Antibiotic Activty Flashcards
Chloramphenicol is classified as a very broad-spectrum antibiotic. Against which of the following groups does it have excellent activity?
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive anaerobes
D) Gram-negative anaerobes
Answer: A, B, C, D
(Chloramphenicol has excellent activity against all four bacterial groups.)
Third-generation fluoroquinolones have excellent activity against which of the following groups of bacteria?
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive anaerobes
D) Gram-negative anaerobes
Are they consider a broad spectrum class of antibiotic?
Answer: B
(They have excellent activity against Gram-negative aerobes but only moderate activity against Gram-positive aerobes and limited activity against anaerobes.)
Yes they are considered very broad!
Third- and fourth-generation cephalosporins have very broad activity. Which category of bacteria is least affected by them?
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive anaerobes
D) Gram-negative anaerobes
Answer: D
(They have excellent activity against Gram-positive and Gram-negative aerobes and moderate activity against Gram-positive anaerobes but limited activity against Gram-negative anaerobes.)
Tetracyclines are considered very broad. They have moderate activity against which type(s) of bacteria?
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive anaerobes
D) Gram-negative anaerobes
Answer: A, B, C, D
Trimethoprim-sulfonamides are classified as broad-spectrum antibiotics. Against which bacterial category do they have poor activity?
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive anaerobes
D) Gram-negative anaerobes
Answer: C, D
(They have excellent activity against Gram-positive and Gram-negative aerobes but poor activity against anaerobes.)
Aminoglycosides are intermediate-spectrum antibiotics. Why are they ineffective against anaerobic bacteria?
A) They are inactivated by anaerobic conditions.
B) They require oxygen for bacterial uptake.
C) Anaerobic bacteria have resistance genes against aminoglycosides.
D) They do not penetrate anaerobic bacterial cell walls.
Answer: B
(Aminoglycosides require oxygen-dependent transport mechanisms for bacterial uptake, making them ineffective against anaerobes.)
Penicillins G and M have narrow-spectrum activity. Against which category of bacteria do they have excellent activity?
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive anaerobes
D) Gram-negative anaerobes
Answer: A, C
(Penicillin G is highly effective against Gram-positive aerobes and anaerobes but has poor activity against Gram-negative bacteria.)
Metronidazole is a narrow-spectrum antibiotic. Which of the following statements is true about its spectrum?
A) It has excellent activity against Gram-positive aerobes.
B) It has excellent activity against Gram-negative aerobes.
C) It has excellent activity against anaerobes.
D) It has excellent activity against both Gram-positive and Gram-negative aerobes.
Answer: C
(Metronidazole is highly effective against anaerobes but has no significant activity against aerobes.)
Colistin is a narrow-spectrum antibiotic. Which type of bacteria does it primarily target?
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive anaerobes
D) Gram-negative anaerobes
Answer: B
(Colistin has excellent activity against Gram-negative aerobes but is ineffective against other bacterial categories.)
Ampicillin and amoxicillin (± clavulanate) are classified as broad-spectrum antibiotics. Against which bacterial group do they have excellent activity?
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive anaerobes
D) Gram-negative anaerobes
A and C
Ampicillin and amoxicillin have broad activity against aerobes and Gram-positive anaerobes but limited activity against Gram-negative anaerobes unless combined with clavulanate
First-generation cephalosporins, such as cefalexin, have broad-spectrum activity. Against which bacterial group do they have excellent activity?
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive anaerobes
D) Gram-negative anaerobes
Answer: A and C
(First-generation cephalosporins are highly effective against Gram-positive bacteria but have only moderate activity against Gram-negative aerobes and anaerobes.)
They are a broad class of antibiotic.
Macrolides (e.g., erythromycin) and lincosamides (e.g., clindamycin) are classified as intermediate-spectrum antibiotics. Against which bacterial group do they have poor activity?
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive anaerobes
D) Gram-negative anaerobes
Answer: B
(Macrolides have excellent activity against Gram-positive aerobes and anaerobes but limited to no activity against Gram-negative aerobes.)
Metronidazole is a narrow-spectrum antibiotic primarily used to treat:
A) Gram-positive aerobes
B) Gram-negative aerobes
C) Gram-positive and Gram-negative anaerobes
D) All of the above
Answer: C
(Metronidazole is highly effective against anaerobes but has no significant activity against aerobes.)
Clavulanic acid is often added to amoxicillin to:
A) Increase its spectrum against Gram-positive aerobes
B) Improve penetration into tissues
C) Provide activity against β-lactamase-producing bacteria
D) Make it effective against anaerobes
Answer: C
(Clavulanic acid is a β-lactamase inhibitor that extends the activity of amoxicillin against resistant bacteria.)
How does metronidazole exert its antibacterial effect?
A) Inhibiting bacterial cell wall synthesis
B) Disrupting bacterial DNA through reactive metabolites
C) Inhibiting ribosomal protein synthesis
D) Blocking folic acid synthesis
Answer: B
Answer: B
(Metronidazole is reduced in anaerobic environments to reactive metabolites that damage bacterial DNA.)
Which of the following bacteria are classified as Gram-positive aerobes? (Select 5)
A) Staphylococcus pseudintermedius
B) Escherichia coli
C) Streptococcus canis
D) Pseudomonas aeruginosa
E) Corynebacterium spp.
F) Clostridium perfringens
G) Rhodococcus equi
H) Bordetella bronchiseptica
Answer:
A) Staphylococcus pseudintermedius
C) Streptococcus canis
E) Corynebacterium spp.
G) Rhodococcus equi
F) Clostridium perfringens (while primarily anaerobic, it can tolerate some oxygen and is sometimes considered facultative)
Identify 5 Gram-negative aerobic bacteria commonly encountered in veterinary medicine.
A) Escherichia coli
B) Staphylococcus aureus
C) Pasteurella multocida
D) Clostridium difficile
E) Bordetella bronchiseptica
F) Pseudomonas aeruginosa
G) Actinomyces spp.
H) Proteus mirabilis
Answer:
A) Escherichia coli
C) Pasteurella multocida
E) Bordetella bronchiseptica
F) Pseudomonas aeruginosa
H) Proteus mirabilis
Which of the following are classified as Gram-positive anaerobes? (Select 5)
A) Clostridium perfringens
B) Fusobacterium necrophorum
C) Bacteroides spp.
D) Clostridium difficile
E) Peptostreptococcus spp.
F) Actinomyces spp.
G) Streptococcus equi
Answer:
A) Clostridium perfringens
D) Clostridium difficile
E) Peptostreptococcus spp.
F) Actinomyces spp.
G) Streptococcus equi (facultative anaerobe but capable of anaerobic growth in certain conditions)
Identify 4 Gram-negative anaerobic bacteria commonly found in veterinary infections.
A) Fusobacterium necrophorum
B) Bacteroides spp.
C) Pseudomonas aeruginosa
D) Clostridium difficile
E) Porphyromonas spp.
F) Escherichia coli
G) Dichelobacter nodosus
Answer:
A) Fusobacterium necrophorum
B) Bacteroides spp. E) Porphyromonas spp.
G) Dichelobacter nodosus
Some bacteria can switch between aerobic and anaerobic respiration, making them facultative anaerobes. Which of the following bacteria belong in this category?
A) Staphylococcus aureus
B) Pseudomonas aeruginosa
C) Escherichia coli
D) Bacteroides fragilis
E) Proteus mirabilis
A) Staphylococcus aureus
C) Escherichia coli
E) Proteus mirabilis
(Facultative anaerobes can use oxygen when present but can also grow anaerobically by fermenting sugars or using alternative electron acceptors.)
