bactericidal effect
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Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 52
Author(s):  
Che Zhao ◽  
Chengju Sheng ◽  
Chao Zhou

Traditional antibacterial hydrogels have a broad-spectrum bactericidal effect and are widely used as wound dressings. However, the biological toxicity and drug resistance of these antibacterial hydrogels cannot meet the requirements of long-term clinical application. Imidazolium poly(ionic liquids) (PILs) are polymeric antibacterial agents exhibiting strong antibacterial properties, as they contain a strong positive charge. In this study, two imidazolium PILs, namely poly(N-butylimidazolium propiolic acid sodium) (PBP) and poly(N-(3,6-dioxaoctane) imidazolium propiolic acid sodium) (PDP), as high efficiency antibacterial agents, were synthesized by polycondensation reaction. Then, the PILs were compounded with polyethylene glycol (PEG) by a thiol-yne click reaction to prepare injectable antibacterial hydrogels. An in vitro assay showed that the injectable antibacterial hydrogels could not only quickly kill Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), but also had low toxicity for human skin fibroblasts cells (HSFs) and human umbilical vein endothelial cells (HUVECs), respectively. Additionally, the lipopolysaccharide (LPS) inflammation model revealed that the injectable antibacterial hydrogels also had anti-inflammatory effects, which would be advantageous to accelerate wound healing.


Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 468
Author(s):  
Ewelina Namiecińska ◽  
Magdalena Grazul ◽  
Beata Sadowska ◽  
Marzena Więckowska-Szakiel ◽  
Paweł Hikisz ◽  
...  

To meet the demand for alternatives to commonly used antibiotics, this paper evaluates the antimicrobial potential of arene-ruthenium(II) complexes and their salts, which may be of value in antibacterial treatment. Their antimicrobial activity (MIC, MBC/MFC) was examined in vitro against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Pseudomonas aeruginosa, Proteus vulgaris and Candida albicans and compared with classic antibiotics used as therapeutics. Selected arene-ruthenium(II) complexes were found to have synergistic effects with oxacillin and vancomycin against staphylococci. Their bactericidal effect was found to be associated with cell lysis and the ability to cut microbial DNA. To confirm the safety of the tested arene-ruthenium(II) complexes in vivo, their cytotoxicity was also investigated against normal human foreskin fibroblasts (HFF-1). In addition, the antioxidant and thus pro-health potential of the compounds, i.e., their nonenzymatic antioxidant capacity (NEAC), was determined by two different methods: ferric-TPTZ complex and DPPH assay.


2022 ◽  
Vol 8 ◽  
Author(s):  
Yashan Feng ◽  
Lei Chang ◽  
Shijie Zhu ◽  
Yongxin Yang ◽  
Baoli Wei ◽  
...  

The uncontrollable rapid degradation rate of the Mg alloy substrate limited its clinical application, and implant-associated infections have been reported to be the main reason for the secondary surgery of orthopedic implantation. The aim of this study was to produce a multifunctional coating on magnesium-based alloys that have improved corrosion resistance, bioactivity, and antibacterial properties through the preparation of polyelectrolytic multilayers (PEMs) consisting of chitosan (CS) and sodium hyaluronate (HA) on silane-modified strontium-substituted hydroxyapatite (hereafter referred to as Bil (SH + CS)/SrHA). The multifunctional coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The results showed the polyelectrolyte complex SH/CS layer to be uniformly and tightly attached on to the surface of silane-treated SrHA. At the same time, a potentiodynamic polarization test and hydrogen evolution test showed the Bil (SH + CS)/SrHA coatings to exhibit superior corrosion resistance than bulk Mg-based alloys. The results of the cell–surface interactions revealed Bil (SH + CS)/SrHA coatings to be in favor of cell initial adhesion and more beneficial to the proliferation and growth of cells with the processing of co-culture. In addition, antibacterial tests demonstrated the strong bactericidal effect of Bil (SH + CS)/SrHA coatings against both Escherichia coli (E. coli) and Staphylococcus (S. aureus), suggesting that Bil (SH + CS)/SrHA coatings can successfully achieve multifunctionality with enhanced corrosion resistance, biocompatibility, and antibacterial properties.


Biology ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 97
Author(s):  
Alessandro Di Cerbo ◽  
Andrea Mescola ◽  
Giuseppe Rosace ◽  
Valentina Trovato ◽  
Roberto Canton ◽  
...  

Aluminum is the second most widely used metal worldwide. It is present as an additive in cosmetics, pharmaceuticals, food, and food contact materials (FCM). In this study, we confirm the bactericidal effect of a special anodizing method, based on TiO2 nanoparticles (DURALTI®) deposited on aluminum disks with different roughness and subjected to two sanitizing treatments: UV and alcohol 70%. Consequently, we perform a time-course evaluation against both Gram-negative and Gram-positive bacteria to better frame the time required to achieve the best result. Approximately 106 CFU/mL of Escherichia coli ATCC 25922; Salmonella Typhimurium ATCC 1402; Yersinia enterocolitica ATCC 9610; Pseudomonas aeruginosa ATCC 27588; Staphylococcus aureus ATCC 6538; Enterococcus faecalis ATCC 29212; Bacillus cereus ATCC 14579 and Listeria monocytogenes NCTT 10888 were inoculated onto each aluminum surface and challenged with UV and alcohol 70% at 0, 15”, 30”, 1′, 5′, 15′, 30′, 1, 2, 4 and 6 h. DURALTI® coating already confirmed its ability to induce a 4-logarithmic decrease (from 106 to 102 CFU/mL) after 6 h. Once each sanitizing treatment was applied, an overall bacterial inhibition occurred in a time ranging from 15′′ to 1′. The results are innovative in terms of preventing microbial adhesion and growth in the food industry.


Author(s):  
HEMANGI TRIVEDI ◽  
PRASHANT K. PURANIK

Objective: To investigate the in vitro antibacterial activity of a naturally occurring polyphenol chlorogenic acid (CGA) and compares it with formulated chlorogenic acid phytovesicles against 4 different bacterial strains; two gram positive [Staphylococcous aureus and Bacillus subtilis] and two gram negative strains [Klebsiella pneumonia and Escherichia coli]. Methods: CGA phytovesicles were developed and optimized using central composite design to improvise CGA’s physicochemical properties. Bactericidal activity was evaluated using agar diffusion, minimum inhibitory concentration (MIC) and time kill assay. The effect of pH and temperature on the antimicrobial activity was determined. Results: The optimized CGA phytovesicles showed entrapment of 96.89% with 30 times better lipophilic solubility than the plain drug. The inhibition zone sizes for CGA phytovesicle ranged from 17-25 mm as compared to 15-20 mm of plain CGA while the MIC values ranged 200-250 µg/ml as compared to 500-550 µg/ml of plain CGA. CGA phytovesicles exhibited a strong bactericidal effect at MIC with a log reduction in the range of 0.90-2.04 in Colony forming units (CFUs) at 24h for different strains as compared to 1.38-2.17 of plain CGA. Furthermore, the antibacterial effect was found to augment with increasing temperature but decreased with alkaline pH. Conclusion: Results strongly supports the hypothesis of potential use of CGA phytovesicles as a mode of drug delivery for its antibacterial use against different resistant bacteria.


Antioxidants ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 109
Author(s):  
María Guerra-Valle ◽  
Patricio Orellana-Palma ◽  
Guillermo Petzold

Helicobacter pylori (H. pylori) infection affects more than half of the world’s population, and thus, about 10 to 20% of people with H. pylori suffer from peptic ulcers, which may ultimately lead to gastric cancer. The increase in antibiotic resistance and susceptibility has encouraged the search for new alternative therapies to eradicate this pathogen. Several plant species are essential sources of polyphenols, and these bioactive compounds have demonstrated health-promoting properties, such as the gut microbiota stimulation, inflammation reduction, and bactericidal effect. Therefore, this review aims to discuss the potential effect of plant-based polyphenols against H. pylori and their role in the gut microbiota improvement.


RSC Advances ◽  
2022 ◽  
Vol 12 (3) ◽  
pp. 1645-1652
Author(s):  
Soma Mimura ◽  
Tomohiro Shimizu ◽  
Shoso Shingubara ◽  
Hiroaki Iwaki ◽  
Takeshi Ito

The time profiles of active cell ratios depended on the growth phase and the absence of some lytic transglycosylases of E. coli. Significant cell damage was not found on the autolysis inhibition condition.


2021 ◽  
Vol 18 (4) ◽  
pp. 33-40
Author(s):  
D. V. Tapalski ◽  
E. V. Karpova

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.


2021 ◽  
Author(s):  
Yong Guk Ju ◽  
Hak Joon Lee ◽  
Hong Soon Yim ◽  
Chang Kyu Lee ◽  
Mingoo Lee ◽  
...  

Abstract The aim of this study was to investigate the in vitro activity of various antimicrobial combinations against carbapenem-resistant Acinetobacter baumannii (CRAB) isolates producing OXA-23 carbapenemases.In vitro activity of six two-drug combinations against CRAB isolates collected from patients with CRAB bacteremia was evaluated using the checkerboard method and time-kill assay [0.5 ×, 1 ×, 2 × minimum inhibitory concentrations (MIC)], to identify potential synergistic and bactericidal two-drug combinations against CRAB isolates, using meropenem, colistin, tigecycline, rifampin, and ceftolozane/tazobactam. All 10 CRAB isolates in our study carried the OXA-58-type and OXA-23-type carbapenem-hydrolyzing oxacillinase. The colistin-ceftolozane/tazobactam combination demonstrated a synergistic effect in both the time-kill assay (using an antibiotic concentration of 1 × MIC) and the checkerboard method, while simultaneously showing a bactericidal effect in the time-kill assay. For all 10 CRAB isolates, time-kill curves showed a significant synergistic bactericidal activity of the colistin-ceftolozane/tazobactam combination at 0.5 × MIC. Overall, there is substantial discordance of synergistic activity between the checkerboard microdilution and time-kill assay (with a concordance of 35%). Our study demonstrated that the two-drug combinations of colistin and ceftolozane/tazobactam can be a potential alternative for treating CRAB infections. The effect of these antibiotic combinations should be evaluated through clinical trials.


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