Medical Pharmacology Chapter 35: Antibacterial Drug Practice Questions

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  • "Diagram depicting formation of cross-links in the bacterial cell wall by a Penicillin-binding protein (PBP, an enzyme) and subsequent suicide inhibition by penicillin.

    • The bacterial cell wall consists of strands of repeating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) subunits.  The NAM subunits have short peptide chains attached to them. (The exact composition of these can vary. The proximal alanine is usually L-ala and the distal two are usually D-ala).

    • The PBP binds the peptide side chains and forms the cross-link with the expulsion of one D-alanine from one peptide side chain.

    • The PBP dissociates from the wall once the cross-link has been formed.

    • Penicillin is added to the system. It enters the active site of the PBP and reacts with the serine group that is important in its enzymatic activity.

    • The beta-lactam ring of penicillin (represented here at the top of the 'P') is irreversibly opened during the reaction with the PBP. Penicillin remains covalently linked to the PEBP and permanently blocks the active site. "

  • Attribution:  Mcstrother, wikipedia:

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  • Source Material: 

    • MacDougall C Chapter 56:  Sulfonamides, Trimethoprim-Sulfamethoxazole, Quinolones and Agents for Urinary Tract Infections in Goodman & Gilman's:  The Pharmcological Basis of Therapeutics, 13e, (Brunto LL Hilal-Dandan R Knollmann BC, eds) McGraw-Hill Education, 2018.

    • Gruenberg K Guglielmo BJ e1-13:  Sulfonamides & Antifolate Medications in Current Medical Diagnosis & Treatment (Papadakis MA McPhee SJ Rabow MW McQuaid KR, eds) 61e McGraw Hill 2022.

    • Beuduy; CE Winston LG Chapter 46:  Sulfonamides, Trimethoprim, & Quinolones in Basic & Clinical Pharmacology (Katzung BG, Editor; Vanderah TW, Associate editor) 15e McGraw Hill 2021.

    • Gupta K Trautner BW Chapter 135:  Urinary Tract Infections, Pyelonephritis and Prostatitis in Harrison's Principles of Internal Medicine 21st Editions, Loscalzo J Fauci A Kasper D Hauser S Longo D Jameson JL,eds) McGraw Hill LLC, 2022.

    • Jawetz, Melnick, & Adelberg's Medical Microbiology (Riedel A Hobdfen JA Miller S Morse SA Mietzner TA Detrick B Mitchell TG Sakanari JA Hotez D Mejia R) 28e, 2019.

    • Kubiak DW Arnaout RA Hammond SP Pharmacology of Bacterial and Mycobacterial Infections:  Cell Wall Synthesis in Principles of Pharmacology:  The Pathophysiologic Basis of Drug Therapy. (Golan DE, editor-in chief, Armstrong EJ Armstrong AW, associate editors) 4e Wolters Kluwer 2017