Deck 12: Drugs, Microbes, Host--The Elements of Chemotherapy

Question 1

Differentiate between antibiotics and synthetic drugs.

Answer 1

Antibiotics are naturally occurring compounds that act against unwanted bacteria. They are the substances that are produced by the natural metabolic processes of a few microorganisms for acting against another microorganism. The antibiotics are generally formed by the aerobic, spore-forming bacteria and fungi. Examples include penicillin which is produced from the mold Penicillium and streptomycin produced from the bacterium Streptomyces griseus.
Synthetic drugs are the antimicrobial substances that are manufactured completely in the laboratory through chemical processes. The development of synthetic antibiotics is often considered to be a tiresome process involving the screening of thousands of possible candidates. Examples include prontosil drug (sulfa drug) and chloromycetin.

Question 2

State the goals of antimicrobial therapy.

Answer 2

This question sets an overview of the important topics covered in this section of the chapter; we will discuss the basic nomenclature required to understand how we treat microbial diseases.
As living organisms, microbes respond to their environment, making changes in their internal environment and outward facing structures to cope with fluctuations in their environment. Over generations, microbes displaying successful adaptations to a particular environment will thrive there, and the course of random mutation will slowly enhance their specificity to that environment.
As larger organisms, our internal environments provide a very successful location for microbes to thrive; some of these microbial are essential and beneficial to us, while others cause diseases.
The purpose of antimicrobial chemotherapy is to kill off a pathogen without hurting the infected individual, but this is often harder than it sounds.
The sources of the drugs we use come from two general locations - organic chemistry or the microbes themselves. Antibiotics are natural compounds produced by microbes to ward off other competing microbes; we have isolated these compounds for use as medicines. Organic compounds can be synthesized in a laboratory and then manufactured using chemical processes; both classes of compounds can have a variety of modes of activity.

Question 3

For the following figures a-e, research the chapter and book to find an appropriate drug to treat an infection with the microbe shown, and explain what its effects on the microbe will be.
(a) Figure 18.1
(b) Figure 6.8b
c) Figure 5.15c
(d) Figure 5.26c
(e) Figure 5.28

Answer 3

No Answer

Question 4

Differentiate between narrow-spectrum and broad-spectrum antibiotics.

Question 5

Discuss the origins of antimicrobial drugs.

Question 6

Can you determine why some drugs have narrower spectra than others? (Hint: Look at their mode of action.)

Question 7

Differentiate between antibiotics, synthetic drugs, and semisynthetic drugs.

Question 8

What kind of tests would determine whether a particular antimicrobial is broad or narrow spectrum?

Question 9

Describe some of the special strategies of antimicrobial therapy.

Question 10

What is the major source of antibiotics and what appears to be the natural function of antibiotics in microbes that produce them?

Question 11

Explain what is meant by a drug's spectrum and how narrow-and broad-spectrum drugs differ.

Question 12

What drug characteristics are most important to consider in therapy?

Question 13

Summarize the five modes of action of antimicrobial drugs, with specific examples of their effects.

Question 14

Why is it better for a drug to be microbicidal than microbistatic?

Question 15

Describe the classes of antibacterial drugs that act on the cell wall and membrane, and list some of their applications.

Question 16

Explain the major modes of action of antimicrobial drugs, and give an example of each.

Question 17

Describe the classes of antibacterial drugs that act on DNA or RNA, and characterize their uses.

Question 18

Explain the concept of competitive inhibition, and describe how a metabolic analog molecule inhibits metabolism.

Question 19

Indicate which types of antibacterial drugs block protein synthesis, and explain how they are used.

Question 20

What are the end effects of drugs that block transcription?

Question 21

Describe some new classes of antibacterial drugs and their applications.

Question 22

Construct a chart that summarizes the modes of action and applications of the major groups of antibacterial drugs (antibiotics and synthetics).

Question 23

Categorize antimicrobial drugs that are effective against fungi, and describe how they are used.

Question 24

Why do the penicillin and cephalosporin groups of drugs have milder toxicity than other antibiotics? What are their primary side effects?

Question 25

Discuss the categories of drugs used to treat parasite infections, and describe their applications.

Question 26

Construct a chart to outline the applications of major groups of antifungal drugs, antiparasitic drugs, and antiviral drugs.

Question 27

Discuss some of the difficulties in giving antiviral drug treatments.

Question 28

Explain why there are fewer antifungal, antiparasitic, and antiviral drugs than antibacterial drugs.

Question 29

Identify several categories of antiviral drugs, and explain how they are used.

Question 30

What is the strategy behind taking several different types of drugs to treat HIV?

Question 31

Describe the development of drug resistance, and explain how it is acquired.

Question 32

Summarize the origins and biological actions of interferon-based drugs.

Question 33

Explain the major mechanisms by which microbes become resistant to drugs.

Question 34

Explain the phenomenon of drug resistance from the standpoint of microbial genetics (include a description of R factors).

Question 35

Discuss some of the ways for reducing levels of drug resistance.

Question 36

Describe the five basic mechanisms of drug resistance.

Question 37

Discuss how drug resistance spreads through a population of microbes and the long-term effects of this.

Question 38

Explain why biofilm infections are often resistant to drugs.

Question 39

Summarize the adverse effects of drugs on the human body.

Question 40

Name several ways that drug resistance can be prevented by medical personnel and patients (see table 12.8).

Question 41

Describe some of the toxic effects of drugs on organs and tissues.

Question 42

Why do drugs that act on bacterial and fungal membranes generally have high toxicity?

Question 43

Discuss how drugs can cause damaging immune responses.

Question 44

Describe the series of events that gives rise to a superinfection, using an example.

Question 45

Explain the ways that drugs alter the normal microbiota and the results.

Question 46

What characteristic of antibiotics and other drugs causes hypersensitivity and allergic reactions?

Question 47

Outline some important factors to consider in drug therapy.

Question 48

Explain why it is better to use a narrow-spectrum drug instead of a broad-spectrum one, if possible.

Question 49

Describe the principles behind sensitivity testing for infectious agents.

Question 50

How are dilution susceptibility tests and disc diffusion tests used to determine microbial drug sensitivity?

Question 51

Explain the uses of the minimum inhibitory concentration and the therapeutic index in drug selection.

Question 52

Briefly describe the Kirby-Bauer test and its purpose.

Question 53

Discuss medical considerations in final drug selection.

Question 54

What would you surmise if you examined a Kirby-Bauer assay and found individual colonies of the plated microbe growing within the zone of inhibition?

Question 55

Summarize the problems in managing antimicrobial drugs.

Question 56

Explain the relationship between the minimum inhibitory concentration and the therapeutic index and what is optimum for each.

Question 57

Discuss the general factors to consider in selecting an appropriate antimicrobial drug.

Question 58

An Introduction to Concept Mapping found at http:\\www.mhhe.com\talaro9 provides guidance for working with concept maps.
Supply your own linking lines and phrases in this concept map.

Question 59

What was the purpose of giving postexposure prophylaxis to the nurse?
a. to treat AIDS
b. to prevent pneumocystis pneumonia
c. to prevent HIV replication in cells
d. to stimulate an immune response

Question 60

Critical thinking is the ability to reason and solve problems using facts and concepts. These questions can be approached from a number of angles, and in most cases, they do not have a single correct answer.
Occasionally, one will hear the expression that a microbe has become "immune" to a drug.
a. What is a better way to explain what is happening?
b. Explain a simple test one could do to determine if drug resistance was developing in a culture.

Question 61

Select the correct answer from the answers provided. For questions with blanks, choose the combination of answers that most accurately completes the statement. A compound synthesized by bacteria or fungi that destroys or inhibits the growth of other microbes is a\an

A) synthetic drug
B) antibiotic
C) antimicrobial drug
D) competitive inhibitor

Question 62

Compose a one- or two-paragraph answer that includes the factual information needed to completely address the question. Check Your Progress questions can also be used for writing-challenge exercises.
Using the diagram as a guide, briefly explain how the three factors in drug therapy interact.

Question 63

An Introduction to Concept Mapping found at http:\\www.mhhe.com\talaro9 provides guidance for working with concept maps.
Use 6 to 10 bolded words of your choice from the Chapter Summary to create a concept map. Finish it by providing linking words.

Question 64

What is a probable reason that tuberculosis therapy must continue for several months?
a. to prevent drug resistance
b. to keep the infection from spreading
c. the TB bacillus grows very slowly
d. the drugs are slow acting

Question 65

Critical thinking is the ability to reason and solve problems using facts and concepts. These questions can be approached from a number of angles, and in most cases, they do not have a single correct answer.
a. Your pregnant neighbor has been prescribed a daily dose of oral tetracycline for acne. Do you think this therapy is advisable for her? Why or why not?
b. A woman has been prescribed a broad-spectrum oral cephalosporin for a strep throat. What are some possible consequences in addition to cure of the infected throat?
c. A man has a severe case of sinusitis that is negative for bacterial pathogens. A physician prescribes an oral antibacterial drug for treatment. What is right or wrong with this therapy?

Question 66

Select the correct answer from the answers provided. For questions with blanks, choose the combination of answers that most accurately completes the statement. Which statement is not an aim in the use of drugs in antimicrobial chemotherapy? The drug should

A) have selective toxicity
B) be active even in high dilutions
C) be broken down and excreted rapidly
D) be microbicidal

Question 67

Compose a one- or two-paragraph answer that includes the factual information needed to completely address the question. Check Your Progress questions can also be used for writing-challenge exercises.
Observe table 12.4 with regard to type of microbe and structures or functions that are affected by drugs. Write a short paragraph that explains the different ways in which drugs can affect microbes and how this affects selectivity of drugs and their spectrum.

Question 68

Summarize the major problems with drug therapy as demonstrated in this case.

Question 69

Critical thinking is the ability to reason and solve problems using facts and concepts. These questions can be approached from a number of angles, and in most cases, they do not have a single correct answer.
You have been directed to take a sample from a growth-free portion of the zone of inhibition in the Kirby-Bauer test and inoculate it onto a plate of nonselective medium.
a. What does it mean if growth occurs on the new plate?
b. What if there is no growth?

Question 70

Select the correct answer from the answers provided. For questions with blanks, choose the combination of answers that most accurately completes the statement. Microbial resistance to drugs is acquired through

A) conjugation
B) transformation
C) transduction
D) all of these

Question 71

Compose a one- or two-paragraph answer that includes the factual information needed to completely address the question. Check Your Progress questions can also be used for writing-challenge exercises.
Drugs are often given to surgical patients, to dental patients with heart disease, or to healthy family members exposed to contagious infections.
a. What word would you use to describe this use of drugs?
b. What is the purpose of this form of treatment?
c. Explain some potential undesired effects of this form of therapy.
d. Define probiotics and give some ways they are used.

Question 72

Critical thinking is the ability to reason and solve problems using facts and concepts. These questions can be approached from a number of angles, and in most cases, they do not have a single correct answer.
From the results shown in figure 12.21, determine which drugs could be used to treat the yeast infection. Taking into account their adverse side effects, which drug would probably be the best choice?

Question 73

Select the correct answer from the answers provided. For questions with blanks, choose the combination of answers that most accurately completes the statement. R factors are ___________ that contain a code for ___________.

A) genes, replication
B) plasmids, drug resistance
C) transposons, interferon
D) plasmids, conjugation

Question 74

Compose a one- or two-paragraph answer that includes the factual information needed to completely address the question. Check Your Progress questions can also be used for writing-challenge exercises.
Write an essay covering some of the main concerns in antimicrobial drug therapy, including resistance, allergies, superinfections, and other adverse effects.

Question 75

Critical thinking is the ability to reason and solve problems using facts and concepts. These questions can be approached from a number of angles, and in most cases, they do not have a single correct answer.
Explain why drugs that interfere with the prokaryotic ribosome can have harmful side effects on a human patient.

Question 76

Select the correct answer from the answers provided. For questions with blanks, choose the combination of answers that most accurately completes the statement. When a patient's immune system becomes reactive to a drug, this is an example of

A) superinfection
B) drug resistance
C) allergy
D) toxicity

Question 77

Compose a one- or two-paragraph answer that includes the factual information needed to completely address the question. Check Your Progress questions can also be used for writing-challenge exercises.
a. Explain the basis for combined therapy.
b. Give reasons why it could be helpful to use combined therapy in treating HIV infection.

Question 78

Critical thinking is the ability to reason and solve problems using facts and concepts. These questions can be approached from a number of angles, and in most cases, they do not have a single correct answer.
In cases in which it is not possible to culture or drug test an infectious agent (such as middle ear infection), how would the appropriate drug be chosen?

Question 79

Select the correct answer from the answers provided. For questions with blanks, choose the combination of answers that most accurately completes the statement. An antibiotic that disrupts the normal flora can cause

A) the teeth to turn brown
B) aplastic anemia
C) a superinfection
D) hepatotoxicity

Question 80

Compose a one- or two-paragraph answer that includes the factual information needed to completely address the question. Check Your Progress questions can also be used for writing-challenge exercises.
Explain the whys and hows of creating a semisynthetic antibiotic.