Comprehensive Nursing Pharmacology Q 3
An infection in a central venous access device is not eliminated by giving antibiotics through the catheter. How would bacterial glycocalyx contribute to this?
A. It protects the bacteria from antibiotic and immunologic destruction.
B. Glycocalyx neutralizes the antibiotic rendering it ineffective.
C. It competes with the antibiotic for binding sites on the microbe.
D. Glycocalyx provides nutrients for microbial growth.
Correct Answer: C. It competes with the antibiotic for binding sites on the microbe.
Glycocalyx is a viscous polysaccharide or polypeptide slime that covers microbes. It enhances adherence to surfaces, resists phagocytic engulfment by the white blood cells, and prevents antibiotics from contacting the microbe.
Option A: The first identified function of the glycocalyx was probably protection. The glycocalyx is a dense, gel-like meshwork that surrounds the cell, constituting a physical barrier for any object to enter the cell. For example, the glycocalyx was identified to play an important role to prevent the entry of pathogens into the cell.
Option B: The endothelial glycocalyx is continuously in contact with the bloodstream and acts as a vital mechanosensor on endothelial cells. Specifically, long proteoglycans with strong glycosylation such as heparan sulfate or chondroitin sulfate are involved in this process. Often, the image of wind brushing through trees is used: In this analogy, the “wind” of the bloodstream acts on the proteoglycan “trees” of the glycocalyx, bending them, which creates a torque that is transferred to the inside of the cells. This leads to various intracellular responses such as the release of the vasodilator nitric oxide, actin cytoskeleton rearrangement, and cell polarization.
Option D: Considering that galectins are both glycocalyx organizing proteins and involved in a variety of cellular processes, it appears as if the glycocalyx can act as a “storage compartment” for galectins and potentially other proteins. Upon triggering events, they are released and translocated into the cell, where they fulfill their respective function.