MCB 2004 Exam 4
Which one of the following causes a disease characterized by the catarrhal, paroxysmal, and convalescent stages?
Bordetella pertussis
Which of the following microbes has NOT been associated with bacterial meningitis? Streptococcus pneumoniae Mycobacterium leprae Haemophilus influenzae Neisseria meningitidis
Mycobacterium leprae
A 25-year-old man presented with fever, malaise, and a rash on his chest, arms, and feet. Which of the following causative agents is most likely to cause these symptoms? Candida HPV HSV-2 Treponema Nesseria
Treponema
Fluoroquinolones are the treatment prescribed for otitis externa, which is due to a __________.
bacterial infection
All of the following can lead to a positive tuberculin skin test EXCEPT being near someone with tuberculosis. previous tuberculosis infection. immunity to tuberculosis. current tuberculosis infection. vaccination
being near someone with tuberculosis
Vaccination is available for all the following EXCEPT rabies. Haemophilus meningitis. Neisseria meningitis. tetanus. botulism
botulism
The common cold __________.
can result from deposition of a single rhinovirus on the nasal mucosa
Which of the following is NOT caused by HSV-1? herpes gladiatorum herpes whitlow cold sores canker sores herpes encephalitis
canker sores
The most common NGU in the United States is treated with
cephalosporins
The lower respiratory tract is protected by all of the following EXCEPT mucous secretions. IgA antibodies. alveolar macrophages. competition with the normal flora of the lungs. the ciliary escalator
competition with the normal flora of the lungs
The structures of the influenza drug Tamiflu and sialic acid, the substrate for influenza virus's neuramidase, are shown in the figure. What is the method of action of Tamiflu?
competitive inhibition
Inflammation of the thin clear membrane lining the eyelid and eye is properly termed
conjunctivitis
Which of the following requires treatment with both antibiotics and antitoxins? scarlet fever diphtheria psittacosis whooping cough tuberculosis
diphtheria
All of the following are true of the common cold EXCEPT it is caused by rhinoviruses and coronaviruses. it is transmitted via aerosols and contact. the duration of symptoms is approximately one week. complications include laryngitis and otitis media. early treatment will drastically reduce the disease symptoms
early treatment will drastically reduce the disease symptoms
The most effective control of mosquito-borne disease is
elimination of the mosquito population.
A possible complication of chickenpox is
encephalitis
Arboviruses cause ________ and are transmitted by ________.
encephalitis; mosquitoes
Which of the following would be selective against the tubercle bacillus?
ethambutol inhibits mycolic acid synthesis
The development of multi-drug resistance in Staphylococcus aureus is a classic example of ______.
evolution
Clostridium difficile-associated diarrhea is usually preceded by
extended use of antibiotics.
A predisposing factor for infection by Clostridium perfringens is
gangrene
Which of the following are symptoms of influenza infection?
muscle pain, fever, headache NOT diarrhea
Which of the following antibiotics is recommended for use against gram-negative bacteria?
polymyxin
The antibiotic chloramphenicol binds to the 50S subunit of the ribosome, as shown in the figure. The effect is to
prevent peptide bond formation in prokaryotes.
More than half of our antibiotics are
produced by bacteria.
Which of the following is greater? the number of reported cases of AIDS last year the number of reported cases of gonorrhea last year The number of reported cases of gonorrhea and AIDS are likely equal.
the number of reported cases of gonorrhea last year
Human-to-human transmission of plague is usually by
the respiratory route
Thrush and vaginitis are caused by
Candida albicans
The patient has vesicles and scabs over her forehead. Microscopic examination of skin scrapings shows gram-positive cocci in clusters. The etiology is
Staphylococcus aureus.
Which of the following organisms would MOST likely be sensitive to natural penicillin?
Streptococcus pyogenes
To date, most of our natural antibiotics have been found to be produced by members of what genus?
Streptomyces
More than half of the antibiotics used today are produced by __________.
Streptomyces species
If Caleb's strain of M. tuberculosis is sensitive to antibiotic treatment, which of the following could be used to treat his infection?
Streptomycin, isoniazid & ethambutol, rifampin
Which statement regarding the skin is FALSE? Sweat contains an enzyme called lysozyme, which breaks down the cell walls of some bacteria. It is waterproof. Sweat glands produce sebum in addition to sweat. The outer layer is composed of dead cells
Sweat glands produce sebum in addition to sweat
Many possible explanations were given as to why the numbers of pertussis infections were increasing, but the most likely explanation was that the DTaP vaccine was not as effective as the DTP at protecting children long-term. Which of the following best describes why this is the case??
The DTaP vaccine is not made with cellular components that would stimulate the immune system as effectively as the DTP vaccine.
Which statement regarding tests for microbial susceptibility to chemotherapeutic agents is FALSE? During the Kirby-Bauer test, a Petri plate with agar medium is uniformly inoculated with a standardized amount of a test organism. The Kirby-Bauer test is useful because it can differentiate bacteriostatic effects from bactericidal effects. A broth dilution test is often used to determine MIC and MBC of an antimicrobial drug. During a disk-diffusion test, a clear zone around the test disk indicates that growth was inhibited
The Kirby-Bauer test is useful because it can differentiate bacteriostatic effects from bactericidal effects
Which of the following is an accurate statement concerning the Sabin and Salk vaccines?
The Sabin vaccine is slightly more dangerous because it is made from live, attenuated virus, and the virus occasionally reverts back to its pathogenic form.
Cystitis is most often caused by
E. Coli
Most nosocomial infections of the urinary tract are caused by
E. Coli
Pyelonephritis usually is caused by
E. Coli
Bacteria Intoxication Examples
Staphylococcus aureus
What is meant when a bacterium is said to become "resistant" to an antibiotic?
The bacterium is neither killed nor inhibited by the antibiotic.
Warts are caused by
papillomavirus
A 25-year-old man presented with fever, malaise, and a rash on his chest, arms, and feet. Diagnosis was based on serological testing. The patient then reported that he had an ulcer on his penis two months earlier. What stage of disease is the patient in?
secondary
A characteristic symptom of plague is
swollen lymph nodes
Which of the following is treated with penicillin? candidiasis syphilis genital warts trichomoniasis genital herpes
syphilis
What is meant by selective toxicity?
Chemotherapeutic agents should act against the pathogen and not the host
The most common cause of traveler's diarrhea is
Escherichia coli.
John went to a picnic. He took home some leftover chicken and rice, heated it on the stove, ate it, and got sick two hours later. John thought the heating made his food safe because it would have killed any bacteria present. He didn't know that __________ produces a heat-stable toxin.
Staphylococcus aureus
In which of the following respects is measles similar to German measles (rubella)?
They can be controlled by vaccination
Why should children younger than 1 year of age NOT be fed honey?
They may contract botulism.
Sulfanilamides interfere with __________.
folic acid synthesis in bacteria
Which of the following antimicrobial agents is recommended for use against fungal infections?
amphotericin B
The most effective means of preventing influenza is
annual vaccination
At home test kit advantages
anyone can purchase and use increased treatment improved communication
Which region of the skin supports the largest bacterial population?
armpits
Newborns' eyes are treated with an antibiotic
as a routine precaution
R-plasmids are most likely acquired via
bacterial conjugation
An eight-year-old girl has scabs and pus-filled vesicles on her face and throat. Three weeks earlier she had visited her grandmother, who had shingles. What infection does the eight-year-old have?
chickenpox
Which of the following pairs is mismatched? otitis externa - Pseudomonas chickenpox poxvirus Buruli ulcer Mycobacterium keratitis Acanthamoeba conjunctivitis Chlamydia trachomatis
chickenpox poxvirus
"Rice water stools" are characteristic of
cholera
The data in the table show that these bacteria
developed resistance to antibiotics
Which of the following is NOT a typical symptom of influenza? fever headache diarrhea chills muscle aches
diarrhea
Epstein-Barr virus has been implicated in all of the following EXCEPT infectious mononucleosis. Hodgkin's disease. Burkitt's lymphoma. nasopharyngeal carcinoma. endocarditis
endocarditis
The symptoms of gas gangrene are due to all of the following EXCEPT microbial fermentation endocarditis hyaluronidase proteolytic enzymes necrotizing exotoxins
endocarditis
Which of the following is mismatched? laryngitis voice loss epiglottitis sore throat sinusitis headache and nasal mucous pharyngitis sore throat otitis media earache
epiglottitis sore throat
Recurring vesicles on the surface of human skin are symptoms of
genital herpes
Which of the following is the most difficult to treat with chemotherapeutic agents? syphilis genital herpes gonorrhea leptospirosis trichomoniasis
genital herpes
Which of the following recurs at the initial site of infection? syphilis chancroid gonorrhea LGV genital herpes
genital herpes
Gums bleeding while brushing one's teeth is most commonly associated with
gingivitis
The most common reportable disease in the United States is
gonorrhea
Niclosamide prevents ATP generation in mitochondria. You would expect this drug to be effective against
helminths
A 25-year-old male presented with fever, malaise, and a rash on his chest, arms, and feet. Diagnosis was based on serological testing. The patient then reported that he had an ulcer on his penis two months earlier. This disease can be treated with
penicillin
Which of the following antimicrobial agents has the fewest side effects?
penicillin
A patient has fever, difficulty breathing, chest pains, fluid in the alveoli, and a positive tuberculin skin test. Gram-positive cocci are isolated from the sputum. The patient most likely has
pneumococcal pneumonia
Brucella bacteria are considered a potential agent of bioterrorism because
they easily become airborne
Which of the following diseases is NOT correctly matched to its vaccine? tuberculosis toxoid diphtheria toxoid whooping cough heat-killed bacteria influenza viruses grown in embryonated eggs pneumococcal pneumonia capsular polysaccharides
tuberculosis toxoid
Which of the following is a symptom of brucellosis?
undulant fever
Which statement regarding the structure or function of the urinary system is FALSE? In the male, the urethra conveys only urine to the exterior. Physiological valves prevent the backflow of urine from the bladder to the kidneys. Normal urine has some antimicrobial properties. In females, the urethra conveys only urine to the exterior
In the male, the urethra conveys only urine to the exterior
Describe the process of periodontal disease. (ESSAY)
Chronic inflammation of the gum tissue surrounding the teeth is associated with the bacterial biofilm (plaque) that covers the teeth and gums. Gingivitis was once seen as the first stage in a chronic degenerative process which resulted in the loss of both gum and bone tissue surrounding the teeth.
A 30-year-old woman was hospitalized after she experienced convulsions. On examination, she was alert and oriented and complained of a fever, headache, and stiff neck. Any of the following organisms could be responsible for her symptoms EXCEPT Haemophilus influenza. Clostridium botulinum. Streptococcus pneumoniae. Listeria monocytogenes. Any of these organisms could be the causative agent
Clostridium botulinum
All of the following are gram-negative rods that cause gastroenteritis EXCEPT Clostridium perfringens. Yersinia enterocolitica. Shigella spp. Escherichia coli. Salmonella typhi.
Clostridium perfringens
Why does Dr. Bell start Caleb on HIV therapy in addition to the antibiotics used to treat the tuberculosis?
Dr. Bell prescribes Caleb HIV therapy because the virus is not affected by the antibiotics used to treat tuberculosis.
Which of the following is NOT treated with antibiotics? Lyme disease Ebola tularemia plague anthrax
Ebola
Membrane transport proteins are required for which mode(s) of antibiotic resistance?
Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins.
T/F A microbe that enters the vagina would likely cause cystitis if left untreated.
False
T/F A positive tuberculosis skin test indicates that the patient has active tuberculosis.
False
T/F Autopsy of a stillborn fetus reveals the cause of death to be meningitis. Cultures show the presence of a gram-positive rod. The likely pathogen is Haemophilus influenza.
False
T/F Only HSV-2 can cause genital herpes.
False
T/F Only microbes produce antimicrobial peptides.
False
T/F PABA serves as the competitive inhibitor in the action of sulfanilamides.
False
T/F Penicillin and streptomycin are commonly used in synergism because they display the same mode of action.
False
T/F The abbreviation "GAS" refers to pathogenic strains of Staphylococcus.
False
T/F Tularemia is considered to be a potential bioterrorism agent due its high infective dose.
False
T/F Vaccination with the influenza vaccine confers lifelong immunity to influenza virus.
False
T/F Women and men typically have the same normal microbiota in their reproductive systems.
False
What is the likely cause for the drop in glucose levels?
N. meningitidis uses the glucose as a source of energy to fuel its growth.
Infants may acquire a serious form of conjunctivitis during birth if they are born to a mother infected with
Neisseria gonorrhoeae
Which of the following is NOT a complication of gonorrhea? pelvic inflammatory disease endocarditis meningitis arthritis None of the answers are correct; all of these are potential complications of gonorrhea
None of the answers are correct; all of these are potential complications of gonorrhea
Which of the following is NOT a predisposing factors to cystitis in females? poor personal hygiene sexual intercourse the length of the urethra the proximity of the anus to the urethra None of the answers is correct; all of these are predisposing factors.
None of the answers is correct; all of these are predisposing factors
Nicole received her diagnosis at her physician's office. Which of the following procedures was most likely used by the physician to confirm her infection?
Nucleic Acid Amplification Testing (NAAT)
Why is it difficult to find good chemotherapeutic agents against viruses?
Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected.
Why is it more difficult to treat viral infections than it is to treat bacterial infections?
Viruses use the host cell's processes to carry out their own reproduction.
You have a culture of bacteria that you suspect is either Staphylococcus aureus or Streptococcus pyogenes. Is there any morphological difference between the two?
Yes. S. aureus tends to grow in clusters, whereas S. pyogenes tends to grow in chains
Dental plaque is an example of
a biofilm.
Assume that your lab partner swabs the side of his face and uses the swab to inoculate a nutrient agar plate. The next day, he performs a Gram stain on the colonies. They are gram-positive cocci. You advise him that he should next look for
a coagulase reaction
Our patient needs antibiotics to overcome this infection and prevent any further complications. Which of the following would be the best choice?
a combination therapy of cephalosporin-class AND macrolide-class.
John's physician said that he might be suffering from Chikungunya fever, an emerging disease that once was limited to Asia, Africa, and Europe, but is now making appearances in the Caribbean and the United States. How did John most likely get infected?
a mosquito bite
The bacteria appear to be in clusters, as opposed to chains. This suggests that your patient has ______.
a staphylococcal infection
Nicole knew that these were both sexually transmitted infections caused by bacteria. Which of the following is correct regarding the causative agents for these diseases? Giardia intestinalis causes syphilis, while Neisseria meningitidis causes gonorrhea. Treponema pallidum causes syphilis, while Neisseria gonorrhoeae causes gonorrhea. Trichomonas vaginalis causes syphilis, while Chlamydia trachomatis causes gonorrhea. Borrelia burgdorferi causes syphilis, while Shigella dysenteriae causes gonorrhea.
Treponema pallidum causes syphilis, while Neisseria gonorrhoeae causes gonorrhea.
T/F An outbreak of viral gastroenteritis occurs in a pediatrics ward. Rotavirus is the most likely causative agent.
True
T/F Anatomically, women have more portals of entry in the reproductive system compared to men.
True
T/F Antiviral drugs target viral processes that occur during viral infection.
True
T/F Blue-green pus is characteristic of Pseudomonas wound infections.
True
T/F Campylobacter gastroenteritis is the leading cause of foodborne illness in the United States.
True
T/F Due to its target, rifamycins can be effective over a broad spectrum
True
T/F Gastroenteritis due to ingestion of food contaminated with Staphylococcus aureus is due to intoxication by enterotoxins.
True
T/F H. pylori is able to survive the acidic environment of the stomach as a result of adaptations that allow it to increase the pH of the immediate environment.
True
T/F Haemophilus influenzae is the most common bacterial cause of pinkeye
True
T/F Infections with Legionella pneumophila are usually transmitted via aerosols from contaminated air conditioning systems, showers, and humidifiers.
True
T/F It is common for a normal, healthy individual to carry potentially pathogenic organisms in their upper respiratory tract.
True
T/F Lactic acid, an end product of fructose fermentation, causes breakdown of tooth enamel and, eventually, cavities.
True
T/F Mycoplasma pneumoniae causes atypical pneumonia, also known as "walking pneumonia."
True
T/F Pathogens of the skin often enter via hair follicles and ducts of the sweat glands.
True
T/F Risks for Q fever include contact with infected cattle and drinking unpasteurized milk.
True
T/F Subacute bacterial endocarditis is commonly the result of infections initially focused on the oral cavity.
True
T/F The varicella-zoster virus is the causative agent of chickenpox and shingles.
True
Which disease or microbe is NOT transmitted across the placenta to the unborn fetus? toxoplasmosis congenital syphilis ophthalmia neonatorum neonatal herpes
ophthalmia neonatorum
Which of the following pairs is mismatched? listeriosis ingestion meningococcal meningitis respiratory route rabies direct contact leprosy direct contact poliomyelitis respiratory route
poliomyelitis respiratory route
Helicobacter pylori can grow in the stomach because it
possesses an enzyme that neutralizes HCl.
On October 5, a pet store sold a kitten that subsequently died. On October 22, rabies was diagnosed in the kitten. Between September 19 and October 23, the pet store had sold 34 kittens. Approximately 1000 people responded to health care providers following local media alerts. These people were given
postexposure prophylaxis
Which of the following are incorrectly matched? varicella-zoster chickenpox herpes zoster shingles parvovirus fifth disease HHV-6 roseola poxvirus fever blisters
poxvirus fever blisters
Which of the following is NOT a characteristic of Bacillus anthracis? is gram-positive forms endospores produces endotoxins found in soil is aerobic
produces endotoxins
Which of the following is NOT a zoonosis? anthrax tularemia brucellosis Hantavirus infection puerperal sepsis
puerperal sepsis
Which of the following pairs is mismatched? pericarditis Streptococcus pyogenes acute bacterial endocarditis Staphylococcus aureus subacute bacterial endocarditis alpha-hemolytic streptococci Burkitt's lymphoma Epstein-Barr virus puerperal sepsis Staphylococcus aureus
puerperal sepsis Staphylococcus aureus
Which of the following does NOT affect eukaryotic cells?
semisynthetic penicillins
Which of the following is NOT a recognized form of anthrax? inhalational septic gastrointestinal cutaneous
septic
A 25-year-old man presented with fever, malaise, and a rash on his chest, arms, and feet. Which of the following will be most useful for a rapid diagnosis?
serological test for antibodies
The symptoms of tetanus are due to
tetanospasmin
Initial treatment for tetanus in an unimmunized person with a puncture wound is
tetanus immune globulin
The antimicrobial drugs with the broadest spectrum of activity are
tetracyclines.
What part of the United States is endemic for RMSF?
the Appalachian region (North Carolina, Kentucky)
Use of antibiotics in animal feed leads to antibiotic-resistant bacteria because
the antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal.
When a patient is treated with antibiotics, __________.
the drug will kill or inhibit the growth of all of the sensitive bacterial cells
Which of the following is NOT an antimicrobial feature of the urinary system? flushing action of urine physiological valves found in the ureter pH of the urine the use of the urethra for seminal fluid in women
the use of the urethra for seminal fluid in women
The eradication of smallpox was possible because
there are no animal reservoirs of the virus
All of the following are transmitted via the respiratory route EXCEPT rubella. chickenpox. tinea. measles. smallpox
tinea
A 45-year-old man has pus-filled vesicles distributed over his back in the upper right quadrant, over his right shoulder, and upper right quadrant of his chest. His symptoms are most likely due to
varicella-zoster virus
Which of the following is NOT caused by infection of the upper respiratory tract? diphtheria whooping cough scarlet fever streptococcal pharyngitis
whooping cough
The primary victims of the influenza pandemic of 1918-1919 were
young adults
Now that we have looked at ways to prevent breeding in mosquitos, another possible prevention is to limit the vector geographically, but recent climate changes have led to changes in location where the mosquito can now be found. Which of the following climate change scenarios has allowed for this increase in vector habitat?
warmer temperatures in northern regions with increased rainfall
Drug resistance occurs
when antibiotics are used indiscriminately.
A driving force of this sort of evolution is natural selection , which is sometimes colloquially referred to as the
"survival of the fittest."
Normal microbiota of the adult vagina consist primarily of
Lactobacillus
Most of the available antimicrobial agents are effective against
bacteria.
In the presence of penicillin, a cell dies because
it undergoes lysis.
The greatest single cause of blindness in the world is
trachoma
The antibiotic actinomycin D binds between adjacent G-C pairs, thus interfering with
transcription
The process of acquiring antibiotic resistance by means of bacteriophage activity is called
transduction
Which of the following is evidence that the arthritis afflicting children in Lyme, Connecticut, was due to bacterial infection?
treatable with penicillin
Select all of the statements that describe a mechanism that would enable a microorganism to resist the action of an antibiotic.
-A microbe develops a transport mechanism in the plasma membrane that rapidly pumps antibiotic out of the bacterial cell. -Target site is modified, so that an antibiotic is unable to bind to its target. -Altered porins in the cell wall block passage of antibiotic through the cell wall. -An enzyme that destroys the antibiotic is produced.
The two most common STI organisms associated with PID in the United States are Chlamydia trachomatis and Neisseria gonorrhoeae. There are many similarities between these STIs. Which of the following statements comparing chlamydia and gonorrhea are true?
-Chlamydia and gonorrhea can infect a patient and be transmitted without causing obvious symptoms. -Chlamydia is found more often in women, whereas gonorrhea is found more often in men. -Patients may be coinfected with both gonorrhea and chlamydia.
What are some of the current challenges to production of the influenza vaccine?
-In order to yield a vaccine, the virus must be produced in eggs -The virus undergoes antigenic changes on a regular basis
Which of the following statements regarding antigenic shift are true?
-Little immunity to virus strains resulting from antigenic shift exists in the population. -Antigenic shift results in a major change in the genetic composition of the virus -Viral strains resulting from antigenic shift contain RNA segments from different species
Select all of the statements that accurately describe the origins and spread of antibiotic resistance.
-Mutations are the ultimate source of antibiotic-resistance genes. -Antibiotic-resistance genes can be passed from one bacterium to another by bacterial transformation. -Antibiotic resistance is readily transmitted to the next generation during binary fission. -Antibiotic-resistance genes can be passed horizontally via transduction. -Antibiotics select for those microbes that have developed resistance, increasing their frequency in the bacterial population. -Antibiotic-resistance genes can be passed horizontally via bacterial conjugation.
Alteration of the drug's target site
-Resistance to clindamycin develops when mutations in bacteria alter the ribosomal binding site to which clindamycin would normally bind. -MRSA (methicillin-resistant Staphylococcus aureus) is resistant to all β-lactam drugs because of a mutation in its penicillin-binding protein (PBP).
Part of the reason for Scott's acne is the overproduction of sebum. Scott's initial instinct is that shutting down production of sebum would be the quickest route to eliminating his acne; however, sebum actually plays an important role in maintaining the skin as a first line of defense against pathogens. Which of the following best describes the role of sebum as a component of the first line of defense?
-Sebum helps to keep the pH of the skin low, which inhibits the growth of microorganisms. -Sebum forms a protective layer over the skin.
Natural selection is a gradual, nonrandom process by which biological traits become more or less frequent within a population. Which of the following are necessary conditions for natural selection to occur within a population of Staphylococcus aureus?
-Traits are hereditary -Some individuals in the population reproduce more than others. -Traits that permit an individual to survive at least until reproduction will increase in frequency over time -Individuals in the population vary from one another
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.
-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. -A delay in treatment can lead to complications that include respiratory, cardiac, and renal failure. -The symptoms of RMSF are similar to those of several other infections, making definitive diagnosis difficult.
Predict which of the following would be outcomes of treatment with Tamiflu.
-a decrease in the release of the viral particles from the cell -overall decrease in the replication rate of influenza -an increase in the ability of the immune system to combat the infection
Predict which of the following are reasonable outcomes of the cytokine storm during the 1918 flu pandemic.
-an excessive inflammatory response leading to extensive tissue damage -increased fluid in the lungs and labored breathing
Interfering with DNA replication
-inhibiting DNA gyrase -interfering with DNA polymerase
Which of the following findings are key to the cause of the outbreak of Colstridium perfringens?
1) The sauce was prepared on an overcrowded steam table and, as a result, did not reach an appropriate temperature to kill any organisms. 2) Large quantities of meat were prepared and kept warm for a long time before they were served.
In the table, the minimal inhibitory concentration of antibiotic X is
10 μg/ml.
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. What is the attack rate of food poisoning among the group who attended the July 4 celebration?
105/150(100)= 70.0%
In the table, as illustrated by the data shown, the minimal bactericidal concentration of antibiotic X is
15 μg/ml.
Which of the following is NOT a characteristic of tuberculosis infection? The adaptive immune response is mostly cell mediated, because Mycobacterium tuberculosis lives and reproduces inside macrophages. A TB diagnosis can be rapidly confirmed because the organism that causes this disease grows quickly. An individual could become infected by standing next to an infected person who is coughing. Treatment requires a minimum of 6 months of antibiotic therapy
A TB diagnosis can be rapidly confirmed because the organism that causes this disease grows quickly
What diagnostic test would be most useful of meningitis?
A lumbar puncture to obtain a sample of cerebrospinal fluid (CSF).
The Big Picture Activity mentioned that because no vaccine is available, prevention is the next method for keeping the number of infections to a minimum. One of the methods recommended by the CDC is to prevent infected individuals from receiving mosquito bites during the first week of their infection. How does this help prevent further spread of infection?
Additional bites would increase the chances of an uninfected vector acquiring the virus.
John mentioned that while in the Caribbean, he had been very careful to wear bug spray when outside and to use a mosquito net around the bed at night. Why were these protective measures not enough to keep him from being infected?
Aedes mosquitoes prefer to live inside buildings, are more resistant to bug spray, and feed during the day.
Rickettsia rickettsii is a gram-negative, obligate intracellular pathogen. Which of the following statements about the R. rickettsii life cycle is FALSE? Like viruses, R. rickettsii requires a eukaryotic host in order to carry out its life cycle. After entering a host, R. rickettsii multiplies to levels high enough to successfully invade cells and establish an infection. During infection, R. rickettsii is able to survive and replicate within eukaryotic cells. In order to cause RMSF, R. rickettsii must enter host cells
After entering a host, R. rickettsii multiplies to levels high enough to successfully invade cells and establish an infection
Why does the physician start Caleb on the antibiotic azithromycin before laboratory results come back?
Antibiotic therapy is started with a broad-spectrum antibiotic because broad-spectrum antibiotics are effective against many gram-positive and many gram-negative bacteria.
Nicole is very upset after receiving news that her ex-boyfriend Paul had tested positive for syphilis and gonorrhea. She makes an appointment with her physician. Nicole receives her test results, which indicate that she is positive for syphilis, but not for gonorrhea. What treatment will her doctor most likely prescribe?
Antibiotics
Which statement regarding Influenzavirus is true?
Antigenic shift can occur because the genome is in several pieces.
In which of the following North American locations would you expect to find the highest incidence of infection with Borrelia burgdorferi?
Atlantic coast
Why are the unreported cases of STIs an important public health concern? (ESSAY)
Because if it goes unreported, then there is no way of knowing how many cases there are out there and then it is hard to tell how likely it is to catch a disease. It increases the chances for the STI to continue to spread. Also, if there is an accurate number of documented cases, public healthcare can increase their knowledge and offer more treatments.
A patient has a paroxysmal cough and mucus accumulation. What is the etiology of the symptoms?
Bordetella
Tetanus, diphtheria, and whooping cough are all bacterial infections. Which of the following bacteria is responsible for causing whooping cough?
Bordetella pertussis
The exam room poster for whooping cough also listed the various vaccines that could be given. The three possible vaccines were the DTP, the DTaP, and the Tdap. The DTP was made with heat-killed whole cells of the bacterium B. pertussis, while the DTaP and the Tdap were made with acellular pertussis components. Which of the following statements regarding the vaccines explains why the DTP vaccine is no longer used?
Bordetella pertussis was not killed during the heating process used on the DTP vaccine and could cause an active infection
In what way are semisynthetic penicillins and natural penicillins alike?
Both are based on β-lactam.
The development of which disease is promoted by mosquito-borne malarial infections?
Burkitt's lymphoma
The patient is suffocating because of the accumulation of dead tissue and fibrin in her throat. What is the etiology of the symptoms?
Corynebacterium
Which of the following does NOT cause otitis media? Streptococcus pneumoniae Moraxella catarrhalis Streptococcus pyogenes Haemophilus influenzae Coxiella burnetii
Coxiella burnetii
Quinolones and fluoroquinolones act against what bacterial target?
DNA gyrase
The name Propionibacterium is derived from the fact that the organism produces propionic acid during fermentative metabolism. Which of the following statements about fermentative metabolism is true?
Fermentation produces significantly less ATP than aerobic respiration; however it generates NAD+, which can be used in glycolysis.
A 30-year-old woman was hospitalized after she experienced convulsions. On examination, she was alert and oriented and complained of a fever, headache, and stiff neck. Which of the following is most likely to provide rapid identification of the cause of her symptoms?
Gram stain of cerebrospinal fluid
A one-year-old boy was listless, irritable, and sleepy. Capsulated Gram-negative rods were cultured from his cerebrospinal fluid. His symptoms were caused by
Haemophilus influenzae
Vaccines can be used to protect at-risk individuals from all of the following liver diseases EXCEPT __________.
Hep C
Compare the modes of transmission for hepatitis A, B, and C. (ESSAY)
Hepatitis A is transmitted through urine or fecal matter. Hepatitis B and C are transmitted through contact with the blood or body fluids of an infected person. In the U.S., it's most often spread through unprotected sex. It's also possible to get hepatitis B by sharing an infected person's needles, razors, or toothbrush. And an infected mother can pass the virus to her baby during childbirth.Hepatitis C is most commonly spread through contact with infected blood. This usually happens by sharing contaminated needles used for injecting drugs. Other less common ways that hepatitis C is transmitted are through sexual contact, birth to a mother with the hepatitis C virus, or a needle stick injury.
Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug?
Humans and other animal hosts lack peptidoglycan cell walls.
_______ antibodies are found in mucosal secretions and help to protect the respiratory system from infection
IgA
The at-home tests work similarly to pregnancy tests and are based on antigen-antibody reactions between the infectious agent and the patient's antibodies. Which class of antibody is most likely to give a result in the assay?
IgG
Why would conjugation to a protein carrier improve the efficacy (i.e. improve the immune response generated by the vaccine) of a polysaccharide vaccine?
In contrast to polysaccharide vaccines, protein-conjugated vaccines elicit a strong T-cell dependent response.
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.
Which of the following statements is FALSE? Amantadine inhibits the release of viral nucleic acid. Acyclovir inhibits DNA synthesis. Fluoroquinolone inhibits DNA synthesis. Azoles inhibit plasma membrane synthesis. Interferon inhibits glycolysis
Interferon inhibits glycolysis
Why is polymyxin only used on the skin?
It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead.
Which of the following statements about staphylococcal food poisoning is FALSE? It is treated by replacing water and electrolytes. It is characterized by rapid onset and short duration of symptoms. It can be prevented by adequate refrigeration of food. It can be prevented by heating foods to 50°C for 15 minutes. It is caused by ingesting an enterotoxin
It can be prevented by heating foods to 50°C for 15 minutes.
Which of the following is NOT true of acne? Antibiotics may be prescribed for moderate cases. It can be treated by eliminating fatty foods from the diet. It is often due to the action of Propionibacterium. Mild cases are treated with topical agents. Drugs that inhibit sebum formation are useful in treating inflammatory acne
It can be treated by eliminating fatty foods from the diet
Which of the following statements about congenital rubella syndrome is FALSE? It does not occur with subclinical infections. It may be fatal to the unborn child. It may result in deafness, blindness, and mental retardation. It is contracted during the first trimester of pregnancy. It can be prevented by vaccinating women prior to pregnancy.
It does not occur with subclinical infections
Which of the following statements about Neisseria meningitis is FALSE? It is encapsulated. A healthy carrier state can exist. It is a gram-positive anaerobe. Its most distinguishing feature is a unique rash. It is typically transmitted by droplet aerosols or direct contact with secretions
It is a gram-positive anaerobe
Which one of the following statements about genital warts is FALSE? It is transmitted by direct contact. It is caused by papillomaviruses. It is always precancerous. It is treated by removing them. It can lead to cervical cancer in women.
It is always precancerous.
Which of the following statements about drug resistance is FALSE? It may be due to enzymes that degrade some antibiotics. It may be due to decreased uptake of a drug. It may be transferred from one bacterium to another during conjugation. It is found only in gram-negative bacteria. It may be carried on a plasmid.
It is found only in gram-negative bacteria.
Which of the following statements about rheumatic fever is FALSE? The incidence has declined in the last ten years. It is an inflammation of the heart. It is a complication of a group A beta-hemolytic streptococcal infection. It is an inflammation of the joints. It is rarely fatal, even when untreated
It is rarely fatal, even when untreated
Microscopic examination of cerebrospinal fluid reveals gram-positive rods. What is the organism?
Listeria
All of the following organisms are transmitted via the respiratory route EXCEPT Neisseria meningitidis. Cryptococcus neoformans. Haemophilus influenzae. Listeria monocytogenes
Listeria monocytogenes
Which of the following contribute to drug resistance in M. tuberculosis?
Many individuals fail to complete their entire regimen of antibiotics. Some physicians prescribe the wrong medication, the wrong dosage, or the wrong length of time for treating tuberculosis. In many areas, tuberculosis antibiotics are unavailable or of poor quality.
Enzymatic inactivation of the antibiotic
Many strains of Neisseria gonorrhoeae are resistant to penicillin because of the production of β-lactamases.
Which of the following statements about rabies is FALSE? Diagnosis is based on immunofluorescent techniques. Hydrophobia is associated with the disease. It is caused by Lyssavirus. Average incubation period is 30 to 50 days after initial infection. Most infections in the U.S. are the result of bites from infected dogs
Most infections in the U.S. are the result of bites from infected dogs
Infection by which of the following is often confused with viral pneumonia?
Mycoplasma
Which one of the following produces small "fried-egg" colonies on medium containing horse serum and yeast extract?
Mycoplasma
Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what?
PABA
Which of the following pairs is mismatched? Spirillum rat-bite fever Pasteurella cat-scratch disease Borrelia relapsing fever Yersinia plague Streptobacillus rat-bite fever
Pasteurella cat-scratch disease
An individual presents with a pinkish-red rash and a red sore throat. Gram-positive cocci are cultured from a throat swab. The cocci are growing in chains. Which of the following is the most likely conclusion?
Patient has scarlet fever
Which of the following statements about leprosy is FALSE? Diagnosis is based on skin biopsy. It is rarely fatal. It is transmitted by direct contact. Patients with leprosy must be isolated. The etiologic agent is acid-fast
Patients with leprosy must be isolated
Which antibiotic is overcome by beta-lactamases?
Penicillin
Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug?
Penicillin disrupts the cell wall, which is located outside of the cell membrane.
Which statement regarding normal microbiota of the urinary and reproductive systems is true? Normal urine has a high level of normal, nonpathogenic microbes. Candida albicans is the predominant bacterium in the vagina. The male urethra is usually highly contaminated with microbes. Pregnancy and menopause are associated with higher rates of urinary tract infections
Pregnancy and menopause are associated with higher rates of urinary tract infections.
A 17-year-old boy has pus-filled cysts on his face and upper back. Microscopic examination reveals gram-positive rods. This infection is caused by
Propionibacterium acnes
Rapid efflux of the antibiotic
Pseudomonas aeruginosa has membrane pumps that export a number of different antibiotics from its cells.
List the disease symptoms and virulence factors associated with Pseudomonas infections. Why can Pseudomonas be difficult to control in a hospital environment? (ESSAY)
Pseudomonas can be difficult to control due to the fact that it is gram-negative and hard to treat with certain antibiotics and also because it mutates.
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.
Explain the difficulties in developing antiviral drugs against DNA viruses, when compared to RNA viruses. (ESSAY)
RNA viruses have a faster mutation rate compared to DNA viruses. Therefore, once a treatment is made, the virus would have already changed and the treatment will need to be updated.
Prevention of penetration to the target site within the microbe
Resistance to tetracycline may result from modified pore proteins in the outer membrane that form a porin too small for the tetracycline to pass through.
How might efflux pumps increase antibiotic resistance in bacteria?
Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.
Which of the following is responsible for epidemics of respiratory disease in infants?
Respiratory syncytial virus (RSV)
What disease does Paul suspect Ron might have contracted? His symptoms include fever, headache, and macular rash.
Rocky Mountain Spotted Fever
Poultry products are a likely source of infection by
Salmonella enterica.
Which of the following mutations would not result in antibiotic resistance?
Silent mutation
Using diphtheria and whooping cough as examples, discuss why it is necessary to continue to vaccinate against diseases that are relatively rare in the U.S. today. (ESSAY)
So that way it does not return and infect the public--especially people that are unable to be vaccinated (infants) or people with weak immune systems.
A child presents with large red patches of skin. The top layers are peeling off. Because the parents report that the child hasn't been burned, you suspect that the lesions are due to infection with __________.
Staphylococcus aureus
Which of the following statements about salmonellosis is FALSE? A healthy carrier state exists. Severity of disease depends on number of organisms ingested. It is often associated with poultry products. The mortality rate is high. It is a bacterial infection
The mortality rate is high
Which statement regarding arboviral encephalitis is FALSE? Most human cases of West Nile virus (WNV) are subclinical or very mild. Horses, as well as humans, are frequently affected by arboviruses. The incidence of disease increases during summer months. The most effective preventive measure for arboviral infections is vaccination
The most effective preventive measure for arboviral infections is vaccination
Which statement correctly describes the normal microbiota of the skin?
The skin's normal microbiota are capable of growth at elevated salt concentrations.
Which of the following statements concerning mumps virus infection is FALSE? The illness frequently begins with painful swelling of one or both parotid glands. The virus is present in urine approximately 10 days after the onset of symptoms. The virus is transmitted in saliva and respiratory secretions. The testes can become inflamed about 2 to 3 weeks after the onset of symptoms
The testes can become inflamed about 2 to 3 weeks after the onset of symptoms
Which of the following statements concerning necrotizing fasciitis is FALSE? The tissue damage is mainly due to the production of endotoxin, which stimulates a severe immune response. It is often associated with streptococcal toxic shock syndrome. It may be caused by several different organisms, but Streptococcus pyogenes is the most common. Some cases require limb amputation
The tissue damage is mainly due to the production of endotoxin, which stimulates a severe immune response
Which statement regarding normal microbiota of the human respiratory system is FALSE? The upper respiratory tract is mostly sterile. The trachea normally may contain a few bacteria. The ciliary escalator in the bronchial tubes keeps the lower respiratory tract nearly sterile. Potentially pathogenic microorganisms are present in nonsterile portions of the respiratory tract but usually do not cause disease
The upper respiratory tract is mostly sterile
Which of the following statements concerning viral sexually transmitted infections (STIs) is true? The viral infections that cause genital warts and herpes can be treated but not cured. The serotypes of human papillomaviruses that cause cancer are the same serotypes that cause large, visible warts. Herpes simplex virus type 1 (HSV-1) causes only oral herpes. Individuals infected with herpesviruses are contagious only if a lesion is present.
The viral infections that cause genital warts and herpes can be treated but not cured.
Which of the following statements about mycoplasmal pneumonia is TRUE?
Treatment is tetracyclines
Which of the following does NOT constitute an advantage of using two antibiotics together? It lessens the toxicity of individual drugs. It allows treatment to be provided prior to diagnosis. Two are always twice as effective as one. It can prevent drug resistance. All of these are advantages of using two antibiotics together.
Two are always twice as effective as one.
Cholera is a waterborne pathogen that causes severe gastrointestinal disease. The organism is a slightly curved, gram-negative rod that likes to grow in the small intestine and causes watery stools and violent vomiting. Complete the following statement: Cholera is caused by the bacterium, __________ and produces __________ that result in severe diarrhea.
Vibrio cholera; exotoxins
Bacteria Infection Examples
Vibrio cholerae Shigella sonnei Escherichia coli Salmonella enterica
Which of the following statements about meningitis is TRUE? Meningitis is an infection of the cerebral tissue resulting when bacteria or viruses cross the blood brain barrier. There are more than 50 bacterial species commonly associated with meningitis. A vaccine exists to protect people against only meningitis caused by H. influenzae. Viral meningitis, while less severe than bacterial meningitis, is more common in occurrence.
Viral meningitis, while less severe than bacterial meningitis, is more common in occurrence
At home test kit disadvantages
kits can make mistakes information leaks increased costs
Which of the following is directly involved in the initiation of dental caries?
lactic acid
Which of the following is caused by Chlamydia? candidiasis Gardnerella vaginosis lymphogranuloma venereum genital herpes trichomoniasis
lymphogranuloma venereum
Which of the following antibiotics does NOT interfere with cell wall synthesis?
macrolides
Bacterial encephalitis and meningitis are difficult to treat because
many antibiotics cannot penetrate the blood-brain barrier
Koplik spots are a diagnostic indicator of
measles
All of the following are characteristic of the Group A beta-hemolytic streptococci EXCEPT hyaluronidase production. M proteins. the ability to dissolve blood clots. methicillin resistance. the ability to damage cell membranes
methicillin resistance
The prodromal (i.e. pre-acute disease stage) symptoms of bacterial meningitis is/are
mild cold symptoms
A patient presents with a fever and flank pain. Microscopic analysis of the urine reveals bacteria at a concentration above 10,000 colony-forming units (CFUs) per milliliter. You perform a leukocyte esterase (LE) test, and it is positive. What is the diagnosis?
pyelonephritis
A positive LE test and 10,000 CFU/ml in urine indicates
pyelonephritis
All of the following are protective factors of the skin and its secretions EXCEPT salt. keratin. pyocyanin production. tightly packed cells. lysozyme production
pyocyanin production
A pathologist detects Negri bodies while examining a brain section taken at autopsy. What was the cause of death?
rabies
Each of the following is caused by prions EXCEPT kuru. rabies. Creutzfeldt-Jakob disease. sheep scrapie. bovine spongiform encephalopathy
rabies
Acute gastroenteritis that occurs after an incubation period of two to three days and commonly affects children is probably caused by
rotavirus
A 9-month-old baby with a macular rash is brought to the hospital. Parents report that the rash started on the face, spread to the rest of the body, and was preceded by coldlike symptoms. There are small reddish spots in the baby's mouth. What is the diagnosis?
rubeola
Which of the following types of infection can result in infertility? leptospirosis bacterial vaginosis salpingitis ophthalmia neonatorum
salpingitis
Exfoliative toxin is responsible for
scalded skin syndrome.
During his presentation to the Microbiology Club, Cody mentions that the cholera epidemic in 2010 came shortly after an earthquake. He also mentions that other cholera epidemics had occurred following natural disasters such as flooding. Which of the following has the greatest impact on the number of cholera cases after a natural disaster? increases in the rodent population sewage contamination in drinking water flood waters mixed with ocean water dead bodies piling up in the streets
sewage contamination in drinking water
Which of the following is/are associated with secondary stage syphilis? a chancre skin rashes of varying appearance personality changes and seizures weakening of the aorta
skin rashes of varying appearance
Most of the normal microbiota of the digestive system are found in the
small intestine and large intestine.
Thorough cooking of food will prevent all of the following EXCEPT beef tapeworm. staphylococcal food poisoning. shigellosis. trichinellosis. salmonellosis.
staphylococcal food poisoning
Which of the following leads to all the others?
staphylococcal infection
Which of the following is treated with antibiotics? botulism streptococcal pneumonia tetanus polio All of these diseases can be successfully treated with antibiotics
streptococcal pneumonia
Consider a Kirby-Bauer disk-diffusion assay. If you put penicillin and streptomycin disks adjacent to one another, the zone of inhibition is greater than that obtained by either disk alone. This is an example of __________.
synergism
Which of the following is likely to spread MRSA among athletes?
taping gels physical contact whirlpool baths shared equipment
Which of the following choices correctly matches the class of antibiotic and its mode of action? Aminoglycosides and tetracyclines are inhibitors of protein synthesis. Penicillins and cephalosporins inhibit nucleic acid synthesis. Sulfonamides inhibit the synthesis of essential metabolites. Lipopeptides inhibit cell wall synthesis.
-Aminoglycosides and tetracyclines are inhibitors of protein synthesis -Sulfonamides inhibit the synthesis of essential metabolites
You ultimately decide to drain the pus from the carbuncle and dress the wound. You instruct the boy and his family about proper wound care and decontamination to prevent the spread and recurrence of the infection. Why did you not prescribe antibiotics in this case?
-Antibiotics will kill off beneficial bacteria -Using antibiotics can accelerate drug resistance in Staph -Antibiotics have side effects -Antibiotics can weaken the immune system
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 rapid, sensitive, and specific. -Indirect FA uses an antibody that reacts with any human antibody. -Indirect FA is more sensitive than direct immunofluorescent testing.
Acne is the result of the inflammatory response. In this case, the inflammation is resulting in acne that is very painful (physically and emotionally) for Scott. However, inflammation is a critical component of a normal immune response. What are the main functions of the inflammatory response?
-destroying and eliminating the invading pathogen -repairing tissue damage resulting from inflammation -"walling off" the site of injury or infection
Dr. Smith prescribes oral erythromycin for Scott. She also recommends that he consider using an over-the-counter gel or cream containing benzoyl peroxide. Although this regimen should be effective at treating Scott's acne, there are some possible side effects. Which of the following are possible side effects of Scott's treatment?
-excessive drying of the skin -gastrointestinal problems resulting from a reduction/elimination of normal intestinal flora
Research has indicated that during the inflammatory response to P. acnes, both the classical and the alternative complement pathways are activated. Which of the following are outcomes of activating complement pathways?
-inflammation -cytolysis -opsonization
Inhibiting cell wall synthesis
-inhibiting lipopolysaccharide synthesis -inhibiting synthesis of peptide cross links -inhibiting bonding of N-acetyl glucosamine to N-acetylmuramic acid -Inhibiting mycolic acid synthesis
Chlamydia PID is just part of the overall spectrum of disease caused by Chlamydia organisms. Even though we now understand more about STIs and their complications, we are still exploring how the organisms "branch out" beyond just a single infection. Which of the following diseases have Chlamydia infection as an etiology?
-lymphogranuloma venereum (LGV) -infertility -trachoma -inclusion conjunctivitis -cervical cancer -pneumonia
Dr. Smith assures Scott that although inflammation may sound scary, there are several possible options for treating Scott's moderate acne. Which of the following would be the most appropriate for Scott's case?
-topical treatment with a product containing benzoyl peroxide -Clear Light, a nonchemical, light-based system -an oral antibiotic such as erythromycin
Megan learned from the poster that there were three main stages of whooping cough. Place the following in order of how they would occur during progression of the infection.
1) Catarrhal 2) Paroxysmal 3) Convalescence
Pyelonephritis may result from urethritis. systemic infections. ureteritis. cystitis. All of the answers are correct
All of the answers are correct
The patient has a sore throat. What is the etiology of the symptoms?
Answer cannot be determined based on information provided.
In the table, the most effective antibiotic tested was
Antibiotic D: 10 mm (zone of inhibition is the largest of the options).
Which of the following statements about puerperal sepsis is FALSE? Its frequency of occurrence has decreased because of antibiotics and aseptic techniques. It is a complication of abortion or childbirth. It begins as a focal infection. It is caused by health care personnel. It is transmitted from mother to fetus
It is transmitted from mother to fetus
Which of the following statements about tularemia is FALSE? It is caused by Francisella tularensis. The most common reservoir is rabbits. It occurs only in California. It may be transmitted by arthropods. It may be transmitted by direct contact
It occurs only in California
As a child, Jamie suffered from rheumatic fever, which caused some major damage to one of her heart valves. She is OK, in general. However, she's been advised against getting body piercings, and her dentist gives her antibiotics before performing some dental procedures. What is the concern?
Jamie is more likely to develop subacute bacterial endocarditis.
A patient who presents with red throat and tonsils can be diagnosed as having
The answer cannot be determined based on the information provided
In the table, the antibiotic that exhibited bactericidal action was
The answer cannot be determined based on the information provided.
In the table, which antibiotic would be most useful for treating a Salmonella infection?
The answer cannot be determined based on the information provided.
Lower respiratory system infections, such as whooping cough, can lead to bronchitis or pneumonia due to the inhibition of normal protective responses. Which of the following explains how the pathogen overcomes normal protective responses of the respiratory system?
The bacteria attach to the ciliated cells of the trachea, thus preventing mucus from being cleared.
The pathogenesis of Vibrio cholerae is due to the organism's ability to produce cholera toxin. This is an A-B toxin that affects host cells in the small intestine. Which of the following correctly describes the mechanism of the toxin?
The cholera toxin causes the host cells to secrete large amounts of fluids and electrolytes.
Why is bacterial meningitis considered more life threatening than viral meningitis?
The immune response generated against bacteria leads to a massive influx of immune cells in the meninges; this response is much less extreme in viral meningitis
Postexposure treatment for rabies includes vaccination and injection of immunoglobulin; why does postexposure vaccination work?
The infection progresses so slowly that there is time for postexposure vaccination to generate immunity.
In untreated individuals, the mortality rate of cholera can be as high as 50%, but in individuals that are given oral rehydration therapy, fatalities are rare. Oral rehydration therapy involves treating the patients with an oral suspension of salt, sugar, and water. Which of the following choices explains why this suspension is used instead of pure water to treat cholera infections?
The salt and sugar in the rehydration solution will replace lost electrolytes and the water replaces the lost water.
Which of the following is FALSE concerning Clostridium species? They can cause gas gangrene and septicemia. They grow well in damaged tissues that are necrotic and have impaired blood flow. They grow only in anaerobic environments. Their main reservoir is rabbits
Their main reservoir is rabbits
Why is vaccination for rubella recommended?
There is a high incidence of congenital infections and birth defects
What is a likely result of the elevated WBC level in Claire's CSF?
There will be an extreme inflammatory response which will eventually lead to shock and ultimately to Claire's death
There are a large number of antibiotics that inhibit protein synthesis at 70S ribosomes found in bacterial cells but do not interfere with protein synthesis at the 80S ribosomes found in eukaryotic cells. Some of these antibiotics bind to the smaller ribosomal subunit and interfere with the reading of the mRNA code, whereas others bind to the larger ribosomal subunit and inhibit the formation of peptide bonds. Unfortunately, some of the antibiotics that inhibit protein synthesis in bacteria exhibit some toxicity to the eukaryotic host cells as well. What is the most likely reason for this toxicity to the host cell?
These antibiotics interfere with protein synthesis within eukaryotic mitochondria.
Staphylococcus aureus is responsible for all of the following EXCEPT boils. carbuncles. pimples. acne. sties
acne
A patient presents with fever and extensive lesions of the labia minora. Her VDRL test was negative. What is the most likely treatment?
acyclovir
A pelvic examination of a 23-year-old woman showed vesicles and ulcerated lesions on her labia. Cultures were negative for Neisseria and Chlamydia; the VDRL test was negative. Which treatment is appropriate?
acyclovir
Which of the following is used to treat shingles?
acyclovir
The physician performs a pelvic exam, which reveals the presence of an abnormal thin, watery vaginal discharge and inflammation of the cervix. The physician then palpates the abdomen (examines by touch and pressure) and finds that the uterus, fallopian tubes, and ovaries are enlarged and tender. The physician takes a swab sample of the cervix and sends it to the laboratory to determine the causal organism. Light microscopy and simple staining of the sample in the lab reveal an organism with a very unique life cycle. The organism is classified as gram-negative, but it stains very poorly compared to other classic gram-negative STI pathogens. The stain shows both a nonreplicating, extracellular infectious elementary body and a replicating, noninfectious reticulate body inside mucosal cells from the cervical epithelium swab. Based on the symptoms and these new laboratory findings, which of the following would be the most likely diagnosis for the patient?
chlamydia
One of the most important phenotypic features that can be used to differentiate among Staph species is their ability to produce ____________ , an enzyme that causes blood clot formation.
coagulase
Epidemics related to bacterial infection of the digestive system are typically caused by
contaminated food and water.
The most common mode of HAV transmission is
contamination of food during preparation.
Which of the following can be transmitted from an infected mother to her fetus across the placenta?
cytomegalovirus
Which of the following produces a permanent carrier state following infection?
cytomegalovirus
A patient complains of fever, severe muscle and joint pain, and a rash. The patient reports returning from a Caribbean vacation one week ago. Which of the following do you suspect?
dengue
A vaccine to provide active immunity to HBV is prepared from
genetically modified yeast.
A pelvic examination of a 23-year-old woman showed vesicles and ulcerated lesions on her labia. Cultures were negative for Neisseria and Chlamydia; the VDRL test was negative. Which of the following is probable?
genital herpes
The pH of the adult vagina is acidic due to the conversion of ________ to ________ by bacteria.
glycogen; lactic acid
If penicillin G is chosen as the best treatment for a given infection, what microorganisms are most likely the cause?
gram-positive bacteria
All of the following are characteristic of Pseudomonas aeruginosa EXCEPT resistance to many types of disinfectants and antibiotics. gram-positive cell wall. rod-shaped. growth in moist environments. production of pyocyanin
gram-positive cell wall
Bacterial intoxications differ from bacterial infections of the digestive system in that intoxications
have shorter incubation times
Injuring the plasma membrane
inhibiting fatty acid synthesis
Which of the following methods of action would be bacteriostatic?
inhibition of protein synthesis
The antibiotic tetracycline binds to the 30S subunit of the ribosome, as shown by the dark black bar on the right portion of the diagram in the figure. The effect is to
interfere with the attachment of the tRNA to mRNA-ribosome complex.
Interfering with RNA synthesis (transcription)
interfering with RNA polymerase
Which of the following symptoms is LEAST characteristic of Clostridium perfringens food poisoning? severe abdominal cramping sudden onset of diarrhea short incubation period moderate vomiting and fever
moderate vomiting and fever
Encephalitis is more common in the summer months because
mosquito populations increase.
All of the following are true of poliomyelitis EXCEPT the oral polio vaccine contains attenuated strains of the virus. infection is due to ingestion of contaminated water. initial sites of viral replication are the throat and small intestine. the majority of cases are asymptomatic. most cases result in muscle paralysis
most cases result in muscle paralysis
