Antibiotics Flashcards by M R

What does the term antibiotic imply?

Against life, primarily targeting bacterial infections

Antibiotics can also include substances that are not strictly antibiotics, such as sulfonamides.

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What is the first discovered antibiotic?

Penicillin

Discovered by Alexander Fleming, penicillin marked the beginning of modern antibiotic therapy.

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What are sulfonamides classified as?

Antibiotics

They were discovered from nitrogen mustards and used before the discovery of penicillin.

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True or false: Antivirals are considered antibiotics.

FALSE

Antivirals target viruses, which are not living organisms, unlike antibiotics that target bacteria.

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What is the primary method for determining antibiotic sensitivity?

Culture and sensitivity test

This involves culturing the organism and testing its growth against various antibiotics.

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What are the two main classes of bacteria?

Gram-positive
Gram-negative

The classification is based on their cell wall structure and response to Gram staining.

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What color do gram-positive bacteria stain in a Gram stain?

Purple

This is due to their thick peptidoglycan cell wall retaining the crystal violet dye.

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What is the role of lipopolysaccharide (LPS) in gram-negative bacteria?

Endotoxin

When released into the bloodstream, LPS can cause endotoxic shock.

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Common gram-positive infections include which bacteria?

Staphylococcus
Streptococcus

These bacteria can cause various infections depending on their site of introduction.

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Common gram-negative bacteria associated with the gastrointestinal tract include:

E. coli
Klebsiella
Proteus
Enterobacter

These organisms can cause infections based on their introduction site.

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What is the difference between broad spectrum and narrow spectrum antibiotics?

Broad spectrum: Effective against both gram-positive and gram-negative bacteria
Narrow spectrum: Effective against specific types of bacteria

Spectrum of activity refers to the range of bacteria an antibiotic can effectively target.

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What does selective toxicity refer to in antibiotics?

Toxic to bacteria, not to humans

Antibiotics should ideally target bacterial cells without harming human cells.

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List the five main modes of action of antibiotics.

Cell wall inhibitors
Cell membrane inhibitors
DNA and RNA synthesis inhibitors
Folic acid synthesis inhibitors
Protein synthesis inhibitors

Each mode targets different bacterial processes to inhibit growth or kill bacteria.

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What is the beta-lactam ring associated with?

Penicillins and cephalosporins

This structural motif is crucial for the action of these antibiotics against bacterial cell walls.

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What are natural penicillins?

Penicillin G
Penicillin V

These are derived directly from organisms and are among the first antibiotics used.

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What are semi-synthetic penicillins?

Methicillin
Ampicillin
Amoxicillin

These are modified forms of natural penicillins to enhance their effectiveness.

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What is the significance of cephalosporins in antibiotic therapy?

Broad spectrum and multiple generations

Cephalosporins are categorized into first, second, third, and fourth generations based on their spectrum of activity.

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What are the two types of penicillins mentioned?

Penicillin G
Penicillin B

These are natural penicillins derived directly from organisms.

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Name some semi-synthetic penicillins.

Methicillin
Ampicillin
Carbenicillin
Amoxicillin

Amoxicillin is noted for being one of the most broad-spectrum and highly prescribed antibiotics.

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What are the generations of cephalosporins?

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First generation
Second generation
Third generation
Fourth generation

All generations are modified from the initial cephalosporins identified in bacteria.

What is the target of the beta-lactam ring?

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Beta-lactamase enzyme

This enzyme can break down the beta-lactam ring, making natural penicillins and first-generation cephalosporins less effective.

What is Augmentin composed of?

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Amoxicillin
Clavulanic acid

Clavulanic acid blocks the beta-lactamase enzyme, enhancing the effectiveness of amoxicillin.

What is the most common adverse reaction to penicillin?

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Allergy

Reactions can range from rash and hives to anaphylactic shock, especially with repeated exposure.

What are carbapenems known for?

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Beta-lactamase resistance
Wide spectrum of activity
Better CNS penetration
-drug of choice for ENTEROBACTOR infection

Imipenem and meropenem are examples of carbapenems used for resistant infections.

What is the drug of last resort mentioned?

Vancomycin ## Footnote It is effective against MRSA infections and does not have a beta-lactam structure.

What syndrome is associated with rapid infusion of **vancomycin**?

Red man syndrome ## Footnote This syndrome is characterized by an infusion reaction affecting the upper body.

What do **polypeptide antibiotics** do?

- cell membrane inhibition -create pores in membrane *amphotercin *triple abx therapy Cause pores to form in the cell membrane ## Footnote They act more like detergents than traditional antibiotics.

What are the components of the **triple antibiotic ointment**?

* Polymyxin- (-) * Neomycin- (protein synthesis) * Bacitracin - (+) ## Footnote This ointment is used topically to prevent infections in cuts.

What is the mechanism of action for **tetracyclines**?

Bacteriostatic - affecting ribosomes —— tox: dont give to children - teeth issues ## Footnote They slow down bacterial growth rather than killing bacteria outright. - good for gram negative

What adverse effect can long-term use of **tetracyclines** cause?

C. difficile infections ## Footnote Disruption of beneficial bacteria can lead to opportunistic infections.

What is a key characteristic of **macrolides**?

Fused ring structure -works at ribosomes ## Footnote Erythromycin is a prototype macrolide antibiotic.

What is the benefit of **azithromycin** (Zithromax)?

Short treatment duration ## Footnote It can be taken for just four days compared to the usual 10 to 14 days for other antibiotics.

What does **chloramphenicol** potentially cause?

Aplastic anemia - macrolide ## Footnote This condition involves a decrease in red and white blood cells.

What do **fluoroquinolones** inhibit?

DNA gyrase ## Footnote This enzyme is crucial for DNA replication.

What is the role of **folic acid** in bacteria?

Synthesis of DNA and RNA ## Footnote Bacteria must produce their own folic acid, unlike humans who obtain it from their diet.

What is the role of **folic acid** in bacteria?

Bacteria must make their own folic acid, which is needed to make DNA and RNA ## Footnote Humans obtain folic acid from their diet, known as vitamin B9.

Name two **inhibitors of folic acid synthesis**.

* sulfanomides * Trimethoprim ## Footnote These inhibitors target the folic acid synthesis pathway in bacteria.

What is the precursor to **folic acid**?

Para-amino benzoic acid ## Footnote This compound is involved in the competitive inhibition process for folic acid synthesis.

What are the two main types of **antifungal agents** mentioned?

* Ketoconazole * Amphotericin ## Footnote Ketoconazole is used for skin infections, while Amphotericin is for systemic infections.

What is the main application of **quinine derivatives**?

Treatment of malaria ## Footnote Hydroxychloroquine is specifically mentioned as useful for malaria infections.

True or false: **Metronidazole** is useful for treating gastrointestinal infections.

TRUE ## Footnote Metronidazole is effective for genitourinary infections and sexually transmitted diseases.

What is a common side effect of **Metronidazole**?

Black hairy tongue ## Footnote This condition occurs due to elongation of filiform papillae on the tongue.

What is the purpose of **Nicosamide**?

Treatment of tapeworms ## Footnote It is specifically used for parasitic infections.

What is the ideal characteristic of an **antimicrobial agent**?

* Soluble * Selectively toxic * Non-allergenic * Stable * Resistance should not be easily acquired * Reasonably priced ## Footnote These characteristics help ensure effective treatment while minimizing side effects.

What is the significance of **natural selection** in bacteria concerning antibiotics?

Bacteria can mutate and develop resistance to antibiotics ## Footnote This can occur through chromosomal mutations or gene exchange via plasmids.

What happens if a patient does not complete their **antibiotic treatment**?

Highly resistant bacteria may survive and cause a relapse of infection ## Footnote Completing the full course of antibiotics is crucial to eliminate all bacteria.

What is a potential consequence of antibiotic use on **normal microbiota**?

Killing off beneficial bacteria ## Footnote This can lead to infections like Clostridium difficile.

What is the purpose of a **fecal transplant**?

To restore beneficial bacteria in patients with Clostridium difficile infections ## Footnote The transplant is taken from a closely related individual to ensure compatibility.

What is the role of **culture and sensitivity** in antibiotic treatment?

To determine which antibiotic will effectively kill the bacteria ## Footnote This helps in selecting the appropriate treatment for infections.

Antibiotics Flashcards

(49 cards)