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Chitosan-Based Nanocarriers
Published in Bhupinder Singh, Om Prakash Katare, Eliana B. Souto, NanoAgroceuticals & NanoPhytoChemicals, 2018
Sumit Sharma, V.R. Sinha, Amita Sarwal, Rahul Shukla
Vancomycin, a glycopeptide antibiotic, is used to treat severe intestinal infections like pseudo-membranous colitis and enterocolitis caused by pathogenic bacteria like Clostridium difficile and Staphylococcus aureus. The problem associated with this drug is its acidic degradation in the stomach and hence lesser availability of active drug at the infection site, that is, ileo-caecal and colonic regions. Chitosan nanoparticles have demonstrated promising colonic delivery with improved antibacterial activity on Staphylococcus aureus. The smaller size of chitosan particles provides a larger surface area and better mucoadhesion due to improved electrostatic interactions of sulfonic acid and sialic acid of mucin and amino groups of chitosan. It has also been observed that nanoparticles obtained from spray-drying are of spherical shape and smooth architecture with greater encapsulation efficiency compared with particles obtained from the freeze-drying process. In vitro release studies revealed that chitosan nanoparticles prepared by ionic gelation with molar ratio of chitosan:tripolyphosphate as 8:1.5 and processed by spray-drying, had the ability to control the release of vancomycin. The percentage fractional amount released at pH 7.4 was found to be approximately 35% after 6 h, whereas it was approximately 4% at pH 2.0 (Cerchiara et al., 2015).
Application of Polymer Drugs to Medical Devices and Preparative Medicine
Published in Severian Dumitriu, Valentin Popa, Polymeric Biomaterials, 2020
M.R. Aguilar, L. García-Fernández, M.L. López-Donaire, F. Parra, L. Rojo, G. Rodríguez, M.M. Fernández, J. San Román
Vancomycin is the prototypical glycopeptide antibiotic, and it remains potent against Gram-positive organisms (e.g., Staphylococcus spp.) commonly encountered in association with indwelling medical devices such as orthopedic hardware, although resistance can occur (Boneca and Chiosis, 2003). Its activity derives from binding d-Ala–d-Ala sequences found at the terminal end of peptidoglycan precursors, that blocks the action of both transglycosylases and transpeptidases by complexing with their substrates and preventing proper cross-linking of peptidoglycan structures, reason why the internalization is not required for its activity (Loll and Axelsen, 2000). Following this rationale, Lawson and coworkers (Lawson et al., 2009) synthesized polymerizable vancomycin derivatives bearing either acrylamide or PEG-acrylate and were tethered from a surface pendant to a polyacrylate backbone through a living radical polymerization, demonstrating that the vancomycin-PEG-acrylate derivatives showed a significant reduction in bacterial colony-forming units (CFU) with respect to nonfunctionalized control surfaces.
A framework for standardized qPCR-targets and protocols for quantifying antibiotic resistance in surface water, recycled water and wastewater
Published in Critical Reviews in Environmental Science and Technology, 2022
Ishi Keenum, Krista Liguori, Jeanette Calarco, Benjamin C. Davis, Erin Milligan, Valerie J. Harwood, Amy Pruden
Vancomycin-resistant Enterococcus is also classified as a “serious” health threat by the CDC, causing an estimated 54,500 hospitalizations per year and 5,400 deaths in 2017 in the United States (CDC, 2019a). Until the late 1980s, the glycopeptide antibiotic vancomycin was considered to be a drug of last resort against Gram-positive infections (Cunha, 1995). However, the emergence and widespread dissemination of vancomycin-resistant Enterococcus highlight the need to identify corresponding targets for environmental monitoring (Tacconelli & Cataldo, 2008). The core of the vancomycin resistance mechanism relies on vanH, vanA, and vanX, which is thought to have originated in the soil bacterium Paenibacillus (Aminov & Mackie, 2007). Among these, the vanA operon gene has been identified as a suitable clinically-relevant ARG target (Ashbolt et al., 2018; Berendonk et al., 2015; Keely, 2019; Rizzo et al., 2013).