Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Mechanisms of Disease 2 Exam 1 > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

The outer membrane of Gram- Negative Cells contains

A

Lipopolysaccharides (LPS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Are gram-positive or gram-negative cells vulnerable to lysozyme and penicillin attack?

A

Gram-positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the name of the polysacharide in Gram- + cell wall that acts as an antigenic determinant?

A

Teichoic Acid (important for serologic identification of many gram + species)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Lipopolysaccharide is composed of 3 covalently linked components, what are they?

A
  1. Outer carbohydrate extending into the surrounding media, O-specific side chain or O-antigen (antigenic determinants)
  2. Center part- water soluble core polysaccharide
  3. Interior- lipid A, toxic to humans and known as gram-negative endotoxin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When bacteria are lysed in efficiently working immune systems, what is released into the circulation and induces septic shock?

A

Lipid A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which 2 gram + RODS produce spores?

A
  • Bacillus

- Clostridium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which 2 gram + RODS DO NOT produce spores?

A
  • Cornyebacterium

- Listeria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the name of the special flagella on Spirochetes that run sideways under the outer membrane sheath?

A

Periplasmic flagella

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which bacteria ribosomal subunit does Erythromycin work on?

A

50s- large subunit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Tetracycline blocks protein synthesis of the ___ subunit

A

30s- small subunit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Properties of Facultative Anaerobes:

A
  • prefer oxygen but can function anaerobically (similar to how we can switch to anaerobic glycolysis)
  • have catalase and superoxide dismutase (SOD)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Properties of Microaerophilic bacteria:

A
  • use fermentation and have no ETC

- can tolerate low amounts of oxygen because they have SOD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does VIRULENCE mean?

A

The degree of organism pathogenicity, ability to cause disease
- depends on the presence of certain cell structures and on bacterial exotoxins and endotoxins (which are virulence factors)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Chemotaxis is:

A

the coordinated manner by which flagella move bacteria toward a chemical concentration gradient or away from the gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the mechanism and associated binding sites for the H and L subunits of Tetanospasmin (Tetanus Toxin) from Clostridium tetani

A
  1. H (Heavy) subunit binds to neuronal gangliosides
  2. L (Light) subunit: blocks release of inhibitory neurotransmitters (glycine, GABA) from Renshaw inhibitory interneurons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which two pathogens have a window period of infection between 6 months to 2 years of age?

A
  • Neisseria meningitidis

- H. Influenzae

17
Q

What is the classic clue that there is an invasive meningococcal infection?

A
  • the appearance of a petechial rash (due to endotoxin release from the meningococus causing vascular necrosis, inflammatory reaction and hemorrhage in the surrounding skin)
18
Q

High risk groups for Neisseria meningitidis are (3):

A
  • Infants (6months-2 years)
  • Army Recruits
  • College Freshmen
19
Q

Which organisms is one of the most common causes of localized pneumonia in patients presenting with fever and productive cough with blood tinged sputum; Gram stain of the sputum has Gram-positive diplococci that are catalase negative, and the inflammatory response is suppurative?

A

Streptococcus pneumoniae

20
Q

A 47-year old man with a history of sickle cell disease has had numerous hospitalizations requiring the placement of intravenous (IV) lines. The patient develops right arm swelling and discomfort at an IV site. His temperature increases to 40.1° C.
The isolated organism is catalase positive, coagulase negative, and non-hemolytic on blood agar media. Which organism is the most likely cause of this patient’s symptoms?

A
  • Staphylococcus epidermis (Remember that staphylococcus aureus is coagulase positive and that s. epidermis produces a biofilm making it highly resistant to antibiotics)
21
Q

What gram-positive cocci is beta-hemolytic, produces a golden yellow pigment when cultured, catalase +, coagulase + and PCR detects rRNA?

A
  • Staphylococcus aureus
22
Q

What are the three most common exotoxin-dependent presentations of staphyloccocus aureus?

A
  1. Gastroenteritis (food poisoning)- rapid onset, rapid recovery
  2. Toxic Shock Syndrome (high grade fever, N/V, watery diarrhea, erythematous rash, hypotension (may lead to frank shock), desquamation of palms and soles
  3. Scalded Skin Syndrome (exfoliative toxin A and B- neonates and older children with skin infections)
23
Q

A throat swab from a tonsillar exudate was submitted for aerobic culture and grew gram-positive, beta hemolytic, catalase negative
cocci; so the appropriate antibiotic was prescribed. Presently, the physical examination reveals hypertension and mild
generalized edema. The physician suspects glomerular disease with hematuria and proteinuria. Which of the following is the most likely microorganism responsible for this child illness?

A

Streptococcus pyogenes (Group A streptococcus)

24
Q

What is the clinical term for isolated pustules that rupture and become crusted; highest incidence in children; probable mode of spread is contact (transmission from carriers or patients)?

A

Impetigo

25
Q

Group A streptococci pyogenes is identified by the presence of (diagnostic cultures and stains):

A

The presence of beta-hemolytic colonies with susceptibility to bacitracin on blood agar is diagnostic for Group A streptococci

26
Q

What are the biological hallmarks (tissue-destroying proteins) of staphyloccal aureus infections?

A

The hallmark of staphylococcal infection is the abscess/pus
- Hyaluronidase to break down connective tissue
- Lipase and Proteases
- Protein A: binds IgG prevents opsonization, disables the immune system
Coagulase (forms fibrin around the bacteria)
Hemolysins and leukocidins: destroys WBCs., RBCs

27
Q

Bacillus anthracis (Anthrax) encodes toxins on a plasmid containing 3 separate proteins, what is the plasmid called and what are the 3 separate components (nontoxic by themselves but together produce the systemic effects of Anthrax)?

A
  • plasmid pXO1
  • Separate proteins:
    1) Edema Factor (EF)- active A subunit that increases cAMP, impairing neutrophil function, disrupts H20 homeostasis and causes massive edema
    2) Protective Antigen (PA): promotes entry of EF (similar to the B subunit of A-B toxins)
    3) Lethal Factor (LF): zinc metalloprotease that inactivates protein kinases, stimulating the macrophage to release TNF-alpha and IL-1B
28
Q

What is the name of the plasmid in Bacillus anthracis that encodes the three genes necessary to encode for the poly-glutamyl capsule?

A
  • PXO2
29
Q

Bacillus cereus secretes 2 types of enterotoxins, leading to food poisoning, what are they?

A

1) Heat-Labile Toxin
- similar to the enterotoxin in cholera and the LT from E. coli
- causes abdominal pain, N/D
2) Heat-Stable Toxin
- clinical syndrome similar to Staphylococcus aureus
- severe N/V and limited diarrhea

30
Q

The enterics are a large, heterogeneous group of gram-negative rods, what do they TYPICALLY have in common?

A

They all ferment glucose, are catalase positive, oxidase negative and facultative anaerobes

31
Q

An EMB agar plate is one method for differentiating enteric bacteria into lactose fermenters from non-lactose fermenters, what does E. coli look like on an EMB agar?

A

Eosin-methylene blue (EMB) agar plate inoculated with Escherichia coli shows good growthof dark blue-black colonies with metallic sheen indicating vigorous fermentation of lactose and acid production which precipitates the green metallic pigment

32
Q

What are the enteric bacteria that do not ferment lactose?

A

Lactose non-fermenters: Shigella, Yersinia, Salmonella, Vibrio

33
Q

An enteric bacteria that presents clinically with BLOODY diarrhea with mucus and pus. This gram-negative bacteria is non-motile (no H antigen), oxidase negative, non-lactose fermenting and does not produce H2S ?

A
  • Shigella
34
Q

Shigella is very efficient at transmitting infection. Why is it so good at invading the GI tract and what is the most common reason for its transmission?

A

Part of the reason for the efficiency of transmission is because a very small inoculum (10 to 200 organisms) is sufficient to cause infection.
As a result, spread can occur easily by the fecal-oral route and readily occurs in settings where hygiene is poor.

Mechanisms of Disease 2 Exam 1 (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions