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Vancomycin
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
Vancomycin is a branched tricyclic glycosylated peptide obtained from Streptomyces orientalis with antibacterial properties. This antibiotic has bactericidal activity against most organisms and bacteriostatic effect on enterococci. It activates autolysins that destroy the bacterial cell wall, alters the permeability of bacterial cytoplasmic membranes and may selectively inhibit RNA synthesis. Vancomycin is indicated for the treatment of serious or severe infections caused by susceptible strains of methicillin-resistant and ß-lactam-resistant staphylococci. In addition, an oral liquid preparation is indicated for the treatment of Clostridium difficile-associated diarrhea and enterocolitis caused by Staphylococcus aureus, including methicillin-resistant strains (1). In ophthalmology, topical or intravenous vancomycin is currently used to treat sight-threatening bacterial infections of the eyes, including infectious keratitis and endophthalmitis (3). In pharmaceutical products, vancomycin is employed as vancomycin hydrochloride (CAS number 1404-93-9, EC number 604-193-8, molecular formula C66H76C13N9O24) (1).
Bacteriology of Ophthalmic Infections
Published in K. Balamurugan, U. Prithika, Pocket Guide to Bacterial Infections, 2019
Arumugam Priya, Shunmugiah Karutha Pandian
Autolysin is a cell wall degrading enzyme found on the cell envelop. It is activated under conditions such as nutrient starvation and blockage of cell wall synthesis and autolyzes the bacterial cell to release the cytoplasmic content into the surrounding. The cell wall degradation products and the virulent components from cytoplasmic content will exert inflammatory and toxic effect on the host tissue (Mitchell et al., 1997).
Mechanisms of action
Published in Fazal-I-Akbar Danish, Ahmed Ehsan Rabbani, Pharmacology in 7 Days for Medical Students, 2018
Fazal-I-Akbar Danish, Ahmed Ehsan Rabbani
Penicillins cause activation of autolysins by removing autolysin inhibitors. Autolysins on becoming active start destroying the bacterial cell wall. In order to inhibit transpeptidases, penicillins have to reach their targets, i.e. penicillins binding proteins (PBP) located on inner cytoplasmic membranes. They enter through the hydrophilic poring channels in outer membrane of bacteria. It is believed that beta-lactam ring (6-amino-penicillanic acid nucleus) of the bacteria is a structural analogue of D-alanyl-D-alanine. During transpeptidation in the presence of penicillins, beta-lactam ring is incorporated in the cross links rather than D-alanyl-D-alanine and this renders that cross links between peptidoglycan chains weak.
Emergence of coagulase-negative staphylococci
Published in Expert Review of Anti-infective Therapy, 2020
Karsten Becker, Anna Both, Samira Weißelberg, Christine Heilmann, Holger Rohde
The surface-associated S. epidermidis autolysin AtlE confers initial binding to polystyrene [78]. Autolysins are peptidoglycan hydrolases, which function in the cell wall turnover and cell separation [81]. Homologous Atl proteins from other CoNS have similar activities and exhibit the same modular design, such as two distinct enzymatic activities interconnected by three repeat domains [82–85]. Of note, Atl proteins additionally confer attachment to various host factors, among them fibronectin (Fn) and fibrinogen (Fg) [82,84–86]. This is especially important, because foreign bodies, like intravascular catheters, may become coated with host plasma and extracellular matrix proteins as soon as they are inserted [87,88]. AtlE-mediated adhesion may also occur indirectly: its autolytic activities lead to the release of eDNA, which represents an important structural component of the biofilm [89–91]. In agreement, mutagenesis of the active sites of the Atl enzymes is accompanied by the loss of biofilm formation [92].
Oral mucosa grafting in periorbital reconstruction
Published in Orbit, 2018
MSG secretions are predominantly mucous or seromucinous, similar to natural tears.31,80 Mucin lubricates the ocular surface and coats the epithelium, reducing the high surface tension of the eye forming a more stable and durable wet layer. Mucins prevent evaporation of tears by forming a hydrophobic barrier along the lid margin and increase the tear film break-up time.31,68,71 High levels of antimicrobial proteins such as immunoglobulin A (IgA), lactoferrin, lysozyme, and human beta-defensin (hBD) are present in saliva and protect the ocular surface from infection. Labial MSGs are responsible for one-third of salivary IgA secretion and are the main source of Ig A in the oral cavity. IgA is immunologically active against viruses and bacteria, while lactoferrin acts as an iron chelating agent which inhibits bacterial growth. Lysozyme triggers bacterial agglutination and causes lysis of the bacterial cell wall through autolysin activation.68,80 MSGs secretions contain growth factors including epidermal growth factor and transforming growth factor-β, which promote normal growth and differentiation of the ocular surface epithelium as well as corneal reepithelization.31,90 Saliva plays a significant role in the digestion of carbohydrates and fats and is rich in two enzymes, ptyalin, an α-amylase, and lingual lipase. Bennett 91 did not identify any deleterious effect on the ocular surface from ptyalin because of its substrate specificity to polysaccharides.
Discovery of (phenylureido)piperidinyl benzamides as prospective inhibitors of bacterial autolysin E from Staphylococcus aureus
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Jure Borišek, Sara Pintar, Mitja Ogrizek, Simona Golič Grdadolnik, Vesna Hodnik, Dušan Turk, Andrej Perdih, Marjana Novič
The genome of S. aureus strain Mu50 codes for five N-acetyl-glucosaminidases, one of them being AtlE, which belongs to the glycoside hydrolases (GH) 73 family. During growth and division bacteria have to synthesise and degrade peptidoglycan. Cells with inactivated N-acetyl-glucosaminidases have morphological defects as a consequence of impaired ability to increase in size after division and adopt correct mature shape12,13. Further it has been shown that some autolysins have a role in concealing bacteria from the receptor proteins that detect peptidoglycan and thus enable the pathogen to evade the immune system of the host14. Therefore, enzymes involved in the cell wall degradation can be considered as novel, valuable extracellular drug/vaccine targets. It may seem at a first glance contradictory that blocking the enzyme responsible for the degradation of the bacterial cell wall would have antimicrobial effect. However, as described above, the bacteria needs to degrade peptidoglycan in certain stages of growth and division, thus the inhibition of such enzymes would be beneficial. Interestingly, also an alternative molecular engineering approach was developed to enhance the bacteriolytic activity of autolysins and thus make them promising antimicrobial agents15.