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crimsongrasshopper358Lv1

28 Sep 2019

Bacteria that cause sexually transmitted diseases are generally only found in fluid environments (particularly body fluids), and are often gram-negative. Such infections are not transmitted through casual contact. Bacteria that cause respiratory infections and sore throats are commonly transmitted through casual contact, and are often gram-positive. Explain both of these situations using cell wall structure.

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Elin HesselLv2

28 Sep 2019

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Related questions

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?

10,000

100,000

3 million

10 million

22. Mycobacteria are difficult to Gram stain, and are termed âacid-fastâ 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?

copperwhale493

1. All of the following characteristics of skin help make it a good defensive barrier against pathogenic microbes EXCEPT:

Springy elasticity

Saltiness due to production of sweat from sweat glands

Acidic pH due to oily compound (sebum) metabolism

Normal microflora of skin

Constant sloughing off of old dead epithelial skin cells

2. The majority of microorganisms comprising the normal microflora inhabiting the skin surface are:

Gram-positive fungi of the single-celled yeasts

Gram-positive bacteria of the Staphylococcus, Micrococcus, Corynebacterium, and Proprionibacterium genera

Gram-negative bacteria of the Enterobacteriaceae family

Gram-negative bacteria of the Neisseria, Pseudomonas, and Salmonella genera

All of the above

3. The pus-producing skin infection (pyoderma) can be caused by:

Staphylococci

Streptococci

Corynebacteria

A combination of staphylococci, streptococci, and corynebacteria

All of these

4. Which of the following is NOT a characteristic of impetigo?

Common in children

Can be caused by Staphylococcus aureus

Can be caused by Streptococcus pyogenes

Is highly contagious

Can be caused by pseudomonads

5. Which of the following is NOT true about acne?

It is most commonly the result of male sex hormones that stimulate increased sebaceous gland growth and secretion of sebum.

Propionibacterium acnes in particular can turn a mild case of acne into a severe case by causing increased and widespread inflammation, tissue destruction, and scarring.

Common treatments are frequent cleansing of the skin and topical ointments that reduce the risk of infection.

Low doses of oral antibiotics are often prescribed to prevent bacterial infections of lesions and are without side effects.

In most cases, acne disappears or decreases in severity on its own as the body adjusts to the hormonal changes of puberty and sebaceous gland function stabilizes.

6. Which of the following often cause nosocomial infections in burn patients?

Streptococcus pyogenes

Serratia marcescens

Pseudomonas aeruginosa

Staphylococcus aureus

b and c

7. Gas gangrene is most likely associated with infection with:

Staphylococcus aureus

Clostridium perfringenes

Streptococcus pneumoniae

Neisseria gonorrhoeae

Pseudomonas aeruginosa

8. The leading cause of preventable blindness in the world is caused by:

Chlamydia trachomatis

Haemophilus influenzae

Neisseria gonorrhoeae

Staphylococcus aureus

Streptococcus pneumoniae

9. Chickenpox is a disease of chickens and is caused by the poxvirus, cowpox is a disease of cattle, and smallpox is a human disease that commonly affects only children. True or false?

10. Antibiotic is used to treat the eyes of newborn infants when:

The mother has gonorrhea

The mother has genital herpes

Neisseria gonorrhoeae is isolated from the newborn's eyes

Always

The mother has a history of multiple sex partners

11. The virus used to immunize individuals against smallpox causes the disease:

Chickenpox

Measles

Cowpox

Molluscum contagiosum

Warts

12. Which of the following fungal diseases result from an opportunistic fungal infection?

Zygomycoses

Aspergillosis

Candidasis

All of the above

None of the above

13. Rheumatic fever is caused by which organism?

Corynebacterium diphtheriae

Staphylococcus epidermidis

Staphylococcus aureus

Escherichia coli

Streptococcus pyogenes

14. Which of the following components of the respiratory system is normally free of microorganisms?

Lungs

Nasal cavity

Pharynx

Trachea

Bronchi

15. Which of the following is true about diphtheria?

It is caused by strains of Corynebacterium diphtheriae infected with a prophage that carries an exotoxin-producing gene.

A pseudomembrane composed of Corynebacterium diphtheriae cells, damaged epithelial cells, fibrin, and blood cells forms that can block the airway and cause suffocation.

The exotoxin spreads throughout the body damaging multiple organ system by interfering with cellular protein synthesis.

It can be prevented with DTP (diphtheria, tetanus, and pertussis) vaccine and treated with both antitoxin and antibiotics.

All of the above are true.

coppertrout695

The most commonly isolated gram-positive cocci are best differentiated by their:

Gram stain morphology.

catalase reaction.

hemolytic reaction.

both a and b.

both b and c.

ANSWER:

(Level 1, Objective 1)

The novobiocin resistance test is used to

determine treatment options for Staphylococcus saprophyticus.

identify S. saprophyticus.

differentiate S. saprophyticus and S. hominis ssp. novobiosepticus.

both a and b.

ANSWER:

(Level 1, Objective 2)

The slide coagulase and the Staphylococcus latex agglutination tests are similar in that both test for the presence of

protein A.

free coagulase.

clumping factor.

thermonuclease.

ANSWER:

(Level 2, Objective 2)

The esculin/PYR disk test can be used to rapidly identify

Enterococcus spp.

Streptococcus pneumoniae.

Streptococcus pyogenes.

both a and b.

both a and c.

ANSWER:

(Level 1, Objective 2)

The optochin disk test is incubated at/in _____________________.

35Â°C, ambient air.

35Â°C, CO₂.

42Â°C, CO₂.

25Â°C, a capnophilic atmosphere.

ANSWER:

(Level 1, Objective 2)

A catalase-positive, gram-positive coccus that agglutinates in a slide coagulase test as well as in saline should be

reported as Staphylococcus aureus.

reported as Staphylococcus not S. aureus.

retested using another method.

retested for the catalase reaction.

ANSWER:

(Level 2, Objectives 2 and 3)

A positive rapid esculin test appears

dark.

pink.

red after the addition of the reagent.

blue.

ANSWER:

(Level 1, Objective 3)

Yellow colonies on mannitol salt agar indicate the definitive presence of

methicillin-resistant Staphylococcus aureus.

Staphylococcus aureus.

Staphylococcus not S. aureus.

unable to definitively identify.

ANSWER:

(Level 2, Objective 4)

A catalase-negative, gram-positive coccus that is bile esculin positive and 6.5% NaCl broth positive belongs to the Lancefield antigenic group

ANSWER:

(Level 2, Objective 5)

10. A leg wound isolate presents as a yellow pigmented, beta-hemolytic, catalase-positive, gram-positive cocci in clusters. Which of the following tests would you expect to be positive for this isolate?

Novobiocin resistance

Heat-stable thermonuclease

PYR

b and c

a and b

ANSWER:

(Level 2, Objective 5)

11. A catalase-negative coccus in pairs and short chains that is susceptible to ethyl hydrocupreine will also

a. require CO₂ for growth.

b. be alpha hemolytic.

c. be bile soluble.

d. all of the above.

e. b and c.

ANSWER:

(Level 2, Objective 5)

12. The PBP2a latex agglutination test is used to detect catalase-positive, coagulase-positive, gram-positive cocci that are resistant to

a. vancomycin.

b. novobiocin.

c. oxacillin.

d. penicillin.

ANSWER:

(Level 2, Objective 6)

13. A catalase-negative, gram-positive coccus in chains that is positive for esculin and PYR hydrolysis is also vancomycin resistant. What additional antibiotic resistance can this organism exhibit?

a. high level aminoglycosides.

b. ampicillin and penicillin.

c. beta-lactamase production.

d. all of the above.

e. b and c.

ANSWER:

(Level 2, Objective 6)

14. An alpha-hemolytic, catalase-negative, gram-positive coccus that is susceptible to optochin can cause all of the following diseases except

a. pneumonia.

b. sinusitis.

c. meningitis.

d. pharyngitis.

ANSWER:

(Level 2, Objective 7)

15. The catalase-negative, gram-positive coccus that is the most common cause of neonatal sepsis and meningitis

a. has the potential to be vancomycin resistant.

b. hydrolyzes hippurate.

c. is susceptible to bacitracin.

d. is bile soluble.

ANSWER:

(Level 2, Objective 7)

16. Necrotizing fasciitis is caused by a

a. catalase-negative, gram-positive coccus that is susceptible to bacitracin.

b. catalase-negative, gram-positive coccus that produces CAMP factor.

c. catalase-positive, gram-positive coccus that produces coagulase.

d. catalase-positive, gram-positive coccus that is resistant to novobiocin.

ANSWER:

(Level 2, Objective 7)

17. Infections of indwelling devices, such as intravenous catheters, are often caused by catalase-positive, gram-positive cocci that are

a. coagulase positive and thermonuclease negative.

b. coagulase negative and novobiocin resistant.

c. caogulase positive and thermonuclease positive.

d. coagulase negative and novobiocin susceptible.

ANSWER:

(Level 2, Objective 7)

18. Which of the following factors accounts for the virulence of Streptococcus pyogenes?

a. âCâ substance

b. Protein A

c. M protein

d. mecA gene

ANSWER:

(Level 1, Objective 7)

19. The virulence factor most often associated with catalase-negative, gram-positive cocci that are bile soluble is

a. capsule production.

b. vancomycin resistance.

c. hyaluronidase.

d. streptolysin S.

ANSWER:

(Level 2, Objective 7)

20. A catalase-negative, alpha-hemolytic, gram-positive coccus that is resistant to ethyl hydrocupriene is usually considered

a. a member of the normal upper respiratory flora.

b. a pathogen in an expectorated sputum specimen.

c. the causative agent of non-suppurative sequelae.

d. a common urinary pathogen.

ANSWER:

(Level 2, Objective 8)

21. A catalase-positive, coagulase-negative, gram-positive coccus in clusters is isolated from the urine of a 24-year-old female. This isolate will require

a. additional testing to identify.

b. no further testing.

c. a screen for vancomycin resistance.

d. Lancefield grouping.

ANSWER:

(Level 2, Objective 10)

22. A blood culture yields yellow-pigmented, beta-hemolytic, catalase-positive, gram-positive cocci in clusters. The department is out of Staphylococcus latex agglutination reagent. The microbiologist sets up a tube coagulase and mannitol salt agar. She incubates both at 35Â°C in CO₂ overnight. The next day the coagulase test is negative and the mannitol salt agar displays yellow colonies. How will you proceed with these results?

a. Report this organism as Staphylococcus aureus

b. Report this organism as Staphylococcus not S. aureus

c. Repeat the tests due to invalid results

d. Test the organism for novobiocin resistance

ANSWER:

(Level 3, Objective 10)

24. A patient, suspected to have bacterial endocarditis, had two sets of blood cultures drawn. All four bottles are positive with gram-positive cocci in pairs and chains. On sheep blood agar, the gray, transparent, alpha-hemolytic colonies are catalase negative, optochin resistant, ESC negative and PYR negative. Which of the following patient histories correlates with the presence of this organism?

a. 78-year-old male with bacterial pneumonia

b. 47-year-old female with a heart murmur and a history of dental surgery

c. 16-year-old female with a history of untreated pharyngitis

d. 3-day-old premature male

ANSWER:

(Level 3, Objective 10)

25. A translucent colony displaying subtle beta hemolysis is isolated from a placenta culture. The Gram stain revealed gram-positive cocci in pairs. The microbiologist drops 3% catalase reagent onto a colony on sheep blood agar, and it produces bubbles. He then performs a Staphyloccocus latex agglutination and the suspension remains smooth. The next step is to

a. report the organism as Staphylococcus not S. aureus.

b. report the organism as Staphylococcus aureus.

c. repeat the catalase test due to an invalid result.

d. perform a thermonuclease test due to an invalid latex agglutination result.

ANSWER:

(Level 3, Objective 10)