Advanced Microbiology Exam 2

Front 1

Obligate aerobes

Back 1

absolute requirement of oxygen to grow

Front 2

Obligate anaerobes

Back 2

grow only under conditions of high reducing intensity, oxygen is toxic

Front 3

Facultative anaerobes

Back 3

Grow under aerobic or anaerobic conditions

Front 4

Microaerophilic organisms

Back 4

Grow best under low oxygen intensity, high oxygen may be inhibitory

Front 5

Aerotolerant aerobes

Back 5

Can tolerate oxygen but do not use it metabolically

Front 6

Spore-forming, gram-positive, anaerobic bacilli

Back 6

Clostridium spp.

Front 7

Strict anaerobes die within _____ of oxygen exposure

Back 7

10 minutes

Front 8

Enzymes that protect against toxic effects of oxygen production

Back 8

catalase, superoxide dismutase and peroxidase

Front 9

Catalase

Back 9

breaks down hydrogen peroxide to water and oxygen, aerobic or facultative bacteria

Front 10

Peroxidase

Back 10

breaks down hydrogen peroxide to water and oxygen, aerotolerant anaerobes

Front 11

Phase 1 of anaerobe sensitivity to oxygen

Back 11

electrons used in metabolic processes diverted to reduction of molecular oxygen, bacteriostatic, reversible

Front 12

Phase 2 of anaerobe sensitivity to oxygen

Back 12

Killed by toxic substances (superoxide anion, hydrogen peroxide, hydroxyl radical) that accumulate during reduction of molecular oxygen, irreversible

Front 13

_________ can be added to anaerobic transport media to maintain a reduced environment

Back 13

Reducing agents like thioglycolate and L-cysteine

Front 14

________ is more important than maintaining a reduced environment when growing anaerobic organisms

Back 14

Excluding oxygen

Front 15

Most anaerobes that cause infection are also normal flora (T/F)

Back 15

True

Front 16

In the body, most environments hospitable to anaerobes have _______ present because _______.

Back 16

organisms capable of respiration, these organisms maintain an environment of little oxygen and low redox potential

Front 17

Most anaerobic infections are seen in abcesses and necrotizing tissues (T/F)

Back 17

True

Front 18

Brucella blood agar

Back 18

nonselective, used for isolation of any anaerobe, supplemented with vitamin K and hemin

Front 19

Bacteroides bile esculin agar

Back 19

Selective for presumptive ID of B. fragilis

Front 20

Phenylethyl alcohol sheep blood agar

Back 20

inhibits nonanaerobic gram-negative bacilli which might otherwise overgrow anaerobes

Front 21

Culture observations indicative of presence of anaerboes

Back 21

Foul odor, good growth on BBA plate, colonies on anaerobically incubated BBA plate but not on CO2 incubated SBA or CBA plate

Front 22

Anaerobic gram-negative non-spore forming bacilli are usually normal flora (T/F)

Back 22

True, sites include oropharynx, lower GI, vagina, cervix, urethra and external genitalia

Front 23

Bacteroides is the most frequently isolated gram-negative anaerobe in humans (T/F)

Back 23

True

Front 24

Is Bacteroides motile or nonmotile?

Back 24

Nonmotile

Front 25

What antibiotics does B. fragilis have resistance to?

Back 25

Kanamycin, colistin, vancomycin

It is also bile resistant (up to 20%)

Front 26

Prevotella is usually isolated from _______

Back 26

the oral cavity, head/neck, lower respiratory and urogenital tracts

Front 27

What color pigment does Prevotella display on BBA and LKV?

Back 27

brown-black

Front 28

What color does Prevotella fluoresce under UV light on BBA or LKV?

Back 28

brick red

Front 29

Porphyromonas ferments which sugars?

Back 29

None, it is asaccharolytic

Front 30

Fusobacterium is what shape under the microscope?

Back 30

Fusiform with tapered ends. Long and spindle shaped.

Front 31

Colony morphology of Fusobacterium nucleatum

Back 31

Small, slightly convex colonies with ground-glass appearance

Front 32

Peptostreptococcus is considered normal flora on skin (T/F)

Back 32

True, it is also normal flora in the upper respiratory tract, intestinal and genitourinary tract

Front 33

Peptostreptococcus causes _______

Back 33

abcesses and necrotizing soft tissue infections

Front 34

Veilonella is involved in development of ______

Back 34

early periodontal disease as well as meningitis, endocarditis and osteomyelitis

Front 35

Veilonella morphology under microscope

Back 35

tiny, gram-negative diplococci

Front 36

Mobiluncus is motile or non-motile?

Back 36

motile

Front 37

Mobiluncus has what morphology under the microscope?

Back 37

gull-wing or curved rod

Front 38

Mobiluncus causes what illness?

Back 38

Vaginosis, usually associated with Gardnerella vaginalis

Front 39

Propionibacterium acnes is rarely a contaminant in blood cultures (T/F)

Back 39

False, this organism is a very common contaminant of anaerobic blood cultures

Front 40

Actinomycosis

Back 40

"Lumpy jaw"
characterized by painful abcesses in mouth, lungs or GI tract
Purulent drainage from sinus cavities contains "sulfur granules"

Front 41

Clostridium perfringens microscopic morphology

Back 41

Large, boxcar shaped rods, sometimes stain gram negative (even though they are gram positive)

Front 42

Infections associated with C. perfringens

Back 42

gas gangrene, septicemia, gangrenous cholecystitis, anaerobic pulmonary infection, food poisoning

Front 43

Gas gangrene (myonecrosis)

Back 43

Rapid invasion and liquefactive necrosis of the muscle with gas formation and symptoms of toxicity

Front 44

Food poisoning due to Clostridum perfringens is self-limiting (T/F)

Back 44

True, it is caused by an enterotoxin

Front 45

Clostridium difficile has a _______ appearance on CCFA

Back 45

yellow, ground-glass appearance

Front 46

CCFA

Back 46

cycloserine-cefoxitine-egg-fructose agar

Front 47

Clostridium difficile has what odor?

Back 47

Horse-stable

Front 48

Necrotizing bowel disease may be caused by ______

Back 48

Clostridium difficile
rarely, C. ramosum, C. septicum

Front 49

_______ causes pseudomembranous colitis

Back 49

Clostridium difficile

Front 50

C. difficile produces ______, which causes _______ and _______ which causes _______ effects

Back 50

toxin A, fluid accumulation
toxin B, cytopathogenic

Front 51

Botulism is ________

Back 51

a life-threatening neuroparalytic disease caused by the preformed heat-labile toxins of C. botulinum characterized by a descending paralysis

Front 52

Infant botulism is caused by ingesting ______ and causes _______

Back 52

spores, constipation followed by descending paralysis

Front 53

Tetanus is caused by _______

Back 53

a toxin released by C. tetani

Front 54

Tetanus is a _______ paralysis

Back 54

spastic

Front 55

The toxin released by C. tetani is _______. This toxin works by _______.

Back 55

tetanospasmin, blocking inhibitory impulses.

Front 56

Best samples for Clostridium

Back 56

tissue biopsy or aspiration, fecal specimens for C. dificile or C. botulinum

Front 57

Prereduced anaerobically sterilized media

Back 57

Anaerobic blood agar, Laked kanamycin-vancomycin blood agar, phenylethyl alcohol agar, Bacteroides bile esculin agar

Front 58

Anaerobic primary media should not be exposed to oxygen for _____

Back 58

48 hours

Front 59

Bacteroides urealyticus will grow in 20% bile (T/F)

Back 59

False, of the Bacteroides species, only B. fragilis will grow in 20% bile

Front 60

Fusobacterium is sensitive to _______

Back 60

kanamycin and colistin

Front 61

Veilonella is resistant to ______

Back 61

vancomycin

Front 62

If an anaerobic gram-positive cocci is resistant to metronidazole, it is probably _________

Back 62

anaerobic Streptococcus or Staphylococcus

Front 63

Clostridium difficile is lecithinase _______

Back 63

negative, all other Clostridia are positive

Front 64

Most anaerobes are susceptible to first-line antimicrobials (T/F)

Back 64

True, susceptibility testing is usually not necessary

Front 65

Definitive ID of an anaerobe is necessary for treatment if ______

Back 65

a pure culture is developed from a normally sterile site, a known resistant species is isolated or a severe infection is not responding to antibiotics

Front 66

Streptomyces produces several _______ that have been utilized in medicine

Back 66

antibiotics (70-85% of medically important)

Front 67

Streptomyces is introduced into the body by _________ and then spreads _______

Back 67

tissue trauma, subcutaneously

Front 68

Treatment for Streptomyces is _____ and _______

Back 68

antibiotics and surgery

Front 69

Streptomyces is an acid-fast organism (T/F)

Back 69

False, this organism is not acid-fast

Front 70

Streptomyces does NOT reduce nitrate to nitrite (T/F)

Back 70

True

Front 71

Actinomyces has colonies with margins that appear like a _______ or ______

Back 71

molar tooth, raspberry

Front 72

Actinomycosis may be transmitted human to human (T/F)

Back 72

False

Front 73

Treatment for Actinomyces

Back 73

surgical drainage, excise damaged tissue, long-term antibiotic therapy

Front 74

Acid-fast bacteria resist staining with basic dyes due to _______

Back 74

thick cell well with mycolic acid and high lipid content

Front 75

The acid-fast stain utilizes what dye?

Back 75

Carbol fuschin

Front 76

Mycobacteria are intracellular bacteria (T/F)

Back 76

True

Front 77

Mycobacteria grow very slowly due to __________. Growth can take from ________.

Back 77

highly hydrophobic surface. 2-60 days.

Front 78

Tuberculosis incidence rates correlate with what kind of conditions across the world?

Back 78

poor socioeconomic conditions

Front 79

Approximately ______ of the world's population is infected with M. tuberculosis

Back 79

1/3

Front 80

M. tuberculosis symptoms of pulmonary disease

Back 80

coughing (sometimes with sputum or blood), chest pains, weakness, weight loss, fever, night sweats

Front 81

Extrapulmonary tuberculosis is known as _______ and is more common in ______ and ________ patients

Back 81

miliary tuberculosis, children, HIV-infected

Front 82

Presumptive identification of tuberculosis is based on:

Back 82

Patient medical history, presenting symptoms, physical exam, X-ray and detection of acid-fast bacilli from sputum sample

Front 83

Definitive identification of M. tuberculosis is based on:

Back 83

Lack of growth in BACTEC-NAP

Reduction of nitrate to nitrite
Growth in TCH

Niacin accumulation

Appearance of microcolonies with serpentine cords on Middlebrook 7H10 after 5-10 days

Growth on Middlebrook or L-J medium

Front 84

When pathogenic, mycobacteria other than tuberculosis cause _______ infections

Back 84

opportunistic

Front 85

Photochromogenic MOTT organisms produce pigments _______

Back 85

only in the light

Front 86

Scotochromogenic MOTT organisms produce pigments ______

Back 86

in both the dark and the light

Front 87

______ is the most commonly isolated Mycobacteria species in the US

Back 87

M. avian complex

Front 88

MAC is acquired by _______. It has a reservoir of ______ and ______.

Back 88

inhalation or ingestion, animals, water

Front 89

Mycobacterium leprae is transmitted by _____ or _______.

Back 89

inhalation, person-to-person contact

Front 90

M. leprae is considered highly contagious (T/F)

Back 90

False, this pathogen is not considered highly contagious

Front 91

Tuberculoid leprosy is a ______ infection that results in _____ lesions with ______ involvement.

Back 91

localized, skin, nerve

Front 92

In immunocompetent people, a _____ response is mounted to M. leprae and recovery is usually spontaneous

Back 92

cell-mediated

Front 93

The optimal growth temperature for M. leprae is _______

Back 93

30 degrees celsius

Front 94

Characteristics of Aerobic Actinomycetes

Back 94

Morphology similar to fungi, gram positive bacilli, branching, filamenteous hyphae

Front 95

Nocardia stains partially ______

Back 95

acid-fast

Front 96

Nocardia is a facultative ________ organism

Back 96

intracellular

Front 97

Norcardia grows at what temperature?

Back 97

Wide range 22-37 degrees celsius

Front 98

Where is Nocardia found in the environment?

Back 98

In soil, worldwide

Front 99

Nocardia infections are normally seen in what population?

Back 99

immunocompromised

Front 100

Principal routes of infection for Nocardia

Back 100

Pulmonary (usually asteroides) or cutaneous (usually brasiliensis)

Direct contact via soil inhalation or skin trauma (not human to human)

Front 101

Mycetoma

Back 101

granulomatous infection of dermal and subcutaneous tissue that includes swelling, draining sinuses and granules

Front 102

Mechanisms of disease for Nocardia

Back 102

resists oxidative killing by SOD and catalase production leading to granuloma formation

iron-chelator known as nocobactin

Front 103

Treatment for Nocardia

Back 103

drainage, surgery and antimicrobials (but not penicillin, this organism is resistant)

Front 104

Streptomyces are _____ and gram _____ bacilli

Back 104

aerobic, positive

Front 105

Nocardia reduces nitrate to nitrate (T/F)

Back 105

True; Nocardia reduces nitrate; streptomyces does not

Front 106

Describe gram stain, morphology and oxygen requirements for the genus Actinomyces

Back 106

Gram stain/morphology: Gram Positive bacilli
Oxygen requirements: facultative anaerobe

Front 107

MAC organisms (do/do not) produce pigment

Back 107

Do not; MAC (M. avium and M. intracellulare) are nonphotochromagens

Front 108

Crohn's disease is associated with which bacterial species?

Back 108

M. paratuberculosis

Front 109

Differentiate tuberculoid and lepromatous leprosy?

Back 109

Tuberculoid: localized: skin lesions, nerve involvement; spontaneous recovery usually occurs

Lepromatous: More serious: lesions, symmetric nerve damage, loss of cartilage and facial deformity; disseminated infection with immunodepressed pt's - must be treated with multi-drug therapy

Front 110

M. bovis is nitrate ____, niacin ____, and TCH ____ (positive/negative)

Back 110

M. bovis is nitrate, niacin and TCH negative

Front 111

Porphyromonas is sensitive to ____ and resistant to _____

Back 111

Sensitive: Vancomycin
Resistant: Kanamycin and colistin

Front 112

Prevotella is sensitive to _____ and resistant to _____

Back 112

Sensitive: Colistin
Resistant: Kanamycin, vancomycin

Front 113

Bilophila is urease ____ and nitrate ____

Back 113

positive; positive

Front 114

a positive reverse CAMP test is presumptively indicative of which species?

Back 114

Clostridium perfringens

Front 115

C. difficile (does/does not) fluoresce chartreuse on BBA under UV light

Back 115

Does

Front 116

Which two anaerobes cause infection but are not part of normal flora?

Back 116

C. botulinum
C. tetani