The quantitative measurement of the matrix thickness of embedded yeast cells were obtained from CLSM micrographs. Conclusion: In conclusion, the ability of C. rugosa to form biofilms may attribute to one of the virulence factors that causes reduced susceptibility to antifungal agents.
    Matched MeSH terms: Microbial Sensitivity Tests
  7. Ridzuan, P.M., Nasir Mohamad, Salwani Ismail, Nor Iza A. Rahman, Hairul Aini H., Zunariah, B., et al.
    MyJurnal
    Hydroxychavicol (HC) is a phenolic compound of betel leaf (Piper betle). It has been reported to have antifungal properties against dermatophytes including T. rubrum. The aim of this study was to identify the effects of the HC against T. rubrum. Broth dilution method was used to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the HC. Microscopic study of the treated fungus was done by transmission electron microscope (TEM). Cytotoxicity study using pre-adipocyte (3T3-L1) cell line was performed by means of MTT cell proliferation assay. The MIC and MFC results of the HC were both 0.49 µg/ml. Microscopic study revealed the destruction of the fungal cell wall and organelles. Cytotoxicity study showed HC to be non-toxic to the tested human cell line. In conclusion, HC may potentially be used as an alternative therapeutic agent against T. rubrum infections.
    Matched MeSH terms: Microbial Sensitivity Tests
  8. Ding, C.H., Tzar M.N., Biswas S., Muttaqillah N.A.S., Wahab A.A.
    MyJurnal
    Catheter-related bloodstream infections caused by Kodamaea ohmeri are generally not considered due to the relative scarcity of reported cases. This is a case of an 85-year-old man with poorly controlled diabetes mellitus who was initially admitted to our hospital for diabetic ketoacidosis. An internal jugular catheter was inserted as part of the initial management. A week later the patient developed a temperature spike and a yeast identified as Kodamaea ohmeri by ID 32 C (bioMérieux, France) was isolated from both his central and peripheral blood cultures. The catheter was removed and the patient was treated with fluconazole despite the organism’s relatively high minimum inhibitory concentration (2 μg/mL) to this antifungal. The fungemia resolved following a 2-weeks course of fluconazole.
    Matched MeSH terms: Microbial Sensitivity Tests
  9. Ismail CAM, Deris ZZ, Bakar RA, Ismail N
    PMID: 33802184 DOI: 10.3390/ijerph18062834
    Despite modern medicine, there is an increasing trend for cases of the bacterial infection leptospirosis, and this has led to the exploration of alternative medicines from various sources including plants. The aim of this study was to investigate the in vitro anti-leptospiral activity of Phyllanthus amarus extracts alone and combined with penicillin G, ceftriaxone, and doxycycline. Antimicrobial susceptibility testing was performed using the microdilution broth technique upon methanol extract (ME), aqueous extract (AE), and antibiotics against the Leptospira interrogans serovars Australis, Bataviae, Canicola, and Javanica, to determine minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). The results were analyzed using an ELISA microplate reader combined with microscopic analysis. Synergy testing using a checkerboard assay was performed to determine the fractional inhibitory concentration index values of extracts combined with antibiotics against leptospires. Scanning electron microscopy (SEM) was used to investigate morphological changes of leptospires caused by potential anti-leptospiral agents alone and combined with antibiotics. The MICs and MBCs for P. amarus extracts ranged from 100 to 400 µg/mL for AEs and from 400 to 800 µg/mL for MEs. Penicillin G was the most effective anti-leptospiral drug, with MICs and MBCs ranging from <0.01 to 0.78 and <0.01 to 3.13 µg/mL, respectively, followed by ceftriaxone, with both MICs and MBCs ranging from 0.05 to 0.78 µg/mL, and doxycycline, with MICs and MBCs ranging from 0.39 to 3.13 µg/mL and 12.5 to 25 µg/mL, respectively. Combinations of P. amarus extracts and antibiotics did not show synergistic effects on all tested Leptospira serovars, with some combinations demonstrating antagonistic effects. SEM analysis, however, showed distorted Leptospira surfaces. P. amarus AE performed better anti-leptospiral activity than P. amarus ME. The morphological effects of P. amarus extract alone and its combination with antibiotic on Leptospira cells revealed promising anti-leptospiral properties.
    Matched MeSH terms: Microbial Sensitivity Tests
  10. Adnan SN, Ibrahim N, Yaacob WA
    Germs, 2017 Dec;7(4):186-192.
    PMID: 29264356 DOI: 10.18683/germs.2017.1125
    Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) is a worldwide public health threat, displaying multiple antibiotic resistance that causes morbidity and mortality. Management of multidrug-resistant (MDR) MRSA infections is extremely difficult due to their inherent resistance to currently used antibiotics. New antibiotics are needed to combat the emergence of antimicrobial resistance.

    Methods: The in vitro effect of tannins was studied against MRSA reference strain (ATCC 43300) and MRSA clinical strains utilizing antimicrobial assays in conjunction with both scanning and transmission electron microscopy. To reveal the influence of tannins in MRSA protein synthesis disruption, we utilized next-generation sequencing (NGS) to provide further insight into the novel protein synthesis transcriptional response of MRSA exposed to these compounds.

    Results: Tannins possessed both bacteriostatic and bactericidal activity with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 0.78 and 1.56 mg/mL, respectively, against all tested MRSA. Scanning and transmission electron microscopy of MRSA treated with tannins showed decrease in cellular volume, indicating disruption of protein synthesis.

    Conclusion: Analysis of a genome-wide transcriptional profile of the reference strain ATCC 43300 MRSA in response to tannins has led to the finding that tannins induced significant modulation in essential ribosome pathways, which caused a reduction in the translation processes that lead to inhibition of protein synthesis and obviation of bacterial growth. These findings highlight the potential of tannins as new promising anti-MRSA agents in clinical application such as body wash and topical cream or ointments.

    Matched MeSH terms: Microbial Sensitivity Tests
  11. Ismail IH, Al-Bayaty FH, Yusof EM, Gulam Khan HBS, Hamka FA, Azmi NA
    J Conserv Dent, 2021 02 10;23(5):489-496.
    PMID: 33911359 DOI: 10.4103/JCD.JCD_528_20
    Introduction: Enterococcus faecalis can be found in failed endodontic treatment (FET) even after performing primary endodontic treatment (PET). Calcium hydroxide (Ca(OH)2) cannot fully eliminate this microorganism during PET. Brazilian green propolis (bee glue) was found to be more effective against E. faecalis when compared to Ca(OH)2. A much less studied Malaysian geopropolis (MP) as well as Aloe vera (AV) is antibacterial but is unknown against E. faecalis.

    Objective: The objective of this study is to determine the antimicrobial effects of MP, AV, and MP + AV in comparison with Ca(OH)2 against E. faecalis, as an intracanal medicament.

    Materials and Methods: Antimicrobial activity of MP, AV, MP + AV, Ca(OH)2, and dimethyl sulfoxide was tested against E. faecalis using antimicrobial sensitivity testing, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The results were analyzed by Kruskal-Wallis test with Mann-Whitney post hoc test and repeated measures analysis of variance with Bonferroni post hoc test (P < 0.05).

    Results: For agar well-diffusion method, MP + AV gave maximum inhibition zone diameter (mean: 8.11 ± 0.015 mm), MP (mean: 6.21 ± 0.046 mm, Ca(OH)2 (mean: 5.5 ± 0.006), and AV (mean: 5.05 ± 0.012) with P < 0.05. MIC for MP + AV was 2 mg/ml, MP at 8 mg/ml, Ca(OH)2 at 8 mg/ml, and AV at 16 mg/ml. The MBC for MP + AV is at 4 mg/ml, MP at 16 mg/ml, Ca(OH)2 at 16 mg/ml, and AV at 32 mg/ml.

    Conclusion: The combination of MP and AV consistently showed better antimicrobial activity compared to MP and AV alone against E. faecalis. The findings suggest that MP and AV used in combination may be an ideal intracanal medicament in FET and PET.

    Matched MeSH terms: Microbial Sensitivity Tests
  12. Yazid AM, Ali AM, Shuhaimi M, Kalaivaani V, Rokiah MY, Reezal A
    Lett Appl Microbiol, 2000 Jul;31(1):57-62.
    PMID: 10886616
    Eighteen Bifidobacterium strains were tested for their susceptibility to a range of antimicrobial agents. All the strains tested, including the reference culture Lactobacillus acidophilus CH2, were susceptible to several groups of antimicrobial agents, they were cephalosporin (cefamandole, cefazolin, cefaperazone, cefoxitin), polypeptide (bacitracin), macrolide (erythromycin), penicillin (amoxicillin), phenicol (chloramphenicol) and beta-lactam (imipenem). Fourteen strains were resistant to more than 10 antibiotics. The reference culture was resistant to only three antibiotics. The results showed that bifidobacteria are resistant to a wide range of antimicrobial agents.
    Matched MeSH terms: Microbial Sensitivity Tests
  13. Wan-Mohtar WAAQI, Viegelmann C, Klaus A, Lim SAH
    Food Sci Biotechnol, 2017;26(1):159-165.
    PMID: 30263523 DOI: 10.1007/s10068-017-0021-6
    Underutilized mycelium of Ganoderma lucidum BCCM 31549 has been a significant source of a glucan sulfate (GS) possessing therapeutic activities. GS have been evaluated for their antifungaldemelanizing properties and nitrite oxide production from stimulated RAW264.7 macrophages. GS exhibited antifungal activity against Aspergillus niger A60 with a minimum inhibitory concentration of 60 mg/mL and a minimum fungicidal concentration of 100 mg/mL. At 60mg/mL (sublethal) and 30mg/mL (subinhibitory) doses of GS, the mycelium of A. niger A60 was successfully demelanized with a conidiophore head and black pigment reduction. Additionally, GS successfully stimulated RAW264.7 macrophage cells at a concentration of 500 μg/mL to produce 0.45 μM of nitric oxide. The GS-stimulated RAW264.7 macrophages were morphologically similar to those treated with lipopolysaccharide. The results highlight a novel bifunctional property of mycelial GS from G. lucidum.
    Matched MeSH terms: Microbial Sensitivity Tests
  14. Zainal M, Mohamad Zain N, Mohd Amin I, Ahmad VN
    Saudi Dent J, 2021 Feb;33(2):105-111.
    PMID: 33551624 DOI: 10.1016/j.sdentj.2020.01.008
    The objective of this study is to determine the therapeutic efficacy of allicin against Candida albicans (C. albicans) and Staphylococcus aureus (S. aureus), the common etiological agents for denture stomatitis (DS). The minimum inhibitory concentration (MICs), minimum bactericidal concentrations (MBCs) and minimum fungicidal concentration (MFCs) of allicin were determined by the broth microdilution method followed by checkerboard microdilution method for a synergistic interaction between allicin + nystatin and allicin + CHX. The potential of allicin to eradicate C. albicans and S. aureus biofilms was assessed by treating biofilm formed on self- polymerized acrylic resin with allicin at a sub-MIC concentration for 5 min. The commercial denture cleanser (brand X) was used as a positive control. A Kruskal-Wallis test followed by the post-hoc Mann-Whitney U test was applied (SPSS 20.0), and the level of significance was set at P 
    Matched MeSH terms: Microbial Sensitivity Tests
  15. Wong KT, Osman H, Parumasivam T, Supratman U, Che Omar MT, Azmi MN
    Molecules, 2021 Apr 05;26(7).
    PMID: 33916423 DOI: 10.3390/molecules26072081
    A total of fourteen pyrazoline derivatives were synthesized through cyclo-condensation reactions by chalcone derivatives with different types of semicarbazide. These compounds were characterized by IR, 1D-NMR (1H, 13C and Distortionless Enhancement by Polarization Transfer - DEPT-135) and 2D-NMR (COSY, HSQC and HMBC) as well as mass spectroscopy analysis (HRMS). The synthesized compounds were tested for their antituberculosis activity against Mycobacterium tuberculosis H37Ra in vitro. Based on this activity, compound 4a showed the most potent inhibitory activity, with a minimum inhibitory concentration (MIC) value of 17 μM. In addition, six other synthesized compounds, 5a and 5c-5g, exhibited moderate activity, with MIC ranges between 60 μM to 140 μM. Compound 4a showed good bactericidal activity with a minimum bactericidal concentration (MBC) value of 34 μM against Mycobacterium tuberculosis H37Ra. Molecular docking studies for compound 4a on alpha-sterol demethylase was done to understand and explore ligand-receptor interactions, and to hypothesize potential refinements for the compound.
    Matched MeSH terms: Microbial Sensitivity Tests
  16. Ulhaq ZS, Hendyatama TH, Hameed F, Santosaningsih D
    Enferm Infecc Microbiol Clin, 2020 07 04;39(6):283-286.
    PMID: 32636040 DOI: 10.1016/j.eimc.2020.05.016
    INTRODUCTION: Citrus hystrix is widely used by Indonesians as a traditional medicine for gastrointestinal diseases, including Salmonella spp. infection. We investigated the antibacterial activity of the ethanolic peel extract of C. hystrix against Salmonella typhimurium.

    METHODS: The antibacterial activity was evaluated both in vitro and in vivo. The minimum inhibitory concentration (MIC) of the extract was determined at a concentration of 0.625% by agar dilution assay. Later, the in vivo antibacterial activity was examined by the administration of 16mg of the extract daily for three consecutive days in a mouse model infected with S. typhimurium.

    RESULTS: The bacterial loads of S. typhimurium in the ileum, liver, and spleen decreased after 24h of administration of the extract (p=0.00008, p=0.00084, and p=0.00003, respectively).

    CONCLUSION: The ethanolic peel extract of C. hystrix shows antibacterial activity against S. typhimurium, indicating the potential of C. hystrix as an effective treatment for Salmonella spp. infection.

    Matched MeSH terms: Microbial Sensitivity Tests
  17. Muthiah B, Muthukrishnan L, Anita Lett J, Sagadevan S, Kesavan S, Vennila S, et al.
    J Nanosci Nanotechnol, 2020 10 01;20(10):6326-6333.
    PMID: 32384982 DOI: 10.1166/jnn.2020.17897
    Biosynthesis of nanoparticles has now become a novel trend in addressing some of the environmental issues by adopting eco-friendly approaches in manoeuvring nanoparticles for various applications. Plants and micro-organisms have been the potential sources of the biological mode of synthesizing nanoparticles as part of their bioremediation process. This principle has been harnessed for synthesizing nanoparticles either extra or intracellularly. In this line of phyto-mediated synthesis, eucalyptus buds have been used for synthesizing gold nanoparticles (Au NPs) under optimized laboratory conditions. The UV-visible spectrum of the Au NPs showed typical surface plasmon resonance at 550 nm (λmax) with a crystalline phase measuring <100 nm in size and monodispersed as revealed from XRD, FESEM, and AFM analyses. The biological role of phytochemical concoction in reducing and stabilizing the Au NPs was clearly identified from FT-IR studies. The antimicrobial effect of the Au NPs against clinically important pathogens viz. Staphylococcus sp., Pseudomonas sp., Bacillus sp. and E. coli determined using the disk diffusion method showed no significant antibacterial effect at all concentrations. Cytotoxicity studies were carried using Vero and HEp-2 cell lines and the 50% inhibition concentration (IC50) was determined to be 1.25 mg and 0.625 mg/mL respectively. Au NPs with potential antimicrobial and anti-proliferative effects could found profound implications in the field of nanomedicine once the toxicity in vivo has been investigated.
    Matched MeSH terms: Microbial Sensitivity Tests
  18. Qing S, Shoutian Q, Hongyan G, Ming Y, Swamy MK, Sinniah UR, et al.
    J Nanosci Nanotechnol, 2019 07 01;19(7):4109-4115.
    PMID: 30764978 DOI: 10.1166/jnn.2019.16282
    This study reports the biosynthesis of silver nanoparticles (AgNPs) using methanolic leaf extract of Pogostemon cablin Benth. (Patchouli) as a reducing agent, and their potent biological (antibacterial, antioxidant and anticancer) activities. The P. cablin extract when exposed to silver nitrate reduced silver ions to form crystalline AgNPs within 1 h of incubation at room-temperature. UV-visible spectra showed a sharp surface plasmon resonance (SPR) at around 430 nm for the biosynthesized AgNPs and the XRD pattern indicated the crystalline planes of the face centered cubic silver. The FE-SEM analysis revealed the occurrence of predominant spherical shaped AgNPs with a huge disparity in their particle size distribution with an average size of 25 nm, while, the FTIR data confirmed the bio-reduction and capping of AgNPs by several phytocompounds present in the methanolic leaf extract. AgNPs effectively inhibited the growth of all the tested human pathogenic bacterial strains (Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli), while, the methanolic leaf extract failed to inhibit the growth of S. aureus and P. aeruginosa. AgNPs showed the highest free radical scavenging activity (79.0 ± 0.76%) compared to methanolic leaf extract (68.3 ± 0.68%) at 100 μg/ml. Further, the cytotoxicity study using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) confirmed that AgNPs successfully inhibited the human colon adenocarcinoma cell line (HT-29) in a dose dependent manner. At higher concentrations (500 μg/ml), only 4% of cells survived after 72 hrs of exposure with IC50 value of 120 μg/ml. Thus, these findings offer a new source of biomolecules with diverse biological activities.
    Matched MeSH terms: Microbial Sensitivity Tests
  19. Rambabu K, Bharath G, Banat F, Show PL
    J Hazard Mater, 2021 01 15;402:123560.
    PMID: 32759001 DOI: 10.1016/j.jhazmat.2020.123560
    Production of multi-functional zinc oxide nanoparticles (ZnO-NPs) for wastewater treatment through green-approaches is a desirable alternative for conventional synthesis routes. Biomass waste valorization for nanoparticles synthesis has received increased research attention. The present study reports date pulp waste (DPW) utilization as an effective bio-reductant for green-synthesis of ZnO-NPs. A simple and eco-friendly process with low reaction time and calcination temperature was adopted for DPW mediated ZnO-NPs (DP-ZnO-NPs) synthesis. Microscopic investigations of DP-ZnO-NPs confirmed the non-agglomeration and spherical nature of particles with mean diameter of 30 nm. EDX and XPS analysis defined the chemical composition and product purity of DP-ZnO-NPs. UV and photoluminescence studies exhibited surface plasmonic resonance at 381 nm and fluorescent nature of DP-ZnO-NPs. FTIR studies established a formation mechanism outline for DP-ZnO-NPs. XRD and Raman investigations confirmed the crystalline and hexagonal wurtzite phase of DP-ZnO-NPs. DSC/TG analysis displayed the thermal stability of DP-ZnO-NPs with <10 wt% loss upto 700 °C. Photocatalytic degradation of hazardous methylene blue and eosin yellow dyes using DP-ZnO-NPs, showed rapid decomposition rate with 90 % degradation efficiency. Additionally, DP-ZnO-NPs demonstrated significant antibacterial effects on various pathogenic bacteria in terms of zone-of-inhibition measured by disc-diffusion method. Thus, the as-prepared DP-ZnO-NPs is suitable for industrial wastewater treatment.
    Matched MeSH terms: Microbial Sensitivity Tests
  20. Wen X, Cao J, Mi J, Huang J, Liang J, Wang Y, et al.
    J Hazard Mater, 2021 03 05;405:124215.
    PMID: 33109407 DOI: 10.1016/j.jhazmat.2020.124215
    High concentrations of antibiotics may induce bacterial resistance mutations and further lead to fitness costs by reducing growth of resistant bacteria. However, antibiotic concentrations faced by bacteria are usually low in common environments, which leads to questions about how resistant bacteria with fitness costs regulate metabolism to coexist or compete with susceptible bacteria during sublethal challenge. Our study revealed that a low proportion (< 15%) of resistant bacteria coexisted with susceptible bacteria due to the fitness cost without doxycycline. However, the cost for the resistant strain decreased at a doxycycline concentration of 1 mg/L and even disappeared when the doxycycline concentration was 2 mg/L. Metabonomics analysis revealed that bypass carbon metabolism and biosynthesis of secondary metabolites were the primary metabolic pathways enriching various upregulated metabolites in resistant bacteria without doxycycline. Moreover, the alleviation of fitness cost for resistant bacteria competed with susceptible bacteria at 1 mg/L doxycycline was correlated with the downregulation of the biomarkers pyruvate and pilocarpine. Our study offered new insight into the metabolic mechanisms by which the fitness cost of resistant mutants was reduced at doxycycline concentrations as low as 1 mg/L and identified various potential metabolites to limit the spread of antimicrobial resistance in the environment.
    Matched MeSH terms: Microbial Sensitivity Tests
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