Unit 3 Flashcards

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1
Q

What is the name of the group of bacteria that are gram-positive rods often referred to as club-shaped or V & L forms when viewed in a gram stain?

A

Corynebacterium

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2
Q

What is the major virulence factor associated with corynebacterium diphtheriae?

A

Diphtheria toxin

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3
Q

A young girl is brought to her physician by her mother, who says the child has been very sluggish with a fever of 38C (100.5F)for a week. The mother noticed that the child’s tonsils were red and that the previous day the back of her throat turned a gray color and looked to have a gray membrane on it. What disease should the physician suspect?

A

Diphtheria

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4
Q

What organisms displays Babes-Ernst granules on a gram stain?

A

Corynebacterium diphtheria

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5
Q

What media does corynebacterium diphtheria grow on?

A

All of the above
*sheep blood agar (SBA)
*Loeffler
*Cystine-tellurite blood

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6
Q

What test is performed to determine if corynebacterium diphtheria is a toxigenic stain of an organism?

A

Elek test

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7
Q

What corynebacterium species is commonly associated with hospitalized immunocompromised patients?

A

C. Jeikeium

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8
Q

What is one of the most frequently isolated, clinically significant corynebacteria associated with UTIs?

A

C. Urealyticum.

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9
Q

All of the following species of Acranbacterium are clinically significant, except

A

A. Urealyticum

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10
Q

What is the colony morphology of A. Haemolyticum on SBA?

A

A narrow zone of B-hemolysis and a black opaque dot is seen when the colony is scraped away

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11
Q

What organisms are describe are partially acid fast and diphtheroid gram-positive rods with traces of branching on a gram stain?

A

Rhodococcus equi

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12
Q

What organism is a member of the human oropharyngeal biota but has been isolated from people with endocarditis?

A

Rothia dentocariosa

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13
Q

What organism is responsible for spontaneous abortion and stillborn neonates, and can cause meningitis with a fatality rate approaching 50% is newborn?

A

Listeria monocytogenes

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14
Q

Several people from a picnic came down with GI disturbance, and public health officials suspected a case of food poisoning. The food was cultured, and after 24 hours of incubation the hot dogs yield growth on SBA on small, round, smooth gram-positive coccobacilli. Mortality medium was inoculated and an umbrella pattern of motility was observed at room temperature. What organism was isolated as the cause of illness?

A

Listeria monocytogenes

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15
Q

Erysipelothrix rhisopathiae produces all t h following diseases except

A

Meningitis

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16
Q

One of the foremost at a pig farm notices purple sores on one of his workers. The worker has not been feeling well for the past 2 weeks, so the foreman sends him to the physician. The physician takes scrapings from the lesions and sends them to the laboratory for a culture. The gram stain shows 3+ thin, gram-positive rods that have filaments. The culture plates were examined the next day and revealed nonhemolytic, pinpoint, transparent colonies. What is the most likely pathogen?

A

Erysipelothrix rhusiopathiae

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17
Q

What is the name of the bacterium that plays an important role in the health of the female vaginal tract, protecting it against pathogens?

A

Lactobacillus

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18
Q

All of the following are general characteristics of the genus Bacillus, except

A

Cocci

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19
Q

What is the name of the Bacillus sp. that causes anthrax in cattle?

A

B. Anthracis

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20
Q

What is the name of the organism that, before being identified as an important cause of infections is immunocompromised patients, was considered a common laboratory containment?

A

Bacillus subtilis

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21
Q

The three proteins that make up the anthrax toxin include all the following except

A

Cellular factor

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22
Q

How is anthrax spread in animals?

A

Eating plants contaminated with the spores

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23
Q

What form of anthrax is found amount animal workers and has been called woolsorter disease?

A

Inhalation

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24
Q

Which of the following would be considered a diphtheroid ? `

A

Corynebacterium sp.

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25
Q

The presence of gram-variable bacilli on the surface of epithelial cells collected from the vaginal mucosa indicates

A

Bacterial vaginosis

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26
Q

What disease is considered a complication of any from of anthrax (cutaneous, GI or inhalation?

A

Meningitis

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27
Q

What bacteria’s morphology is described as large, square-ended, gram-positive or gram-variable rods found singly on in in chains?

A

Bacillus anthracis

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28
Q

What bacterium produces colonies that are nonhemolytic, large, gray, and flat with an irregular margin on SBA?

A

Bacillus anthracis

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29
Q

All of the following tests should be performed by sentinel laboratories to rule out the possibility of Bacillus anthracis from an isolate except

A

Glucose fermentation

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30
Q

What are the confirmatory tests performed at a state laboratory for Bacillus anthracis?

A

Cell wall polysaccharide end a capsule antigen

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31
Q

What antibiotic, in 2000, was approved by US food and drug administration (FDA) for postexposure inhalation anthrax?

A

Ciprofloxacin

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32
Q

What Bacillus sp. is a relatively common cause of food poisoning and opportunistic infection in susceptible hosts?

A

Bacillus cereus

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33
Q

What other gram-positive rod is similar to bacillus anthracis morphologically and metabolically?`

A

B. Cereus

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34
Q

Which of the following is true about Nocardia spp.??

A

All of the above
* the organisms grow on strand are nonselective media
*growth may take a week or more
*infections occur in immunocompromised patients

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35
Q

All of the following are commonly encounter Nocardia spp. except

A

N. Transvalensis

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36
Q

What is the name of the iron-chelating compound by Nocardia spp?

A

Nocobactin

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37
Q

What is the name of the Nocardia sp. that most frequently causes a cutaneous infection? `

A

N. Brasíliensis

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38
Q

How can Nocardia spp. be presumptively identified?

A

Filamentous, branching organisms with a carbolfuchsin acid-fast stain with a weak acid decolonizer but not a kinyoun acid fast stain

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39
Q

What is it that although Nocardia spp. grow on most common nonselective laboratory media, many are missed when the cultures are read?

A

These organisms require 3-6 days to grow

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40
Q

Why is it important to differentiate infection with Nocardia spp. in pulmonary infections?/

A

All of the above
*antifungal agents do not kill organisms
*these organisms are resistant to penicillin
*these organisms are susceptible to sulfonamides

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41
Q

What is the name of the genus of organisms that are primarily Saprophytic and resemble aerobic actinomycetes with the morphology and disease they cause?

A

Streptomyces

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42
Q

What is the name of the genus whose members are called nocardioforms?

A

Gordonia

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43
Q

Colonies of Bacillus anthracis are described as

A

Medusa heads

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44
Q

The colonies of this organism form large, rough, greenish, hemolytic colonies on blood agar, what organism is it?

A

Bacillus cereus

45
Q

Typically, all Neisseria spp. are all of the following except

A

Motile

46
Q

To which category do most Neisseria spp. belong?

A

Capnophilic

47
Q

Which of the following can be found as part of the commensal biota of the upper respiratory tract?

A

N. Meningitidis

48
Q

Gonococcal infections occur primarily in all the following sites, except

A

Uterus

49
Q

The virulence factors for Neisseria spp. include all of the following except

A

Exotoxin

50
Q

How are Neisseria gonorrhoeae infections transmitted?

A

Sexual contact

51
Q

What is the most common manifestations of Neisseria gonorrhoeae infection in men?

A

Purulent urethral discharge and dysuria

52
Q

What does blood-borne dissemination of Neisseria gonorhoeae usually result in?

A

Purulent arthritis

53
Q

If a female is symptomatic, what are the most common symptoms of Neisseria gonorrhoeae infection?

A

Cervical discharge and dysuria

54
Q

What is a major cause of pelvic inflammatory disease in women?

A

Untreated Gonococcal cervicitis

55
Q

What disease is most commonly associated with newborns passing through a birth canal infected with Neisseria gonorrhoeae?

A

Ophthalmia neonatorum

56
Q

What is the specimen of choice in males for genital infections?

A

Purulent urethral discharge

57
Q

How should a specimen for Neisseria gonorhoeae culture be transported to the Laboratory?

A

Placed in Amies with charcoal transport system and transported to the laboratory immediately

58
Q

If a male is infected with Neisseria gonorrhoeae, what would be the results of a Gram stain of Purulent urethral discharge reveal?

A

Many polymorphonuclear WBCs, some with gram-negative intracellular diplococci and gram-negative diplococci

59
Q

If a Gram stain of urethral discharge from a male has more than four polymorphonuclear leukocytes per field but no bacteria, what organism is suspected of causing the infection?

A

Chlamydia trachomatis

60
Q

What type of swab of should be used for a Neisseria gonorrhoeae culture?

A

Dacron

61
Q

Why do Thayer-Martin and Martin-Lewis media have antimicrobial agents added?

A

To prevent overgrowth of normal biota

62
Q

Under what condition should the inoculated plates for Neisseria gonorrhoeae culture should be incubated?

A

35 C and 3-5% carbon dioxide

63
Q

A microbiologist reading potential genital cultures on a Martin-Lewis plate should look for what colony morphology if Neisseria gonorhoeae is suspected?

A

Small, tan, translucent

64
Q

An oxidative-positive, gram-negative diplococcus produces bubbles in 30% hydrogen peroxide. What is the organism?

A

N. Gonorrhoeae

65
Q

Which of the following is characteristic of Moraxella catarrhalis?

A

Tributyrin positive

66
Q

What antimicrobial agents are recommended for treatment of uncomplicated Gonococcal infections?

A

Cephalosporins

67
Q

How is Neisseria meningitidis most commonly spread?

A

Respiratory droplets

68
Q

The symptoms of meningococcal meningitis include all of the following, except

A

Backache

69
Q

A young adult goes to the emergency department complaining of headache, dizziness, stiff neck, and purpura with a petechial skin rash. What two tests should the physician immediately perform>

A

Blood and CSF culture

70
Q

What is the name of the condition in which there is hemorrhage in the adrenal glans?

A

Waterhouse-Friderichsen syndrome

71
Q

A microbiologist does a Gram stain on a CSF. She sees intracellular and extracellular gram-negative diplococci. What is the most likely organism?

A

N. Sicca

72
Q

What media should be used to isolate Neisseria meningitis from respiratory samples?”

A

Selective and nonselective

73
Q

In carbohydrate substrate test, a gram-negative diplococcus produces acid only from glucose and maltose. You should suspect

A

N. Meningitidis

74
Q

What organism is a commensal of the upper respiratory tract and has become an opportunistic pathogen causing upper and lower respiratory tract infections in otherwise healthy children and the older adults

A

Moraxella catarrhalis

75
Q

nonpathogenic commensal Neisseria spp. include all the following except

A

N. Menigitidis

76
Q

All of the following are characteristics of haemophilus spp. except

A

Gram-positive cocci

77
Q

Which species are associated with infection in humans?

A

All of the above
*Haemophilus influenzae
*H. Aegyptius
*H. Ducreyi

78
Q

A microbiologist is reading a sputum culture and notices tiny, translucent colonies growing closely around a B-hemolytic colony on sheep blood agar (SBA). The colonies growing in the area where the blood has be hemolyzed. What is the probable identity of the organism that is growing closely to the B-hemolytic organism, ad why are they growing in the hemolyzed area?

A

Haemophilus spp., because they need the factor V in this area

79
Q

Which one of the virulence factors associated with Haemophilus spp. plays the most significant role in the invasiveness of the organism?

A

Capsule

80
Q

A mother brings her lethargic, feverish baby into the ER. The baby is diagnosed with meningitis, and the physician does a spinal tap. The CSF gram stain shows many tiny gram-negative rods. What is the most probable identification of this organisms?

A

Haemophilus influenzae

81
Q

The bacterium is the causative agent of kennel cough in dogs and is occasionally associated with respiratory tract infections in humans

A

Bordetella bronchiseptica

82
Q

What Haemophilus species is called the Koch-Weeks bacillus?

A

H. Aegyptius

83
Q

What organisms causes Brazilian purpuric fever (BPF)?

A

H. Influenzae biogroup Aegyptius

84
Q

What medium will sustain the growth of most Haemophilus spp?

A

Chocolate agar (CHOC)

85
Q

A microbiologist is reading a sputum culture and notices that there is no growth on the sheep blood and MacConkey (MAC) agar plates, but there is heavy growth on the chocolate plate. The colonies on the plate are translucent, moist, smooth, and convex, with a mousy odor. What is the most likely identification of the organism?

A

H. Influenzae

86
Q

Which species of Haemophilus requires both X and V factors?

A

H. Influenzae

87
Q

What is the drug of choice for treating a life-threatening illness caused by H. Influenzae?

A

Ceftriaxone

88
Q

The HÁČEK group includes all of the following except

A

Clostridium difficile

89
Q

What organisms often are involved in septicemia in the granulocytopenic patient?

A

Capnocytophaga spp.

90
Q

What organisms often are involved in septicemia in the granulocytopenic patient?

A

Capnocytophaga spp.

91
Q

All of the following are normal inhabitants of the human oral cavity except

A

Capnocytophaga fusofurium

92
Q

What organism is likely to cause an infection after a cat bite?

A

Pasteurella spp.

93
Q

What is the most frequently isolated pasteurella species?

A

P.multocida

94
Q

All of the following organisms are associated with human illness, except

A

B. Ovis

95
Q

What is the name of the organism that causes tularemia, which can be contracted from rabbits?

A

Francisella tularensis

96
Q

What are the names of the two diseases caused by Legionella species?

A

Legionnaires disease and Pontiac fever

97
Q

What organism produces a community-acquired pneumonia, with symptoms different than a streptococcus pneumoniae infection, leading to the designation of atypical pneumonia?

A

Legionella pneumophila

98
Q

What medium is used to isolate legionella?

A

Buffered charcoal yeast extract (BCYE)

99
Q

All of the following are rapid methods used to definitively ID legionella species except

A

Indirect immunofluorescence

100
Q

What is the drug of choice for treating a legionella infection?

A

Macrolide

101
Q

What organism causes the disease called whooping cough?

A

Bordetella pertussis

102
Q

What agar is used to isolate Bordetella pertussis?

A

Bordet-Gengou

103
Q

How is pertussis spread?

A

Respiratory droplets

104
Q

What is the specimen of choice for Bordetella pertussis?

A

Nasopharyngeal swabs

105
Q

What is the drug of choice for treating Bordetella pertussis infection?

A

Erythromycin

106
Q

A technician is working the night shift and receives a CSF specimen on an infant. The technician makes a Gram stain of the spinal fluid, then reads the smear under the microscope. The report the technician sends to the physician reads as follows: “gram-negative bacillus, small and pleomorphic.” What bacteria are being implied as the infecting agent?

A

Haemophilus influenzae

107
Q

A microbiologist is reading plates from a CSF culture. She notices that there is growth on CHOC, but no growth on SBA or MAC agar. The gram stain showed a gram-negative bacillus. What organism can this be?

A

Haemophilus influenzae

108
Q

A microbiologist is reading the plates from a sputum culture. There is growth only on the chocolate plate. When the microbiologist takes off the lid of the culture plate, he notices a distinct “mousy” smell. What organism can this be ?

A

Haemophilus sp.

109
Q

This organism is described as glistening, silver, and resembling a mercury droplet on media supplemented with horse blood

A

Bordetella pertussis