A Salmonella species is grown for 8 hours. In this time, each cell divides about four times. What is the generation time?

If a bacterium that normally lives in the gastrointestinal tract is plunged into a salty solution, what would occur?

a. Halophilic adjustment

b. Osmotic concentration

c. Lysis

d. Plasmolysis

e. Nothing

After performing the streak plate method, what feature(s) would you look for on the agar plate to determine if you have a pure culture?

Which of the following pathogens would hyperbaric oxygen therapy, a treatment that increases the level of dissolved oxygen in tissues, most likely ward off? Select all that apply.

a. Anaerobic thermophile

b. Anaerobic mesophile

c. Facultative anaerobic thermophile

d. Facultative anaerobic mesophile

e. Microaerophilic mesophile

Choose the false statement about binary fission.

a. It generates genetically diverse daughter cells.

b. It is an asexual form of reproduction.

c. It is the most common way that prokaryotes divide.

d. It leads to exponential population growth.

e. If it occurs in a single plane, it could generate chains of bacteria.

Match the term to the proper description(s). A term can have more than one description.

In a closed batch system, not all cells are expected to die, even as the death phase advances. Why?

Which direct enumeration method differentiates living from nonliving cells?

a. Manual cell counts

b. Measuring dry weight of cells

c. Viable plate count

d. Measuring biochemical activity

e. Coulter counter

Match the term to the proper description(s). A term can have more than one description.

You are collecting a clinical sample for microbiological analysis. Which of the following is the most important thing you must do?

a. Follow aseptic protocols.

b. Refrigerate the samples immediately after collection.

c. Determine if the potential pathogen is an aerobe or strict anaerobe.

d. Determine if normal flora have been removed before the sample is collected.

Label each statement that follows as true or false, and correct the false statements so they are true:

a. Most pathogens would be considered mesophilic alkaliphiles.

b. Sterilization is a form of decontamination.

c. Disinfection is a form of decontamination.

d. High-level germicides achieve sterilization.

e. Ionizing radiation is a form of chemical microbial control.

f. Standard pasteurization is a way to sterilize milk.

You have a patient who is suffering from a Clostridioides difficile infection. Which of the following would most likely be recommended to decontaminate small heat-stable equipment used for the patient?

a. Autoclave all equipment at 121°C for 15 minutes.

b. Boil equipment for 3 minutes.

c. Place the equipment in a hot-air oven at 121°C for 15 minutes.

d. Treat all equipment with a detergent solution.

e. None of the above.

Choose the false statement about turbidity as an enumeration method.

a. It is an indirect enumeration method.

b. It is performed using a spectrophotometer.

c. It must be done using a liquid culture.

d. It differentiates between live and dead cells.

e. It is a rapid enumeration method.

_____________ microbes use oxygen in metabolism, while _____________ do not.

If you were a manufacturer of electronic pacemakers for heart implantation, which agent would you most likely use to treat your product?

a. Ethanol

b. Iodophor

c. Glutaraldehyde

d. Autoclave

e. Ethylene oxide

A broad-spectrum drug is best described as

a. bactericidal against a wide range of species.

b. bacteriostatic against a wide range of species.

c. effective against a wide range of species.

d. empiric therapy.

e. selectively toxic.

Assume a bacterium makes beta-lactamase. Could you still use a glycopeptide drug to treat an infection caused by this bacterium? Explain your reasoning.

If a gene encoding a bacterial transpeptidase enzyme undergoes mutation, which of the following antimicrobials may no longer be effective against the mutated bacterium?

a. Macrolides

b. Polypeptide drugs

c. Tetracyclines

d. Penicillins

e. Quinolones

Mark the following as true or false, and then correct the false statements so they are true.

a. Human cells make drug efflux pumps.

b. The minimum bactericidal concentration is the minimum concentration of the drug that kills at least 50 percent of the bacteria present.

c. The E-test can reveal if a drug is bactericidal or bacteriostatic.

d. A drug that is bactericidal at one dose may be bacteriostatic at another dose.

e. The antifolate combination therapy trimethoprim-sulfamethoxazole may be used to treat protozoan infections.

Why is it challenging to obtain selectively toxic drugs against fungi, protozoans, and viruses?

Choose the false statement(s). Select all that apply.

a. Antifungal drugs may target cholesterol in fungal cell membranes.

b. Azole and polyene drugs promote cell lysis by impacting fungal cell plasma membranes.

c. Echinocandin drugs inhibit fungal cell wall synthesis.

d. Antifungal drugs may target DNA replication.

e. Antifungal drugs may target protein synthesis.

Match the antimicrobial drug to its feature. Some features may be used more than once, and some may not be used at all.

Which sensitivity test is best for determining the minimum bactericidal concentration and the minimum inhibitory concentration of a drug?

A patient who is not a healthcare worker is diagnosed with C. difficile pseudomembranous colitis. What most likely led to this infection?

a. The patient was recently treated with a bacteriostatic drug.

b. The patient was recently treated with a broad-spectrum drug.

c. The patient was treated with a bactericidal drug.

d. The patient recently became immune compromised and therefore had an increased risk for infection.

e. The patient was recently exposed to someone with an active C. difficile infection.

Match the antimicrobial drug class to its action. You may assign more than one drug class to a given action and some actions may not be applicable.

A patient has an uncomplicated infection with a Gram-negative bacterium. He also has a history of penicillin allergy. Which drug is the best treatment option for this patient?

a. Ampicillin

b. A first-generation cephalosporin

c. A carbapenem

d. Isoniazid

e. Azithromycin

Which drug family would be the most effective to treat a patient diagnosed with a MRSA infection?

a. Penicillins

b. Third-generation cephalosporins

c. Carbapenems

d. Lincosamides

e. Aminoglycosides

What advantages might a semisynthetic antimicrobial drug have over an antibiotic?

Choose the true statement(s) about therapeutic index (TI). Select all that apply.

a. A drug with a high therapeutic index would be effective above the dose at which it is potentially toxic.

b. A narrow TI is preferable.

c. A drug for which the maximum safe dose is close to the minimum effective dose would have a high TI.

d. It is one measure of a drug’s general safety.

e. A drug that is not selectively toxic would most likely have a high TI.

The difference between a synthetic drug and a semisynthetic drug is that

a. the semisynthetic drug is a modified synthetic drug.

b. the synthetic drug is a modified natural drug.

c. the synthetic drug is a modified semisynthetic drug.

d. the semisynthetic drug is a modified natural drug.