Controlled release of metal phenolic network protected phage for treating bacterial infection

Phage is a promising therapeutic agent for treating antibiotic resistant bacteria. However, in the process of treatment, phage may be cleared by the immune system and cleaved by protease, which could affect the efficacy of phage. In order to solve the above problems, phage encapsulation is usually adopted. In this study, we employed metal phenolic network (MPN) for efficient phage encapsulation which could protect phage from the cleavage of protease, and keep cytotoxicity weak. In the model of skin wound infection, the encapsulated phage could be released in response to pH change to achieve good antibacterial effect. Furthermore, the MPN encapsulation could prolong the T4 phage residence time at the wound. Our findings suggest that MPN can be a promising material for phage encapsulation.

Antiadhesion and antibiofilm potential of Fagonia indica from Cholistan desert against clinical multidrug resistant bacteria

High resistance to antimicrobials is associated with biofilm formation responsible for infectious microbes to withstand severe conditions. Therefore, new alternatives are necessary as biofilm inhibitors to control infections. In this study, the antimicrobial and antibiofilm activities of Fagonia indica extracts were evaluated against MDR clinical isolates. The extract exhibited its antibiofilm effect by altering adherence and disintegration of bacterial cell wall. Fagonia indica has antibacterial effect as minimum inhibitory concentration (MIC) values ranging from 125 to 500 µg mL-1 and minimum bactericidal concentration (MBC) value was 500-3000 µg mL-1 against multidrug resistant (MDR) clinical isolates. The extract exhibited its antibiofilm effect by altering adherence and disintegration of bacterial cell wall. Fagonia indica had antibacterial effect as minimum inhibitory concentration (MIC) values ranging from 125 to 500 µg mL-1 and minimum bactericidal concentration (MBC) value was 500-3000 µg mL-1 against MDR isolates. The maximum inhibitory effects of Fagonia indica chloroform extract on biofilm formation was observed on Staphylococcus aureus (71.84%) followed by Klebsiella pneumoniae (70.83%) after 48 hrs showing that inhibition is also time dependent. Our results about bacterial cell protein leakage indicated that MDR isolates treated with chloroform extract of Fagonia indica showed maximum protein leakage of K. pneumoniae (59.14 µg mL-1) followed by S. aureus (56.7 µg mL-1). Cell attachment assays indicated that chloroform extract resulted in a 43.5-53.5% inhibition of cell adherence to a polystyrene surface. Our results revealed that extracts of Fagonia indica significantly inhibited biofilm formation among MDR clinical isolates, therefore, could be applied as antimicrobial agents and cost effective biofilm inhibitor against these MDR isolates.

Optimizing ZnO/CdS Nano Composite Controlled by Fe Doping Towards Efficiency in Water Treatment and Antimicrobial Activity

Nanocrystalline composite zinc oxide (ZnO) and CdS with Fe doping thin films grown on glass substrate by chemical method. The parameters like temperature of the solution, UV exposure, pH of solution, immersion time, immersion cycles, have been controlled and standardized for nanocrystalline film. The synthesis NPs were analyzed by X-ray diffraction (XRD). Rietveld method shows that Fe-doped composite ZnO/CdS is a single pure phase and wurtzite structure. Samples were analyzed by sophisticated various instrument like XRD, UV- Visible spectrometer, HRTEM, HRSEM and composition was analyzed by EDX attached with HRTEM. The band gap was calculated by absorption spectroscopy and found that absorption was blue-shifted. The electron structure shows that doping changes the crystal structure and transition level create better efficiency and creates octahedral symmetry. The antibacterial studies showed that the 5.0 wt% Fe-doped exhibited maximum antibacterial effect.

Susceptibility to antibiotic combinations of Klebsiella pneumoniae and Acinetobacter baumannii strains isolated from COVID-19 patients

Objective. To assess the susceptibility of K.pneumoniae and A.baumanii strains isolated from hospitalized COVID-19 patients to antibiotics and their combinations.Materials and methods. The minimum inhibitory concentrations (MICs) of meropenem and colistin were determined for 47 A.baumannii and 51K.pneumoniaestrains isolated from the hospitalized COVID-19 patients by the broth microdilution method. The susceptibility to 11 antibiotic combinations was assessed using the method of multiple combination bactericidal testing.Results. Colistin resistance was detected in 31.9 % of A.baumannii strains (MIC50 — 0.5 mg/l, MIC90 — 16 mg/l) and in 80.4 % of K.pneumoniaestrains (MIC50 — 16 mg/l, MIC90 — 256 mg/l). It has been shown that double antibiotic combinations with the inclusion of colistin exhibit bactericidal or bacteriostatic activity against 76.6–87.2 % of A.baumannii strains. Combinations with the addition of meropenem, colistin and macrolides exhibited bactericidal activity against 78.4–80.4 % of K.pneumoniae strains. Combinations of two carbapenems were not active, the combination of meropenem-colistin had a bactericidal effect only in 13.7 % of K.pneumoniae strains.Conclusion. Widespread colistin resistance was found in carbapenem-resistant K.pneumoniae and A.baumannii strains isolated from the hospitalized COVID-19 patients. The combinations of antibiotics that have a synergistic antibacterial effect in their pharmacokinetic/pharmacodynamic concentrations have been determined.

FEATURES OF OBTAINING GELS BASED ON AGAR-AGAR FOR COSMETOLOGY AND MEDICINE WITH ANTIBACTERIAL PROPERTIES

In the modern world, special attention is paid to materials with controlled characteristics. In this aspect, polymers and materials based on them have a number of specific properties for effective use in medicine and cosmetology. Humic substances satisfy most of these features, so their use is very important. The study of the features of the processes of gelation in polymer systems such as agar-agar, which has rather universal properties, makes it possible to use it as a basis for gels and polymer carriers, as well as in the processes of obtaining medical and cosmetic materials with different properties, which can be important in solving a number of topical issues. In particular, these are lightweight and cheap to manufacture antiseptic gels, dressings on wounds with absorption and protective properties, all kinds of cosmetics. In the article, a study was carried out to study the processes of gelation and the features of the rheological properties of hydrogels based on agar-agar in order to obtain modern hydrogels with an antibacterial effect. It was found that the introduction of humic acids into the composition of polymer hydrogels slows down the processes of structure formation, which leads to a decrease in the viscosity of all the studied compositions. Also, a decrease in the melting temperature of hydrogel jellies with an increase in the content of humic acids in them indicates a reduced level of gelation, which also leads to an increase in the time of loss of stickiness of polymer hydrogels. It has been shown that humic acids in polymer hydrogels have high antibacterial activity and almost completely stop the processes of mold formation in them. It was found that the most effective from the point of view of obtaining hydrogels with an antibacterial effect are agar-agar compositions with a humic acid content of 15 %. Thus, cosmetic polymer hydrogels with an antibacterial effect have been developed, which can be used in the treatment of hands, face and other areas of the skin that are open and contact for humans to combat coronavirus bacteria.

Liquid-Assisted Electrospinning Three-Dimensional Polyacrylonitrile Nanofiber Crosslinked with Chitosan

Electrospinning has become a popular nanotechnology for the fabrication of tissue engineering scaffolds, which can precisely regulate fiber diameter and microstructure. Herein, we have prepared a three-dimensional polyacrylonitrile (PAN) nanofiber by liquid-assisted electrospinning. The spacing between PAN nanofibers can reach to 15-20 μm, as the uniform internally connected pore structure can be formed, through the regulation of parameters. Furthermore, the chitosan attached to the as-prepared nanofibers gives the material antibacterial effect and increases its biocompatibility. Meanwhile, the special structure of chitosan also provides the possibility for further loading drugs in dressings in the future. This newly developed nanocomposite seems to be highly suitable for wound healing due to its unique properties of biodegradability, biocompatibility, and antimicrobial effectiveness.