Master Vancomycin Mechanism with Picmonic for Medicine

Because gram negative bacteria produce their cell walls via a different mechanism, vancomycin is not active against gram negative bacteria and only has antibiotic effects on gram positive organisms.

This antibiotic inhibits the cell wall mucopeptide synthesis via forming hydrogen bond interactions with the terminal D-alanyl-D alanine moieties of the cell wall peptides. This binding to the D-Ala-D-Ala prevents synthesis of long polymers of N-acetylmuramic acid and N-acetylglucosamine which forms the backbone strands of the bacterial cell wall and also prevents the polymers from forming cross links.

This antibiotic inhibits the cell wall mucopeptide synthesis via forming hydrogen bond interactions with the terminal D-alanyl-D alanine moieties of the cell wall peptides. This binding to the D-Ala-D-Ala prevents synthesis of long polymers of N-acetylmuramic acid and N-acetylglucosamine which forms the backbone strands of the bacterial cell wall and also prevents the polymers from forming cross links.

Resistance to vancomycin develops when the D-Ala-D-Ala moiety changes to D-ala-D-lac, preventing binding of vancomycin.

Vancomycin is commonly used in the treatment of Staph aureus infections that are highly resistant to penicillin derivatives including MRSA (methicillin resistant Staph aurues). Staphylococcus aureus is a gram positive cocci that can cause a wide range of illnesses from minor skin infections to life-threatening diseases like pneumonia, osteomyelitis, and endocarditis.

Vancomycin is indicated in pseudomembranous colitis infections caused by Clostridium difficile when the infection is unresponsive to metronidazole treatment. For this indication, vancomycin is given orally rather than the typical IV route.

Enterococci are gram positive cocci that were previously classified as Group D streptococcus due to Lancefield group D classification. Important clinical infections caused by Enterococcus species include urinary tract infections and subacute endocarditis. An important feature of this genus is a high level of antibiotic resistance. Many enterococci are intrinsically resistant to beta lactam antibiotics and resistance to vancomycin (VRE) has been increasing in the last few decades.