Vancomycin, derived from Nocardia orientalis, belongs to the tricyclic glycopeptide antibiotic type. It is indicated to kill gram-positive cocci and bacilli. The bacterial cell wall faces drastic changes between intra- and extracellular pressure. The strict structure of peptidoglycan composing the cell wall prevents the cell from lysing and collapsing.
Having a chemistry of amphoteric glycopeptide antibiotic (chemical formula C66H75CL2N9O24), vancomycin causes major damage to the infection organisms by binding to the carboxyl terminal D-Ala-D-Ala sequence of peptidoglycan intermediates produced during bacterial cell wall synthesis. This action leads to the inhibition of the formation of cross-links in peptidoglycan. Once the peptidoglycan is not structurally formed correctly, it loses the ability to prevent the bacterial cell wall from collapsing, and the cells basically explode under the pressure.
Vancomycin comes in powder form in injection vials and in capsule form for oral use. Some hospital personnel compound vancomycin oral solution, using the powder for injection and vancomycin enema. Because of the relatively high cost of vancomycin, it is important that the medication is utilized only when necessary and with the correct route of administration. I would like to bring to the attention of my colleagues and pharmacists the appropriate treatment of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas colitis caused by Clostridium difficile.
It is very important for a pharmacist to correctly advise a physician about the proper route of administration of an antibiotic. For a systemic infection such as MRSA, the use of oral vancomycin is not recommended because of the low absorption and low serum concentrations. Likewise, intravenous (IV) administration of vancomycin is not indicated for the treatment of Pseudomonas colitis caused by Clostridium difficile, due to the low concentrations achieved in the colon, which are not enough to show an infection-killing effect. Therefore, a pharmacist should advise the following:
Dr. Motylev is a pharmacy manager in the hospital setting.