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Reed Brooks Diagnostic Microbiology > Test 4 > Flashcards

Test 4 Flashcards

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1
Q

Anaerobes usually fail to grow under what conditions?

A

usually fail to grow in the presence of oxygen thus carry out fermentation

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2
Q

Anaerobes can be either gram positive or gram negative

T/F

A

True

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3
Q

aerotolerant

A

(5% O2) anaerobic bacteria not killed by small amounts of oxygen
1-Clostridium
2-Actinomyces spp.
*grow best under anaerobic conditions

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4
Q

Most anaerobes are _______________.

A

obligat (strict) anaerobes requiring 0% O2.

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5
Q

How long does it take for obligate anaerobes begin to die with brief exposure to O2

A

~10 minutes

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6
Q

Anaerobic organisms lack…..

A

1-superoxide dismutase
2-catalase
enzymes required to break down reactive oxygen species during aerobic metabolism, harmful to bacteria

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7
Q

Obligate Aerobes

A

(21% O2, and 0.3% CO2, ambient air AKA room temp) cannot grow anaerobically
-Have no fermentative pathways, typically produce superoxide dismutase

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8
Q

Obligate Anaerobes

A

( 5-10 % hydrogen and CO2 both, 80-90% N) grow only in or near 0% O2 levels
-Lack superoxide dismutase, generally lack catalase, are fermenters that cannot use oxygen as a terminal electron acceptor

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9
Q

Microaerophiles

A

(5-10% O2) CO2 (8-10%) only grow under reduced O2 levels

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10
Q

Facultative anaerobe

A

can grow under aerobic or anaerobic conditions thus some can be normal flora-skin
*will respire aerobically until oxygen is depleted and then
ferment

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11
Q

Capnophiles

A

like increased CO2(5-10%) and 15% O2.

*Candle jars achieve about 3-5% CO2 and 8-10% O2

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12
Q

Anaerobes are the most abundant bacteria in …..

A

the human gastrointestinal tract.

  • the number of bacteria increase as you move distally
    ex. . colon has more than the duodenum
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13
Q

What are the most abundant bacteria (normal flora)

in the human colon?

A

Bacterioides spp.

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14
Q

Why are bacteria like Bacterioides important for us to have?

A
  • these bacteria are important in the breakdown of food products into forms our body can absorb.
  • they also break down carcinogens.
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15
Q

Clostridial spp- normal flora?

A

many Clostridial app are part of normal flora-GI and skin

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16
Q

additional anaerobes as normal flora of skin and/or

upper respiratory tract:

A

1-Propionibacterium
2-Prevotella
3-Fusobacterium

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17
Q

Microaerophilic gram positive thin rods with spiral forms,

normal flora of female genital tract

A

Lactobacillus

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18
Q

Lactobacillus

1-colony morphology on sheep blood
2-hemolytic pattern
3-catalase

A

1-pinpoint
2-alpha hemolytic-resembles streptococci
3-negative

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19
Q

Endogenous infections

A

opportunistic infections, pathogens gain access to sterile sites (trauma)

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20
Q

Exogenous infection sources

A

rusty nails

skin puncture

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21
Q

botulism

A

ingestion of improperly canned foods

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22
Q

Human to human spread

A

C. difficile

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23
Q

Disease Transmission of Anaerobes (4)

A

1-Endogenous infections
2-Exogenous sources
3-Ingestion of improperly canned foods (botulism)
4-Human to human spread (C. difficile)

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24
Q

Infection sites (9)

A

1-Brain/lung/liver/intra-abdominal abscess
2-Chronic otitis media
3-Dental infections (abscess formation)
4-Aspiration pneumonia
5-Peritonitis/appendicitis/cellulitis
6-Trauma/surgical wounds
7-Post-abortion sepsis-gynecological infections
8-Myonecrosis
9-very rarely urine (only 1% isolated from urines are anaerobes)
-Voided or catheterized urine not acceptable (normal flora contaminants)
-Suprapubic bladder aspirate is acceptable

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25
Q

Specimens that limit the amount of normal flora contamination? (3)

A

1-aspirates
2-tissue
3-blood

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26
Q

Acceptable specimens for anaerobes?

A

aspirated material or tissue biopsy

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27
Q

which is preferred, needle aspiration or swab?

A

needle aspiration

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28
Q

Disadvantages of swabs?

A
  • small amounts
  • drying
  • normal flora contamination-is normally taken from from skin or mucosal surfaces
  • toxic exposure to air
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29
Q

Blood specimens should always be collected utilizing…

A

both aerobic and anaerobic blood culture bottles

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30
Q

How are blood cultures collected?

A

-sanitize the collection site (skin) with iodine or clorhexidine gluconate in combo with 70% isopropyl alcohol.

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31
Q

Specimens to accept?

A
  • skin-aspirates of wounds are acceptable
  • Swabs not preferred-they may contain anaerobes associated with normal flora that normally inhabit hair follicles and sebaceous glands(i.e. more easily contaminated with normal flora, also O2 is present on skin surface
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32
Q

skin aspirates

A
  • aspirations typically contain less contamination with normal flora and are thus preferred over swabs
  • once in the syringe, the extra needs to be expelled
  • the aspirate should then be injected into an oxygen free transport tube or vial preferably containing PRAS media.
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33
Q

When should swabs be used?

A

when aspirated material is not possible or tissue is unavailable

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34
Q

The steps for processing sputum specimens

A

1-digestion-liquify mucus with mucolytic agents to release bacteria from mucin
2-decontamination-eliminate normal flora, high lipid content of Mycobacteria cell walls makes them resistant to this step
3-neutralization-with phosphate buffer or water
4-concentration

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35
Q

Nonphotochromagens (organisms)

A

Mycobacteria avium/intracellular complex

  • M. shimoidae
  • M. genavense
  • M. xenopi
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36
Q

Mycobacteria xenopi

A

Nonphotochromagen that is found in hot water taps in hospitals, causes pulmonary infections and disseminated disease

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37
Q

What is MAC?

A

Mycobacteria avian complex

Important pathogen in AIDS patients

Pulmonary infections and lymphadenitis
exhibit mucus production, if long standing can cause mechanical stress on bronchioles and result in bronchiectasis

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38
Q

Difference between MAC and TB?

A

MAC is not spread person to person, rarely presents with granulomas or tissue death

TB does

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39
Q

ID scheme for TB

A

Culture growth within 4-8 weeks that is rough, dry, buff, non-pigmented on Lowenstein-Jensen media

  • Acid-fast: strong + with slightly curved, beaded rods
  • niacin: +
  • Nitrate reduction: +
  • 68 degree catalase test: -
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40
Q

Rapid Growers

organisms

A

Mycobacteria fortuitum
M. chelonae

Can grow on MacConkey with CV omitted

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41
Q

All Mycobacteria produce…

A

Niacin

M. tuberculosis and simile are “positive” due to high accumulation of niacin in the media due to lacking the enzyme to convert niacin to niacin ribonucleotide

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42
Q

Percentage of O2 and CO2 for….

Obligate aerobes
Obligate anaerobes
Microaerophiles
Facultative anaerobes
Capnophile
A 
Obligate aerobes- 21% O2, 0.3% CO2
Obligate anaerobes- 0% O2, 5-10% H and CO2
Microaerophiles-5-10% O2, 8-10% CO2
Facultative anaerobes- doesn't matter
Capnophiles- 15% O2, 5-10% CO2
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43
Q

What type of bacteria are most abundant in the human gastrointestinal tract

A

Anaerobes

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44
Q

As you move more distally, the number of bacteria increases or decreases?

A

Increases

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45
Q

Cell wall deficient bacteria

A

Mycoplasma and Ureaplasma

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46
Q

2 major groups of Leptospira app.

A

1-interrogans-causes human leptospirosis

2-L. biflexa- environmental strains

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47
Q

2 groups of Mycobacteria

A

Mycobacterium tuberculosis complex-humans are natural reservoirs
*All are slow growers and have non-pigmented colonies!
(NTM) Nontuberculosis Mycobacterium-found in the environment and can transiently colonize skin, GI, and RT

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48
Q

Causative agent of cervical identities in children

A

Mycobacteria scrofulaceum

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49
Q

Which organism colonizes with a “fried egg” appearance on agar?

A

Mycoplasma hominis

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50
Q

Clostridium botulinum

Spores are:
Virulence Factors:
Group 1 and 2:
Group 3:
Group 4:
A 
Spores are: subterminal (racket shape)
Virulence Factors:  neurotoxin causing flaccid paralysis
Group 1 and 2: human botulism
Group 3:  animal botulism
Group 4:  not disease associated
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51
Q

Mycoplasma and Ureaplasma
1-Media
2-ID
3-Treatment

A

1-Media-SP4 media
2-ID-molecular method (off of specimen) or serodiagnosis
3-Treatment- tetracycline-resistant to beta-lactams due to lacking cell wall

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52
Q

Most definitive test to ID Mycobacteria

A

Niacin

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53
Q

Safety precautions for Mycobacterium

AST Levels 1-3

A

AST 1-grow organism and stain, but not ID
AST 2- ID TB only
AST 3-ID all Mycobacteria and perform susceptibility testing

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54
Q

What allows an organism to be acid fast and which actinomycetes are acid-fast, which ones are not?

A

mycelia acid content in the cell wall

Acid fast: Nocardia and Rhodococcus

Non-Acid fast: Streptomyces

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55
Q

Nonculticatable Nontuberculosis Mycobacterium

A

M. leprae

  • Obligate intracellular bacteria that cannot be grown in vitro
  • found in armadillos and mice
  • Causes leprosy
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56
Q

Mycobacteria specimen sources

A

virtually any tissue or organ

  • sputum (collected early morning for 3 consecutive days)
  • Tissue granuloma
  • Urine
  • Bone
  • CSF
  • Blood
  • GI
  • Stool
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57
Q

Mycobacteria specimen processing

A
  • Specimens from sterile sources can be directly plated to media
  • digestion/decontamination, neutralization, and concentration of sputum cultures
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58
Q

TB Pathogenesis

post established infection

A

After ~3 weeks, TH1 cells release cytokines that cause macrophages to mount a bacterial response and granuloma formation and recruit monocytes, which differentiate into “epithelioid” like cells that wall off the bacteria

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59
Q

TB Epidemiology

A

Not every person exposed will become infected

Contagious-inhalation of a single bacilli

Prevalent in elderly, chronic malnourished, alcoholics, homeless, crowded living conditions

1/3 of the world’s population is infected

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60
Q

Mycoplasma and Ureaplasma

1-Lack
2-Normal flora of
3-Pathogenesis

A

1-Lack cell walls
2-Normal flora of the mouth, URT, upper GI
3-Mycoplasma pneumonias-causes walking pneumonia, primary atypical pneumonia
-Mycoplasma hominis-systemic infection in neonates, urogenital infection in adults
-Ureaplasma urealyticum-isolated from stillborn infants, controversial cause of chorioamnionitis

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61
Q

BSL 3 requires….

A
  • directional air flow
  • labs and hoods equipped with air pressure gauges
  • respirators
  • disposable clothing to be autoclaved
  • Nonpermeable walls and surfaces in rooms
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62
Q

TB

1-Primary:
2-Secondary:
3-Miliary:

A

1-Primary: initial infection in a previously exposed individual with 2 potential outcomes:
-Latent TB: exposure, develop antibodies, and test positive skin test, but no active disease not contagious
-Active infection/Disease
2-Secondary: (Reactivation) person with latent TB manifests later with disease
3-Miliary: spreads to other organs hematogenously

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63
Q

TB Pathogenesis

establishing the infection

A

Respiratory droplets from infected individual get suspended in air and inhaled and the droplets make their way to alveoli.

Macrophage migrate to the alveoli and take up the bacteria via endocytosis, but are unable to kill the bacteria due to mycobacteria blocking the fusion of the lysosome with the phagosome through protein inhibition

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64
Q

Scotochromagens

organisms

A

(Mycobacteria)

  • M. scrofulaceum
  • M. szulgai
  • M. gordonae
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65
Q

Photochromagens

organisms

A

(Mycobacteria)

  • M. kansasii
  • M. marinum
  • M. asiaticum
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66
Q

What are Runyon groups

A

Nontuberculosis Mycobacteria

Photochromagens-require light to form pigment following
incubation in the dark
Scotochromagens-produce pigment in dark or light
conditions
Nonphotochromagens-non-pigmented regardless of
incubation conditions
Rapid Growers-take <7 days to grow on solid media

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67
Q

Organisms part of the Mycobacterium tuberculosis complex

A
  • M. tuberculosis
  • M. bovis
  • M. africanum
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68
Q

Lowenstein-Jensen media

A

The medium most often used for isolation and cultivation of Mycobacterium spp.

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69
Q

Mycobacteria spp characteristics

A 
non-spore forming
slender, gram +/variable bacilli
slow growing (2-60 days)
(due to high lipid content in the cell wall causing them to clump making nutrient uptake more difficult)
Obligate aerobes (CO2 enhances some)
Acid-fast
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70
Q

ID for Mycobacteria

A

Biochemical/Growth characteristics

High Performance Liquid Chromatography

T-SPOT-TB blood test

Molecular methods

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71
Q

Incubation of Mycobacteria spp

A

If skin specimen-25-30 degrees C
(M. marium, M. ulcerans)

35 degrees C in the dark, 5-10% CO2 and high humidity

TB takes 2-4 weeks to grow and susceptibility testing takes an additional 2-4 weeks for a total of 4-8 weeks on average

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72
Q

What should be done for optimal recovery of Mycobacteria

A 
-uses and least one solid media:
Middlebrook 7H10 ( non-selective)
egg-potato base (Lowenstein-Jensen and Petragnant)
-AND at least one liquid media:
BACTEC 12B
Middlebrook 7H9 broth
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73
Q

Non cultivatable Mycobacteria

Mycobacteria leprae

A

Causes Leprosy (Hansen’s Disease)
-chronic disease of the skin, mucous membranes,nerve tissue
obligate intracellular bacteria-never cultured in vitro
-Humans are the primary reservoir
Transmission via contact with infected skin/nasal secretions

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74
Q

Stain methods for Mycobacteria

A

1-Acid-fast: high lipid content binds fuchsin dye and resists destaining
-(Ziehl-Melson (hot), Kinyoun (cold)-higher concentration of phenol to accelerate staining process)
2-Fluorochrome: Mycobacteria have affinity to flurochrome (Auramine O with/without rhodamine)

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75
Q

BSL 3

A

Recommended BSL when working with Mycobacterium

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76
Q

Pigment production of:

1-Scotochromagens
2-Photochromagens
3-Nonphotochromagens

A

1-Scotochromagens-deep yellow-orange in both dark and light
2-Photochromagens-light exposure
3-Nonphotochromagens- non-pigmented in either dark or light (can produce pale yellow, buff,tan, but do not intensify upon light exposure)

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77
Q

Mycobacteria that have positive nitrate reduction

A

M. tuberculosis (strong positive)

M. kansasii

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78
Q

Clinical Screening for TB

A

QuantiFERON-TB Gold In-Tube test
-test for interferon-gamma release from the T-cells after stimulation via 3 proteins derived from M. tuberculosis

Purified Protein Derivative (PPD)- Intradermally

  • delayed appearance of indurated reaction with or without erythema
  • positive test does not distinguish between current or past infection/exposure
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79
Q

General Characteristics of Anaerobes

A

Cannot grow in presence of Oxygen (some are aerotolerant-5% O2), thus can only ferment

Can be both gram+ and gram-

Lack superoxide dismutase and catalase, which are used to break down reactive oxygen radicals

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80
Q

Anaerobe specimens of choice

A

aspirates, tissue, blood (where limited normal flora)

Disadvantage of swabs: organism is toxic if exposed to air, dry, small amount, normal flora contamination

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81
Q

Anaerobic PEA

A

inhibits proteus swarming and facultative enterobacteriaceae, but allows growth of gram+ bacteria

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82
Q

A major cause of pelvic inflammatory disease and ectopic pregnancy

A

Chlamydia trachomatis

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83
Q

Clostridium spp are exceptional at causing disease due to…….

A
  • Ubiquitous in nature
  • Spore-forming
  • Rapid proliferation in nutrient rich and O2 deprived environments
  • Produce various toxins
84
Q

Cause of nonvenereal syphilis and its transmission

A

Treponema pallidum subsp. Endemicum

Transmitted mouth-to-mouth via utensils

85
Q

3 blood cultures and a stool sample

A

Specimen required for diagnosis of suspected Clostridium perfringens associated with enteritis necroticans…..

86
Q

What is Scrapies?

A

A prion disease infecting sheep and goats.

87
Q

Chronic Wasting Disease….

Currently found where?

A

Deer and elk

growing concern about transmission to livestock

No documented transmission to humans

88
Q

Difference between actinomycetoma and eumycotic mycetoma

A

Actinomycetomas are caused by actinomycetes

Eumycotic mycetoma are caused by fungi

89
Q

What should be used to sanitize the collection site when obtaining blood for a blood culture?

A

iodine
or
clorhexidine gluconate in combo with 70% isopropyl alcohol

90
Q

Prion Pathogenesis

A

Through a mutation or exposure, cellular prion protein PRPc undergoes conformational change to the abnormal PRPsc protein.

PRPsc is insoluble and initiates an autocatalytic reaction leading to the accumulation of amyloid in the CNS which then leads to neurodegeneration.

91
Q

Bacteriodes fragile Group

1-Gram:
2-Carb utilization
3-Pigment
4-Esculin
5-Susceptible to
6-Resistant to
7-Normal Flora
A 
1-Gram: gram - rods
2-Carb utilization: saccharolytic
3-Pigment: non-pigmented
4-Esculin: +
5-Susceptible to: rifampin
6-Resistant to: penicillin, kanamycin, vancomycin, collistin
7-Normal Flora: GI tract
92
Q

Nocardia

1-Gram stain:
2-Catalase:

A

1-Gram stain: gram stain + (variable), branching filamentous bacteria capable of fragmenting in rods and cocci
2-Catalase: +

93
Q

What is absolute concentration?

A

inoculate organism to media with various known concentrations of antibiotics and look for inhibition (provides MIC)

Used for conventional susceptibility testing for mycobacteria

94
Q

What type of bacteria are most abundant in the human gastrointestinal tract

A

Anaerobes

95
Q

What are actinomycetes?

A

elongate to form branching, filamentous forms resembling hyphae of fungi

96
Q

Natural habitat of Chlamydia trachomatis

A

Humans

97
Q

Pathogenesis of Chlamydia trachomatis

A

Trachoma-ocular eye infection causing blindness

Lymphogranuloma venereum (LGV) move beyond the mucosa of the genital tract and invade regional lymph nodes

Caused by L1,L2 and L3 strains

Genital infection-urethritis, cervicitis, proctitis, eppididymitis

Treated with azithromycin or doxycycline

98
Q

Clues that anaerobes are present in a sample

A

Foul odor upon opening an anaerobic jar or bag
(metabolic and products from C. diff and Fusobacterium are fetid)

Colonies are present on anaerobic media, but not on non-anaerobically incubated/prepared media

99
Q

All PRAS media should be supplemented with

A

hemin, blood, vitamin K

100
Q

Types of PRAS media

A

1-Anaerobic Phenylethylene alcohol agar (PEA)
2-Kanamycin-Vancomycin liked blood (KVLB)
3-Kanamycin-vancomycin blood agar
4-Bacterioides bile-esculin agar (BBE)
5-Thioglycollate broth

101
Q

What is a mycetoma?

A

infection of subcutis with draining sinus tracts following traumatic inoculation often in the lower limbs with white to yellow granules

102
Q

Prions are typically resistant to:

A

formalin and paraffin embedding

103
Q

Streptomyces

1-Gram stain
2-Branching
3-Acid fast
4-Causes
5-treatment
A

1-Gram stain: gram +, branching filaments with no mycelia acids

2-Branching: extensive with chains and spores
3-Acid fast: negative
4-Causes: actinomycetoma
5-treat with streptomycin

104
Q

The disease-producing capabilities of TB is associated with the ability to….

A

Escape death by multiplication in alveolar macrophage

105
Q

Aerobic Actinomycetes

A
  • Nocardia
  • Streptomyces
  • Rhodococcus

AEROBIC

106
Q

Clostridium perfingens ID

A

Reverse CAMP test

  • streak Strep. Agalactiae
  • C. perfingens produces positive bowtie result

*included on Vitek 2 ANC Card

107
Q

Causative agent of the third most common cause of bacterial food poisoning

A

Clostridium perfringens strains producing CPE (enterotoxin)

Typically self-limiting

108
Q

A suprapubic urine aspirate is collected and submitted for anaerobic cultivation.
After incubation for 72 hours, the organism is gram +, aerotolerant, catalase - and motile

A

Lactobacillus

109
Q

Clostridium botilinum

1-Found
2-Toxin

A

1-found: soil, water

2-toxin: botulism toxin

110
Q

Anaerobic specimens should always initially be plated to….

A

1 anaerobic blood agar
AND
2 PRAS media

111
Q

Anaerobic chambers (Glove Box)

A

allow for anaerobic conditions from inoculation forward

112
Q

What is a GasPak?

A

An envelope with 2 tablets

  • one containing citrate, sodium bicarbonate
  • one containing sodium borohydride

Heat and water get produced (O2 reacts with H)
Methylene blue indicator that turns white when anaerobic conditions are achieved

113
Q

How does the Anaerobe jar work?

A

Vacuum the air from the jar and replace it with
CO2, N, and H
OR
Add a GasPak

114
Q

Devices to create anaerobic conditions

A
  • Candle Jar
  • anaerobe jar or pouches
  • holding jars
  • anaerobe chambers
115
Q

Sulfer granules in a specimen indicate the presence of….

A

Actinomyces spp

116
Q

Chlamydia spp.

1-Type of organism:
2-Cannot be grown on…..
3-Important species:

A

1-Type of organism: obligate intracellular bacteria
2-cannot be grown on…..cell-free media
3-Important species: C. trachomatis, C. psittaci (more common in birds), C, pneumoniae (causes pneumonia, bronchitis, or pharyngitis in humans)

117
Q

Rhodococcus

Pathogenesis

Treatment

A

Some are facultative intracellular bacteria that reside within macrophages

Infections stem from pulmonary, skin, to osteomyelitis

Treat with erythromycin in combo with rifampin

118
Q

Digestion/ Decontamination Agents or sputum cultures

A

6% NaOH, 5% Oxalic acid (can be harmful to Mycobacterium….timing critical)

Trisodium phosphate zephiran

MOST COMMON: N-acetyl-L-cysteine (NALC)
NaOH method

(NALC is mucolytic, NaOH is mucolytic and a decontaminant….15 minute incubation period)

119
Q

3 Forms of Creutzfeldt-Jakob Disease

A

1-Sporadic-disease develops with no known history. PRPc—->PRPsc in a possible cascading manner
2-Hereditary-genetic mutation in PRNP gene
3-Acquired-transmitted by exposure to brain or other nervous tissue (EX: dura implant)

120
Q

Clostridium difficile Pathogenesis

A

Normal flora in a small amount of people; nosocomial infection

Opportunistic pathogen- long term antibiotic administration wipes out normal flora and C. diff establishes infection

121
Q

Causative agents of typhus

A
  • Rickettsia prowazekii (epidemic)
  • Rickettsia typhi (endemic/murine)

fever, headache, rash
doxycycline is curative

122
Q

Distinguishing characteristics of prions

A
  • long incubation periods
  • spongiform changes associated with neuronal loss
  • failure to induce inflammatory response
123
Q

2 FDA approved nucleic acid amplification tests to detect Mycobacteria straight from a specimen

A
  • Enhanced Amplified Mycobacterium Tuberculosis Direct Test (E-MTD, Gen-Probe)
  • Amplicor Mycobscterium Tuberculosis Test
124
Q

Porphyromonas

1-gram:
2-Pigment:
3-carb utilization:
4-Cause infections where:
5-Normal flora:
A 
1- gram- rod
2-Pigment:  bright red fluorescence
3-carb utilization:  assacharolytic
4-Cause infections where:  head regions
5-Normal flora:  oral cavity
125
Q

Prevotella melaninogenica

1-gram:
2-Normal flora:
3-carb utilization:
4-Pigment:

A

1-gram: gram - rod
2-Normal flora: oral cavity, RT,GI and genitourinary tracts
3-carb utilization: fermentation**
4-Pigment: depends on the strain….black pigment on lake blood agar

brick red fluorescence

126
Q

Fusobacterium

1-gram:
2-normal flora:
3-Cause infections where:

A

1-gram: gram - rod (fresh sample-slightly curved; loose curve from culture)
2-normal flora: oral cavity
3-CAuse infections where: above the thorax

127
Q

For sputum specimen processing, why is it important to digest/decontaminate, neutralize, and concentrate?

A

To kill normal flora that outgrow TB and also release TB from cells and/or mucin

128
Q

Tween 80 Hydrolysis

A
  • toxic to certain organisms
  • IDs mycobacteria possessing lipase that splits tween 80 into oleic acid and polyoxyethylated sorbitol

2 drops of Tween 80 is added to 1 mL saline and inoculated

Color change from orange to pink/red= positive result
M. kansasii ++ TB complex -

129
Q

Causative agent of cervical adenines in children

A

Mycobacteria scrofulaceum

130
Q

Nocardia species responsible for >80% actinomycete infections in humans

A

N. asteroides

131
Q

Clostridium tetani

1-spores:
2-hemolysis:
3-Vaccine:
4-Causes:

A

1-spores: oval with terminal/subterminal location (drumstick or tennis racket)
2-hemolysis: beta
3-Vaccine: DTaP
4-Causes: tetanus

132
Q

Infant Botulism

A

Neurotoxin production occurs in vivo

Bacteria colonize GI mucosa

Treatment: high quality supportive care (nutrition and respiratory functions)

antibiotics can speed up toxin release=bad

133
Q

What is double zone of hemolysis and which organism process it on anaerobic BAP?

A

Inner zone of complete (beta) cell lysis and outer zone of incomplete (alpha) lysis due to alpha toxin and lecithinase activity

134
Q

Bacteriodes spp

typically cause infections where?

A

below the diaphragm

Abscesses, bacteremia

135
Q

Clostridium difficile

Exotoxins poduced?

A

-Toxin A: enterotoxin, causes inflammation of intestinal mucosa
Toxin B: cytotoxin, causes cellular death

136
Q

How to distinguish between CFJ and Variant CFJ….

A

CFJ-manifests in the elderly

vCFJ- manifests in younger adults with prominent psychiatric or sensory symptoms with delayed onset of neurologic abnormalities

137
Q

Botulism Pathogenesis

A

Neurotoxin enters body through GI tract, RT, or mucous membranes
Enters the blood stream and/or lymphatics and makes its way to neuromuscular junctions
blocks neurotransmitter release
(symptoms:cranial muscle paralysis, double vision, dilated pupils, slurred speech, dry mouth, dysphagia, paralysis spreads to limbs and respiratory dysfunction ensues)

138
Q

What are spirochetes?

A

Long, slender, coiled gram- rods with fibrils and an outer sheath

Fibrils: flagella-like organelles imparting motility

139
Q

Rhodococcus

1-Inhabit:
2-Media:
3-Gram stain:
4-Catalase:

A

1-Inhabit: soil, farm animals, fresh and salt water
2-Media: SBAP with chloramphenicol + cyclohexamide
3-Gram stain: gram +, branching filamentous capable of fragmenting into rods and cocci
4-Catalase: +

140
Q

Foodborne Botulism

A

Symptoms occur 6-36 hours after ingesting pre-formed neurotoxin

Treat with ventilation and antitoxin and drugs that induce
bowel movement or vomiting

Specimens: serum, gastric contents, feces, suspected food

141
Q

Causative agents of Spotted Fever and geographic location

A

Rickettsia conorii: Europe, Middle East Israeli Spotted Fever

Rickettsia rickettsii: US Rocky Mountain Spotted Fever

142
Q

4 forms of botulism

A

1-Foodborne (home canned foods)
2-Infant (honey consumption)
3-Wound (only form antibiotics are used to as treatment)
4-Inhalation (bioterrism)

143
Q

Rickettsia

1-Type of organism
2-gram stain
3-host/reservoir
4-Vector
5-Culture requires
A

1-Type of organism: Obligate intracellular bacteria
2-gram stain: small, pleomorphic gram- rods
3-host/reservoir: humans are accidental hosts, animals are the reservoir
4-Vector: ticks, lice, and fleas
5-Culture requires….embryonated eggs

144
Q

Survivors of Rocky Mountain Spotted Fever can acquire what future problems and why?

A

Vasculitis due to the bacteria invading endothelial cells lining blood vessels, which can possibly cause bleeding in the brain

145
Q

What are prions?

A

transmissible spongiform encephalopathies (TSEs)

Rare progressive neurodegenerative disorders that affect both humans and animals

146
Q

Clostridium spp.

1-gram:
2-endospore forming:
3-catalase:
4-many species are normal flora of:

A

1-gram: gram + bacili
2-endospore forming: yes
3-catalase: -
4-many species are normal flora of: gut, female genital tract, oral mucosa

147
Q

Rocky Mountain Spotted Fever

A

Caused by Rickettsia rickettsii
60% of cases occur in North Caroline, Oklahoma, Arkansas, Tennessee, and Missouri

fever, headache, and rash after 2-5 days after fever onset and can be fatal if not treated within 8 days

148
Q

Clostridium perfringens

1-found:
2-Normal flora:
3-toxin:
4-Infection:

A

1-Found: soil,water,contaminated feces, kitchen counters
2-Normal flora: (some strains) intestines
3-toxin: 12 different types
4-Infection: soft tissue infections (cellulitis, myonecrosis, food poisoning, enteritis necroticans)

149
Q

Clostridium tetani

1-toxin:
2-Tetanus=
3-Symptoms:
4-Treatment:

A

1-toxin: tetanospasmin (disrupts nerve impulses to muscles)
2-Tetanus=sustains contraction (lockjaw)
3-Symptoms: Risus sardonicus, drooling, sweating, cardia arrhythmias
4-Treatment: DTaP vaccine, debridement of wound, antibiotics, antitoxin

150
Q

Nocardia media and morphology

A

Middlebrook’s agar

Orange, glaborous colonies

musty basement odor

151
Q

Lowenstein-Jensen agar

Petragnani

A

Lowenstein-Jensen-coagulated whole eggs glycerol (enhances growth), potato flour, Malachite green

Petragnani-coagulated whole eggs, egg yolks, whole milk, potato, potato flour, Malachite green

Malachite green inhibits other microbes

152
Q

Peptococcus niger

1-gram:
2-Normal flora:
3-Disease:
4-Anaerobic BAP morphology

A

1-gram: gram + cocci in pairs or tetrads
2-Normal flora: GI tract
3-Disease: not associated with human disease
4-Anaerobic BAP morphology: tiny black, convex, smooth colonies that turn light gray when exposed to air

153
Q

Preferred specimen to ID Chlamydia trachomatis

A

urine

154
Q

Clostridium difficile causes

A

Pseudomembranous colitis:
-associated with the mucosal inflammation is the deposition of a pseudomembrane on the mucosal surface composed of fibrin, neutrophils and dead bacterial cells.

155
Q

Clostridium difficile

1-Specimen:
2-Odor:
3-selective media:
4-ID:
5-treatment:
A

1-specimen: watery stool culture
2-odor: horse stable
3-selective media: Cycloserine-cefoxitin fructose agar
4-ID: Culture, automation, serology, enzyme immunoassays to detect toxin(s)
5-treatment: discontinuation of current antibiotic use, vancomycin for severe cases, possible surgical intervention

156
Q

Cycloserine-cefoxitin fructose agar (CCFA)

A

egg yolk base selective to C. diff

yellow, ground glass colonies

157
Q

KVLB agar

A

selective for gram- obligate anaerobes
(Prevotella, Bacteriodes)

Vancomycin inhibits growth of all gram +
Kanamycin inhibits growth of all gram -, facultative
anaerobic bacilli

158
Q

Gerstmann-Straussler Syndrome…..
What is it and what is it caused by?
How is it diagnosed?

A

An autosomal dominant mutation of the PRNP gene that results in loss of coordination (due to cerebellum deterioration) followed by slowly delayed mental dysfunction.

Genetic testing, family history, radiographic amyloid plaques, and history and physical are diagnostic

159
Q

The lifecycle of Chlamydia app is similar to _____by……

A

The lifecycle of Chlamydia app is similar to parasites by having an intracellular form (reticulate body) and an extracellular, inert form (elementary body)

160
Q

In HIV/AIDS patients, chronic pulmonary disease may be associated with infection as a result of……

A

Mycobacterium avium complex

161
Q

Most mycobacteria produce catalase….

What kind of catalase do organisms in the TB complex not produce?

A

Heat-stabile catalase

162
Q

Causative agent of Granulocytic Anaplasmosis

A

Anaplasma spp.

163
Q

Gold standard to ID Rickettsia rickettsii

A

Serology to detect the R. rickettsii antigen

164
Q

Creutzfeldt-Jakob Disease typically manifests in at which age and death can occur within how many months?

A

60 years old

6 months

165
Q

An example of a potentially accepted anaerobe swab is from the _____ and why?

A

uterus

because it is a sterile site, but the distal portions of the female genital tract need to be sterilized when collecting the specimen

166
Q

Transportation of Anaerobic specimens

A

Need to mock in vivo conditions (warm, moist)

aspirated material-in an oxygen free transport tube or vial

Tissue-placed in anaerobic transport tubes or vials with pre-reduced anaerobically sterilized (PRAS) media

167
Q

Why is Treponema palladium difficult to culture?

A

lacks the ability to carry out the Krebs cycle and components of oxidative phosphorylation making it difficult to grow on artificial media

Very dependent on the host to so many things for its survival

168
Q

Examples of samples that would need to be rejected for anaerobic work due to large normal flora contamination

A
  • Throat and nasopharyngeal swabs
  • gingival swabs
  • feces (except for C. diff and C. botulinum)
  • voided or catheterized urine
  • surface swabs
  • mucous membrane swab that was not decontaminated
169
Q

Fatal Familial Insomnia…

What is it and what is it caused by?

What makes it different from other prion diseases?

A
  • A prion disease that interferes with sleep and causes severe mental deterioration and is caused by a genetic defect ( autosomal dominant).
  • Differs from other prion diseases in that it primarily affects the thalamus, which controls sleep
170
Q

Identification of Borrelia

A
  • Peripheral blood smears with Wright’s stain
  • Cultivation on Modified Kelly’s media
  • serology via ELISA to detect antibodies to the bacterium
171
Q

Borrelia burgdorferi gram stain morphology

A

gram - spirochete

172
Q

Disease Transmission of Anaerobes

  • Endogenous
  • Exogenous
A

Endogenous: opportunistic pathogens gain access to sterile sites (trauma)

Exogenous: exposure from an external source (ingestion,rusty nails, skin puncture)

Human to human spread (C. diff)

173
Q

Fatal Familial Insomnia….

1-Typically manifests what age?
2-Death occurs when?
3-Symptoms?
4-How can abnormalities be detected?

A

1- Manifests around 30 years old
2- 7-73 months after symptom onset
3- Sleep disturbances, muscle spasms, stiffness, eventually mental deterioration
4-PET scan can detect abnormalities

174
Q

Define polymicrobic

A

-a mix of different organisms at site of infection

facultative and anaerobes

175
Q

Thioglycollate Broth

A

Contains a small amount of agar to prevent diffusion of O2 into the media

176
Q

BBE agar

A
  • presumptive ID for Bactericides that can grow in 20% bile and hydrolyze scullion
  • Gentamycin-inhibits facultative anaerobes and most gram- anaerobic organisms
  • Look for brown/black colony growth and blackening of the media
177
Q

Photochromagens are capable of pigment production when….

A

Exposed to 1-2 hours of light after incubation in the dark

178
Q

Clinical Presentation for Pulmonary TB

A
  • Low grade fever/chills
  • anorexia/weight loss
  • fatigue
  • night sweats
  • productive cough
179
Q

Cell wall deficient bacteria

A

Mycoplasma and Ureaplasma

180
Q

Treatment for TB

A

9-12 month prescription containing a combination of 2-3 of the following:

  • Isoniazid
  • Rifampin
  • Pyrozinamide
  • Ethambutol

Multidrug resistant TB- resistant to Rifampin and Isoniazid

181
Q

Peptostreptococcus anaerobius

1-gram:
2-normal flora:
3-Cause:

A

1-gram: gram + coccobaccili in chains
3-normal flora: yes
2-Cause: endocarditis, GU and GI tract infections, periodontal disease, gingivitis

182
Q

Actinomycosis

A

Chronis infection with local abscissa with formation of oozing sinus tracts containing SULFUR GRANULES
(decaying teeth)

183
Q

Agent that causes Yaws in children and its transmission

A

Treponema pallidum subsp. Pertenue

Transmitted person-to-person via breaks in the skin

184
Q

Stages of Lyme Disease

A

Stage 1: erythema chronicum migrans (bulls-eye lesion),
headaches, fatigue, chills
Stage 2: disseminations via blood, joint and muscle pain, cardiac arrhythmia, carditis
Stage 3: chronic arthritis and possible neurologic involvement

185
Q

Which substances are effective, partially effective, and ineffective at inactivating CFJ?

A
  • Effective: Incineration, Autoclaving at increased temperatures, bleach, formic acid
  • Partially Effective: chlorine dioxide, glutaraldehyde, iodophores, urea
  • Ineffective: Boiling, alcohol, formalin, HCl, hydrogen peroxide, UV/microwave radiation
186
Q

If a patient’s medical history includes abnormal shaking/ jerking movements, rapid mental deterioration, dementia with seizures, previous dural implants, or human growth hormone treatment, this may be suggestive of which disease?

A

Creutzfeldt-Jakob

187
Q

Actinomyces israelii

1-normal flora:
2-gram:
3-Causes:
4-Similar in structure to:

A

1-normal flora: mouth, gums, teeth
2-gram: gram + rod
3-Causes: Actinomycosis
4-Similar in structure to: fungi (filamentous in pus or tissue)

188
Q

Leprosy

Hansen’s Disease

A

Can be found in SW U.S.
-armadillos may serve as reservoir

May remain asymptomatic for 2-10 years

Nerve involvement that can be debilitating if left untreated

Treatment: clofazimine, rifampin, dapsone

189
Q

Anaerobic BAP

A

supplemented with yeast, hemmin, vitamin K, cysteine

non-selective

190
Q

Veillonella parvula

1-gram:
2-normal flora:
3-Cause infections in:
4-Fluorescence:
5-Can create
A

1-gram: gram- diplococcic in pairs, clusters, and/or short chains
2-normal flora: mouth and GI
3-Cause infections in: sinuses, lung, heart, bone, and CNS
4-Fluorescence: red
5-Can create: biofilm with Strep. Mutans, which together imparts greater resistance to S. mutants to various antimicrobials

191
Q

Propionibacterium spp.

1-normal flora:
2-typically associated with:
3-Can cause:
4-Most common anaerobic contaminant in:

A

1-normal flora: skin
2-typically associated with: acne
3-Can cause: endocarditis, CNS infection, osteomyelitis, arthritis
4-Most common anaerobic contaminant in blood cultures

192
Q

Clostridium perfringens

Enterocolitis necroticans

A

Inflammation of the jejunum and ileum with necrosis.

-Often segmental in nature, perforation is possible (medical emergency).

At risk groups:

  • Protein deprivation
  • Poor hygiene, food handling
  • Africa, Asia more common
193
Q

Nocardia

1-Inhabit:
2-Transmission:
3-Media/Growth:
4-treatment

A

1-Inhabit: soil,water, decomposed plant material
2-Transmission: inhalation or inoculation via cuts
3-Media/Growth: SBAP or CAP for 48-72 hour
-Middlebrook’s agar
4-treat with sulfanilamides

194
Q

Most common STD in the U.S.

A

Chlamydia trachomatis

195
Q

Kuru….

is linked to….

transmission….

incubation period….

A
  • cannibalism in indigenous people in the highlands of Paupau New Guinea
  • human-to-human transmission
  • Incubation period: 10-13 years, possibly up to 50
196
Q

Erlichia chaffeensis

1-Types of organism:
2-Transmission:
3-Disease course:

A

1-Obligate intracellular bacteria
2-Transmitted via the Lone Star Tick (Amblyomma americium)
3- fever, headache, chills, vomiting, confusion, joint pain

197
Q

Tuskegee Experiment

A

400 black men with syphilis were enrolled in the study

These participants were not informed of their diagnosis, rather than being told they had “bad blood”

Penicillin was found to be a cure for syphilis, but men were not treated or informed

198
Q

Identification of T. pallidum

A

Direct detection-obtain sample from primary skin lesion and utilize dark-field microscopy or fluorescent antibody staining

Molecular (PCR)

Serodiagnosis-detect regain (non-treponemal antibodies) and treponemal antibiodies

199
Q

What is Yaws?

A

Affects skin, bone, and cartilage

Initial skin lesion that remain untreated can result in disfigurement of nose/bones, thickening and cracking of palms of hands and soles of the feet

Transmitted person-to-person via cracks in the skin and humans are the only reservoir

Treated with a single dose of azithromycin

200
Q

Borrelia treatment

A

Doxycycline for adults

Amoxicillin for children

201
Q

The three stages of Syphilis

A

1-primary stage: chancre, skin lesion at site of bacterial penetration develops 10-90 days after the initial infection.
Bacteria proliferate and enter the blood and lymphatics
2-secondary stage: diffuse skin lesions over the entire body, flu-like symptoms 2-10 weeks after 1’ stage

*can enter a latency period where the infection becomes subclinical
Tertiary stage: involvement of all tissues 10-25 years after initial infection, including the brain (neurosyphilis can dementia)

202
Q

6 Diseases/Disorders caused by prions?

A 
1-Creutzfeldt-Jakob
2-Variant Creutzfeldt-Jakob
3-Mad-Cow
4-Gerstmann-Straussler Schnieke
5-Fatal Familial Insomnia
6-Kuru
203
Q

Syphilis is caused by _____, is the _____ most common STD in the U.S. and is only found where?

A

Syphilis is caused by Treponema palladium, is the 3rd most common STD in the U.S and is only found in humans

204
Q

1-Borrelia species of most importance?

2-Causes what disease?

3-Vector?

A

1-B. burgdorferi sensu strict

2-Lyme disease

3-Ixodes (black-legged, deer) tick
B. mayonii, discovered in 2013 also causes this and has the same vector

205
Q

Leptospirosis….

1-What is it?
2-How is it transmitted?
3-Two(2) stages?

A

1-a zoonotic disease that colonizes renal tubules of carrier animals
2-transmitted via contact with urine or blood through breaks in skin and mucous membranes
3-Septicemic stage: fever, headache, progresses to immune stage
-Immune stage: marked by IgM presence and can cause aseptic meningitis

Reed Brooks Diagnostic Microbiology (2 decks)

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