MMSC438 Final Exam 2024 with correct Question and Answers

MMSC438 Final Exam 2024 with correct Question and Answers Antibiotic vs. antimicrobial -antibiotic: substance produced by a MO that inhibits the growth or kills other MOs -antimicrobial agent: substance produced by MOs or synthetic means that inhibits the growth or kills MOs (antibacterial, antiviral, antifungal, ant parasitic) Properties of antimicrobial agent -selectively toxic: active against targeted causative agent but not harmful to patient (limited side effects, no allergies, low toxicity, and low impact on normal biota) -able to penetrate/distribute to infected tissues -active concentrations of drug are achieved rapidly in body (active in blood, body fluids and exudate) -organisms do not develop resistance -cost effective Cell wall synthesis inhibitors -beta lactam: penicillin, cephalosporin, carbapenem, monobactam -glycopeptide: vancomycin, teicoplanin Beta lactam mechanism of action Irreversible binding to enzymes responsible for mature peptidoglycan molecule -Trans peptidase/transglycolase (AKA penicillin binding proteins, PBPs): enzymes responsible for incorporation f glucans and AAs into peptidoglycan penicillins (beta-lactam) -the "-cillins" -penicillin G and V, ampicillin, amoxicillin, methicillin, ticarcillin -beta lactam ring present cephalosporin generations (beta-lactam) -the "cephs/cefs" -1st gen: mostly active against GP; ex: cephalexin, cephalothin -2nd gen: active against GP and GN (including H. influenzae, Enterobacter and some Neisseria); ex: cefoxitin, cefotetan -3rd gen: active against GN and can penetrate into CSF; ex: cefotaxime, ceftriaxone, ceftazidime -4th gen: active against more GN, many GP and has b-lactamase stability; ex: cefepime -5th gen: like 4th gen but more GP coverage and b-lactamase stability, active against MRSA; ex: ceftaroline monobactams (beta-lactam) -ex: aztreonam carbapenems (beta-lactam) -the "penems" -ex: ertapenem, imipenem, meropenem glycopeptides inhibit peptidoglycan synthesis by binding to the 2 terminal d-alanine on the pentapeptide chain, which blocks the cross-linking vanocmycin and teicoplanin -active against GP only (ex. MRSA and C. dif) -too large to enter GN outer membrane plasma membrane damage (antimicrobial mechanisms of action) polypeptide family: polymyxin and colistin (break apart GN outer membranes) protein synthesis inhibitors -tetracycline -macrolide -aminoglycoside -chloramphenicol -lincosaminde -ketolide tetracycline drugs -tetracycline -doxycycline macrolide drugs -erythromycin