Commonly Used Antimicrobials

Front 1

what is an antimicrobial agent?

Back 1

chemical compounds biosynthetically or synthetically produced which either destroy or usefully suppress the growth or metabolism of a variety of microscopic or submicroscopic forms of life.

Front 2

what is the essential feature of effective antimicrobial agents?

Back 2

the ability to inhibit the growth of microorganisms at concentrations tolerated by the host.

Front 3

what do antimicrobial agents generally target?

Back 3

anatomic structures or biosynthetic pathways unique to microorganisms

Front 4

what is a bactericide?

Back 4

antibacterial which destroys bacteria

Front 5

what is a bacteriostatic agent?

Back 5

an antibacterial that mere suppresses growth

Front 6

what are the four classes of antimicrobial agents?

Back 6

antibacterial, antiviral, antifungal, and antiparasitic

Front 7

what are the two subcategories given for antifungals?

Back 7

fungistat and fungicide

Front 8

what are the two subcategories given for antiparasitic?

Back 8

antiprotozoal and antihelminthic

Front 9

define antibiotic.

Back 9

antimicrobials of microbial origin, most of which are produced by fungi or by bacteria of the genus Streptomyces

Front 10

define antimicrobial.

Back 10

any substance with sufficient antimicrobial activity that it can be used in treatment of infectious diseases.

Front 11

define chemotherapeutic.

Back 11

a broad term that encompasses antibiotics, antimicrobials and drugs used in the treatment of cancer. In the context of infectious diseases, it implies the agent is not an antibiotic.

Front 12

define Minimal inhibitory concentration.

Back 12

a laboratory term that defines the lowest concentration (ug/mL) able to inhibit growth of the microorganism.

Front 13

define minimal bacterial concentration

Back 13

minimum level to kill all of the bacteria.

Front 14

define resistant.

Back 14

organisms that are inhibited by clinically achievable concentrations of an antimicrobial agent.

Front 15

define sensitive.

Back 15

term applied to microorganisms indicating that they will be inhibited by concentrations of the antimicrobic that can be achieved clinically.

Front 16

define spectrum.

Back 16

an expression of the categories of microorganisms against which an antimicrobial is typically active

Front 17

what is a narrow-spectrum? Broad-spectrum?

Back 17

narrow: has activity against only a few organisms.
broad: has activity against organisms of diverse types

Front 18

define susceptible.

Back 18

term applied to microoranisms indicating that they will be inhibited by concentrations of the antimicrobic that can be achieved clinically.

Front 19

what are the five considerations that determine which antimicrobial is appropriate for the infection?

Back 19

1) the infecting organism and its antimicrobial susceptibilities
2) the type of infection
3) host factors (age, drug allergies, renal function, etc)
4) factors associated with antimicrobial agents (dosage, routes of administration, etc)
5) public health considerations

Front 20

what are the three possible sources of antimicrobial agents?

Back 20

biological origin, chemically synthesized and molecular manipulation

Front 21

what common antimicrobial has a biological origin?

Back 21

penicillin

Front 22

T/F
benzyl penicillin is a narrow-spectrum agent.

Back 22

TRUE

Front 23

what affect does benzyl penicillin have on gram positive cocci, gram negative cocci and enteric gram negative bacilli?

Back 23

Gram positive cocci- highly active
Gram negative cocci- highly active
Gram-negative bacilli- little activity

Front 24

If you needed an antibacterial antimicrobic that would inhibit cell wall synthesis, what are your two choices?

Back 24

B-lactams and glycopeptides.

Front 25

If you needed an antibacterial antimicrobic that would inhibit cell Protein synthesis, what are your four choices? what is the acronym?

Back 25

MCAT: Macrolides, Chloramphenicol, tetracyclines, and aminoglycosides

Front 26

If you needed an antibacterial antimicrobic that would inhibit nucleic acid synthesis, what are your four choices? What is the mnemonic?

Back 26

Queen Folate Married Rifampin:
Quinolones
folate inhibitors
metronidazole
rifampin

Front 27

If you needed an antibacterial antimicrobic that would act on the outer and cytoplasmic membrane, what are your two choices?

Back 27

polymyxin B and Colistin

Front 28

what are four subcategories of B-lactam?

Back 28

penicillins, cephalosporins, carbapenems, monobactams

Front 29

what are the two subcategories of glycopeptides?

Back 29

Vancomycin and teicoplanin

Front 30

what enzyme catalyzes the cross-linking of the amino acid side chains?

Back 30

transpeptidase

Front 31

what category of antimicrobials binds to transpeptidase preventing it from carrying out its function?

Back 31

B-lactams

Front 32

which antimicrobial binds directly to the amino acid of the cell wall preventing the binding of transpeptidase?

Back 32

vancomycin

Front 33

what infection is vancomycin used to treat?

Back 33

MRSA: methicillin Resistance Staphylococcous aureus

Front 34

T/F
the ring of the B-lactam is not essential for antibacterial activity.

Back 34

FALSE

It is absolutely essential!

Front 35

T/F
B-lactams can only affect bacteria will cell walls.

Back 35

True.

Front 36

what is the classic example of a bacteria that is not sensitive to B-lactams?

Back 36

mycoplasm

Front 37

how are b-lactams classified?

Back 37

by chemical structure

Front 38

what is a B-lactam with one or more rings called?

Back 38

monobactam

Front 39

what is B-lactam with a ring that is fused to a five member penem ring?

Back 39

penicillins and carbapenems

Front 40

what is a b-lactam with a ring fused to a six member cephnem ring?

Back 40

cephalosporins

Front 41

from what genus is penicillium derived from?

Back 41

streptomyces

Front 42

which type of penicillin is injectible? which can be taken orally?

Back 42

injectible: Penicillin G
Orally: Penicillin V

Front 43

what is penicillin G active against?

Back 43

gram positive organisms, gram negative cocci, and some spirochete

Front 44

what can broad spectrum penicillins do?

Back 44

penetrate the outer membrane of some Gram-negative bacteria

Front 45

what are the four types of penicillins?

Back 45

penicillin G, Penicillin V, broad spectrum penicillins and penicillinase-resistance pencillins

Front 46

what are the three subcategories of broad spectrum penicillins?

Back 46

ampicllin, carbenicillin, and ticracillin

Front 47

what are the three subcategories of penicillnase-resistance penicillins?

Back 47

methicillin, nafcillin, oxacillin

Front 48

what is the purpose of penicillinase-resistant penicillins?

Back 48

inhibits enzyme penicillinase produced by certain pathogens

Front 49

how are cephlosporins classifed?

Back 49

by generation

Front 50

what does a fourth generation cephalosporin have in relation to a first generation?

Back 50

a wider spectrum

Front 51

what is manipulated in cephalosporins to create more generations?

Back 51

side chain

Front 52

what is the activity of the first generation cephalosporins?

Back 52

gram positive organisms that resembles that of penicillinase-resistance penicillin

Front 53

what are the two subcategories of cephalosporins?

Back 53

cephazolin and cephalexin

Front 54

what is the activity of the second generation cephalosporins?

Back 54

expanded activity against B-lactams producing Gram-negative organisms. Expanded activity against enterobacteriacea species and activity against anaerobes.

Front 55

what is the number one normal flora in the gut that second generation cephalosporins act against?

Back 55

Bacteroides fragilis

Front 56

what are the three third generation cephalosporins?

Back 56

ceftriaxone, cefotaxime and cetazidime

Front 57

what are the two subcategories of second generation cephalosporins?

Back 57

cefoxitin and cefaclor

Front 58

what is ceftazidime used against? what is the clinically correlation?

Back 58

pseudomas aeruginosa; chosen in a febrile bone marrow transplant patient.

Front 59

what can ceftriaxone or cefotaxime be used against?

Back 59

childhood meningitis

Front 60

what are the three major causes of childhood meningitis?

Back 60

Neisseria meningitidis, streptococcus pneumoniae, and hemophilus influenzae

Front 61

what is the most common cause of meningitis in neonatals?

Back 61

steptocococcus pneumoniae

Front 62

what is the most common cause of meningitis period?

Back 62

neisseria meningitidis

Front 63

what is the activity of a fourth generation cephalosporin?

Back 63

wide spectrum antimicrobial effects: enhanced ability to penetrate the outer membrane of many gram-negative bacteria; resistant to many Gram-negative B-lactamases. Also active against wider spectrum of enterobacteriaceae.

Front 64

what is the only fourth generation cephalosporin?

Back 64

cephepime

Front 65

what are the two types of carbapenems? which one requires a coadministration of cilastatin and why?

Back 65

imipenem and meropenem; imipenem requires the cilastatin coadministration because imipenem is rapidly hydrolyzed by renal tubular dehydropeptidase 1 and cilastatin is an inhibitor of that enzyme.

Front 66

which B-lactam has the broadest spectrum? why?

Back 66

carbapenems: combination of easy penetration of gram-negative and gram-positive bacterial cells and a high level of resistance to B-lactamases.

Front 67

what was the first monobactum licensed in the US?

Back 67

aztronam

Front 68

to what specifically is the spectrum of aztreonam limited to?

Back 68

aerobic and facultatively anaerobic gram-negative bacteria

Front 69

why are anaerobic superinfections and major distortions of the bowl flora less common with aztreonam?

Back 69

because aztreonam does not produce a general suppression of gut anaerobes

Front 70

what is the main use of glycopeptides?

Back 70

against multiresistant Gram-positive infections including those caused by strains of staphylococci that are resistant to the penicillinase resistant penicillins and cephalosporins.

Front 71

where do the aminoglycosidases bind to in order to prevent protein synthesis of microbials?

Back 71

bind to multiple sites on both the 30S and 50S ribosomes--> preventing tRNA from forming initiation complexes.

Front 72

where do tetracyclines bind in relation to protein synthesis?

Back 72

30S ribosomes

Front 73

what does chloramphenicol block?

Back 73

formation of the peptide bond between the amino acids

Front 74

what does erythomycin and macrolides block?

Back 74

translocation of tRNA from the acceptor to the donor side on the ribosome.

Front 75

what are three important aminoglycosides used?

Back 75

steptomycin, gentomyocin and aminocasin

Front 76

what do sulfonamides block?

Back 76

folate precursors of DNA synthesis

Front 77

what affect does metronidazole have on DNA?

Back 77

inflicts breaks in the DNA itself

Front 78

what does rifampin inhibit?

Back 78

synthesis of RNA from DNA by inhibiting DNA polymerase

Front 79

what do quinolones inhibit?

Back 79

DNA topoisomerase and thus prevent the supercoiling required for the DNA to "fit" inside the bacterial cell.

Front 80

what affect to polymyxin B and colistin have on cell membranes?

Back 80

they bind to cell membranes of susceptible Gram-negative bacteria and alter their permeability resulting in loss of essential cytoplasmic components and bacterial death.

Front 81

polymyxin B and colistin use are now limited to what kind of applications?

Back 81

topical

Front 82

what are the consequences of indiscriminate use of antibacterial drugs?

Back 82

- can lead to a plethora of side effects and drug interactions
- hypersensitivity reactions
- microbial superinfections
- drive up the cost of health care
- antagonisms between certain agents
- foster the emergence of bacterial resistance, rendering previously valuable drugs useless

Front 83

what are the unique viral events that occur in viral replication?

Back 83

attachment, penetration, uncoating, RNA-directed DNA synthesis (reverse transcription) and assembly and release of the intact virion.

Front 84

how can viral attachment be inhibited?

Back 84

by having an antibody bind to the extracellular virus and prevent the attachment of the virus to a cell receptor on the host cell

Front 85

how can we inhibit penetration of the virus?

Back 85

by using a neuraminidase inhibitor which will inhibit the fusion of an viral enveloped protein with the host cell membrane.

Front 86

what are the 2 neuraminidase inhibitors that selectively inhibit the neuraminidase of influenza A and B viruses? which one is oral and which one is a spray?

Back 86

oseltamivir (oral) and zanamivir (spray)

Front 87

what does neuraminidase do?

Back 87

aids in the release of newly formed viral particles form infected cells

Front 88

what are the agents in the antiviral inhibiting viral uncoating group? which one should be used cautiously with renal impaired patients?

Back 88

Rimantadine and amantadine (cautious in renal impaired patients)

Front 89

what is the activity of rimantadine and amantadine? How effective are these antivirals?

Back 89

active against ONLY influenza A. 70% effective in preventing influenza A illness when given daily during influenza outbreaks.

Front 90

what are idoxiuridine and trifluorothymidine used to treat? what type of treatment?

Back 90

herpetic keratitis; topical

Front 91

what is acyclovir used to treat? how?

Back 91

herpes simplex viruses (1 and 2), varicella zoster virus (less than HSV), and cytomegalovirus (least). Inhibits the thymidine kinase.

Front 92

what is gancyclovir used to treat? what is it in relation to acyclovir?

Back 92

cytomegalovirus and other herpes viruses; an analogue of acyclovir

Front 93

what is a classic example of an inhibitor of viral RNA synthesis/

Back 93

ribavirin

Front 94

this drug is standard treatment for HCV infections and is somewhat beneficial in RSV infections of infants.

Back 94

ribavirin

Front 95

what is the job of foscarnet? how?

Back 95

to inhibit viral DNA polymerase by blocking the pyrophosphate-binding site of viral DNA polymerase.

Front 96

what are interferons?

Back 96

host cell encoded proteins synthesized in response to double stranded RNA.

Front 97

what do interferons inhibit? what does it protect?

Back 97

viral protein synthesis and protects uninfected cells

Front 98

what are interferons effective against?

Back 98

hepatitis C and B and papilloma virus infections

Front 99

what are higher rates of replication associated with?

Back 99

higher rates of spontaneous mutation

Front 100

what is the selective pressure of the drug?

Back 100

probability of mutation is increased to the point that virus replication is substantially reduced

Front 101

T/F
single stranded RNA viruses have a slower rate of mutation than double.

Back 101

false.....

single has a higher rate.

Front 102

T/F
some genes within a virus are more susceptible than others.

Back 102

true :)

Front 103

what are the two groups of chemotherapeutics against parasitic infections?

Back 103

antiprotozoan drugs and antihelminthic drugs

Front 104

what do antiprotozoan drugs do?

Back 104

interfere with nucleic acid synthesis (majority) or with carbohydrate metabolism (less common)

Front 105

what do antihelminthic drugs do?

Back 105

compromise worm's glycolytic pathways or neuromuscular function

Front 106

what are arsenicals used against?

Back 106

trypansomiasis

Front 107

what do heavy metals do to parasitic enzymes?

Back 107

binds and inactivates the SH group

Front 108

what are the four antimalarial quinolones? which one is the safest?

Back 108

quinine, 4-aminoquionolines (safest), 8-aminoquionolines, and 4-quinolinemthanols

Front 109

what do antimalarial quinolones do?

Back 109

accumulate in the parasitized host cells and inhibit nucleic acid synthesis. Also inhibits heme peroxydase leading to accumulation of heme metabolites lethal to parasites.

Front 110

which antimalarial quinolones is used against chloroquine resistant parasites?

Back 110

4- quinolinemethanols

Front 111

what does quinone inhibit?

Back 111

parasites electron transport chain resulting in specific blockade of pyrimidine biosynthesis.

Front 112

what are the two example of folate antagonists?

Back 112

sulfonamide and trimethoprim

Front 113

what does benzimidazole inhibit? what does protozoan does this taregt?

Back 113

fumerate reductase and polymerization of tubulin (cytoskeleton protein); helminths

Front 114

what member of the benzimidazole group is used against intestinal nematodes and trichinosis?

Back 114

thiabendozole

Front 115

which member of the benzimidazole group is effective against cestodes (tapeworms, hymenolepis, and echinococcus)?

Back 115

mebendzole

Front 116

what is praziquantel used to treat?

Back 116

schistosomiasis and clonorchiasis.