BIO 299 Exam 3

Antiviral drugs that target reverse transcriptase would be used to treat infections caused by:

HIV

Your patient has been on antibiotics for 6 weeks after a case of streptococcal endocarditis, an infection of the inner heart wall. The infection clears up. However, the patient just visited you about a urinary tract infection, and the lab verified that the culprit was E. coli. What do you hypothesize happened in this situation?

Her normal microbiota in the genitourinary tract were killed, allowing E. coli (not killed by the antibiotics) to establish an infection.

Treponema pallidum is the bacterium that causes syphilis. The gram-negative spirochete has never been cultured on bacteriological media. Select the statement that most accurately describes this disease-causing microbe:

Koch's postulates cannot be fulfilled for this disease

Over 50 percent of all sales of medically important antibiotics in the United States are for livestock use. Why is this problematic for humans?

Resistant bacteria grow in the animals and may then be passed to humans

Agents that can denature microbial proteins include all of the following except

X rays.

Each of the following results in drug resistance except a drug

being used as a nutrient by the cell.

The antifungal drug that can be used to treat serious systemic fungal infections is

amphotericin B

Filtration sterilization

can remove viruses.

Some microbial control agents are able to _____ cell proteins by breaking bonds that maintain the native state, the three-dimensional configuration of the proteins.

denature

Which of the following is an example of sequelae?

arthritis from Lyme disease

Infections that go unnoticed because there are no symptoms are called

asymptomatic

The chemical agent/s that produce/s highly reactive hydroxyl-free radicals and also decomposes to O2 gas is

hydrogen peroxide

Pasteurization

reduces the number of vegetative forms.

Which of the following represents the use of osmotic pressure as a microbial control method?

salting of meat

Which of the following is a mismatched term and description?

secondary infection - infection spreads to several tissue sites

An endotoxin is

secreted by pathogenic organisms

Disinfection of beverages such as apple juice, milk, and wine is optimally achieved by

pasteurization

Which antimicrobial method does not sterilize?

pasteurization

The dried residues of fine droplets from mucus or saliva that harbor and transmit pathogen are

droplet nuclei

Which of the following acids is not used to destroy or inhibit microbial cells in food?

phosphoric acid

The use of vaginal inserts of Lactobacillus to restore a healthy acidic environment is an example of

probiotics

If you were a bacterial cell, which of the following would be the most beneficial for you to have or be able to make for the survival of your species?

endospore

The use of a drug to prevent imminent infection is called

prophylaxis

Primaquine and chloroquine are drugs used in the treatment of ___ infections.

protozoan

Which of the following is not true of chloramines?

form trihalomethanes with organic compounds

Electrons are ejected from atoms in cells when organisms are exposed to

gamma rays and X rays.

Which of the following does not illustrate the use of universal precaution methods in the handling of patients and body substances?

healthcare worker with active, open lesions handling patients

Which control method would not be a suitable choice for killing Mycobacterium in a capped culture tube?

ultraviolet (germicidal) light

Leukopenia is the _____ in the level of white blood cells in a patient.

decrease

A drug exhibiting which therapeutic index value would be the safest, most effective to use on a patient?

20

Microbial resistance resulting from mutation occurs because

All of the choices are correct

Reservoirs include

All of the choices are correct

Endospores can be inactivated by

All of the choices are correct.

Which of the following is not a factor that affects germicidal activity?

All of the choices are factors

Which of the following is not a normal portal of exit of an infectious disease?

All of these are normal exit portals.

Your little girl is in the ICU ward of a hospital, and you would like to take her favorite little cloth doll to her. However, it must be sterilized. Your choices of sterilization are ethylene oxide gas, ultraviolet radiation, or an iodophor containing solution. Which of the following is an accurate evaluation of these choices?

Betadine is not feasible as a choice since most iodophore solutions do not sterilize.

Which is correct regarding the rate of microbial death?

Cells in a culture die at a constant rate.

______ carriers are shedding and transmitting pathogens a long time after they have recovered from an infectious disease.

Chronic

Which of the following is not true of endogenous retroviruses?

ERVs cause disease

Which of the following blocks HIV binding to host cell receptors?

Fuzeon

Your patient has a rash, a fever, and a very high white blood cell count. Blood specimens are taken, put into culture bottles, and sent down to the microbiology lab for incubation and analysis. Select the statement that best reflects why microbial analysis of blood is an important step in patient diagnosis:

Microbial growth in blood samples may indicate sepsis.

_____ heat is more rapidly effective and efficient compared to _____ heat.

Moist; dry

The major source of naturally produced penicillin is the mold

Penicilium chrysogenum

The prevalence rate of tuberculosis in one particular county in Texas is 7/1000 people, while the incidence rate for 2011 is 2/1000 people. Analyze this data and summarize the situation.

Prevalence rate is higher than incidence rate because the number of people still alive with tuberculosis is higher because of better treatments.

You have given a dosage of an antibiotic to a patient for his infection, but the patient is not getting any better. The MIC tests shows that the drug that you prescribed, at the dosage that was given, should work against this particular strain of bacterium. What do you think might be the problem?

The drug might be broken down in the patient's body before it can have its full effect on the bacterium.

Your friend Joe recently visited the doctor for steroid injections into his knee to reduce swelling due to previous knee injury. Within a couple of days, he had an infection caused by Pseudomonas, a very pathogenic and drug resistant bacterium. Luckily, Joe went to the doctor immediately and received antibiotics. The doctor tells him that problem has occurred to many other people across the U.S. Predict the most likely cause of this situation:

The staff giving the steroid injections did not use proper aseptic technique

You are studying a newly identified infectious disease within a population. Think of the typical graph of the course of infection--incubation period through to convalescent period. The new disease reveals a course of infection characterized by fluctuating symptoms, with intermittent periods of invasion (acute period) between prodromal periods. The whole course of infection occurs over a period of months or even years. Based upon the information presented, select the statement that most accurately reflects this new infectious disease:

This infectious disease exhibits latency

The patient has a staphylococcal infection of the blood, a septicemia--very serious and possibly deadly. As the doctor, you would like to prescribe a relatively non-toxic and inexpensive drug out of the cephalosporin family. However, if the patient harbors a strain of Staphylococcus that is resistant to a variety of antibiotics, you would prefer to use vancomycin-- which is highly effective against Staphylococcus. Which of the following explains why the cephalosporin drug is preferred for use over the vancomycin?

Vancomycin is very toxic, and the Staphylococcus strain could become resistant leaving no back-up drugs with which to treat the infection

All of the following are phenols or phenolics except

Zephiran

Sulfa drugs work on

a. nucleic acid biosynthesis. b. ribosome biosynthesis. NOT c. peptidoglycan biosynthesis. d. folic acid biosynthesis.

HEPA filters are used to remove microbes from

air

The term _____ refers to the presence of small numbers of bacteria in the blood.

bacteremia

Placing organisms at 4oC is

bacteriostatic.

Someone who inconspicuously harbors a pathogen and spreads it to others is a

carrier

The drug used against intestinal anaerobic bacteria, that can also alter normal biota leading to antibiotic-associated colitis, is

clindamycin.

Which term-definition pair is mismatched?

coagulase - dissolve fibrin clots

Each of the following affect cell walls except

erythromycin

Heavy metals work by

inactivating proteins

Which of the following is not a therapeutic benefit of interferon?

increases white blood cell count

The time from when pathogen first enters the body and begins to multiply, until symptoms first appear is the

incubation period

Bacterial toxins are chemical products made by bacteria. A person ingests some honey containing Clostridium botulinum. The C. botulinum is actively growing and releases toxin in the honey. The person becomes ill from ingesting the toxin. This is an example of a/n

intoxication

All of the following act as surfactants except

iodine

Which drug is used to treat cases of tuberculosis?

isoniazid

Which antibiotic is used to treat MRSA and VRE infections?

linezolid

The drug used for several protozoan infections is

metronidazole

A clinical microbiologist makes serial dilutions of several antimicrobials in broth, and then incubates each drug dilution series with a standard amount of a patient's isolated pathogen. What is this microbiologist setting up?

minimum inhibitory concentration (MIC) test

The total number of deaths in a population due to a disease is the _____ rate.

mortality

Which of the following antimicrobials does not inhibit DNA synthesis?

penicillin

What type of chemical will allow some bacteria to be resistant to many penicillins?

penicillinase

Keratinase has the greatest effect on the

skin.

Ethylene oxide is

sporicidal

Which of the following antibacterial drug groups does not target protein synthesis?

sulfonamides

The _____ are drugs that deposit in developing teeth and cause a permanent brown discoloration.

tetracyclines

The lowest temperature needed to kill or inactivate all microbes in 10 minutes is the

thermal death point (TDP).

When would Koch's postulates be utilized?

to determine the cause of a new disease in a microbiology research lab

Which antimicrobial does not interfere with protein synthesis?

trimethroprim

Intermittent sterilization, which uses 3 days of lower temperature steam for short periods of time, is also called

tyndallization.

The easiest microbial forms to kill or inhibit are

vegetative bacteria and fungi

Which of the following is transmission of disease from mother to fetus?

vertical

An infection spread between animals and humans is a:

zoonosis.