Vancomycin, derived from Nocardia orientalis, belongsto the tricyclic glycopeptide antibiotic type. It isindicated to kill gram-positive cocci and bacilli. Thebacterial cell wall faces drastic changes between intra- andextracellular pressure. The strict structure of peptidoglycancomposing the cell wall prevents the cell from lysing andcollapsing.
Having a chemistry of amphoteric glycopeptide antibiotic(chemical formula C66H75CL2N9O24), vancomycincauses major damage to the infection organisms by bindingto the carboxyl terminal D-Ala-D-Ala sequence of peptidoglycanintermediates produced during bacterial cell wallsynthesis. This action leads to the inhibition of the formationof cross-links in peptidoglycan. Once the peptidoglycanis not structurally formed correctly, it loses the ability toprevent the bacterial cell wall from collapsing, and the cellsbasically explode under the pressure.
Vancomycin comes in powder form in injection vials andin capsule form for oral use. Some hospital personnel compoundvancomycin oral solution, using the powder forinjection and vancomycin enema. Because of the relativelyhigh cost of vancomycin, it is important that the medicationis utilized only when necessary and with the correctroute of administration. I would like to bring to the attentionof my colleagues and pharmacists the appropriate treatmentof methicillin-resistant Staphylococcus aureus (MRSA)and Pseudomonas colitis caused by Clostridium difficile.
It is very important for a pharmacist to correctly advise aphysician about the proper route of administration of anantibiotic. For a systemic infection such as MRSA, the use oforal vancomycin is not recommended because of the lowabsorption and low serum concentrations. Likewise, intravenous(IV) administration of vancomycin is not indicated forthe treatment of Pseudomonas colitis caused by Clostridiumdifficile, 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.