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Med Micro > Exam 2 > Flashcards

Exam 2 Flashcards

1
Q

Typhoid fever is usually spread by which route?

A

fecal oral

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2
Q

Modern plague is usually spread by which route?

A

bite of an infected flea

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3
Q

In terms of pathological effects, Salmonella enterica and Vibrio cholerae both differ from Salmonella typhi in that they both:

A

have their effects while passing through the GI tract without entering the bloodstream

typhoid fever is a systemic infection. Salmonella enterica and vibrio generally stay local.

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4
Q

Which of the following is the most important virulence factor for Streptococcus pneumoniae?

A

capsule

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5
Q

What test is used to differentiate between e.coli and salmonella/shigella?

A

lactose fermentation

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6
Q

which test is used to distinguish between staph and streps?

A

catalase test

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7
Q

Transmission of shigellosis to humans is primarily from

A

humans

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8
Q

In the US, the bubonic plague agent is:

A

endemic (consistently present in the animal population with sporadic disease in people)

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9
Q

One difference between bubonic plague and the pneumonic form of plague is

A

the route of infection

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10
Q

The bacterium that causes bubonic and pneumonic plague is:

A

Yersinia pestis

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11
Q

Death by cholera is caused by:

A

dehydration

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12
Q

What does the B part of an AB toxin do?

A

bind to the cell to deliver the A part

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13
Q

Typhoid mary could have stopped spreading typhoid fever if she had:

A

washed her hands frequently

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14
Q

Bacteroides are typically found in:

A

the gut

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15
Q

Group B streptococcus is also known as:

A

streptococcus agalactiae

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16
Q

Which of the following is responsible for the acidic pH of the female genital tract?

A

lactobacilli

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17
Q

Most cases of salmonellosis

A

recover spontaneously and do not require antimicrobials

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18
Q

The whooping cough vaccine is a(n):

A

Acellular vaccine consising of purified bacterial components

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19
Q

Which of the following is the mechanism by which the Vibrio toxin results in the loss of large quantities of fluids?

A

activation of adenylate cyclase and accumulation of cAMP

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20
Q

A culture of skin lesions from a patient with pyoderma (impetigo) shows numerous colonies surrounded by a zone of beta hemolysis on a blood agar plate. A gram-stained smear shows gram positive cocci. If you found the catalase test to be negative, which one of the following organisms would you MOST probably have isolated?

A

streptococcus pyogenes

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21
Q

The pathogenesis of scarlet fever involves:

A

an erythrogenic exotoxin

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22
Q

The pathogenesis of toxic shock syndrome involves:

A

a superantigen

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23
Q

The pathogenesis of cholera involves:

A

toxin mediated diarrhea

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24
Q

Symptoms of gonorrhea are due to:

A

the potent immune response which leads to lots of white cells and inflammation - NOT TOXINS

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25
Q

The affecting toxin of Ritter’s disease is an epidermolytic toxin which

A

destroys the binding between the layers of skin cells

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26
Q

rheumatic fever occurs after a ___ infection with ___

A

throat; strep pyogenes

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27
Q

It is believed that tissue damage in rheumatic fever is due to a(n):

A

autoimmune reaction

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28
Q

`When growing on blood agar plates, Streptococcus pneumoniae usually produces

A

alpha hemolysis

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29
Q

Protein A of Staphylococcus aureus is antiphagocytic because it

A

binds to the Fc portion of IgG

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30
Q

Most infections of catheters and shunts are due to

A

Coagulase negative Staphylococcus epidermidis

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31
Q

The group classification of Streptococcus pneumoniae is

A

none of the above (it is non-groupable)

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32
Q

What type of diarrhea does cholera produce?

A

watery diarrhea without blood, no white cells in the stool, and no organisms in the blood culture (THINK RICE WATER STOOL)

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33
Q

True or False: Pseudomonas aeruginosa is commonly found in nature

A

True

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34
Q

True or False: Neisseria meningitides produces an exotoxin that leads to the characteristic rash

A

False: presence of the bacteria and the endotoxin lead to the petechial rash

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35
Q

True or False: the most important treatment of necrotizing fascitis is antibiotic therapy

A

False: antimicrobials without surgery will not treat this infection

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36
Q

True or False: Certain M types of Streptococci are associated with the development of rheumatic fever

A

True

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37
Q

The principle species of staphylococci found on the skin is

A

epidermidis

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38
Q

Of the following, which is the most serious staph skin infection? (boil, carbuncle, furuncle, folliculitis)

A

carbuncle

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39
Q

The term “selective toxicity” means

A

A drug is harmful for bacteria but not for the host

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40
Q

An antimicrobial agent that is bactericidal is a drug that

A

kills bacteria

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41
Q

Which of the following describes a difference between Escherichia coli (a gram negative) and Staphylococci aureus?

A

S.aureus has teichoic acid and E.coli doesn’t

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42
Q

The Staphylococcus aureus protein A binding to Ab and the Streptococcus pyogenes hyaluronic acid capsule are pathogenic strategies to

A

hide bacterial antigens from the host immune response

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43
Q

What bacterial structure or substance is primarily associated with antigenic variation in the Group A streptococci?

A

M protein

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44
Q

An important principle of fermentation is that

A

oxygen is not used as a final electron acceptor

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45
Q

The treatment of this disease requires both antibiotics and anti-toxins:

A

diptheria

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46
Q

Tetanospasmin causes:

A

uncontrolled muscle contractions

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47
Q

Which of the following is important for the bacterium to survive in the presence of oxygen?

A

catalase

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48
Q

E. coli, a facultative anaerobe, is placed on 2 plates of solid plate medium, and each plate is grown under different environmental conditions: one aerobic, the other anaerobic. Which of the following would describe the observed growth of the E. coli on each plate?

A

The colonies on the aerobic plate would be larger than the colonies on the anaerobic plate.

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49
Q

Acute glomerulonephritis is a complication that follows infection by which one of the following organisms?

A

streptococcus pyogenes

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50
Q

Which of the following is a virulence factor Staphylococcus aureus uses to avoid phagocytosis?

A

protein A

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51
Q

which of the following is responsible for most of the symptoms of gonorrhea?

A

the host inflammatory response due to bacterial endotoxin activity

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52
Q

which of the following is an immune mediated post-streptococcal disease?
scarlet fever, acute glomerulonephritis, streptococcal pharyngitis, impetigo

A

acute glomerulonephritis

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53
Q

which of the following is referred to as the “flesh eating bacterium”?

A

streptococcus pyogenes

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54
Q

superantigens contribute to disease because they:

A

stimulate T cells non-specifically leading to inappropriate cytokine release

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55
Q

which of the following is a “heat labile” toxin?

A

botulism toxin (remember grad school soup story?)

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56
Q

A patient has an infection of an intravenous catheter. Which of the following is the most likely organism?

A

coagulase negative staphylococcus epidermidis

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57
Q

Which of the following is the source of the gas in gas gangrene

A

fermentation of carbohydrates by the bacteria in the tissue

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58
Q

Botulism toxin acts by:

A

inhibiting acetylcholine release

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59
Q

A toxoid is:

A

an inactivated toxin used in a vaccine preparation

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60
Q

what is the major difference between adult botulism and infant botulism?

A

in infant botulism the bacteria are growing in the body and producing the toxin whereas in adult botulism the toxin is in the body but the bacteria aren’t

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61
Q

which of the following is the most important step in the treatment of pseudomembranous colitis?

A

stop the broad spectrum antimicrobial that has led to the development of the disease

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62
Q

diptheria toxin activity is due to:

A

irreverisbly halting protein synthesis in the target cell

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63
Q

Shiga toxin activity is due to:

A

increased cAMP levels in the target cell

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64
Q

Listeria monocytogenes is best described as:

A

a gram positive, non-spore forming bacillus

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65
Q

Which of the following describes Streptococcus pyogenes?

A

gram positive, facultative anaerobe, beta hemolytic

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66
Q

Which of the following is the mechanism by which the Neisseria gonorrheae pilin undergoes antigenic variation?

A

there is one expression location in the chromosome and multiple partial genes that recombine into the expression locus

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67
Q

Which of the following is the mechanism by which the ETEC toxin results in the loss of large quantities of fluids?

A

activation of adenylate cyclase and accumulation of cAMP

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68
Q

what is the typical route for acquiring infant botulism?

A

ingestion of clostridium botulinum endospores

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69
Q

what is the typical route for acquiring adult botulism?

A

ingestion of clostridium botulinum preformed toxin

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70
Q

The patient is a 3 year old child with fever and pain in her left ear. On physical examination, the drum is found to be perforated and a bloody exudate is seen. Gram stain of the exudate reveals gram positive cocci in groups of 2. Which of the following is the most likely cause?

A

Streptococci pneumoniae

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71
Q

The typical source of staphylococcus aureus that leads to cellulitis is:

A

normal flora on the skin

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72
Q

Which of the following Staphylococcus aureus virulence factors helps the bacterium avoid phagocytosis?

A

protein A

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73
Q

Enzyme that breaks down connective tissue:

A

hyaluronidase

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74
Q

How would clostridia be identified on a culture?

A

gram positive, spore forming, anaerobe

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75
Q

The patient is a 27-yr old woman who was treated with oral ampicillin for cellulitis caused by Streptococcus pyogenes. Several days later, she developed bloody diarrhea. Her physician thinks that she has pseudomembranous colitis. Which of the following best describes the causative organism?

A

anaerobic gram-positive rod that produces an exotoxin (The organism is Clostridium difficile, so it is gram positive anaerobe like all of the other Clostridia. The disease is mediated by the exotoxin that it makes)

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76
Q

Which of the following is the chief virulence factor for Neisseria meningitidis?

A

Polysaccharide capsule

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77
Q

Which of the following best describes the early signs of toxic shock syndrome?

A

abrupt onset fever

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78
Q

Bacteroides are

A

gram negative rods

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79
Q

Which of the following is responsible for the bright red rash associated with scarlet fever?

A

a bacterial exotoxin

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80
Q

Most infections of catheters and shunts are due to

A

coagulase negative staphylococci (like staph epidermidis)

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81
Q

Which of the following is responsible for most of the symptoms associated with gonorrhea?

A

bacterial endotoxin (symptoms of gonorrhea are due to the potent inflammatory response which is due to the bacterial endotoxin)

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82
Q

Which of the following can lead to Pseudomembranous colitis in the right patient?

A

Clostridium difficile

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83
Q

Neisseria gonorrhoeae can change the antigenic nature of their pili to evade the host immune defenses. N. gonorrhoeae change the antigenic nature of their pili by:

A

moving silent gene sequences into sites of active gene expression

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84
Q

Which of the following is responsible for strep throat?

A

streptococcus pyogenes

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85
Q

The patient is a 6 year old boy with papular and pustular skin lesions on his face. A serous, “honey colored” fluid and crusty areas are found at the lesions. You suspect impetigo. A gram stain of the area reveals neutrophils and gram-positive cocci in chains. If the clinical sample were cultured on blood agar plates which of the following would you be most likely to see?

A

Beta hemolytic colonies that are catalase negative

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86
Q

Which of the following can be described as a tissue invasive clostridial disease?

  • gas gangrene
  • pseudomembranous colitis
  • infant botulism
  • adult food-borne botulism
A

gas gangrene

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87
Q

Tetanus toxin activity leads to a sustained contraction of muscle groups. What process is directly affected by the tetanus toxin activity?

A

It blocks neurotransmitter release at inhibitory synapses

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88
Q

Lancefield group antigens are

A

cell wall carbohydrates

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89
Q

Neisseria gonorrhoeae produces acid when grown on

A

glucose

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90
Q

Which of the following is contained in the tetanus vaccination?

A

tetanus toxoid

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91
Q

A 10-year old boy with a scraped knee developed a cellulitis that is treated with antibiotics. Two weeks later he notices cloudy, reddish, urine and his face is swollen. The physician suspects acute glomerulonephritis. What is the mechanism of injury to the kidneys in this case?

A

immune complex mediated

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92
Q

What is the cellular target of the diphtheria toxin?

A

an elongation factor necessary for protein synthesis

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93
Q

Your patient is a 20 year old woman with a sudden onset of fever to 104o and a severe headache. The physician suspects meningitis and performs a spinal tap. Gram stain of the spinal fluid reveals many neutrophils and many gram negative diplococci. Of the following bacteria, which one is the MOST likely to be the cause?

  • S.aureus
  • N.meningitidis
  • S.pneumoniae
  • S.pyogenes
A

Neisseria meningitidis

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94
Q

Movement of Listeria monocytogenes inside of the host cells is caused by

A

inducing polymerization of host cell actin

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95
Q

An 11-yr old boy develops a mild fever and pain in his upper arm. An x-ray film of his arm shows a lytic lesion in the upper part of the humerus with periosteal elevation over the lesion (the problem is in the bone). The patient is taken to surgery where the lesion is cleaned up, the dead parts of the bone and pus are removed. Culture from the lesion yields gram-positive cocci. A test shows the organism is a staphylococcus and not a streptococcus. Based on this information, you know the organism is

A

catalase positive

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96
Q

Which of the following is the best strategy for managing wound care if you are worried about tetanus in someone who received the complete tetanus series immunization 2 years ago

A

clean the wound

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97
Q

Which of the following is the predominant bacterial species in the gut?

  • bacteroides fragilis
  • escheria coli
  • streptococcus pyogenes
  • clostridium difficile
A

bacteroides fragilis

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98
Q

The patient is a 3 year old child with fever and pain in her left ear. On physical examination, the drum is found to be perforated and a bloody exudate is seen. Gram stain of the exudate reveals gram positive cocci in groups of 2. Which of the following is the most likely cause?

A.Neisseria meningitidis
B.Corynebacterium diphtheria
C.Streptococci pyogenes
D.Streptococci pneumoniae

A

Streptococci pneumoniae

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99
Q

Tetanus toxin acts by

A

interfering with the release of neurotransmitters for inhibiting impulses

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100
Q

Which of the following is responsible for most of the symptoms associated with gonorrhea?

A

bacterial endotoxin

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101
Q

The primary mechanism of the pathogenesis of Corynebacterium diphtheriae is

A

the inactivation of elongation factor 2

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102
Q

Neisseria gonorrhoeae produces acid when grown on

A

glucose

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103
Q

Two days ago the patient developed an erythematous sunburn-like rash. She also has had headache, muscle aches, and abdominal cramps. Her blood pressure is 70/40 (low). Pelvic exam shows she is having her menstrual period with a tampon in place; otherwise the exam is normal. Her blood work suggests that her kidneys are not functioning well. Her illness is likely caused by

A

A toxin that binds to and activates T cells nonspecifically

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104
Q

Corynebacterium diphtheriae strains that produce the diphtheria toxin are

A

lysogenic for a particular bacteriophage

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105
Q

A 6-year old boy develops fever and headache. He is taken to the emergency room where he is noted to have a stiff neck, suggesting meningitis. A lumbar puncture is done and culture of the cerebrospinal fluid grows Neisseria meningitidis serogroup B. Which of the following would be considered for his family members?

A

prophylactic antimicrobials

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106
Q

Staphylococcal protein A binds to which of the following?

A

Antibody Fc part

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107
Q

Which of the following identifies the organism’s genus? Neisseria meningitidis serotype W-135.

A

Neisseria

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108
Q

Listeria infections are acquired by:

A

eating contaminated food

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109
Q

An 18 year old man develops fever with pain in the right lower quadrant of his abdomen. After initial evaluation he is taken to the operating room. At surgery a ruptured appendix with an abscess is found. Bacteroides fragilis is cultured from the abscess fluid. Which of the following factors assisted with the abscess formation by B. fragilis?

A

capsule

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110
Q

A conjugated vaccine can best be described as

A

an antigen that is attached to another component to increase the immune response

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111
Q

Cell morphology of streptococci=

A

cocci arranged in chains

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112
Q

Transmission of tetanus from person to person

A

doesn’t happen

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113
Q

Which of the following is responsible for the symptoms of staphylococcal food poisoning

A

bacterial exotoxin

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114
Q

Which of the following is an illness that is NOT mediated by a (exo)toxin?

A.Gonorrhea
 	B.Staphylococcal food poisoning
 	C.Tetanus
 	D.Botulism
A

Gonorrhea

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115
Q

Which of the following is most often associated with gas gangrene?

A

Clostridium perfringens

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116
Q

MRSA stands for:

A

methicillin resistant staphylococcus aureus

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117
Q

Provide a plausible explanation for why someone could have developed meningitis despite having received the vaccine.

A

the strain of N.meningitidis that the person has uses the type B capsular antigenes which aren’t in the vaccine

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118
Q

pneumococcal pneumonia is caused by:

A

streptococcus pneumoniae

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119
Q

the oxidase test indicates:

A

the presence of cytochrome oxidase

120
Q

Which of the following statements concerning Bacteroides fragilis is INCORRECT?

  • the capsule of B. fragilis is an important virulence factor
  • B. fragilis can survive short exposures to oxygen
  • B. fragilis is a gram-negative rod that is part of the normal flora of the colon
  • B. fragilis forms endospores, which allow it to survive in the soil
A

B.fragilis forms endospores, which allow it to survive in the soil

121
Q

Antibiotic drops are placed in infants’ eyes at birth to prevent blindness due to infections with

A

Neisseria gonorrheae

122
Q

Acute glomerulonephritis is a nonsupperative complication that follows an infection by which of the following organisms?

A

Streptococcus pyogenes

123
Q

The major antigens in the Streptococcus pneumoniae vaccine are

A

capsule polysaccharides

124
Q

An outbreak of sepsis by Staphylococcus aureus has occurred in the newborn nursery. Based on what you know about S. aureus and the normal flora, what is the most likely source of the organism?

A

nose

125
Q

Superantigens directly activate:

A

T cells

126
Q

The best prophylaxis for the prevention of tetanus is

A

tetanus toxoid Ag vaccine

127
Q

A culture of skin lesions from a patient with impetigo shows numerous colonies surrounded by a zone of complete lysis on the blood agar plate. A gram stain of the cultured bacteria shows gram positive cocci. If you found the catalase test to be negative, which of the following organisms is most likely?

A

streptococcus pyogenes

128
Q

The most important protective function of the antibody stimulated by the tetanus immunization is

A

to neutralize the toxin of the pathogen

129
Q

In the body tetanus toxin leads to

A

spastic paralysis

130
Q

In the body botulism toxin leads to

A

flaccid paralysis

131
Q

The diphtheria toxin acts by

A

inhibiting protein synthesis by inactivating an elongation factor

132
Q

Which of the following is not a feature of either Neisseria gonorrheae or Neisseria meningitidis?

  • polysaccharide capsule
  • pili
  • IgA protease
  • M protein
A

M protein

133
Q

Which of the following statements about Corynebacterium diphtheria is INCORRECT?

A.antitoxin can be used to treat patients with diphtheria
B.diphtheria toxoid should not be given to children under the age of 1 year
C.. C. diphtheria is a gram-positive rod that does not form spores
D.toxin production is dependent on the presence of a lysogenic phage

A

diphtheria toxoid should not be given to children under the age of 1 year

134
Q

Each of the following statements concerning Clostridia are correct EXCEPT:

A. botulism, which is caused by ingesting preformed toxin, can be prevented by boiling food prior to eating
B. pathogenic clostridia are found both in the soil and in the normal flora of the colon
C. anaerobic conditions at the wound site are not required to cause tetanus, because the endospores will form in the presence of oxygen
D. Antibiotic-associated (pseudomembranous) colitis is due to a toxin produced by Clostridium difficile

A

anaerobic conditions at the wound site are not required to cause tetanus, because the endospores will form in the presence of oxygen

135
Q

Your patient has subacute bacterial endocarditis caused by Coagulase negative Staphylococci. Which of the following is the most likely source for the infection?

A

an IV catheter

136
Q

Which of the following is responsible for the symptoms of staphylococcal food poisoning?

A

a bacterial exotoxin

137
Q

The soil is the natural habitat for certain microorganisms of medical importance. Which of the following is LEAST likely to reside there?

A.Clostridium tetani
 	B.Neisseria gonorrheae
 	C.Bacillus anthracis
 	D.Listeria monocytogenes
A

Neisseria gonorrheae

138
Q

The chief virulence factor for Neisseria gonorrheae is

A

endotoxin

139
Q

Meningitis and death occur in 3 adults who had eaten bologna that had the same brand and lot number, and was purchased from the same store. One of the adults was a renal transplant patient, and 2 were cancer patients. Although their family members had also eaten the bologna at the same time, they only suffered from an upset stomach. Which of the following is the most likely contaminant in the bologna?

A

Listeria monocytogenes

140
Q

Which of the following is the typical way that pseudomembranous colitis is diagnosed?

A

detection of the bacterial exotoxin in the stool

141
Q

Without proper treatment, most cases of gas gangrene would result in:

A

death of the patient

142
Q

We are particularly worried about a new strain of Clostridium difficile. What seems to be different about this new strain?

A

it makes greater quantities of the toxins

143
Q

A farmer stepped on a rusty nail and is treated with tetanus antitoxin (TIG) and given the Td injection. What does his treatment tell you about his tetanus vaccination status at the time of his injury?

A

It had been at least 5 years since his last tetanus booster

144
Q

Which of the following is the best prophylaxis for the prevention of tetanus?

A

tetanus toxoid vaccine

145
Q

Corynebacteria diphtheriae strains that produce the diphtheria toxin are

A

lysogenic for a particular bacteriophage

146
Q

The most important protective function of the antibody stimulated by diphtheria toxoid immunization is

A

to neutralize the toxin of the bacteria

147
Q

A 12-year-old girl is suffering from a fever, headache, stiff neck, and rash on her arms and trunk. Her cerebrospinal fluid (CSF) contains white cells, an increased protein concentration, and decreased glucose. A gram negative diplococcus is isolated from the CSF. Which of the following bacterial components is responsible for the rash?

A

endotoxin

148
Q

If a patient has a prosthetic heart valve and develops staphylococcal endocarditis, which of the following is the most likely organism causing the infection?

A

coagulase negative staphylococci

149
Q

The symptoms of Ritter’s disease are due to

A

a tissue specific bacterial exotoxin

150
Q

Superantigens are bacterial exotoxins that activate:

A

T cells

151
Q

The end result of superantigen activity is that

A

Lots of cytokines are released in an uncontrolled manner

152
Q

Which of the following is one of the major concerns regarding Group B streptococcal infections during pregnancy?

A

neonatal meningitis

153
Q

Which of the following best describes Beta hemolysis?

A

Complete hemolysis of red blood cells, which leads to a cleared zone in the blood agar

154
Q

Which of the following is the most important virulence factor for Streptococcus pneumoniae?

A

capsule

155
Q

The Rapid Strep Test detects which of the following streptococcal antigens?

A

Group A streptococcal cell wall carbohydrates

156
Q

An immune response to which of the following streptococcal structures can lead to rheumatic fever and rheumatic heart disease after streptococcal pharyngitis?

A

M proteins

157
Q

Which of the following best describes the typical way the most common form of Group A streptococcal infections are transmitted to the anatomic site of concern?

A

through respiratory secretions

158
Q

The patient has subacute bacterial endocarditis caused by a member of the virdans group of streptococci. Which of the following sties is MOST likely to be the source of the organism?

A

mouth

159
Q

How do you treat legionnaire’s disease?

A

antimicrobials that can penetrate through the eukaryotic cell membrane (erythromycin, newer macrolides or tetracycline)

160
Q

What should NOT be used to treat legionnarie’s disease?

A

beta lactam antimicrobials (such as penicillins or cephalosporins)

161
Q

Describe the pathogenesis of Legionella

A

inahaled bacteria via aerosols; if bacteria reach the lungs, cytokines from T cells activate alveolar macrophages to engulf them –> bacteria enter and grow within the macrophage (b/c macrophages look like amoebas)

162
Q

Oxygen requirements of legionella:

A

aerobe

163
Q

Oxygen requirements of helicobacter:

A

microaerophilic (grows best in low concentrations of o2 or without any o2)

164
Q

Oxygen requirements of clostridia:

A

anaerobic

165
Q

The primary/index case of C.difficile-associated diarrhea is:

A

endogenous mode, precolonized patients using antimicrobials

166
Q

C.diff-associated diarrhea (CDAD) is:

A

toxin mediated

167
Q

Gas gangrene is caused by:

A

Clostridium perfringens

168
Q

What type of infection is gas gangrene?

A

invasive infection

169
Q

Why might gas gangrene look gram negative on a slide?

A

due to age of the individual bacteria- when the cell wall is old and “breaking apart” it becomes easier to decolorize and the cells look gram negative

170
Q

What is the most important type of C.perfringens for human disease?

A

type A

171
Q

The pathogenesis of gas gangrene is due to:

A

toxins (alpha toxin); lyses RBCs, WBCs, platelets and endothelial cells; increases vascular permeability, lots of bleeding and tissue destruction; some toxin effects are local, some are systemic –> may lead to shock and renal failure

172
Q

Why is hyperbaric oxygen used as treatment for gas gangrene?

A

it inhibits the production of the alpha toxin, and suppresses growth of the organism

173
Q

Where are the spores from C.botulinum found?

A

soil

174
Q

Botulism is considered an:

A

intoxication (NOT AN INFECTION)

175
Q

Most common form of botulism is:

A

infant botulism

176
Q

How do you treat infant botulism?

A

supportive care, passive immunity with high titer anti-toxin (enough to neutralize any toxin not yet internalized into neurons);

DO NOT TREAT WITH ANTIBIOTICS- killing bacteria in the gut increases toxin release

177
Q

Where is clostridium tetani found?

A

spores found in dirt (worldwide)

178
Q

Where does germination of clostridium tetani spores occur?

A

germination of spores when inoculated into a puncture wound

179
Q

What are the oxygen requirements for clostridium tetani?

A

strict anaerobe

180
Q

How does the C.tetani toxin spread?

A

(bacteria don’t spread, toxin does); Toxin moves to peripheral motor neuron terminals, enters the axons, and travels to the spinal cord

181
Q

Where is bordetella usually found?

A

human reservoirs only!!

182
Q

Describe the pertussis toxin

A

It is an A-B toxin that leads to increased mucus production and increased activity of adenyl cyclase

183
Q

During what stage of B.pertussis are cold-like symptoms present?

A

Catarrhal

184
Q

During what stage of B.pertussis are violent bouts of coughing present?

A

paroxysmal

185
Q

During what stage of B.pertussis are LOTS of bacteria present?

A

Catarrhal

186
Q

Best way to eliminate whooping cough=

A

vaccination

187
Q

At what point of B.pertussis might antibiotics be useful?

A

catarrhal stage

188
Q

From time of onset, how long are culture, PCR and serology diagnostic tests sensitive for B.pertussis?

A 
culture= 0-2 weeks
PCR= 0-4 weeks
serology= 2-12 weeks (2-8 is best)
189
Q

How do you treat B.pertussis patients?

A

-macrolide antimicrobials b/c they are protein synthesis inhibitors and will halt synthesis of toxin

190
Q

Most deaths related to B.pertussis are caused by:

A

secondary infections

191
Q

What vaccine is given for B.pertussis?

A

Acellular pertusiss vaccine (DTaP)

192
Q

What does the pertussis vaccine contain?

A

DTaP contains purified pertussis components (PT and FHA) and is given in 5 doses before kindergarten

193
Q

What causes fever in those with B.pertussis?

A

endotoxin (LPS)

194
Q

Oxygen requirements for pseudomonas:

A

aerobe (must use TCA and ETC)

195
Q

How does pseudomonas show up on an agar plate?

A

green or blue-green (fluorescein and pyocanin)

196
Q

Where is pseudomonas found?

A

moist places (hospital environements- soil in plants/cut flowers); grows in a wide range of temperatures with minimal nutrition; resistant to many disinfectants

197
Q

What makes cystic fibrosis patients more likely to get P.aeruginosa?

A

viscous mucus secretions are ideal environment for P.aeruginosa infections

198
Q

How is P.aeruginosa treated?

A

difficult to treat; resistant to alot of things (restrictive porins); combination therapy

199
Q

Oxygen requirements of vibrio species:

A

facultative anaerobe

200
Q

Where are vibrio species found?

A

water environments; contaminated water, fish, shellfish (filter feeders) – levels increase in warm months; can be concentrated by filter feeders

201
Q

How is vibrio cholera subdivided?

A

by their O antigen on their LPS

202
Q

Why is a large dose of vibrio cholera needed to cause disease?

A

V.cholera is very sensitive to stomach acid

203
Q

Why do bladder infections provoke such a strong inflammatory response?

A

b/c of the LPS endotoxin in E.coli

204
Q

What is a unique characteristic of E.coli that is used in diagnostic testing?

A

ferments lactose; on EMB agar, if it ferments lactose there will be a green sheen

205
Q

EPEC is also known as:

A

pediatric diarrhea

206
Q

True or False: EPEC is toxin mediated

A

FALSE (probably not toxin mediated)

207
Q

Vibrio cholerae and ETEC cause what type of diarrhea?

A

secretory or watery diarrhea; no blood or pus and NO TISSUE INVASION; site= small intestine

208
Q

EHEC causes what type of infection? what type of stool? and occurs where?

A

hemorrhagic colitis; copious, liquidlike, bloody diarrhea with no leukocytes, NO TISSUE INVASION; large intestine

209
Q

Since shigella is invasive, what type of response/diarrhea does that produce?

A

diarrhea with lots of blood and pus; very painful

210
Q

How is shigella usually transmitted?

A

person to person

211
Q

What is the source of most of the symptoms of shigella?

A

inflammatory response

212
Q

What makes EHEC unique (used for diagnostic testing)?

A

does not ferment sorbitol

213
Q

EHEC is toxin mediated by:

A

shiga toxin producing E-coli

214
Q

What 2 diseases does salmonella usually cause?

A

gastroenteritis and typhoid fever

215
Q

Most infections of salmonella result from:

A

ingestion of contaminated foods (salmonella is normal flora for a number of animals); may be spread fecal-oral in children

216
Q

Oxygen requirements for campylobacter:

A

microaerophilic

217
Q

What are the number 1 & 2 causes of bacterial diarrhea in the US?

A

1= salmonella

2=campylobacter

218
Q

What is the reservoir of campylobacter?

A

animals (uncooked poultry)

219
Q

What is Guillain-Barre syndrome?

A

demyelinating neuropathy of peripheral nerves often preceeded by campylobacter infection

220
Q

What is the reservoir of typhoid fever?

A

humans

221
Q

How is typhoid fever transmitted?

A

orally ingested –> penetration of intestinal epithelium

222
Q

What are the symptoms of typhoid fever?

A

fever, malaise, little or no diarrhea (b/c bacteria move on pretty quickly), abdominal pain

223
Q

How do you treat typhoid?

A

prolonged antibiotics to try to get rid of carrier state; surgical removal of gallbladder (reservoir)

224
Q

What is the yersinia causative agent of gastroenteritis?

A

Y.entercolitica

225
Q

What is the causative agent of black death?

A

Yersinia pestis

226
Q

Your patient has an abscess. Which of the following is most likely the source for the infection?

droplet nuclei, recent dental procedure, ruptured colon, an IV catheter

A

a ruptured colon

227
Q

What is the function of streptokinase?

A

it lyses fibrin clots

228
Q

Typical route of infection with Legionella is:

A

inhalation of contaminated water

229
Q

Which of the following host defense mechanisms is the most important for preventing cholera?

A

gastric acid

230
Q

For which of the following enteric illnesses is a chronic carrier state MOST likely to develop?

  • shigella enterocolitis
  • cholera
  • campylobacter enterocolitis
  • typhoid fever
A

typhoid fever

231
Q

Oxygen requirement of Campylobacter=

A

microaerophilic

232
Q

Oxygen requirement of Salmonella=

A

facultative anaerobe

233
Q

One week old child presents to doctor with eye infection. Sample of discharge from the eye is found to contain paired, gram negative cocci. What disease is the child suffering from and how did she contract it?

A

Opthalamia neonatorum caused by Neisseria gonorrheae. The mother was infected with N.gonorrheae and the bacteria got into the childs eyes during delivery.

234
Q

What is a possible outcome of opthamia neonatorum?

A

blindness

235
Q

Why isnt microscopy a good means of diagnosing Staphylococcal food poisoning?

A

b/c the symptoms of the food poisoning are due to the presence of the toxin, not the bacteria. the bacteria might have been killed by the heating of the food or have been eliminated by the body. the toxin wouldn’t be seen by microscopy

236
Q

How would the lab distinguish between E.coli and Shigella or Salmonella?

A

all 3 would ferment glucose but only E.coli would ferment lactose

237
Q

Approximately 10% of children with EHEC will develop:

A

Hemolytic uremic syndrome (HUS)

238
Q

Name the organism that causes whooping cough.

A

Bordetella pertussis

239
Q

What is the benefit of administering antibiotics during the catarrhal stage of whooping cough?

A

preventing whooping cough. during this stage, the bacteria have not yet made enough toxin to cause damage and the bacteria are susceptible to killing by the antibiotic before they are able to make the toxin

240
Q

What is a limitation of antibiotic administration during the catarrhal stage of whooping cough?

A

symptoms of this stage are those of any respiratory tract illness, making it difficult to diagnose

241
Q

What is one similarity between Streptococcus pneumoniae and Corynebacterium diptheria?

A

route of transmission

242
Q

What is one difference between Strep pneumoniae and Corynebacterium diptheria?

A

diptheria uses a toxin, strep attaches and leads to inflammation

243
Q

Which toxin would my grad school professor have been concerned about when she decided to boil her soup extra long before eating it?

A

Botulism toxin

244
Q

Recall of contaminated raw spinach due to contamination with EHEC, O157:H7. What does each of the abbreviations stand for?

A

EHEC= Enterohemorrhagic Escherichia coli
O157=LPS antigenic type #157
H7= flagella antigenic type #7

245
Q

What organism causes typhoid fever?

A

Salmonella enterica ssp.typhi

246
Q

What clinical sample(s) would contain the typhoid fever bacterium?

A

stool, blood, urine

247
Q

Six weeks after initial treatment for typhoid fever, pt becomes ill with the same symptoms as before and the same organism is identified from her clinical sample. Why did she have this recurrence?

A

This organism can colonize the gall bladder and lead to persistent carrier status; requires lengthy antimicrobial treatment beyond the typical acute illness

248
Q

What kind of antigen is in the pneumococcal vaccine?

A

23 polysaccharide capsule antigens

249
Q

When a patient has gas gangrene, we don’t usually see white cells in the affected tissue. Why?

A

the clostridia that lead to gas gangrene make many toxins and enzymes that degrade tissue. These toxins and enzymes also destroy any white cells that are recruited to the site

250
Q

What should you recommend for patient who presents with pseudomonas colitis?

A

discontinue current antibiotic; administer metronidazole or oral vacomycin

251
Q

Patient with Pseudomembranous colitis is unable to leave the bed for walks, or to use the restroom. He is also receiving IV fluids. What precautions should be taken with this patient?

A

be careful about cleaning up after this patient. You would want to be certain endospores from this patient don’t end up being transferred to any other patient

252
Q

You are rounding with the medical team as the hospital pharmacist. The patient being presented is a 24 year old man, who has been diagnosed with peritoneal ascess. The medical staff suggests an antimicrobial regimen that is particularly effective against gram +, anaerobes. They turn to you for your contribution. (2 pts)
a. What do you say?

A

This infection will require treatment with more than a single antimicrobial. It is appropriate to use a drug that is effective against gram + anaerobes, but you will also need to address the facultative anaerobic and gram – organisms too.

253
Q

You are rounding with the medical team as the hospital pharmacist. The patient being presented is a 24 year old man, who has been diagnosed with gas gangrene. The medical staff suggests an antimicrobial regimen that is particularly effective against gram + bacteria. They turn to you for your contribution. (2 pts)
b. What do you say?

A

Antimicrobials will not be enough for this patient. Antibiotics are important, but this patient will also need surgery to get rid of any necrotic poorly perfused tissue.

254
Q

What are the antigens that are used in the meningococcal vaccine?

A

polysaccharide capsular antigens

255
Q

Which of the following is the means by which the gonococcus is protected from antibodies found in the genital mucosa?

A

IgA protease

256
Q

Salmonella can be described as:

A

gram negative bacillus that does not ferment lactose

257
Q

Which of the following is the action of the cholera toxin?

A

activation of adenylate cyclase

258
Q

Which of the following is most associated with bloody diarrhea containing pus?

A

Shigella species

259
Q

Guillian-Barre syndrome is often associated with recent infections with which of the following infectious agents?

A

Campylobacter

260
Q

The pathogenesis of which of the following organisms is most likely to involve invasion of the intestinal epithelium?

  • Enterotoxigenic E.coli
  • Shigella flexneri
  • Enteropathogenic E.coli
  • Vibrio cholera
A

Shigella flexneri

261
Q

Anatomical site typically colonized by Strep pneumoniae=

A

upper respiratory tract

262
Q

Why is it particularly important to treat cases of typhoid fever with antibiotics?

A

b/c a carrier state is common after typhoid fever infections

263
Q

What toxin does Campylobacter diptheriae produce?

A

lysogenic bacteriophage

264
Q

The Campylobacter diptheria usually seen in the homeless is:

A

cutaneous diptheria

265
Q

Where is listeria monocytogenes commonly found?

A

common in nature - found in almost every animal

266
Q

Under what conditions does listeria monocytogenes grow?

A

grows at refrigerated temps (small initial contamination grows to be a major contaminant)

267
Q

Death from botulinum tetani is usually due to:

A

respiratory failure

268
Q

How is tetanus diagnosed?

A

clinical presentation – no diagnostic lab test for tetanus

269
Q

What defenses prevent entry of bordetella?

A

microflora in the mouth and nose, mucus and ciliated cells

270
Q

What defenses eliminate bordetella microbes that get into the lungs?

A

alveolar macrophages

271
Q

What does bordetella pertussis attach to?

A

ciliated epithelial cells; ciliary action slows –> toxin released –> epithelial cells die –> cough

272
Q

What kills ciliated cells when bordetella pertussis is present?

A

tracheal cytotoxin

273
Q

What causes fever in pts with bordetella pertussis?

A

endotoxin (LPS)

274
Q

Why is pseudomonas considered a “tough bug”?

A
  • wide range of temperatures
  • requires minimal nutrition
  • resistant to many disinfectants
275
Q

What is treatment for pseudomonas?

A
  • resistant to alot of things (restrictive porins)
  • patient is typically immunocompromised
  • combination therapy
  • regional antibiotic use effects resistances
  • third generation cephalosporins are often active
276
Q

How do you prevent pseudomonas aeruginosa?

A
  • educate CF patients
  • reduce environmental spread
  • take care of respiratory equipment and moist surfaces
277
Q

What species of shigella predominates in the US? In other parts of the world?

A

S.sonnei; S.flexneri

278
Q

Bloody diarrhea with pus and pain are symptoms of shigella that are caused by:

A

inflammatory response

279
Q

How do you treat shigella?

A

oral rehydration; since antimicrobial resistance is a problem, don’t use unless in severe cases b/c it can shorten illness

280
Q

How do you confirm/diagnose EHEC?

A

confirm with O157 sera in the lab b/c EHEC does not ferment sorbitol

281
Q

What are the 2 virulence factors of salmonella?

A
  1. endotoxin

2. survives in macrophages

282
Q

Y.enterocolitica is found in:

A

contaminated meats, milk, and water; generally colder climates

283
Q

How is bubonic plague transported?

A

transported to regional LN via lymphatics

284
Q

What is plasminogen?

A

a blood protein that dissolves fibrin clots

285
Q

What does Yersinia PLA do?

A

prevents fibrin clot formation, removes barrier to spread; also degrades complement components

286
Q

What causes 80% of UTIs or cystitis?

A

E.coli

287
Q

The strong inflammatory response seen in bladder infections is caused by:

A

LPS

288
Q

Where are vibrio species found?

A

found in water environments; contaminated water, fish, shellfish (filter feeders)

289
Q

The transmission of cholera is associated with:

A

poor sanitary conditions

290
Q

Since bacteroides can withstand short exposure to oxygen, they’re:

A

catalase + and superoxide dismutase +

291
Q

The serogroups of N.meningitidis that cause disease are:

A

serogroups A,B,C,Y and W-135. In US, almost all cases= B,C, and Y

292
Q

What is the flaw of the N.meningitidis vaccination?

A

no group B antigen in the vaccine

293
Q

Purpuric then Petechial rash is an indication of:

A

N.meningitis

294
Q

How is N.meningitis prevented?

A

Vaccination with MCV4 at age 11; booster at 16-18;

295
Q

MCV4 is conjugated to:

A

conjugated to diptheria toxoid

Med Micro (3 decks)

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