Chapter 34 Microbiology

Who is usually credited with the discovery of penicillin?

Whose discovery of streptomycin stimulated an intense search for other antibiotics?

The use of arsenic compound Salvarsan as a treatment for syphilis is credited to

Chemotherapeutic agents that are natural products of microorganisms are most specifically referred to as __________.

Who is generally credited with the discovery of sulfanilamide as a chemotherapeutic agent?

__________ __________ are activities of a chemotherapeutic agent that damage the host either by inhibiting the same process in the host as in the target cell or by damaging other processes.

The minimum lethal concentration (MLC) is the lowest concentration of drug from which organisms fail to recover when removed from the drug.

Agents that are static and, therefore, do not kill infecting microorganisms are not useful as chemotherapeutic agents.

A drug that disrupts a microbial function not found in animal cells usually has a higher therapeutic index.

The drug level required for the clinical treatment of a particular infection is called the

Which of the following inhibits protein synthesis?

Which of the following is likely to have the most toxic side effects to humans?

Isoniazid is a narrow-spectrum antibiotic that

Consider an antibacterial drug. In which of the following cases would the action of the drug be considered primarily bacteriostatic?

Chemotherapeutic agents that are chemically modified natural products of microorganisms are most specifically referred to as __________.

Chemotherapeutic agents that are artificially produced are most specifically referred to as __________.

The ratio of toxic dose to therapeutic dose is called the

The minimal lethal concentration (MLC) is the

The lowest concentration of an antibiotic that prevents growth is the

Which of the following is a desirable general characteristic of antimicrobial drugs?

When a chemotherapeutic agent is effective against many different pathogens, it is said to be a __________ antibiotic.

In a disk diffusion assay for drug susceptibility, a drug producing a larger clear zone is always more effective than a drug than to one producing a smaller clear zone.

Which of the following affects the size of the clear zone in a disk diffusion test of antimicrobial susceptibility?

The E test is

In the broth dilution test, the highest concentration of the antibiotic resulting in no growth after 16 to 20 hours of incubation is the MIC.

Which of the following is not true about Kirby-Bauer disk diffusion method?

Which of the following does not inhibit protein synthesis?

The most selective antibacterial agents are those that interfere with bacterial cell wall synthesis. This is because

In addition to inhibiting the transpeptidation reaction in cell wall synthesis, penicillins may also destroy bacteria by

It is difficult to treat central nervous system infections because

Aminoglycoside antibiotics

Sulfonamides and other drugs that inhibit folic acid synthesis have a high therapeutic index because

Antibiotics that are given by injection are said to have a(n) __________ route of administration.

Sulfonamides inhibit the production of folic acid and, therefore, inhibit the synthesis of __________.

Which of the following is (are) true about cephalosporins?

Bacitracin

Vancomycin

Which of the following is a useful mechanism of action for an antibacterial drug?

Which of the following antibiotics specifically inhibits DNA synthesis?

Protein synthesis inhibitors have a low therapeutic index because they usually cannot discriminate between prokaryotic and eukaryotic ribosomes.

Ampicillin, like penicillin, must be administered by injection because it is rapidly degraded in the stomach and cannot, therefore, be given orally.

A(n) __________ is a drug that blocks the function of a metabolic pathway.

Which of the following is normally treated by antifungal creams and solutions?

The treatment for pneumonia caused by Pneumocystis jiroveci in AIDS patients is

_______________ ________________ from Streptomyces spp. binds to the sterols in fungal membranes, disrupting membrane permeability and causing leakage of cell constituents.

Treatment of fungal infections is more difficult than treatment of bacterial infections because the greater metabolic similarity between the fungi and their hosts limits the ability of a drug to have a selective toxicity.

A neuraminidase inhibitor called __________ is sometimes used in the treatment of people infected with influenza viruses.

Which of the following is sometimes useful against viral infections?

Which of the following is the major reason why it has been difficult to treat viral infections with chemotherapeutic agents?

________ and ________ can be used to prevent influenza A infections, reducing the incidence of influenza by 50 to 70% in an exposed population.

All of the following are reverse transcriptase inhibitors used to treat HIV infection except

The antiviral drugs currently approved for use in HIV disease include

Drugs are used to treat malaria include

Metronidazole is used to treat Entamoeba infections.

The antimicrobial action of artemisinin is not well understood but this chemical appears to

Most of the drugs used to treat protozoan infection have insignificant side effects; because protozoa are prokaryotes, the potential for drug action on host cells and tissues is less than it is when targeting bacteria.

________, which is used to treat Toxoplasma gondii, is an analog of ________, an integral component of the eukaryotic electron transport system.

Bacteria in biofilms or abscesses may be replicating very slowly and are therefore resistant to chemotherapy because many agents affect pathogens only if they are actively growing and dividing.

The chemotherapeutic agent must reach levels in the body that are ________ the pathogen's MIC value if it is going to be effective.

The concentration of an antimicrobial drug that is reached in the body will depend on

Penicillin is frequently injected but not normally given orally because it is rapidly degraded in the stomach.

Genes for drug resistance may be present

One way in which organisms may exhibit resistance to a drug is the ability to pump the drug out of the cell immediately after it has entered.

The effects of most antimicrobial drugs are greater if the microorganisms are actively growing.

R plasmids, transposons, integrons and gene cassettes have each contributed to the spread of bacterial antibiotic resistance.

One way that the development of drug resistance in viruses has been reduced has been by the use of a cocktail of several drugs at high doses.

The drug of last resort that is generally used in treating infections caused by methicillin resistant Staphylococcus aureus is

Development of drug resistance is not discouraged by

Which of the following is (are) used by microorganisms to become resistant to a particular drug?

A plasmid bearing one or more antibiotic resistance genes is a(n)