2012 Micro Exam 3

1.

1 point

What Gram negative, capnophilic, commensal, oral bacterium expresses cytotoxins and collegenases and also activates osteoclasts?

Aggregatibacter actinomycetemcomitans

Porphyromonas gingivalis

Prevotella intermedia

Streptococcus mutans

2.

1 point

Which periodontal disease agent expresses fimbrillin on its surface, which helps this bacterium attach to gingival fibroblasts?

Porphyromonas gingivalis

Prevotella intermedia

Streptococcus mutans

Aggregatibacter actinomycetemcomitans

3.

1 point

A Gram positive bacterium that with round-shaped cells in clusters was isolated from a skin
infection. The bacterium proved to be coagulase positive. Which among the following is most
likely the identity of this bacterium?

Streptococcus pyogenes

Staphylococcus aureus

Staphylococcus epidermidis

Streptococcus pneumoniae

4.

1 point

Which organism causes flaccid paralysis?

Clostridium botulinum

Neiserria gonorrhoeae

Vibrio cholera

Clostridium tetani

5.

1 point

Which of the following is characteristic of dentoalveolar abscesses?

is always characterized by “sulphur granules”

infection usually polymicrobial (multiple species)

Staphylococcus aureus is the predominant organism

infection is usually by a single bacterial species

6.

1 point

Which is not a property of bacteria in a dental biofilm?

rapid growth

upregulation of genes for polysaccharide synthesis

metabolic interactions between closely spaced bacteria

increased resistance to antimicrobial agents

7.

1 point

Which of the following is the Gram negative, obligate intracellular pathogen responsible for
community acquired respiratory infections linked to atherosclerosis?

Mycobacterium tuberculosis

Chlamydia pneumoniae

Pseudomonas aeruginosa

Treponema pallidum

8.

1 point

The Ziehl-Neelson staining method is used to identify which bacterium?

Pseudomonas aeruginosa

Vibrio cholera

Mycobacterium tuberculosis

Treponema pallidum

9.

1 point

What anaerobic, black pigmented bacterium is an agent of periodontal disease?

Actinomyces naeslundii

Streptococcus mutans

Prevotella intermedia

Aggregatibacter actinomycetemcomitans

10.

1 point

Treponema pallidum is the agent of

dysentery

typhoid fever

syphilis

whooping cough

11.

1 point

Which strict anaerobe is a soil organism that can infect deep wounds?

Pseudomonas aeruginosa

Clostridium difficule

Clostridium perfingens

Bacillus anthracis

12.

1 point

You wish to alter a strain of Neisseria gonorrhoeae so that its ability to attach to host receptors is impaired. To achieve your objective you would hope to isolate the cells which are defective for

Pilli

Lipopolysaccharide

p II protein

Capsule

13.

1 point

What ubiquitous Gram negative rod is an opportunistic pathogen that expresses an exotoxin that ADP ribosylates elongation factor 2, causing inhibition of cellular translation?

Salmonella enterica

Pseudomonas aeruginosa

Shigella flexneri

Vibrio cholera

14.

1 point

What bacterium is not transmitted from person to person, but colonizes water sources, which
are a common source of human infection?

Pseudomonas aeruginosa

Legionella pneumophila

Bacillus anthracis

Listeria monocytogenes

15.

1 point

Which one of the following are associated with root surface caries

Actinomyces species

Streptococcus mutans

Prevotella intermedia

Porphyromonas gingivalis

16.

1 point

A culture of Treponema pallidum lost the ability to attach to host receptors. You might predict that these organisms were defective in

A surface structure at the tapered end of the spirochete

IgA protease

Polysaccharide capsule

Flagella

17.

1 point

What role does catalase have for those pathogenic bacteria that express it?

Degrades ECM molecules allowing bacteria to penetrate tisue

Prevents phagocytic cysteine proteases

Increased resistance to phagocytosis

Prevents phagocytes from interalizing bacteria

18.

1 point

What role does the arginine deiminase system play for oral bacteria?

production of an acidic environment by creating lactate

as a component of a PEP-PTS group translocation transporter

pumping of protons out of the cell to make the intracellular environment less acidic

production of an alkali environment by creating ammonia

19.

1 point

Streptococcal Antigen I/II

is component of a PEP-PTS group translocation transporter

binds glucosyltransferases in the bacterial biofilm

is a proton pump in the bacterial membrane

binds human salivary glycoproteins

20.

1 point

After a camping trip in a wooded area, a patient was suspected to have Lyme disease. All of the following signs might indicate that this patient is in the primary or early stage of Lyme disease EXCEPT

Flu-like symptoms

Arthritis

Evidence of a tick bite

Erythema migrans

Circulating IgM antibodies to the flagella of Borellia burgdorferi

21.

1 point

Bacteria of which genus are Gram positive branched rods (mycobacteria) that are opportunistic pathogens, causing bronchopulmonary infections and brain abscesses?

Bordetella

Nocardia

Chlamydia

Mycobacterium

22.

1 point

What is recognized as the major group of organisms involved in caries?

Aggregatibacter actinomycetemcomitans

Streptococcus mutans

Prevotella intermedia

Porphyromonas gingivalis

23.

1 point

Some oral bacteria near the tooth surface produce glucosyltransferases. These enzymes

catalyze the formation of lactic acid

form glucan polymers

decrease oxygen levels near the tooth

attack the dentin

24.

1 point

These gram negative diplococci express cell-surface lipid oligosaccharides to which they add
sialic acid.

Pseudomonas aeruginosa

Neisseria gonorrhoae

Helicobacter pylori

Dordetella pertusis

25.

1 point

What is the agent of whooping cough?

Yersina Pestis

Bordetella pertussis

Francscella tularensis

Cornyebacterium diphtheriae

26.

1 point

What is a virulence factor that contribute to Prevotella intermedia’s ability to disseminate into the bloodstream?

Mucin MG1

Cystatin

Collagenase

Chromogranin A

27.

1 point

The initial exudative lesion in the lung of a patient with tuberculosis:

Heals early in the course of the disease

Stimulates the production of autoantibody against lung tissue

Is detectable by X-rays

Is a granuloma

28.

1 point

Which enteric bacterial pathogens can cause hemolytic-uremic syndrome?

Enterohemorrhagic E. coli

Chigella Flexneri

Vibrio CHolera

Salmonella enterica

29.

1 point

These gram positive rods express a toxin that kills cells, typically in the throat, producing a pseudomembrane.

Corynebacterium diphtheriae

Bacillus anthracis

Helicobacter pylori

Pseudomonas

30.

1 point

21. Which is the form in which Chlamydia pneumoniae is transmitted from cell to cell?

granuloma

elementary body

reticulate body

spore

31.

1 point

Which of the following is not true about cholera?

The causitive bacterium is a component of the normal human flora

watery diarrhea is associated with this disease

The causitive agent is a Gram negative curved rod

Cholera toxin is an ADP ribosylating enzyme

32.

1 point

Necrotizing fasciitis can result from an abscess containing which bacterium?

Streptococcus pyogenes

Enterococcus faecilis

Streptococcus mutans

Streptococcus pneumoniae

33.

1 point

Which Gram positive enteric bacterium causes opportunistic infections and is often resistant to
vancomycin?

Enterococcus faecilis

Enterohemorrhagic E. coli

Campylobacter jejune

Enterotoxic E. coli

34.

1 point

22. What factor is important for Streptococcus mutans to bind and invade heart tissue?

glucosyltransferase

IgA protease

Collagen binding protein

LPS

35.

1 point

Coaggregation in the formation of a biofilm refers to

the precipitation of minerals into a surface

different types of bacteria binding to each other

adsorption of bacterial polymers onto a surface

the polymerzation of glucose moieties

36.

1 point

Gonorrhoea in the complicated local disease of the female usually results in growth of etiologic agent in the

Fallopian tubes

Anal mucosa

Cardiovascular system

Bone

37.

1 point

Which of the following manifestation would indicate that a patient had primary syphilis

Gummas

Infarction of nerve cells

Presence of a genital ulcer with hard edges

Generalized skin rash included the palms of the hand

38.

1 point

The capsule of this gram positive diplococcus of the upper respiratory tract prevents C3b opsonization?

Streptococcus pneumoniae

Mycobacterium tuberculosis

Chlamydia pneumoniae

Pseudomonas aeruginosa

39.

1 point

The Pseudomonas aeruginosa virulence factor elastase does not degrade which of the
following?

Plasma membrane

Laminin

Fibrinogen

Collagen

40.

1 point

Which of the following obligate human pathogens are gram negative diplococci?

Salmonella typhimurium

Neisseria gonorrhoeae

Vibrio cholera

Escherichia coli

41.

1 point

Which host molecule in the oral cavity has antibacterial activity by aggregating and clearing microbes via lectin-like interactions?

human β-defensin 1

calprotectin

von Ebner gland protein

mucin MG1

42.

1 point

Ticks are vectors for which pathogen?

Bordetella pertussis

Nocardia spp.

Borrelia burgdorferi

Treponema pallidum

43.

1 point

What virulence factor of Streptococcus pyogenes coats the bacterial cell surface and has anti-C3b activity?

M Protein

F Protein

G Protein

Streptokinase

44.

1 point

The presence of “sulphur granules” in pus discharge from a dentoalveolar infection occurs in

Ludwig’s angina

periodontal abscess

osteomyelitis of the jaw

cervicofacial actinomycosis

45.

1 point

With what disease is Aggregatibacter actinomycetemcomitans strongly associated?

Localized aggressive periodontitis

Ludwig’s Angina

Dental caries

Suppurative Osteomyelitis of the Jaws

46.

1 point

What bacterium is an enteric Gram positive coccus that generally causes disease in the elderly and individuals confined to long hospitalizations?

Streptococcus pyogenes

Enterococcus faecilis

streptococus mutans

shigella flexneri