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Different morphological forms of Helicobacter pylori (gram-staining, light miscroscope, magnification  1000) a) mainly rod-like cells from a 18 h culture (Brucella broth, 37 C, b) mainly coccoid cells from a 60 h culture (Brucella broth, 37 C, micro- microaerobic environment); aerobic environment)
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Helicobacter pylori infections have been associated with the pathogenesis of a number of stomach and gastroduodenal diseases. In order to find alternative drugs for their treatment the search is increasingly focused on new antimicrobial products. However, no standardized methods are available to test the anti-Helicobacter pylori activity in particu...
Context in source publication
Context 1
... serum (FCS). The flask was cov- ered with a loosely fitted cap and incubated for 18 AE 2 h at 37 C under microaerophilic conditions. Before inoculation the bacterial cells were checked for their morphology by gram-staining and light microscopy at a final magnification of  1000. Cultures showing a high proportion of coc- coid cell shapes (see Fig. 2) were discarded. The inoculum was adjusted to a final cell count of approximately 5  10 5 cfu/ml, which was controlled by the spiral plating counting method (Spiral System Cincinnati, OH, USA). Determination of the MIC and MBC based on a modified broth micro- dilution method according to DIN 58940 part 8 and appendix 1 (1997). ...
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Background:
Increased prevalence of antibiotic resistance to Helicobacter pylori (H. pylori) infection worldwide has driven the search for a new therapeutic candidate. Recently, sitafloxacin, a novel 4-quinolone agent, has emerged as a new therapeutic option for H. pylori eradication, in Japan. However, data on its efficacy for H. pylori eradicati...
Citations
... 63 The broth microdilution technique is reported to be accurate and easy to perform. 64 Although both culture-based tests have the disadvantage of being labor-and time-intensive in the laboratory, their greatest advantage is that they can reliably assess resistance to all antimicrobial agents present. ...
As the rate of discovery of drug-resistant Helicobacter pylori cases increases worldwide, the relevant societies have updated their guidelines for primary eradication regimens. A promising strategy against drug-resistant H. pylori is tailored therapy based on the results of an antibiotic susceptibility test; however, it is difficult to apply this strategy to all cases. Although culture-based antibiotic susceptibility tests can assess resistance to any antimicrobial agent, their greatest disadvantage is the time required to draw a conclusion. In contrast, molecular-based methods, such as polymerase chain reaction, can rapidly determine the presence of resistance, although a single test can only test for one type of antimicrobial agent. Additionally, the limited availability of facilities for molecular-based methods has hindered their widespread use. Therefore, low-cost, minimally invasive, simple, and effective primary regimens are needed. Several studies have compared the efficacy of the latest primary eradication regimens against that of tailored therapies, and their results have shaped guidelines. This article reviews the latest research on empirical and tailored treatments for H. pylori infections. Evidence for the superiority of tailored therapy over empirical therapy is still limited and varies by region and treatment regimen. A network meta-analysis comparing different empirical treatment regimens showed that vonoprazan triple therapy provides a superior eradication effect. Recently, favorable results towards vonoprazan dual therapy have been reported, as it reached eradication levels similar to those of vonoprazan triple therapy. Both vonoprazan dual therapy and tailored therapy based on antibiotic susceptibility tests could contribute to future treatment strategies.
... Determination of the minimum inhibitory and bactericidal concentrations of crude extract and supernatant of isolated strains were conducted based on the method used by Weseler et al (24) with some modifications. The serial dilutions (1.95 µg/mL to 1 mg/mL) were prepared from each of the crude extracts and supernatant of bacteria, separately. ...
... Studies assessing the antibacterial properties of PSMs include comparisons of the effects of different types of PSMs against different bacteria strains, see Table 2 . PSMs have also been reported to have antifungal properties against Candida albicans, Candida tropicalis and Candida parapsilosis [64][65][66][67][68][69][70] . In addition, PSMs inhibit proliferation of multidrug resistance pathogens [ 71 , 72 ]. ...
There is a global epidemic of non-healing wounds. Chronic inflammation, overexpression of pro-inflammatory cytokines, oxidative stress and bacterial infection are implicated in delayed wound healing. Natural extracts are a rich source of bioactive molecules called plant secondary metabolites (PSMs) that include terpenes and phenols. These molecules may facilitate wound healing through their antioxidant, anti-inflammatory, and antibacterial activity. After briefly outlining the process of wound healing and how it is compromised in chronic wounds, this review focuses on investigating how PSMs-based polymers may improve wound healing. Best methods for incorporating PSMs into wound dressings are reviewed and critically compared. The exiting body of literature strongly suggests that PSMs-based polymers incorporated into wound dressings could have clinical value in aiding wound healing.
Statement of significance
Chronic wounds develop by the persistence of inflammation, oxidative stress and infection. Chronic wounds affect the worldwide population, by reducing quality of life of patients with significant cost to healthcare systems. To help chronic wounds to heal and overcome this burden, materials with anti-inflammatory, antioxidant and antibacterial properties are required. Plant secondary metabolites (PSMs) are volatile materials that have all these properties. PSMs-based polymers can be fabricated by polymerization techniques. The present review provides an overview of the state-of-the-art of the wound healing mechanisms of PSMs. Current developments in the field of PSMs-based polymers are reviewed and their potential use as wound dressings is also covered.
... After development, HPTLC plates were dried at 105ºC and scanned densitometrically at 254 nm. 23 . Each extract was dissolved with DMSO (10% final volume) and diluted with Mueller Hinton Broth (OXOID) media to a final concentration of 10; 5; 2.5; 1.25; 0.625 and 0.3125 mg / ml. ...
In continuing the inventory and investigation of Sumatra lichen, a collection of five species from the genus Stereocaulon has been carried out. In metabolite profiling analysis, the four main compounds, i.e. atranorin, MOC, lobaric acid, and stictic acid, were rapidly isolated as marker compounds by chromatography methods from S. halei and S. montagneanum. Then, the extracts from each species were analyzed using HPTLC densitometry measured at five wavelengths of 220, 254, 280 320, and 365 nm. Atranorin and MOC are two compounds found in all five Stereocaulon species tested. Subsequently, atranorin quantification was done by densitometric scanning at 254 nm from the ethyl acetate extract of each Stereocaulon species. The highest atranorin concentration was detected from S. graminosum (325,498 mg/g extract) and equivalent to 0.065 mg/g dried whole thallus, while the lowest was from S. verruculigerum (23,356 mg/g extract) and 0.023 mg/g dried whole thallus. Furthermore, all extracts and main compounds resulting from the isolation were evaluated for their antibacterial activity by the microdilution method. Ethyl acetate and acetone extracts from S. massartianum (1) showed the highest antibacterial activity against E. faecalis (MIC = 1.25 mg/mL).
... Determination of the minimum inhibitory and bactericidal concentrations of crude extract and supernatant of isolated strains were conducted based on the method used by Weseler et al (24) with some modifications. The serial dilutions (1.95 µg/mL to 1 mg/mL) were prepared from each of the crude extracts and supernatant of bacteria, separately. ...
Background: Actinobacteria are widespread and live in a variety of habitats. Today, these bacteria are very important due to the production of various secondary metabolites with different biological activities. The present study aimed to isolate strains of Actinobacteria from different habitats (the Persian Gulf, Gandom Beryan area in the Lut Desert, and some plant roots). The anticancer and antimicrobial activities of secondary metabolites of these isolates were also investigated. Methods: Samples were taken from water of the Persian Gulf, soil of Gandom Beryan area in the Lut Desert, and plant roots. For isolation of Actinobacteria, samples were cultured in ISP2, ISP4, AIA, Gauze, M1, ISP3, and GYP media. Bacterial strains were identified based on the colony and bacterial morphology and confirmed using the specific primers for Actinobacteria. The anticancer and antimicrobial activities of crude metabolite extracts and supernatant of the isolates were evaluated on MCF-7 and Staphylococcus aureus PTCC 112 and Pseudomonas aeruginosa PTCC 1214 strains. Results: The results showed that the supernatants of 7 isolates (ga31, ez, sa, mar2, rz, ga33, and ga5) and the metabolite extracts of 4 strains (ga31, ga5, rz, and ez) had anticancer activity. Overall, ga31 was the best strain with anticancer activity of more than 75%. When evaluating the antimicrobial activity of bacterial secondary metabolites, we found that only two strains (ga31 and ga5) had antimicrobial activity against S. aureus PTCC 1112. Conclusions: In general, strain ga31, which has high anticancer and antimicrobial activities, could be a good candidate for new trials in the pharmaceutical industry.
... The antimicrobial assays were performed with the help of a modified protocol [53]. To the 96 microwell plates (NEST, China), 24 h old bacterial cultures (50 µL, 1.5 × 10 7 CFU/mL) and test sample (50 µL, various dilutions) were added. ...
The pervasiveness of oral bacterial infections in diabetic patients is a serious health concern that may produce severe complications. We investigated 26 Ayurvedic medicinal plants traditionally used for treatment of the oral bacterial infections with the aim to look for new promising drug leads that can be further employed for herbal formulation design. The plants were grouped into three categories based on traditional usage. All plant extracts were examined for antibacterial, antibiofilm and antiquorum-sensing properties. The plants with significant activities including Juglans regia, Syzygium aromaticum, Eruca sativa, Myristica fragrans, Punica granatum and Azadirachta indica were further analyzed using HPLC-DAD-QToF and GC-MS. In silico and in vitro activity was evaluated for selected constituents. Finally, it could be concluded that eugenol and 2-phenylethylisothiocyanate are major contributors towards inhibition of bacterial biofilms and quorum sensing.
... Antimicrobial activity assay MIC of each peptide against gram-positive bacterium (S. aureus) and gram-negative bacterium (E. coli) was determined using the broth microdilution assay as described with slight modification [58]. Briefly, midlogarithmic phase cells were diluted to 2.0 × 10 5 CFU/mL in Mueller-Hinton Broth growth medium. ...
The emergence of multidrug resistance bacteria poses a great health theat. Therefore, it is a crucial demand to obtain new antibacterial drugs. Antimicrobial peptides (AMPs) have the characteristics of wide antimicrobial spectrum and lower drug resistance, hence, it is hopeful to substitute for classical antibiotics. In this study, two classic methods, comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA), were used to analyze the structural feature of AMPs against Staphylococcus aureus or Escherichia coli, respectively. Subsequently, the models established by three-dimensional quantitative structure–activity relationships (3D-QSAR) (for S. aureus, CoMFA: Q² = 0.512, R² = 0.943, F = 59.916; CoMSIA: Q² = 0.645, R² = 0.993, F = 339.242; for E. Coli, CoMFA: Q² = 0.507, R² = 0.913, F = 66.862; CoMSIA: Q² = 0.573, R² = 0.966, F = 96.84) have good predictability and stability was constructed. Seven novel small AMPs were designed and synthesized based on the theoretical model. The novel AMPs showed potent antibacterial activity against S. aureus and E. coli while causing low host toxicity. This study provides a potential therapeutic option using 3D-QSAR models guiding the design and modification of novel AMPs, to address the prevalent infections caused by MDR bacterial.
... La CMI fue determinada por el método de microdilución en pozo, propuesto por Weseler con algunas modificaciones [15]. A cada pozo se le adicionaron 50 μL de cada suspensión bacteriana a una concentración McFarland 0,5. ...
Desde el punto de vista de salud pública, el patotipo de Escherichia coli Productor de Toxina Shiga (STEC) es el más relevante en la actualidad, debido a los síntomas y mortalidad que ocasiona, además de su demostrada multirresistencia antibiótica. El principal reservorio de esta bacteria es el ganado vacuno, razón por la cual la ingestión de alimentos derivados de estos animales de abasto es una de las principales fuentes de infección para el ser humano. El objetivo de este estudio fue determinar el efecto antibacteriano de aceites esenciales y extractos de plantas no diluidos frente a cepas STEC in vitro y en muestras de carne. Los resultados del ensayo in vitro revelaron que el aceite esencial de Lippia origanoides fue el que exhibió mayor efecto antimicrobiano evidenciando, en promedio, halos de inhibición en placa de 24,58 mm y una Concentración Mínima Bactericida de 1,8%. Adicionalmente, no se obtuvo crecimiento bacteriano luego de inocular un cocktail de cepas STEC en muestras de carne refrigerada adicionadas con este aceite esencial, durante un periodo de incubación de nueve días. Por tanto, el uso del aceite esencial de Lippia origanoides puede ser un método alternativo de control para este patógeno en carnes. Este es el primer reporte de inhibición de cepas STEC no O157 con Lippia origanoides en muestras de carne.
... Future work should also focus on determining minimum inhibitory concentrations of clinically relevant antibiotics for N. gonorrhoeae, such as ciprofloxacin, ceftriaxone, and azithromycin using XTT as an indicator. While this has never been explored for gonorrhea, XTT determined MIC values have been verified for Pseudomonas aeruginosa [55], Mycobacterium tuberculosis [56], and Helicobacter pylori [57]. Although there is still more work to be done, we hope that the research discussed here provides a starting point to a colorimetric liquid microdilution or a paper microfluidic device susceptibility testing of N. gonorrhoeae, as has been developed for other organisms [35,58]. ...
N . gonorrhoeae is one of the most pressing antibiotic resistant threats of our time and low-cost diagnostics that can easily identify antibiotic resistance are desperately needed. However, N . gonorrhoeae responds so uniquely to growth conditions that it cannot be assumed gonorrhea will respond to common microbiological methods used for other pathogenic organisms. In this paper, we explore visual colorimetric indicators of N . gonorrhoeae growth that can be seen without a microscope or spectrophotometer. We evaluate growth media, pH indicators, resazurin-based dyes, and tetrazolium-based dyes for their use in simple colorimetric system. Overall, we identified Graver Wade media as the best at supporting robust gonococcal growth while also providing the least background when analyzing results of colorimetric tests. XTT, a tetrazolium-based dye, proved to show to brightest color change over time and not negatively impact the natural growth of N . gonorrhoeae . However, other dyes including PrestoBlue, MTT, and NBT are less expensive than XTT and work well when added after bacterial growth has already occurred. By identifying the specific use cases of these dyes, this research lays the groundwork for future development of a color-based antibiotic susceptibility low-cost test for N . gonorrhoeae .
... The MIC of S. cerevisiae extract was determined using a colorimetric method in which the clear-cut end-points were determined via a colour change. Visual detection of bacterial growth via turbidity or pellet formation in the wells may be difficult and could lead to inaccurate results (50). To detect the presence of bacterial growth, p-iodonitrophenyltetrazolium violet was used as an indicator. ...
Research background:
Antioxidants are important compounds present at low concentrations that inhibit oxidation processes. Due to the side effects of synthetic antioxidants, research interest has increased considerably towards finding natural sources of antioxidants that can replace the synthetic ones. The emergence and spread of antibiotic resistance require the development of new drugs or some potential sources of novel medicine. This work aims to extract the secondary metabolites of Saccharomyces cerevisiae using ethyl acetate as a solvent and to determine the antioxidant and antimicrobial activities of these extracted metabolites.
Experimental approach:
The antioxidant activity of the secondary metabolites of S. cerevisiae were determined using DPPH, ABTS and FRAP assays. Furthermore, the antimicrobial potential of the ethyl acetate extract of S. cerevisiae against Cutibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis was assessed.
Results and conclusion:
Five out of 13 of the extracted secondary metabolites were identified as antioxidants. The antioxidant activity of the S. cerevisiae extract exhibited relatively high IC50 of 455.26 and 294.51 μg/mL for DPPH and ABTS respectively, while the obtained FRAP value, expressed as ascorbic acid equivalents, was 44.40 μg/mL. Moreover, the extract had a significant antibacterial activity (p<0.05) against Staphylococcus aureus and Staphylococcus epidermidis at the concentrations of 100 and 200 mg/mL, respectively. However, no inhibitory effect was observed against Cutibacterium acnes as the extract was only effective against the bacterium at the concentrations of 300 and 400 mg/mL (inhibition zones ranging from 9.0±0.0 to 9.3±0.6) respectively (p<0.05). Staphylococcus aureus was highly sensitive to the extract, with a MIC value of 18.75 mg/mL.
Novelty and scientific contribution:
This report confirmed the efficacy of the secondary metabolites of S. cerevisiae as a natural source of antioxidants and antimicrobials and suggested the possibility of employing them in drugs for the treatment of infectious diseases caused by the tested microorganisms.
