Chapter 14

_______ kill their target bacteria.

Bactericidal drugs

Our greatest concerns are ________ and cross resistance.

multidrug-resistant microbes (MDRs)

Who is credited with the discovery of penicillin

Alexander Fleming

____ can occur between two antimicrobials or between antimicrobials and nonantimicrobials being used to treat other conditions.

Antagonism

___________ typically work by destroying or interfering with microbial structures and enzymes, either killing microbial cells or inhibiting of their growth.

Antimicrobial drugs

_____ cause a reversible inhibition of growth, with bacterial growth restarting after elimination of the drug

Bacteriostatic drugs

_______ who studied crystallography at Oxford University, used X-rays to analyze the structure of a variety of natural products.

Dorothy Hodgkin

The _____ is an alternative method used to determine MIC and is a combination of the Kirby-Bauer disk diffusion test and dilution methods.

Etest

(T/F) If drug A produces a larger zone of inhibition than drug B on the Kirby-Bauer disk diffusion test, drug A should always be prescribed.

FALSE

(T/F) Narrow-spectrum antimicrobials are commonly used for prophylaxis following surgery

FALSE

(T/F) β-lactamases can degrade vancomycin

FALSE

Fleming and his colleagues were credited with discovering and identifying penicillin, but its isolation and mass production were accomplished by a team of researchers at Oxford University under the direction of ___________

Howard Florey and Ernst Chain

__________ are antibacterials that block steps in the biosynthesis of peptidoglycan, making cells more susceptible to osmotic lysis.

Inhibitors of Cell Wall Biosynthesis.

_____ discovered the antibacterial activity of a synthetic dye, prontosil, that could treat streptococcal and staphylococcal infections in mice.

Josef Klarer, Fritz Mietzsch, and Gerhard Domagk

The ____________ has long been used as a starting point for determining the susceptibility of specific microbes to various antimicrobial drugs.

Kirby-Bauer disk diffusion test

In 1909, after screening more than 600 arsenic-containing compounds, ________ found one such "magic bullet" (compound 606)

Paul Ehrlich

The first natural antibiotic

Penicillin

______ led a research team that discovered several antimicrobials, including actinomycin, streptomycin, and neomycin.

Selman Waksman

(T/F) Echinocandins, known as "penicillin for fungi," target β(1→3) glucan in fungal cell walls.

TRUE

(T/F) The rate of discovery of antimicrobial drugs has decreased significantly in recent decades.

TRUE

______ involves the production of proteins that bind and sequester drugs, preventing the drugs from binding to their target.

Target Mimicry

Which of the following types of drug-resistant bacteria do not typically persist in individuals as a member of their intestinal microbiota? a. MRSA b. VRE c. CRE d. ESBL-producing bacteria

a. MRSA

Which of the following is an antimalarial drug that is thought to increase ROS levels in target cells? a. artemisinin b. amphotericin b c. praziquantel d. pleconaril

a. artemisinin

In the Kirby-Bauer disk diffusion test, the _______ of the zone of inhibition is measured and used for interpretation. a. diameter b. microbial population c. circumference d. depth

a. diameter

Which of the following resistance mechanisms is commonly effective against a wide range of antimicrobials in multiple classes? a. efflux pump b. target mimicry c. target modification d. target overproduction

a. efflux pump

Which of the following routes of administration would be appropriate and convenient for home administration of an antimicrobial to treat a systemic infection? a. oral b. intravenous c. topical d. parenteral

a. oral

Which of the following antimicrobial drugs is synthetic? a. sulfanilamide b. penicillin c. actinomycin d. neomycin

a. sulfanilamide

Which of the following does not bind to the 50S ribosomal subunit? a. tetracyclines b. lincosamides c. macrolides d. chloramphenicol

a. tetracyclines

___________ can be used to determine a particular drug's minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC)

antibacterial dilution tests

Which of the following drug classes specifically inhibits neuronal transmission in helminths? a. quinolines b. avermectins c. amantadines d. imidazoles

b. avermectins

Which of the following is not a type of β-lactam antimicrobial? a. penicillins b. glycopeptides c. cephalosporins d. monobactams

b. glycopeptides

Which of the following combinations would most likely contribute to the development of a superinfection? a. long-term use of narrow-spectrum antimicrobials b. long-term use of broad-spectrum antimicrobials c. short-term use of narrow-spectrum antimicrobials d. short-term use of broad-spectrum antimicrobials

b. long-term use of broad-spectrum antimicrobials

when a patient is immunocompromised, a ____ drug is essential for the successful treatment of infections.

bactericidal

In a patient with strong immune defenses, _____ and ______ drugs can be effective in achieving clinical cure.

bacteriostatic and bactericidal

A ___________ targets a wide variety of bacterial pathogens

broad-spectrum antimicrobial

Which of the following techniques cannot be used to determine the minimum inhibitory concentration of an antimicrobial drug against a particular microbe? a. Etest b. microbroth dilution test c. Kirby-Bauer disk diffusion test d. macrobroth dilution test

c. Kirby-Bauer disk diffusion test

Which of the following is not an appropriate target for antifungal drugs? a. ergosterol b. chitin c. cholesterol d. β(1→3) glucan

c. cholesterol

Which of the following resistance mechanisms describes the function of β-lactamase? a. efflux pump b. target mimicry c. drug inactivation d. target overproduction

c. drug inactivation

Which of the following antimicrobials inhibits the activity of DNA gyrase? a. polymyxin B b. clindamycin c. nalidixic acid d. rifampin

c. nalidixic acid

These are generally designed to increase the range of bacteria targeted, increase stability, decrease toxicity, or confer other properties beneficial for treating infections.

chemical modifications of semisynthetic antimicrobial

In _____ a single resistance mechanism confers resistance to multiple antimicrobial drugs.

cross-resistance

Which of the following is a nucleoside analog commonly used as a reverse transcriptase inhibitor in the treatment of HIV? a. acyclovir b. ribavirin c. adenine-arabinoside d. azidothymidine

d. azidothymidine

Which of the following resistance mechanisms is the most nonspecific to a particular class of antimicrobials? a. drug modification b. target mimicry c. target modification d. efflux pump

d. efflux pump

The utility of an antibiogram is that it shows antimicrobial susceptibility trends a. over a large geographic area. b. for an individual patient. c. in research laboratory strains. d. in a localized population.

d. in a localized population.

Which of the following terms refers to the ability of an antimicrobial drug to harm the target microbe without harming the host? a. mode of action b. therapeutic level c. spectrum of activity d. selective toxicity

d. selective toxicity

Which of the following has yielded compounds with the most antimicrobial activity? a. water b. air c. volcanoes d. soil

d. soil

The most common mode of action for antifungal drugs is the __________

disruption of the cell membrane.

- the amount of medication given during a certain time interval.

dosage

The overuse and misuse of antimicrobials, inappropriate use of antimicrobials, subtherapeutic dosing, and patient noncompliance with the recommended course of treatment are all factors of what?

drug resistance

__________ the lowest drug concentration that kills ≥99.9% of the starting inoculum.

minimal bactericidal concentration (MBC),

___________ the lowest concentration of drug that inhibits visible bacterial growth

minimal inhibitory concentration (MIC),

Each class of antibacterial drugs has a unique _________ the way in which a drug affects microbes at the cellular level.

mode of action

_________ are colloquially known as "superbugs" and carry one or more resistance mechanism(s), making them resistant to multiple antimicrobials.

multidrug-resistant microbes (MDRs)

If the pathogen causing an infection has been identified, it is best to use a _______ antimicrobial and minimize collateral damage to the normal microbiota.

narrow-spectrum

A _______ targets only specific subsets of bacterial pathogens.

narrow-spectrum antimicrobial

Because antimicrobial drugs have very specific targets, structural changes to those targets can ____ drug binding, rendering the drug ineffective.

prevent

________genes may code for enzymes that chemically modify an antimicrobial, thereby inactivating it, or destroy an antimicrobial through hydrolysis.

resistance

_____________ is the method used to introduce a drug into the body, is also an important consideration for drug therapy.

route of administration

An important quality for an antimicrobial drug is _________ meaning that it selectively kills or inhibits the growth of microbial targets while causing minimal or no harm to the host.

selective toxicity,

A ________ is a chemically modified derivative of a natural antibiotic.

semisynthetic antimicrobial

A ____ develops when the antibacterial intended for the preexisting infection kills the protective microbiota, allowing another pathogen resistant to the antibacterial to proliferate and cause a secondary infection.

superinfection

A yeast infection is a common example of a ___

superinfection

A _________ is a drug that is developed from a chemical not found in nature.

synthetic antimicrobial

The decision of whether to use a bacteriostatic or bactericidal drug depends on

the type of infection and the immune status of the patient

Which clinical situation would be appropriate for treatment with a narrow-spectrum antimicrobial drug? a. treatment of a polymicrobic mixed infection in the intestine b. prophylaxis against infection after a surgical procedure c. treatment of strep throat caused by culture identified Streptococcus pyogenes d. empiric therapy of pneumonia while waiting for culture results

treatment of strep throat caused by culture identified Streptococcus pyogenes

The diameter of the __________, measured in millimeters and compared to a standardized chart, determines the susceptibility or resistance of the bacterial pathogen to the drug.

zone of inhibition

A scientist discovers that a soil bacterium he has been studying produces an antimicrobial that kills gramnegative bacteria. She isolates and purifies the antimicrobial compound, then chemically converts a chemical side chain to a hydroxyl group. When she tests the antimicrobial properties of this new version, she finds that this antimicrobial drug can now also kill gram-positive bacteria. The new antimicrobial drug with broad-spectrum activity is considered to be which of the following? a. resistant b. semisynthetic c. synthetic d. natural

​B. semisynthetic