16. All of the following are true about ear infections EXCEPT:
Middle ear infections (otitis media) often produce a puslike exudate (referred to as otitis media with effusion) due to infection by genera of Streptococcus, Haemophilus, or various species of anaerobes.
External auditory canal (otitis externa) infections are typically caused by Staphylococcus aureus or Pseudomonas aeruginosa.
After successful treatment of middle ear infections with antibiotics, sometimes tubes are inserted to prevent fluid accumulation, repeated infections, and hearing loss.
Pseudomonad infections are common in swimmers because these organisms are able to produce a soluble greenish-blue pigment.
Repeated ear infections in children often decrease markedly because as the child ages and the Eustachian tube changes shape and develops an angle that prevents most organisms from reaching the middle ear.
17. Why are colds difficult to treat and prevent?
Different cold viruses predominate during different seasons.
Because there are so many different types of rhino- and coronaviruses, each with different antigens, development and administration of vaccines are currently prohibitive.
Although some human interferons have been shown to block or limit rhinovirus infections, delivery to infection sites is difficult, and unwanted side effects can occur.
All of the above.
Both a and c.
18. Which of the following is NOT true about parainfluenza viruses?
Most infants by the age of 6 months have been exposed to and develop antibodies against all 4 parainfluenza viruses.
They cause rhinitis characterized by nasal, pharyngeal, and bronchial inflammation, primarily in children.
Parainfluenza virus infection can be prevented by vaccination.
They can cause noisy respiration (stridor) and acute obstruction of the larynx called croup.
The viruses are spread by direct contact or by large droplets.
19. In whooping cough, patients experience violent coughing episodes during the _________ stage and can have bluing of the skin or _________ due to lack of oxygen from massive mucus and bacterial airway blockage.
Paroxysmal; cyanosis
Catarrhal; pigmentation
Convalescent; osmosis
Pneumotic; hydrolysis
Primary; emesis
20. Penicillins have no effect on Mycoplasma pneumoniae because:
Mycoplasmas are viruses
Mycoplasmas possess beta lactamases
Mycoplasmas are too small
Mycoplasmas are eukaryotes
Mycoplasmas lack cell walls
21. How many cases of tuberculosis are reported globally each year?
10
10,000
100,000
3 million
10 million
22. Mycobacteria are difficult to Gram stain, and are termed “acid-fast” due to their:
Ability to survive in acidic conditions
Resistance to drying
Thick, waxy cell walls
Resistance to sunlight
Lack of a peptidoglycan layer
23. Which of the following is true about pathogenic mycobacteria?
They have a long generation time of 12 to 18 hours.
They are obligate anaerobes sensitive to small amounts of oxygen.
They are highly resistant to drying and can remain viable in dried sputum 6 to 8 months later.
Both a and b.
Both a and c.
24. Clinical symptoms of tuberculosis are primarily due to:
Host inflammatory response
Mycotoxins
Endotoxin
Mucus production
Exotoxin
25. What characteristic of Coxiella burnetii, the causative agent of Q fever, allows it to survive for up to 2 years?
Metachromatic granule
Exotoxin
Endospore
Hemagglutinin
Cilia
26. The normal microflora of the heart includes species of:
Gram-positive bacteria
Gram-negative bacteria
Fungi
Viruses
None of these
27. Which of the following is commonly directly responsible for causing septic shock today?
Bacterial hemagglutinins
Bacterial endotoxins
Bacterial exotoxins
Fungal aflatoxins
Bacterial neurotoxins
28. All of the following are symptoms of septic shock EXCEPT
Shock
Lymphangitis
Chills
Fever
Collapsed blood vessels
29. What is the most likely explanation of how Streptococcus pyogenes causes rheumatic fever?
Strep throat infections migrate down to the heart.
Endotoxin production causes septicemia.
Vegetation followed by fibrin deposition.
Cross-reactivity of an antibody for a Streptococcus pyogenes antigen to a heart cell antigen.
It is an opportunistic infection triggered by coronary artery disease and atherosclerosis.
30. Bacterial endocarditis is an infection and inflammation of the lining and valves of the heart and occurs as a result of transient bacteria attaching to fibrin from exposed collagen fibers of damaged valvular surfaces. True or false?
