SET 9 - Hauer PDF

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SET 9 Paul Ehrlich 1904 - developed concept of selective toxicity and effectively treated African sleeping sickness

Sahachiro Hato 1910 - effectively treated syphilis

Domagk, Jacques, and trefouel 1935 - discovered sulfa drugs

Ernest Duchesne 1896 - first discovered penicillin but was lost

Alexander Fleming 1928 - credited with discovery of penicillin

Florey, Chain, and Heatley 1939 - demonstrated effectiveness of penicillin and won nobel prize

Selman Waksman 1944 - discovered streptomycin and won nobel prize

ability of drug to kill or inhibit pathogen while damaging host as little as possible Define selective toxicity

grug level required for clinical treatment Define therapeutic dose

drug level at which drug becomes too toxic for patient

Define toxic dose

ratio of toxic dose to therapeutic dose Define therapeutic index

undesireable effects of drugs on host cells Define side effects

attack only a few different pathogens Define narrow-spectrum drugs

attack many different pathogens Define broad-spectrum drugs

kills microbes Define cidal agent

inhibits growth of microbes Define static agent

cidal Is penicillin static or cidal?

lowest concentration of drug that inhibits growth of pathogen Define minimal inhibitory concentration (MIC)

lowest concentration of drug that kills pathogen Define minimal lethal concentration (MLC)

innoculate media with dif concentrations of drug and plate with lowest concentration that showed no growth is MIC Describe dilution susceptibility tests

discs with drugs are placed in petri dishes with a lawn of bacteria, drug diffuses into agar and absorbed by cells which is lethal Describe disk diffusion tests

clear zones of no growth around disks Define zone of inhibition

Kirby-Bauer Method What is the most common disk diffusion test?

E test

Inhibit cell wall, protein, and nucleic acid synthesis as well as block metabollic pathways What are 4 ways drugs affect microbes?

beta-lactam group of antibiotics

cell wall synthesis inhibitors How do beta-lactam antibiotics work?

produce beta-lactamases (penicillinases) which hydrolyze the beta-lactam ring of the drugs How do cells become resistant to beta-lactam antibiotics?

block enzymes that catalyze transpeptidation bonds between peptidoglycan preventing cell wall synthesis and eventual lysis of cell How do penicillins work?

acts only on growing cells What is one drawback of penicillin?

1-5% What percentage of adults in US are allergic to penicillin?

cephalosporins A broad-spectrum antibiotic that can be used by patients that are allergic to penicillin

vancomycin drug of last resort, inhibitor of cell wall synthesis, important in treatment of antibiotic resistant staphylococcal and enterococcal infections

penicillins cephalosporins vancomycin teicoplanin Name 4 drugs that inhibit cell wall synthesis

bind to 30S subunit of ribosome and inhibit translation How do aminoglycoside antibiotcs work?

tetracylcine broad spectrum, bacteriostatic antibiotic that inhibits translation, used to treat acne

tetracycline macrolides chrloramphenicol Name 3 antibiotics that inhibit translation

competitively bind to enzymes blocking pathway How inhibitors of metabolic pathways work?

sulfa drugs trimethoprim Name 2 drugs that inhibit metabolic pathways

inhibit DNA or RNA polymerase or DNA helicase Describe how inhibitors of nucleic acid synthesis works

quinolone Name a drug that inhibits nucleic acid synthesis

fungal cell morphology similiar to human cells Why is treating fungal infections so difficult?

a disease caused by infection with a fungus Define mycoses

inhibit sterol, protein, and DNA synthesis How would a mycoses affect host cells?

amphotericin B 5-flucytosine

fluconazole Name 3 drugs commonly used to treat mycoses

tamiflu drug given to patients if in early stages of flu

inhibitors of reverse transcriptase, fusion, and protease What are 3 mechanisms anti-HIV drugs target?

cocktails of drugs In all cases of treating infections, what have proven to be the most effective treatment?

ability of drug to reach site of infection susceptibility of pathogen to drug ability of drug to exceed MIC What are the main factors influencing the effectiveness of antimicrobial drugs

Arise spontaneously from mutations and are then selected for How does resistance originate?

cocktails of drugs use drugs only when necessary new drugs bacteriophages Describe some ways of overcoming drug resistance

lots of organisms in nature produce natural antimicrobial molecules Where did antimicrobial drugs originate?

satellite colonies What are colonies called that grow in the zone of inhibition?

amino acids - most are made from other organisms, these drugs go into cells and perform a function Most antibiotics can be classified as what types of molecules?

a substrate that has a higher affinity for an enzyme than its natural substrate Define competitive inhibitor

an enzyme that relieves strain while double-strand DNA is being unwound by helicase by introducing negative supercoiling of the circular DNA to counteract the positive supercoiling strain placed on the DNA, performed before replication Describe the function of DNA gyrase

hydrophobic Are most drugs hydrophilic or hydrophobic?

viruses that have single host organisms or mutate slowly What kind of viruses are easy to vaccinate against

large number of antibiotics needed to kill bacteria only one bacteriophage needed to kill bacteria Why are bacteriophages more effective than antibiotics?...