Practice Final Part 1

Members of the genus (Bacillus/Enterococcus/Mycobacterium) are part of the normal microbiota of humans.

Enterococcus

Members of the Enterobacteriaceae can be distinguished from each other by

both motility and the ability to ferment lactose

Sexually transmitted chlamydia is similar to infection with Yersinia pestis in that they both can produce

buboes

Enterococcus faecalis bacteria can be distinguished from other Gram-positive cocci because enterococci

can grow in the presence of bile salts.

What vector is implicated in the spread of the disease in this clinical case?

cat flea

The presence of ________ can be used to distinguish Staphylococcus from other Gram-positive cocci.

catalase enzyme

What is the treatment of choice for this disease?

doxycycline

Which of the following is NOT a disease generally associated with Neisseria gonorrhoeae?

dysentry

The most significant streptococcal pathogens are found in which of the following Lancefield groups?

A & B

Why does tuberculosis involve months of antibiotic treatment?

The bacteria grow very slowly.

What virulence factor(s) do all Gram-negative bacteria share?

lipid A

Salmonella and Shigella, both causes of diarrhea, can be distinguished by which of the following tests?

motility

Which of the following is an effective way to prevent many staphylococcal infections?

proper cleansing of wounds

When a UTI spreads to the kidneys it is called (cystitis/pyelonephritis/urethritis).

pyelonephritis

A virulence factor common to many members of the Enterobacteriaceae which permits them to deliver harmful proteins directly to cells is

type III secretion system

Enterobacteriaceae are rarely pathogenic.

false

Virulence factors associated with this organism include all of the following, EXCEPT __________.

flagella

Which of the following would be the LEAST likely way you could contract syphilis?

from an unclean toilet seat

Neisseria gonorrhoeae infection in men is

an acute painful infection with pus discharge.

Which of the following is the best way to avoid infection by Neisseria meningitidis?

avoidance of crowded living conditions

The ability to produce (hyaluronidase/lipase/proteases) enables Staphylococcus aureus to penetrate and spread through tissues.

hyaluronidase

What diagnostic test could be used to verify the diagnosis?

immunofluorescent antibody stain of a blood smear from this patient

Rickettsiosis is caused by Rickettsia rickettsii, a pathogen that

infects the lining of blood vessels and leads to leaking of plasma into tissue.

Streptococcus pneumoniae is found as part of the normal microbiota of the mouth and pharynx and yet can cause disease in some people when it is inhaled into the lungs. Why do you think this is?

If Streptococcus pneumoniae is inhaled from the nasopharynx into lungs damaged by a previous viral infection or in an immune-compromised person, it can flourish.

From the preliminary analysis, it would appear that individuals who consumed barbecue with Bubba-Qs sauce had the highest attack rate, followed by the dry-rubbed barbecue. Some of the individuals who said they ate the barbecue with the sauce did not become ill. Which one of the following is the most likely explanation for such an occurrence?

Individuals who became ill may have consumed larger quantities of the food than individuals who did not become ill.

The pathology of cepacia syndrome is often complex and due to multiple factors. All of the following factors may contribute to the development of cepacia syndrome EXCEPT which one?

Burkholderia cepacia produces an inducible beta-lactamase.

The bacterium ________ is a common cause of bacterial gastroenteritis contracted from contaminated food, especially poultry.

Campylobacter jejuni

Which of the following bacteria is responsible for the most common bacterial gastroenteritis in the United States, usually accompanied by frequent, bloody diarrhea?

Campylobacter jejuni

Why were corticosteroids contraindicated in this case?

Corticosteroids are immunosuppressive.

Which of the following tests would be useful in identifying Escherichia coli?

E. coli is a Gram-negative bacillus that ferments lactose and glucose, but not sucrose. It is motile and does not utilize citrate or urea.

During a stay in the hospital, an accident victim develops symptoms of bacteremia. A blood sample shows the presence of Gram-positive cocci in pairs. Lab tests determine that the bacteria are nonhemolytic and bile salt tolerant. The bacteremia is likely due to

Enterococcus

One of the best parts about working at the free clinic is being in contact with the doctors. Doctor Myers is the only full-time paid doctor; the rest all volunteer their time. Some of the doctors volunteer once a week and others only once a month, but they are all very nice and they eat their lunch with the staff and LPNs. Many of the LPNs are just starting out in their careers and so the lunches often turn into educational experiences. Today Dr. Myers is eating lunch with them, so Wanda asks her how she will tell Rebecca and Jake about the pregnancy and the C. trachomatis infection, and what treatment she will recommend for Rebecca.__________ is the treatment of choice for C. trachomatis.

Erythromycin

A sample from a public water supply contains Gram-negative rod-shaped bacteria that ferment lactose with gas production. Which of the following microbes would be the most likely candidate for this contaminant?

Escherichia coli

Which of the following coliforms is the most common cause of non-nosocomial urinary tract infections?

Escherichia coli

Hemolytic uremic syndrome is caused by

Escherichia coli O157:H7.

Infection with ________ may result in peptic ulcers and stomach cancer.

Helicobacter pylori

Streptococcus pneumoniae is found as part of the normal microbiota of the mouth and pharynx and yet can cause disease in some people when it is inhaled into lungs. Why do you think this is?

If Streptococcus pneumoniae is inhaled from the nasopharynx into lungs damaged by a previous viral infection or in an immune compromised person, it can flourish.

Are Clostridium botulinum vegetative cells required to be present for foodborne botulism to occur?

No, foodborne botulism is caused by the botulinum toxin produced by the bacteria, not the bacteria themselves.

How will the prescribed penicillin kill S. pyogenes that is causing Shelly's infection?

Penicillin will interfere with peptidoglycan synthesis, ultimately weakening the cell wall and leading to cellular lysis.

Which of the following is a characteristic of biological transmission from Dermacentor to a human host?

R. rickettsii is transmitted to the human host during a bite, when tick saliva enters the wound

Epidemic typhus, spread by lice, is caused by

Rickettsia prowazekii.

Gangrenous secondary infections with Clostridium are associated with which of the following diseases?

Rocky Mountain spotted fever

He is admitted to the hospital, and more testing is ordered. That afternoon, Paul calls Ron to see whether he wants to go hiking the next weekend. Ron's wife answers the phone and lets Paul know that Ron is in the hospital and very sick. After she describes the symptoms, Paul asks whether the doctors have been informed that Ron was likely exposed to a tick bite. She says she doesn't think so, and Paul tells her that she should tell the doctors right away. What disease does Paul suspect Ron might have contracted?

Rocky Mountain spotted fever

Further testing reveals this is a strain of E. coli O157:H7. What virulence factor produced by this strain could cause the heart and lung damage observed in this case?

Shiga-like toxin

Treponema pallidum is a spirochete. How does this morphology contribute to the pathogenesis of this organism?

Spirochetes like Treponema pallidum have a tightly coiled, helical morphology, which allows them to move by rotation and burrow into tissues.

A clinical specimen from a syphilis lesion showed NO spirochetes under the microscope when viewed in the hospital laboratory. Why is this?

Spirochetes typically do not survive transport.

Which practice would NOT be a good way to prevent foodborne botulism?

Storing canned foods at room temperature.

Otitis media may lead to dangerous meningitis in children due to infection with

Streptococcus pneumoniae.

What effect will the penicillin have on Shelly's cells?

The penicillin will not have any impact on Shelly's cells because it targets peptidoglycan, which is found only in bacteria.

A gastroenteritis which usually resolves in 72 hours is contracted from eating shellfish contaminated with

Vibrio parahaemolyticus.

Resistance of Pseudomonas to a wide range of antibacterial agents is partly due to its

ability to metabolize many drugs.

Streptococcus pneumoniae was originally named Diplococcus pneumoniae. Why was the genus name Diplococcus originally given to this organism? (prefix)

The prefix "di-" means two, and these organisms are usually found in pairs under the microscope.

How was this disease transmitted?

This is most commonly transmitted by unprotected sex.

Some studies have indicated that the ID50 for Vibrio cholerae can be as high as 108 organisms. Which of the following most likely explains the requirement for this relatively high ID50?

To establish infection, V. cholerae must survive the host immune response and the acidic environment of the stomach.

How do clinicians primarily screen for tuberculosis in patients?

Tuberculin skin test

Over 90% of urinary tract infections (UTIs) are caused by Escherichia coli strains. UTIs are 14 times more common in women than in men. Why do you think this is?

UTIs caused by E. coli are 14 times more common in women than in men because women have a shorter urethra than men and the proximity of the urethra to the anus is much closer in women.

Among adults Chlamydia trachomatis is an STD, but among children who are not sexually active, it can cause ocular infections which may be spread

on hands or by flies.

Undiagnosed or untreated infections with Neisseria gonorrhoeae in can progress to

pelvic inflammatory disease (PID)

Analysis of the second swab has confirmed that the causative organism is Streptococcus pyogenes, a gram-positive organism. Imagine that you are the technician looking at the Gram stain from Shelly's culture. What would you expect to see as you look through the microscope?

purple, spherical-shaped organisms arranged in chainlike formations

One of the primary reasons the disease is able to evade the body's immunity is that it __________.

resists digestion by phagocytes

Which of the following diseases is considered an autoimmune disease triggered by bacterial infection?

rheumatic fever

Strep throat may progress to ________, characterized by a skin rash and a bright red swollen tongue.

scarlet fever

In approximately 10% of patients tubercles rupture and reactivate infection. This is known as _____ tuberculosis.

secondary

The true pathogen (Salmonella/Shigella/Yersinia) is a noncoliform, nonmotile, oxidase-negative member of the Enterobacteriaceae that does not produce hydrogen sulfide.

shigella

A strain of Staphylococcus aureus that loses the ability to produce staphylokinase will be unable to do which of the following?

spread to new locations in the body

Which of the following stages of syphilis is ALMOST NEVER seen in developed countries?

tertiary syphilis

What part of the United States is endemic for RMSF?

the Appalachian region (North Carolina, Kentucky)

Which of the following is NOT a virulence factor for Helicobacter pylori?

the ability of H. pylori to enter cells for protection

Gonorrhea is often asymptomatic in women because __________.

the cervix is usually the site of infection

Over 90% of Staphylococcus aureus isolates are penicillin-resistant. Why?

they produce β-lactamase

People can reduce the chances of contracting rabbit fever by avoiding rabbits, muskrats, and (fleas/lice/ticks).

ticks

An effective vaccine is available to prevent (gonorrhea/salmonellosis/typhoid).

typhoid

A student camping in a wilderness area where Rocky Mountain spotted fever is endemic discovers a tick on her leg. She easily removed it because it had just attached to her leg. What is her risk for contracting RMSF?

very low, because Rickettsia rickettsii is activated only after hours of feeding

Which of the following streptococci is associated with dental caries?

viridans streptococci

A student was bitten by a tick and fears that she may be at risk for contracting tularemia. She removed the tick a very short time after it had bitten her. Is she at risk for tularemia?

yes, because Francisella is one of the most infectious of all bacteria

The normal habitat for Vibrio cholerae is (humans/animals/water).

water

The use of super-absorbent tampons has been implicated in which of the following staphylococcal diseases?

toxic shock syndrome

What is the causative pathogen for bubonic and pneumonic plague?

Yersinia pestis

The IV regimen administered by Ron's doctors is consistent with the CDC's recommendation that doxycycline be administered when RMSF is suspected. Apply your knowledge of RMSF to choose the most likely reasons behind this recommendation.

-A delay in treatment can lead to complications that include respiratory, cardiac, and renal failure. -Without prompt treatment, RMSF can have a mortality rate as high as 20%. -Most tests that can definitively identify R. rickettsii are not very effective early in infection. -The symptoms of RMSF are similar to those of several other infections, making definitive diagnosis difficult.

Which of the following conclusions are supported by the current research data?

-Burkholderia cepacia complex appears to be very diverse in its habitat and distribution. -It would appear that the environment may serve as a reservoir for acquiring Burkholderia cepacia complex strains. -Genomovars III and II appear to be the most virulent or transmissible to humans.

Which of the following are properties of exotoxins?

-Exotoxins are protein molecules. -Very small amounts of exotoxin can be lethal. -Exotoxins target specific cellular structures or molecules.

An indirect immunofluorescence assay is described as the CDC "gold standard serological test" for RMSF. Keeping in mind the principles behind indirect fluorescent-antibody (indirect FA) testing, which of the following characteristics contributes to its choice as the gold standard?

-Indirect FA will detect R. rickettsii-specific antibodies present in the patient's serum. -Indirect FA is more sensitive than direct immunofluorescent testing. -Indirect FA uses an antibody that reacts with any human antibody. -Indirect FA is rapid, sensitive, and specific.

Which of the findings listed below support the hypothesis?

-Protein levels within the ileum loop fluid are increased up to 1000 units of toxin. -Increasing levels of sodium, potassium, bicarbonate, and chloride ions, as well as water, are secreted as toxin concentrations are increased from 25, 50, 100, and 150 units. -Histological observation indicates that morphological alteration and sloughing of epithelial cells occurs up to a maximum of 1000 units.

Disease research and epidemiology bring together many different facets to help us better understand disease pathology and spread. Which of the following statements are true?

-The interactions that occur between a microbe and host influence the evolution of both. -Bacterial exotoxins can be altered to create toxoids, which can be used to produce protective immunity in a host. -Some pathogens are able to cause disease within a host without penetrating the body.

Why does Dr. Turner change Chloe's initial antimicrobial therapy? Which of the following are valid reasons why Chloe's antimicrobial therapy should be changed?

-The isolate is confirmed to be Burkholderia cepacia. -Results of antimicrobial susceptibility testing were conflicting.

Which of the following findings are key to the cause of the outbreak?

-The sauce was prepared on an overcrowded steam table and, as a result, did not reach an appropriate temperature to kill any organisms. -Large quantities of meat were prepared and kept warm for a long time before they were served.

Because Chloe is complaining of stomachache and is refusing food, Dr. Turner orders tests to evaluate Chloe for pancreatic insufficiency. Which of the following test results would indicate pancreatic insufficiency?

-detection of fat in the feces, which indicates that fats are not being digested and appropriately absorbed in the intestine -reduced pancreatic elastase levels

The ability of Vibrio cholerae to cause disease depends on a number of factors. Which of the following are general requirements for any organism to cause disease within a host?

-gaining access to the host via a portal of entry -evasion of host defenses -adherence to host tissues

Today, Wanda is preparing a young woman, Rebecca, for the doctor's examination. Rebecca and her husband, Jake, are pretty sure that Rebecca is pregnant and they are very excited about becoming parents. Wanda asks a series of background questions, and then takes the woman's temperature, weight, and blood pressure. Dr. Myers comes in, introduces herself, and tells the young woman that she will be doing a pelvic exam with Pap smear, along with the pregnancy test. Wanda gets the supplies ready for the doctor, gives the girl a gown, and steps out of the room. After the examination, Dr. Myers asks Rebecca and Jake to make a follow-up appointment to discuss the results of the tests and, if appropriate, to make a prenatal care plan.At home that night, Wanda returns to her studies of the Chlamydia group of bacteria.

-is an infection of conjunctiva -can be caused by introduction of bacteria into the eye via a fomite in adults -is the leading cause of nontraumatic blindness in humans -can be passed to a child during birth

Chloe's mother wants to have another child. However, she is concerned that a second child might also have CF, so she encourages Chloe's stepfather to be tested. Tests reveal that he does NOT carry the CF gene. What is the chance that a second child born to Chloe's mother and stepfather will have CF?

0% chance of having CF

As an epidemiologist, Dr. Thompson is interested in determining the frequency with which a specified event occurs within a particular population at a certain instant or during a particular period. This measure is known as a rate. In epidemiologic practice, an attack rate is the most commonly used method of determining the extent or frequency with which a disease is experienced by a population of individuals. In this instance, Dr. Thompson is interested in knowing what percentage of the individuals who attended the July 4 celebration became ill. The attack rate is the number of individuals treated and/or had symptoms divided by the number of attending individuals. What is the attack rate of food poisoning among the group who attended the July 4 celebration?

105/150(100)= 70.0%

Rickettsia rickettsii is a gram-negative, obligate intracellular pathogen. Which of the following statements about the R. rickettsii life cycle is FALSE?

After entering a host, R. rickettsii multiplies to levels high enough to successfully invade cells and establish an infection.

It is estimated that _____ of the world's population may be infected with tuberculosis.

33%

In which of the following cases would you suspect wound botulism?

A person injures herself while gardening. Four days later she begins to feel weak and dizzy, with blurred vision and progressive paralysis.

Although cholera can be treated with antibiotics, data suggest that antibiotic treatment alone is NOT the most effective therapy. Which of the following statements describes the most likely reason for supplementing antibiotic therapy?

Antibiotic therapy addresses only the growth of V. cholerae; it doesn't address the extreme dehydration suffered by a person infected with V. cholerae.

What is the name of the vaccine given to prevent TB in countries where it is endemic?

BCG vaccine

Based on its Gram status, why are penicillin and other beta-lactam antibiotics effective against Streptococcus pneumoniae?

Beta lactam antibiotics are effective against Streptococcus pneumoniae because it is a Gram positive organism and does not have an outer membrane.

Streptococcus pneumoniae was originally named Diplococcus pneumoniae. Why was the genus name Diplococcus originally given to this organism?

Beta lactam antibiotics are effective against Streptococcus pneumoniae because it is a Gram positive organism and does not have an outer membrane.

What is one virulence factor that differentiates Staphylococcus aureus from other species of staphylococci?

It can produce coagulase.

The pneumococcal vaccine was made using the purified capsular material from 23 common strains of Streptococcus pneumoniae, but it is not effective against all strains. Why is this?

It cannot cover all the strains of Streptococcus pneumoniae because not all strains have the same antigens on their surface.

Which of the following is the result of inhalation of aerosols of fresh water containing a bacterial parasite of protozoa?

Legionnaires' disease

Strains of Streptococcus pneumoniae can cause disease only when a capsule is present. Why is the presence of a capsule considered a virulence factor?

The capsule prevents the bacterium from being digested after endocytosis in the cells of the host.

Even though Escherichia coli can cause, on occasion, severe human disease, there is no vaccine developed for it. Why do you think this is?

There is no vaccine developed for Escherichia coli because it is an advantageous part of our normal intestinal flora.

Wanda recently started a job at a local free women's health clinic. She took this job because she was raised in a family that struggled financially, so the free clinics were an important aspect of her childhood health care and she wants to give back to her community. Although the clinic sees women for a variety of issues, the most common visits are related to family planning and prenatal care. Because of this, Wanda is reading about sexually transmitted infections in order to be better at her job. From her school studies, Wanda is familiar with the infectious agent, symptoms, and treatment of many sexually transmitted infections, but she is particularly interested in the statistics from the local Health Department about STI rates in the area. When Wanda reads that C. trachomatis is the most common STI in the region, she decides to investigate the Chlamydia group of bacteria further. Which of the following are true for the Chlamydia group of bacteria?

They are all very small in size. They are all intracellular parasites.

Mycobacterium tuberculosis is considered a(n) __________.

aerobe

Genes for beta-lactamase are present in Burkholderia cepacia but are not normally expressed unless they are induced. Exposure to which of the following agents most likely induced the expression of beta-lactamase resistance in Burkholderia cepacia? (Select the one best answer.)

cephalexin

Based on the recommendations in this textbook, which antibiotic would be the treatment of choice for this disease?

cephalosporin

If the mother has (chlamydia/syphilis/yaws) at the time of birth, the pathogen can infect the newborn's eyes and may cause blindness.

chlamydia

Which of the following streptococcal infections is usually fatal?

necrotizing fascilitis

Why did his sexual partners believe they were not infected with a STD?

clinical signs/symptoms in females are often not detectable, especially early in the infection

In cystic fibrosis, a defective gene and its protein product lead to the production of thick and dehydrated mucus because of __________.

defective secretion of chloride ions and excess absorption of sodium

The Ixodes tick can infect humans with Borrelia burgdorferi during which stage(s) of its life cycle?

either as a nymph or an adult

An 85-year-old man arrives one summer morning at the clinic of his Florida retirement community with severe headache, chills, muscle pain, and nausea. He reports that the symptoms developed quite suddenly. He has had no rash. During the interview the man states that he is a World War II veteran of the battle for Guadalcanal in the South Pacific, a golfer, and an avid bird watcher who spends many hours in the woods near his home. He had not noticed any fleas, ticks, or lice on his body, but he had been almost "eaten alive" by chiggers. His cat had a few fleas, but he had "gotten the little buggers." He had not been out of the United States in 40 years. What disease is this man most likely to have?

endemic typhus

Pseudomonas aeruginosa is a true pathogen with a long list of virulence factors.

false

The patient reports having been sexually active with two or three women in the previous six months. Because his partners reported being "absolutely sure" that they wouldn't get pregnant and carried no sexually transmitted diseases, the patient had not used a condom. What disease does this patient have? What is the common name for this disease?

gonorrhea; " the clap"

How would you know if you were "eaten alive" by chiggers?

intense itching, especially of the feet and lungs

Treponema pallidum is transmitted almost solely by sexual contact because __________.

it is extremely fastidious and sensitive

The most important virulence factor of Vibrio cholerae is

its ability to produce a potent exotoxin.

Coliforms are distinguished from noncoliforms by their ability to ferment (glucose/citrate/lactose).

lactose

Which of the following symptoms is LEAST characteristic of Clostridium perfringens food poisoning?

moderate vomiting and fever