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Bacteriology Exam 1 > Antimicrobial Agents & Antibiotics > Flashcards

Antimicrobial Agents & Antibiotics Flashcards

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1
Q

What are the Different Mechanisms of Action of Antimicrobial Agents & Antibiotcs

A

Inhibition of Cell Wall Synthesis, Inhibition of Nucleic Acid Synthesis, Metabolites, Inhibition of Protein Synthesis, and Disruption of Cytoplasmic Membrane

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2
Q

Which Antimicrobial Agents/Antibiotics act by Inhibition of Cell Wall Synthesis

A

Penicillins, Bacitracin, Cephalosporins, Vancomycin, Carbapenam

“P-B-C-V-C stop dat Cell Wall Syntheesee”

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3
Q

Which Antimicrobial Agents/Antibiotics act by Disruption of Cytoplasmic Membrane

A

Polymyxins

“Mix up dat cytoplasmic membrane”

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4
Q

Which Antimicrobial Agents/Antibiotics act by Inhibition of Protein Synthesis

A

Aminoglycosides, Phenicols, Lincosamides, Macrolides, Pleuromutilins, Aminocyclitols, Tetracyclins

“Co-O’s and ‘Cyclins Stop Protein Syn.”

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5
Q

Which Antimicrobial Agents/Antibiotics act as Metabolites

A

Diaminopyrimidines, Sulfonamides

“Diamino’s and Sulfonamides act as metabolites”

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6
Q

Which Antimicrobial Agents/Antibiotics act by Inhibition of Nucleic Acid Synthesis

A

Novobiocin, Nitroimidazoles, Rifamycin, Quinolones, Fluoroquinolones,

“N-N-R-F-Quin-Quins stop that Nucleic Acid Syn.”

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7
Q

Which Antimicrobial Agents/Antibiotics affect only Gram (+)

A

Beta-Lactams, Lincosamides, Macrolides, Pleuromitilins, Diaminopyrimidines

“B-L-M-P-D only affect + B’s

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8
Q

Which Antimicrobial Agents/Antibiotics affect only Gram (-)

A

aminocyclitols, aminoglycosides, sulfonamides

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9
Q

Which Antimicrobial Agents/Antibiotics are broad spectrum

A

Fluoroquinolones, Phenicols, Tetracyclins, Sulfonamides, Diaminopyrimidines,Ceftiofur

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10
Q

What are the different Fluoroquinolone groups and what spectrum are they

A

Group I: narrow
Group II: broad
Group III: broad, including strict anaerobes but not approved in the US

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11
Q

Fill in the blank:

1) Additive antibiotics have ______ when used together.
2) Antibiotics that have greater effect when used together are said to have ______.
3) ______ antibiotics have negative effects when used together

A

1) no benefit, no greater effect
2) synergism
3) Antagonistic

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12
Q

4 Indications for antimicrobial combinations

A

1) polymicrobial infections
2) serious infections
3) overcome enzymatic destruction of drugs
4) decrease toxicity and provide broad spectrum activity

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13
Q

Give examples of antimicrobials that are used fro growth promotion and state why they are used (why is resistance not as big of a concern)

A

Ionophores (monensin), Quinoxalines (Carbadox), Glycophospholipid (bambermycin)

these drugs not used in humans

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14
Q

What are the 4 basic mechanisms of antimicrobial resistance

A

Modify target of Abx, Destroy/inactivate Abx, Develop resistant biochemical pathways, Pump Abx out of cell

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15
Q

List 3 ways in which antimicrobial resistance can be transferred

A

Transformation, transduction, conjugation

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16
Q

T/F? Normal flora do not serve as reservoirs for resistant genes

A

False, they DO

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17
Q

Can a single R plasmid confer resistance to multiple antibiotics

A

Yes, often contain multiple several different genes encoding different antibiotic-inactivating enzymes

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18
Q

What methods are approved for antimicrobial susceptibility testing

A

Disk Diffusion, Agar dilution, broth dilution

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19
Q

Which drug(s) are beta-lactams

A

Have a four-membered cyclic amide ring, called β-lactam. Include Penicillins, Cephalosporins, Carbapenams and Monobactams.

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20
Q

Which drug(s) are aminoglycosides

A

Amikacin, Gentamicin, Kanamycin, Neomycin, Streptomycin.

Contain two or more amino monosaccharides connected by glycosidic linkages

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21
Q

Which drug(s) are aminocyclitols

A

Spectinomycin

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22
Q

Which drug(s) are macrolides

A

Erythromycin, spiromycin, tylosin, and azithromycin

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23
Q

which drug(s) are natural tetracyclines? Semisynthetic?

A

natural: tetracycline, chlortetracycline, oxytetracycline
semisynthetic: doxycycline and minocycline

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24
Q

Which drug(s) are phenicols

A

chloramphenicol and florfenicol

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25
Which drug(s) are lincosamides
lincomycin, clindamycin, and pirilmycin
26
Which drug(s) are glycopeptides and what are they used for
vancomycin, treat MRSA
27
Which drug(s) are cyclic peptides
Polymyxin
28
Which drugs are quinolones and fluoroquinolones
Q's: Naladixic acid F's: all the 'floxacins - enrofloxaxin, norfloxacin, ciprofloxacin
29
Which Macrolides are natural, semisynthetic, and synthetic
Natural: Erythromycin, Spiramycin, Tylosin Semisynthetic: Tulathromycin, Tilmicosin, Tildipirosin, Tylvalosin
30
Describe the general purpose of each enzyme and their specific actions: hyaluronidase, coagulase, streptokinase
These enzymes are virulence factors that help bacteria cause disease inside the host hyaluronidase: breaks down hyaluronic acid, intercellular cement. This allows the pathogen to get past protective epithelial cells and penetrate into deeper, more vulnerable tissues to start an infection. coagulase: causes fibrin formation to protect the bacteria from the host's defenses (such as phagocytes) streptokinase: dissolves the fibrin clot formation from coagulase and allows bacteria to spread to other tissues/blood
31
Which antibiotic has the ability to penetrate encapsulated abscesses? What diseases is it used to treat? What is its mechanism of action?
Rifampin, leprosy, tuberculosis, inhibits synthesis of mRNA
32
What are 2 types of immunization
passive: administration of Ab's or antibody containing serum for rapid protection/treatment active: administration og antigen to stimulate specific antibody production
33
What are mutant live vaccines
modified live vaccines, usually modified so that they are temperature-sensitive (can't grow in host) or auxotrophic (require certain nutrients that aren't found in the host to grow)
34
What kind of vaccines are usually administered with an adjuvant
killed or inactivated vaccines
35
Define bacterin and autogenous bacterin
bacterin is a killed whole-cell vaccine. Autogenous means the vaccine was made from an isolate from a farm or herd in which the vaccine is used
36
Give an example of an A1B1 toxin, A2B toxin, and AB5 toxin What do the A & B mean
A1B1: tetanus, botulism A2B: anthrax AB5: Shiga toxins Toxins are composed of A&B subunits, A confers toxicity and B is what allows toxin to bind to the receptors on the cell surface. Only the A portion enters the cell
37
Name 3 common signs of endotoxin in the body
fever, intravascular coagulation, shock
38
List 2 serious conditions or clinical syndromes induced by high [endotoxin]
disseminated intravascular coagulation & shock
39
List what may be T/F about this statement: penicillins can penetrate the outer membrane of gram positive bacteria What would a correct version say?
penicillins can NOT penetrate the outer membrane of gram NEGATIVE bacteria gram(+) do not have OM
40
What is the mechanism of action for enterotoxins
disrupt cAMP and cGMP pathways
41
What do you call the time between entry of a pathogen and start of clinical signs
incubation period
42
What is the difference between an endemic and epidemic
endemic: disease occurring persistently in a population or area epidemic: disease occurring in a large number of people at a particular time
43
Define latent infection
pathogen remains inactive until conditions become favorable to cause an infection
44
Difference between obligate and facultative pathogens
Facultative pathogens can grow inside and outside of cells. Can be cultured in bacteriological media Obligate pathogens can only grow inside cells. Can be cultured in lab in tissue culture media
45
list the ways a facultative intracellular pthogen can survive inside a phagocytic cell
evasion - secrete enzymes (hemolysin) to break out of phagolysosome and survive in cytoplasm inhibition of phagosome-lysosome fusion by expressing proteins that disrupt cell signaling survive harsh conditions within phagolysosome
46
What are the different categories of exotoxins and give examples of each
1) Disrupt cell membrane: hemolysins 2) Inhibit protein synthesis: Shiga toxins 3) Disruption of 2nd messenger pathways: enterotoxins of E. coli and Salmonella 4) Superantigens: enterotoxins from staphylococcus spp. 5) Act as proteases: neurotoxins - tetanus & botulinum toxins
47
Name the common modes of infection by pathogens
Ingestion, Inhalation, Venereal, Vector-borne, Direct entry
48
T/F, Carbapenams are used for small animals on label and are narrow spectrum. Give 2 examples of carbapenams
F: they are broad spectrum and off label for small animal, in humans used as drug to treat multi-drug resistant bacterial infections. Imipenam and meropenam
49
Difference between using antibiotics therapuetically and for metaphylaxis
Therapeutic = all and only sick animal given antibiotics Metaphylaxis = treating clinically healthy animals in a herd after onset of disease
50
Give 2 examples of beta-lactamase inhibitors and what is the magnitude of their antimicrobial activity
clavulonic acid and sulbactam. None to little antimicrobial activity
51
Which classes of antibiotics/antimicrobial agents are synthetic
Quinolones, fluoroquinolones, sulfonamides, diaminopyrimidines, nitroimidazoles, nitrofurans
52
How do penicillins work
these drugs bind to an enzyme, transpeptidase (penicillin binding proteins), preventing cross linking of glycan molecules that for the cell wall
53
Are Doxycycline and Minocycline natural or synthetic? What advantages do they have over other tetracyclines?
they are more lipid soluble and more highly bound to plasma proteins which allow them to have a longer retention time in the body
54
Are tetracyclines bacteriocidal or bacteriostatic
bacteriostatic
55
# Choose correct answers: Chloramphenicol is a narrow/broad spectrum antibiotic with bacterio-static/cidal activity.
Broad, bacteriostatic
56
What kind of side effects do you have to worry about with chloramphenicol
toxicity, causes aplastic anemia and neutropenia in humans
57
Which antibiotic is only used in animals, is active against gram + bacteria, and is given via intramammary infusion to treat mastitis
Pirlimycin
58
Why are polymyxins only given as a topical
they cause systemic toxicity
59
Name this antibiotic: This antibiotic inhibits ______, an enzyme involved in supercoiling of DNA. It is typically used in combination with penicillins and tetracylcines. Give an example of another antibiotic class that shares its mechanism of action with this drug.
novobiocin, DNA gyrase Nitroimidazole: metronidazole Rifamycin: Rifampin Fluoroqionolone: enrofloxacin
60
List each enzyme's function DNA gyrase: Topoisomerase I Topoisomerase IV
DNA gyrase (topoisomerase II): introduces negative strands (coiling) Topoisomerase I: removes supercoiling Topoisomerase IV: unlinks the two circular molecules of DNA during replication
61
Which group of fluoroquinolones are not approved in the US: Groups I, II, or III
Group III
62
Which fluoroquinolone is used extra-label in small animals
ciprofloxacin
63
Why are nitroimidazoles used in companion animals and not food animals?
it has potential carcinogenicity
64
Which group of drugs were the first synthetic antimicrobial agents used to treat bacterial infections
Sulfonamides
65
True or False: ionophores have no therapeutic activity against bacterial infections
True
66
Which 2 kinds of drugs have antagonistic activity? additive?
penicillin and tetracyclines are antagonistic | penicillin and streptomycin are additive
67
Which antibiotics are used off label in small animals
Imipenam, Meropenam, Azithromycin, Ciprofloxacin
68
Which rRNA sequence is used for bacteria? Fungi?
16S rRNA for bacteria, 18S rRNA for fungi
69
Do gram (+) bacteria, specifically firmicutes, have a high or low GC content? What about Actinobacteria?
Firmicutes have low GC and Actinobacteria have high GC
70
What would be some examples of phenotypic characteristics of bacteria
cell size, shape, arrangement, staining characteristics, growth characteristics, biochemical reactions,
71
Do bacteria tend to take up basic or acidic dyes better?
Basic dyes because bacteria are negatively charged
72
What are 3 staining techniques used for bacteria
Simple, differential, special
73
What kind of bacterial infections are acid-fast stains used for and what cell structure does this stain work on?
Mycobacterial infections, mycolic acid (waxy coat)
74
What kinds of structures do special stains target
Capsules (or background of capsule as capsule itself does not stain well), spores, flagella
75
What dye is used to stain spores
Malachite green
76
What are some typical types of serological tests
Neutralization, Precipitation, Agglutination, Western Blot
77
What kind of serological testing do you use for toxins
Neutralization
78
What are the 3 steps to PCR identification
Denaturation, Annealing, Elongation aka Separation, Binding, Synthesis
79
If the first cycle of PCR yields 4 copies, how many copies does the 3rd cycle yield
16 copies
80
What are the 4 different antigens on bacteria aka Serotypes
Somatic (O), Capsular (K), Flagellar (H), Fimbrial (F)
81
What is the mechanism of action for Ceftiofur, narrow or broad specturm, and what diseases is it used for
Inhibits cell wall synthesis, broad spectrum, treat respiratory infections for large animals, foot rot in cattle
82
Choose/fill in correct answers: Aminoglycosides are primarily effective against gram (+)/(-) bacteria, and require _____ to be transported into the cell. Thus, they are effective/ineffective against aerobes/anaerobes. These drugs have a antagonistic/synergistic effect when used with Beta-lactams
gram (-), oxygen, ineffective, anaerobes, synergistic
83
What class of drug is Spectinomycin in? What is it used for? Is it bacteriostatic or bacteriocidal?
Aminocyclitols, bacteriostatic, respiratory infections in cattle, and E. coli infections in pigs, avian salmonellosis
84
N-acetyl transferase and phosphorylase are enzymes that confer resistance to which class of drugs
Aminoglycosides
85
What is Tylosin used for? What is its mechanism of action and what class is it in? Hint: Its used for cattle.
Cattle: Pneumonia, foot rot, metritis, pink eye, mastitis
86
Which semisynthetic macrolide is used for respiratory infections in cattle and swine and is given as a single dose prophylactically to cattle upon arrival at a feedlot. Why is this drug not used in humans?
Tilmicosin Very toxic in humans (fatal!) Affects the heart
87
What is Tylvalosin used for?
Penumonia caused by Mycoplasma hyopneumoniae in swine, Swine proliferative enteritis caused by Lawsonia intracellularis, Mycoplasmosis caused by M. gallisepticum and M. synoviae in poultry

Bacteriology Exam 1 (1 decks)

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