Pharmacology
Summary
Vancomycin is a potent glycopeptide antibiotic effective against gram-positive bacteria, including MRSA, by inhibiting cell wall synthesis through binding to D-ALA-D-ALA terminiof peptidoglycan peptides.
It's effective against gram-positive bacteria such as staphylococcus, streptococcus, C. difficile, and enterococcus species, and it's used in treating bloodstream infections caused by methicillin-resistant Staph aureus, or MRSA. Vancomycin inhibits cell wall synthesis in bacteria by binding to the D-ALA-D-ALA terminus of peptidoglycan peptides (unlike penicillins which bind to the penicillin-binding proteins, or PBPs). Vancomycin is also resistant to beta-lactamases, making it a potent antibiotic against resistant strains.
Primarily administered intravenously, vancomycin has broad distribution in the body, and it's a go-to antibiotic for severe systemic infections in hospital settings and in immunocompromised individuals prone to multi-drug resistant bacteria. Its uses include treating MRSA osteomyelitis, staphylococcal infections, and hospital-acquired pneumonia. Before using vancomycin, it should be confirmed that no other alternative drugs to reduce resistance are available, and that the bacterial strain is susceptible to vancomycin. Some adverse effects due to vancomycin use include vancomycin flushing syndrome, thrombophlebitis at the injection site, ototoxicity and nephrotoxicity.
Lesson Outline
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FAQs
Vancomycin works by binding to the D-ALA D-ALA portion of the bacterial cell wall precursor, disrupting the bacterium's ability to synthesize its cell wall. The inability to properly form a cell wall makes the bacteria more susceptible to environmental pressures and ultimately leads to their death.
Though methicillin-resistant Staph aureus (MRSA) produces altered penicillin-binding proteins (PBPs) that are resistant to beta-lactams, these altered PBPs are ineffective against vancomycin, making it a suitable treatment for MRSA infections. Furthermore, beta-lactamases (enzymes produced by some bacteria to resist beta-lactam antibiotics) are ineffective against vancomycin.
Yes, vancomycin--- possibly in combination with cefepime, ceftazidime, or meropenem--- can be used as empiric treatment for healthcare-acquired meningitis, especially if penicillin-resistant Strep pneumoniae is suspected.
Vancomycin can cause a variety of side effects. These include flushing, commonly referred to as "red man syndrome", which results from histamine release by mast cells in response to rapid infusion of the drug. Other potential side effects include thrombophlebitis, ototoxicity, nephrotoxicity, eosinophilia and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome. Due to the potential for toxicity, it's necessary to monitor plasma levels during treatment with vancomycin.
Yes, vancomycin can be used to treat Enterococcus infections. However, a variation of Enterococcus called VRE (Vancomycin-resistant Enterococcus) has a resistance mechanism (D-ALA-D-LAC) that makes it resistant to Vancomycin. Oral vancomycin can also be used to treat Clostridioides difficile infections; it settles in the gastrointestinal tract while only minimally being absorbed into circulation, allowing it to directly target the bacteria causing pseudomembranous colitis.
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