Poly (ε-caprolactone)/Poly (lactic acid) fibers produced by rotary jet spinning for skin dressing with antimicrobial activity

The rotary jet spinning technique permits the production of biomaterials that can be used as devices that come into contact with biological systems (including biological fluids) for diagnostic or surgical applications. These materials are composed of synthetic or natural compounds and allow the incorporation of drugs for therapeutic purposes. Two solutions containing 50% poly(lactic acid) (PLA) and 50% poly(ε-caprolactone) (PCL) diluted in three different solvents were prepared for rotary jet spinning (RJS) process. Vancomycin, an antibiotic indicated for the treatment of severe staphylococcal infections in patients with penicillin allergy, was added in the polymer solutions, to obtain drug-loaded fibrous mats. Morphological surface characterization by scanning electron microscopy revealed heterogeneous pores in the microfibers. Vancomycin loading interfered with the morphology of all samples in terms of fiber size, leading to smaller diameter fibers. Attenuated total reflectance/Fourier transform infrared spectroscopy was used for identification of the samples. The vibrational characteristics of PCL/PLA and vancomycin were consistent with expectations. Vero cell culture assays by the extract dilution and direct contact methods revealed the absence of cytotoxicity, except for the sample prepared with 50% of PCL and of a 9/2 (V/V) vancomycin content, with the growth of confluent and evenly spread cells on the fibrous mats surface. Microbiological analysis, performed on Staphylococcus aureus by the halo inhibition test and by the broth dilution method, showed that the antibacterial activity of vancomycin was maintained by the loading process in the polymer fibers. The results showed that rotary jet spinning produces satisfactory amounts of Vancomycin-loaded fibers, as potential web dressing for wound repair

Myxopyronin B inhibits growth of a Fidaxomicin-resistant Clostridioides difficile isolate and interferes with toxin synthesis

The anaerobic, gastrointestinal pathogen Clostridioides difficile can cause severe forms of enterocolitis which is mainly mediated by the toxins it produces. The RNA polymerase inhibitor Fidaxomicin is the current gold standard for the therapy of C. difficile infections due to several beneficial features including its ability to suppress toxin synthesis in C. difficile. In contrast to the Rifamycins, Fidaxomicin binds to the RNA polymerase switch region, which is also the binding site for Myxopyronin B. Here, serial broth dilution assays were performed to test the susceptibility of C. difficile and other anaerobes to Myxopyronin B, proving that the natural product is considerably active against C. difficile and that there is no cross-resistance between Fidaxomicin and Myxopyronin B in a Fidaxomicin-resistant C. difficile strain. Moreover, mass spectrometry analysis indicated that Myxopyronin B is able to suppress early phase toxin synthesis in C. difficile to the same degree as Fidaxomicin. Conclusively, Myxopyronin B is proposed as a new lead structure for the design of novel antibiotics for the therapy of C. difficile infections.

Effects of Etlingera elatior inflorescence extract on beneficial bacteria of the healthy human gut

Background: Etlingera species is an enduring plant in the Zingiberaceae family, with more than 100 species local to many countries. It has been utilized commonly as a culinary spice or eaten crude for its therapeutic impacts. This research is intended to study the effects of E. elatior inflorescence, which is commonly known as bunga kantan in Peninsular Malaysia, upon the microbiota of healthy human gut. Material and methods: The closed bud E. elatior inflorescence was cleaned and dried in the hot air oven and grounded into fine powder. The extract from the E. elatior inflorescence was obtained using hot water extraction method. The effects of the inflorescence extract on L. rhamnosus and L. acidophilus were studied through micro-broth dilution process where different concentration of sample was incorporated into a broth medium followed by the application of a standardized volume of Lactobacillus sp. into the medium of the 96 well plate. Results: Growth was seen in both L. rhamnosus and L. acidophilus, indicating that E. elatior inflorescence acted like a prebiotic towards L. acidophilus and L. rhamnosus Conclusion: E. elatior inflorescence concentrate acts like a prebiotic towards L. acidophilus incomparable to L. rhamnosus

Antibacterial, Antifungal and Antihelminthic Properties of Ethanolic, Methanolic and Water Extracts of Pollen

Microorganisms and helminthes can cause serious diseases in humans as well as in animals. The use of antimicrobial and antihelminthic drugs have created selective pressure and caused resistance to antibiotics used against them, thus it necessitates the use of honey bee’s derived natural products. One such bee derived product is pollen, collected by worker honey bees from the flowering plants and modify it by adding its salivary secretions. The present study embodies use of pollen as antimicrobial and antihelminthic substance. Among microorganisms 4 Gram (+ve) bacteria; (Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus pneumoniae) and 3 Gram (-ve) bacteria; (Escherichia Coli, Pseudomonas aeruginosa, Salmonella enteric) and 2 yeasts (Candida albicans and Saccharomyces cerevisiae) were used and the methodology used disc diffusion assay and broth dilution method. The antihelminthic effect was observed among amphistomes via bioassay method under in vitro conditions. For observations three types of pollen extracts (ethanolic, methanolic and water extract) were prepared and positive controls used were; Ampicillin for antibacterial, Amphotericin B for antifungal and Albendazole for anti-helminthes. The antimicrobial activities were determined by measuring the zones of inhibition diameters in millimeters after 24 hours of incubation at optimum temperature for each microbe and also by broth dilution method. Results obtained showed that the water extract of pollen was found to be most effective against bacteria used in the present study where; Gram (+ve) bacteria were more susceptible as compared to the Gram (-ve) bacteria. It was also observed that among yeasts; Saccharomyces cerevisiae was more susceptible towards ethanolic extract of pollen while Candida albicans showed more inhibitions towards water extract of pollen. Results also demonstrated that none of the extracts of pollen was found to be effective against Helminthes (amphistomes) used in the present study.

Chemical constituents and bactericidal and fungicide potential of the essential oil of Pimenta dioica Lindl against pathogenic microorganisms

This study evaluated the chemical profile and antimicrobial activity of essential oil (EO) of P. dioica. The EOs were extracted by hydrodistillation and chemically characterized by gas chromatography coupled to mass spectrometry (GC/MS). The total phenolics were quantified by the Folin Ciocalteu method. For the antimicrobial assay, the Disc Diffusion and Broth Dilution method were applied to obtain the minimum inhibitory concentration and minimum bactericidal concentration. The main constituent of the EO was eugenol. The EO showed bactericidal activity against E. coli, S. aureus, P. aeruginosa, Salmonella sp., B. cereus, P. mirabilis, K. pneumoniae, S. sonnei, C. albicans, Fusarium sp., Penicillium sp. and Aspergilus sp. The results obtained are encouraged by the potential use of the EO studied in the control and combat of pathogenic microorganisms.

Facile Synthesis of Crosslinked Cu:ZnS-Lignocellulose Nanocomposite: A Potent Antifungal and Antisporulant System Against The Tea Pathogen Exobasidium Vexans

The objective of the present study was to synthesize Cu doped ZnS nanocore crosslinked with lignocellulose (represented as Cu:ZnS-lignocellulose nanocomposite) for antifungal action against the devastating tea blister blight pathogen Exobasidium vexans. The characteristic features of the nanocomposite were analyzed via different physicochemical techniques like FTIR, XRD, XPS, SEM, SEM-EDX, Elemental mapping, PCS, and UV-PL studies. The FTIR and XPS investigations revealed the crosslinking between lignocellulose and the Cu:ZnS. The presence of lignocellulose was seen to attribute a potent antifungal efficacy, also enhancing the stability of the resulting nanocomposite in aqueous suspensions. The antifungal efficacy confirmed through disk diffusion and broth dilution assays have a maximum zone of inhibition of 1.75 cm2 and a MIC50 of 0.05 mg/ml against E. vexans. Additionally, the antisporulant activity was evident as the basidiospores failed to germinate in presence of the Cu:ZnS-lignocellulose nanocomposites. This shows potential for stemming the rapid infectivity of E. vexans by achieving disease inhibition at the early stage. Finally, the comparison with two commonly used commercial fungicides (copper oxychloride and fluconazole) demonstrated > 10-fold higher antifungal activity for Cu:ZnS-lignocellulose nanocomposites.

Antimicrobial Activity of Cymbopogon (Lemongrass) on Enterococci

Aim: The aim of this study was to investigate antimicrobial activity against Enterococcus bacteria. Materials and Methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by the Broth Dilution Method. The antibiotic susceptibility test against the test organisms was performed by the Disc Diffusion Method. Results and Discussion: Antimicrobial activity of Cymbopogon oil was examined against common Enterococcus bacteria using broth microdilution assay and the disc diffusion method. Zone of inhibition was seen when Cymbopogon oil was kept with enterococcus bacteria, this proves to be bacteriostatic. Conclusion: Lemongrass oil proved to be bacteriostatic against Enterococcus, further research to be done to implement Lemongrass oil as an antibacterial agent.

Evaluation of Antifungal Activity of Carbonate Solvent – Part:1

Antimicrobial agents have been used in leather manufacturing to prevent leather products from microbial contamination. In this work, the antifungal activity of green solvent such as propylene carbonate was investigated against the mixed culture of fungi isolated from wet-blue using broth dilution/well diffusion. A concentration of 5% and above (propylene carbonate) showed effective antifungal activity against the mixed culture of fungi and the efficiency of propylene carbonate on the mixed culture increased with increasing concentration/volume. Propylene carbonate exhibited fungistatic activity against the mixed culture of fungi but it lost its activity after a certain period and fungal growth was observed again. It was also found that 2% propylene carbonate in chrome tanning process effectively inhibited the fungal growth and the wet-blue can be preserved up to 30 days without any fungal attack.

Antibacterial Activity of Biodegradable Plastic from Chromolaena odorata (Pokok Kapal Terbang) Leaves

The aim of this research project was to develop antimicrobial films from blends of C. odorata and PVA and test the films for microbial activity using broth dilution methods for Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. The result shows that CO/PVA80 successfully inhibit the growth of target bacteria. In antibacterial activity analysis, CO/PVA80 showed 50% higher compare with pure PVA film, PVA100. Other than that, the high percentage of PVA in the blend films, the greater the thickness, Tensile Strength (TS) and Young’s Modulus (YM), while the Elongation Break (EB) of the prepared films decreased. The 0.5 mm CO/PVA80 film shows a good result in mechanical properties which is TS 6.55 MPa, YM 182 MPa and EB is 7.47%. A CO/PVA80 were show a smooth texture, lacked of macropore and good characteristic with a SEM analysis. These results suggest that CO/PVA80 films have good compatibility to form an antimicrobial film as a new material for medical application especially for wound healing.