Microbiology Chapter 10 Flashcards

Questions and Answers

What is microbial antagonism?

the ability of the normal flora to outcompete and outgrow pathogens

What is superinfection?

Superinfection is a disease caused by an organism that is often an opportunist or one that was present in low numbers.

What causes thrush?

Candida albicans

Which of the following classifications would best describe Candida albicans?

Yeast Signup and view all the answers

If the patient were to get a subsequent urinary tract infection, what should the doctor prescribe knowing that she is susceptible to thrush?

The doctor should prescribe an antibiotic specific for the bacterial species causing the urinary infection. Signup and view all the answers

Who was the most likely source of infection for this child?

uncle Signup and view all the answers

What is DOT?

Directly Observed Therapy Signup and view all the answers

Which drug for the treatment of tuberculosis inhibits RNA production and colors body secretions red-orange?

rifampin Signup and view all the answers

What is the therapeutic index?

drug dose the patient can tolerate divided by the effective dose Signup and view all the answers

How did the multi-drug-resistant strains of Mycobacterium tuberculosis, like those in the prison, arise?

conjugation and exchange of resistance factors located on plasmids Signup and view all the answers

Match the following descriptions of cellular structures with the type of cell in which they are found.

Hami = Archaea Peptidoglycan cell wall = Bacteria Organelles = Eukaryotes 80S ribosome in cytosol = Eukaryotes Glycocalyx = Both Eukaryotes and Prokaryotes Cytoskeleton = Both Eukaryotes and Prokaryotes DNA = Both Eukaryotes and Prokaryotes 70S ribosome in cytosol = Prokaryotes (Archaea and Bacteria) Fimbriae = Prokaryotes (Archaea and Bacteria) Signup and view all the answers

Which among the following cell features of bacteria are potential targets for Dr. Ehrlich's 'magic bullets'?

Cell wall Signup and view all the answers

The ____________ is a defining characteristic of bacteria which is not found in eukaryotes.

peptidoglycan cell wall Signup and view all the answers

The cytosol of bacteria contains ____________ which has components different from the structure of eukaryotes.

70S ribosomes Signup and view all the answers

When a nurse rubs your skin with rubbing alcohol prior to administering an injection, what process(es) is he carrying out?

Both A and B Signup and view all the answers

Which of the following is NOT an important consideration when preparing to use a chemical to disinfect a diaper changing table in a public restroom?

Whether or not hand sanitizer is available at the changing table Signup and view all the answers

Many MRSA strains are sensitive to other antibiotics. Which of the following methods would be the best way to evaluate sensitivity to other antibiotics?

Disk diffusion Signup and view all the answers

In examining a MRSA strain, researchers find that degraded penicillin is found in the culture medium. What is the most likely mechanism of resistance?

Production of beta-lactamase Signup and view all the answers

Clostridium difficile is a common healthcare-associated infection. It is often transferred between patients on the hands of health care workers. Rank the following prevention and control strategies from most beneficial (1) to least beneficial (4).

<ol> <li>Hand hygiene with soap and water; 2. Use of gloves; 3. Use of approved chemical disinfectants in patient rooms; 4. Hand hygiene with alcohol gels.</li> </ol> Signup and view all the answers

Which antibiotic is overcome by beta-lactamases?

Penicillin Signup and view all the answers

How might efflux pumps increase antibiotic resistance in bacteria?

Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps. Signup and view all the answers

Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what?

PABA Signup and view all the answers

Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug?

Penicillin disrupts the cell wall, which is located outside of the cell membrane. Signup and view all the answers

Membrane transport proteins are required for which mode(s) of antibiotic resistance?

Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins. Signup and view all the answers

What is meant by selective toxicity?

Chemotherapeutic agents should act against the pathogen and not the host. Signup and view all the answers

Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug?

Humans and other animal hosts lack peptidoglycan cell walls. Signup and view all the answers

Why is polymyxin only used on the skin?

It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead. Signup and view all the answers

Quinolones and fluoroquinolones act against what bacterial target?

DNA gyrase Signup and view all the answers

Why is it difficult to find good chemotherapeutic agents against viruses?

Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected. Signup and view all the answers

The first true antibiotic was , which was discovered by .

penicillin; Alexander Fleming Signup and view all the answers

Who proposed the concept of chemotherapy, that compounds might selectively kill pathogens without harming people?

Paul Ehrlich Signup and view all the answers

Which of the following is a primary advantage of semisynthetic drugs?

They are more effective than the unmodified natural antibiotics Signup and view all the answers

Which of the following antimicrobial drugs would likely be useful to treat a methicillin-resistant Staphylococcus aureus infection because it effectively blocks initiation of translation?

oxazolidinones Signup and view all the answers

Which of the following is NOT a beta-lactam antibiotic?

Vancomycin Signup and view all the answers

Which of the following is NOT a direct mode of action of antimicrobial drugs?

Inhibition of flagella formation Signup and view all the answers

Bacitracin blocks the transport of NAG and NAM across the cytoplasmic membrane to the cell wall. This would result in weak cell walls and __________.

cell lysis due to the effect of osmotic pressure Signup and view all the answers

Beta-lactam antibiotics such as penicillins, have an effect on which of the following types of cells?

Bacterial cells Signup and view all the answers

Amoxicillin is very effective for treating infections with Gram-positive bacteria but rarely causes side effects in humans. This is an example of

selective toxicity Signup and view all the answers

The first antimicrobial widely available for treatment of bacterial infections was a synthetic compound which

was an antimetabolic analog. Signup and view all the answers

Which of the following antifungals works by binding to ergosterol in membranes?

Both B and C Signup and view all the answers

A drug is structurally similar to PABA and inhibits folic acid synthesis. It is most likely a(n)

sulfonamide Signup and view all the answers

Which of the following statements is true of selective toxicity?

It takes advantage of structural and/or metabolic differences between host and pathogen. Signup and view all the answers

Antimicrobials known as 'attachment antagonists' are particularly useful for preventing

virus infection. Signup and view all the answers

The antifungals known as polyenes interact with ________, a lipid unique to fungus membranes.

ergosterol Signup and view all the answers

The tetracyclines interfere with

protein synthesis. Signup and view all the answers

AZT and Valaciclovir are antiviral nucleoside analogs that interfere with

nucleic acid synthesis. Signup and view all the answers

Polymyxin is effective against only some Gram-negative bacteria; therefore, it is considered a

narrow-spectrum drug. Signup and view all the answers

An antimicrobial disk on a Kirby-Bauer plate that shows no zone of inhibition indicates that the microbe being tested is

resistant to the drug. Signup and view all the answers

Put the following routes of administration in order, from the route that results in the highest concentration of drug in the bloodstream to the route that results in the lowest concentration: a. topical b. intravenous c. oral d. intramuscular

b, d, c, a Signup and view all the answers

Label each figure with the appropriate route of antimicrobial administration.

Oral = Tablets or liquids taken by mouth Intramuscular and one-time intravenous = Injections into muscle or one-time direct injection into the bloodstream Continuous intravenous = Infusion of the drug directly into the bloodstream over time Signup and view all the answers

The drug metronidazole is effective on both bacteria and some protozoa. It can therefore be described as a

broad spectrum Signup and view all the answers

Which of the following groups of drugs can become incorporated into the bones and teeth of a fetus?

Tetracyclines Signup and view all the answers

Which of the following can result when antibiotic therapy disrupts the normal microbiota?

Both A and B Signup and view all the answers

The broth dilution test can provide information for determining

both the MIC and the MBC (with an additional step). Signup and view all the answers

Infection of the ________ would be the hardest to treat with antimicrobial drugs.

brain Signup and view all the answers

Which of the following activities can be shown to increase resistance among microbial populations?

Taking antibacterial drugs for viral infections Signup and view all the answers

Which of the following is NOT associated with microbial mechanisms of resistance?

Denaturation of proteins Signup and view all the answers

The cooperative activity of drugs such as beta-lactam antibiotics and clavulanic acid, a β-lactamase inhibitor, is known as

synergism Signup and view all the answers

Some bacteria are resistant to antimicrobials due to the activity of ________, which removes many of them.

efflux pumps Signup and view all the answers

It is inappropriate to prescribe antibacterial agents to treat colds or flu because

these diseases are caused by viruses. Signup and view all the answers

Why does the physician start Caleb on the antibiotic azithromycin before laboratory results come back?

Antibiotic therapy is started with a broad-spectrum antibiotic because broad-spectrum antibiotics are effective against many gram-positive and many gram-negative bacteria. Signup and view all the answers

Which of the following choices correctly matches the class of antibiotic and its mode of action?

Both A and B Signup and view all the answers

If Caleb's strain of M. tuberculosis is sensitive to antibiotic treatment, which of the following could be used to treat his infection?

All of the above Signup and view all the answers

Why does Dr. Bell start Caleb on HIV therapy in addition to the antibiotics used to treat the tuberculosis?

Dr. Bell prescribes Caleb HIV therapy because the virus is not affected by the antibiotics used to treat tuberculosis. Signup and view all the answers

Which of the following contribute to drug resistance in M. tuberculosis?

All of the above Signup and view all the answers

Study Notes

Microbial Antagonism & Infections

Microbial antagonism refers to the normal flora's ability to outcompete and inhibit pathogens.
Superinfection occurs due to disease caused by opportunistic organisms that proliferate after normal flora is disrupted by antibiotics.
Thrush, a type of superinfection, is primarily caused by Candida albicans.
Candida albicans is classified as a yeast.

Antibiotic Prescribers & Treatment Strategies

For recurrent urinary tract infections in patients susceptible to thrush, prescribe an antibiotic specific to the bacterial species.
Infection sources can trace back to family contacts, highlighting the uncle as a likely source in a case scenario.
Directly Observed Therapy (DOT) ensures adherence to treatment protocols.

Antimicrobial Therapy & Resistance

Rifampin is an antibiotic for tuberculosis that inhibits RNA production and can color body secretions red-orange.
Therapeutic index measures drug tolerance versus effective dose, an important consideration for antibiotic prescriptions.
Multi-drug-resistant strains of Mycobacterium tuberculosis can arise through conjugation and plasmid-mediated resistance factor exchange.
Membrane transport proteins are integral in mechanisms like efflux pumps and beta-lactamase production that enhance bacterial resistance.

Bacterial Characteristics & Antibiotic Targets

Bacteria are classified into Archaea and Bacteria domains, distinguished by their structures like cell walls and ribosome types.
Peptidoglycan in bacterial cell walls is a vital target for chemotherapy as it is absent in humans.
The effectiveness of drugs like penicillin is compromised by enzymes like beta-lactamase, produced by resistant bacteria.

Disinfection & Infection Control

Effective hand hygiene with soap and water is crucial in preventing healthcare-associated infections like Clostridium difficile.
Disk diffusion is the method used to evaluate antibiotic sensitivity.

Selective Toxicity & Chemotherapeutic Strategies

Selective toxicity is the principle where chemotherapeutic agents target pathogens without harming the host.
Chemotherapeutics that act on peptidoglycan cell walls are favorable as humans lack these structures.

Antifungal Treatments & Mechanisms

Antifungal agents such as amphotericin B and nystatin bind to ergosterol, unique to fungal membranes, disrupting their functionality.
Fungal resistance can emerge, and polyenes are a class of antifungals that specifically interact with ergosterol.

Routes of Administration & Drug Efficacy

Routes of administration impact drug concentration, ranked highest with intravenous, followed by intramuscular, oral, and topical.
Metronidazole is a broad-spectrum drug effective against both bacteria and protozoa.
Tetracyclines can inadvertently affect fetal development.

Mechanisms of Microbial Resistance

Factors like antibiotic use against viral infections, incomplete treatment courses, and incorrect medication administration contribute to drug resistance.
Efflux pumps can enhance resistance by actively removing antibiotics from bacterial cells.

Treatment Protocols for Infections

Broad-spectrum antibiotics like azithromycin are often administered initially due to their effectiveness against various bacteria.
Specific treatment regimens for tuberculosis can include streptomycin, isoniazid, ethambutol, and rifampin.

HIV Therapy in Conjunction with Antibiotics

Initiating HIV therapy alongside tuberculosis treatment is crucial, as TB antibiotics do not affect the HIV virus directly.

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Test your understanding of key concepts in microbiology with these flashcards from Chapter 10. Topics covered include microbial antagonism, superinfection, and causes of thrush. Perfect for reinforcing your learning and preparing for exams.

Microbiology Chapter 10 Flashcards

Questions and Answers

What is microbial antagonism?

What is superinfection?

What causes thrush?

Which of the following classifications would best describe Candida albicans?

If the patient were to get a subsequent urinary tract infection, what should the doctor prescribe knowing that she is susceptible to thrush?

Who was the most likely source of infection for this child?

What is DOT?

Which drug for the treatment of tuberculosis inhibits RNA production and colors body secretions red-orange?

What is the therapeutic index?

How did the multi-drug-resistant strains of Mycobacterium tuberculosis, like those in the prison, arise?

Match the following descriptions of cellular structures with the type of cell in which they are found.

Which among the following cell features of bacteria are potential targets for Dr. Ehrlich's 'magic bullets'?

The ____________ is a defining characteristic of bacteria which is not found in eukaryotes.

The cytosol of bacteria contains ____________ which has components different from the structure of eukaryotes.

When a nurse rubs your skin with rubbing alcohol prior to administering an injection, what process(es) is he carrying out?

Which of the following is NOT an important consideration when preparing to use a chemical to disinfect a diaper changing table in a public restroom?

Many MRSA strains are sensitive to other antibiotics. Which of the following methods would be the best way to evaluate sensitivity to other antibiotics?

In examining a MRSA strain, researchers find that degraded penicillin is found in the culture medium. What is the most likely mechanism of resistance?

Clostridium difficile is a common healthcare-associated infection. It is often transferred between patients on the hands of health care workers. Rank the following prevention and control strategies from most beneficial (1) to least beneficial (4).

Which antibiotic is overcome by beta-lactamases?

How might efflux pumps increase antibiotic resistance in bacteria?

Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what?

Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug?

Membrane transport proteins are required for which mode(s) of antibiotic resistance?

What is meant by selective toxicity?

Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug?

Why is polymyxin only used on the skin?

Quinolones and fluoroquinolones act against what bacterial target?

Why is it difficult to find good chemotherapeutic agents against viruses?

The first true antibiotic was __________, which was discovered by __________.

Who proposed the concept of chemotherapy, that compounds might selectively kill pathogens without harming people?

Which of the following is a primary advantage of semisynthetic drugs?

Which of the following antimicrobial drugs would likely be useful to treat a methicillin-resistant Staphylococcus aureus infection because it effectively blocks initiation of translation?

Which of the following is NOT a beta-lactam antibiotic?

Which of the following is NOT a direct mode of action of antimicrobial drugs?

Bacitracin blocks the transport of NAG and NAM across the cytoplasmic membrane to the cell wall. This would result in weak cell walls and __________.

Beta-lactam antibiotics such as penicillins, have an effect on which of the following types of cells?

Amoxicillin is very effective for treating infections with Gram-positive bacteria but rarely causes side effects in humans. This is an example of

The first antimicrobial widely available for treatment of bacterial infections was a synthetic compound which

Which of the following antifungals works by binding to ergosterol in membranes?

A drug is structurally similar to PABA and inhibits folic acid synthesis. It is most likely a(n)

Which of the following statements is true of selective toxicity?

Antimicrobials known as 'attachment antagonists' are particularly useful for preventing

The antifungals known as polyenes interact with ________, a lipid unique to fungus membranes.

The tetracyclines interfere with

AZT and Valaciclovir are antiviral nucleoside analogs that interfere with

Polymyxin is effective against only some Gram-negative bacteria; therefore, it is considered a

An antimicrobial disk on a Kirby-Bauer plate that shows no zone of inhibition indicates that the microbe being tested is

Put the following routes of administration in order, from the route that results in the highest concentration of drug in the bloodstream to the route that results in the lowest concentration: a. topical b. intravenous c. oral d. intramuscular

Label each figure with the appropriate route of antimicrobial administration.

The drug metronidazole is effective on both bacteria and some protozoa. It can therefore be described as a

Which of the following groups of drugs can become incorporated into the bones and teeth of a fetus?

Which of the following can result when antibiotic therapy disrupts the normal microbiota?

The broth dilution test can provide information for determining

Infection of the ________ would be the hardest to treat with antimicrobial drugs.

Which of the following activities can be shown to increase resistance among microbial populations?

Which of the following is NOT associated with microbial mechanisms of resistance?

The cooperative activity of drugs such as beta-lactam antibiotics and clavulanic acid, a β-lactamase inhibitor, is known as

Some bacteria are resistant to antimicrobials due to the activity of ________, which removes many of them.

It is inappropriate to prescribe antibacterial agents to treat colds or flu because

Why does the physician start Caleb on the antibiotic azithromycin before laboratory results come back?

Which of the following choices correctly matches the class of antibiotic and its mode of action?

If Caleb's strain of M. tuberculosis is sensitive to antibiotic treatment, which of the following could be used to treat his infection?

Why does Dr. Bell start Caleb on HIV therapy in addition to the antibiotics used to treat the tuberculosis?

Which of the following contribute to drug resistance in M. tuberculosis?

Study Notes

Microbial Antagonism & Infections

Antibiotic Prescribers & Treatment Strategies

Antimicrobial Therapy & Resistance

Bacterial Characteristics & Antibiotic Targets

Disinfection & Infection Control

Selective Toxicity & Chemotherapeutic Strategies

Antifungal Treatments & Mechanisms

Routes of Administration & Drug Efficacy

Mechanisms of Microbial Resistance

Treatment Protocols for Infections

HIV Therapy in Conjunction with Antibiotics

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The first true antibiotic was , which was discovered by .