The antibacterial effect of AgNPs was investigated by determining MIC/MBC and growth kinetics assay. The lowest MIC/MBC was found to be in the range of 11.25-22.5 µg ml(-1) . The growth kinetics curve shows that 25 µg ml(-1) AgNPs strongly inhibits the bacterial growth. Confocal laser scanning electron microscopy (CLSM) shows that as the concentration of NPs increases, reduction in the number of cells was observed and at 50 µg ml(-1) of NPs, 100% death was noticed. Scanning electron microscopy (SEM) shows cells were severely damaged with pits, multiple depressions, and indentation on cell surface and original rod shape has swollen into bigger size. High resolution-transmission electron microscopic (HR-TEM) micrograph shows that cells were severely ruptured. The damaged cells showed either localized or complete separation of the cell membrane. The NPs that anchor onto cell surface and penetrating the cells may cause membrane damage, which could result in cell lysis. The interaction of AgNPs to membrane biomolecules; lipopolysaccharide (LPS) and L-α-phosphatidyl-ethanolamine (PE) were investigated by attenuated total reflectance-fourier transform infrared (ATR-FTIR) spectroscopy. LPS and PE showed IR spectral changes after AgNPs exposure. The O-antigen part of LPS was responsible for interaction of NPs through hydrogen bonding. The phosphodiester bond of PE was broken by AgNPs, forming phosphate monoesters and resulting in the highly disordered alkyl chain. The AgNPs-induced structural changes in phospholipid may lead to the loss of amphiphilic properties, destruction of the membrane and cell leaking. The biomolecular changes in bacterial cell envelope revealed by ATR-FTIR provide a deeper understanding of cytotoxicity of AgNPs.
Poor growth with underweight for age, decreased length/height for age, and underweight-for-height are all relatively common in children with CHD. The underlying causes of this failure to thrive may be multifactorial, including innate growth potential, severity of cardiac disease, increased energy requirements, decreased nutritional intake, malabsorption, and poor utilisation of absorbed nutrition. These factors are particularly common and severe in low-and middle-income countries.Although nutrition should be carefully assessed in all patients, failure of growth is not a contraindication to surgical repair, and patients should receive surgical repair where indicated as soon as possible.Close attention should be paid to nutritional support -primarily enteral feeding, with particular use of breast milk in infancy -in the perioperative period and in the paediatric ICU. This nutritional support requires specific attention and allocation of resources, including appropriately skilled personnel.Thereafter, it is essential to monitor growth and development and to identify causes for failure to catch-up or grow appropriately.
The ability of bacteria to develop antibiotic resistance and colonize abiotic surfaces by forming biofilms is a major cause of medical implant-associated infections and results in prolonged hospitalization periods and patient mortality. Different approaches have been used for preventing biofilm-related infections in health care settings. Many of these methods have their own demerits that include chemical-based complications; emergent antibiotic-resistant strains, and so on. Silver nanoparticles (AgNPs) are renowned for their influential antimicrobial activity. We demonstrate the biofilm formation by extended spectrum b-lactamases-producing Escherichia coli and Klebsiella spp. by direct visualization applying tissue culture plate, tube, and Congo red agar methods. Double fluorescent staining for confocal laser scanning microscopy (CLSM) consisted of propidium iodide staining to detect bacterial cells and concanavalin A-fluorescein isothiocyanate staining to detect the exopolysaccharides matrix were used. Scanning electron microscopy observations clearly indicate that AgNPs reduced the surface coverage by E. coli and Klebsiella spp. thus prevent the biofilm formations. Double-staining technique using CLSM provides the visual evidence that AgNPs arrested the bacterial growth and prevent the exopolysaccharides formation. The AgNPs-coated surfaces effectively restricted biofilm formation of the tested bacteria. In our study, we could demonstrate the complete antibiofilm activity AgNPs at a concentration as low as 50 lg/ml. Our findings suggested that AgNPs can be exploited towards the development of potential antibacterial coatings for various biomedical and environmental applications. These formulations can be used for the treatment of drug-resistant bacterial infections caused by biofilms, at much lower nanosilver loading with higher efficiency.
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