Unit 2

Question 1

A gram positive cocci recovered from a urine culture of a 15 year old girl is alpha hemolytic, bile esculin positive and optochin negative and is most likely:

Answer 1

E. faecalis

Question 2

The primary reservoir for S. aureus is the:

Answer 2

anterior nares

Question 3

Which enzymes contribute to the virulence of S. aureus?

Answer 3

hyaluronidase and coagulase

Question 4

True or False?

The normal habitat of Bacillus anthracis is the human nasopharynx.

Answer 4

False

Question 5

Which morphologic feature is a major cinsideration in determining an identification strategy for streptococci?

Answer 5

Hemolytic pattern

Question 6

Which group of streptococci is associated with the production of pyrogenic exotoxin (SPE) and Streptokinase?

Answer 6

Group A

Question 7

True or False?

Initial symptoms of staphylococcal poisoning will occur 2-6 hours after eating contaminated food.

Answer 7

True

Question 8

A black eschar on the skin is indicative of what condition.

Answer 8

Cutaneous anthrax

Question 9

The organism that exhibits characteristic end over end tumbling motility when incubated in nutrient broth at room temperature for 1-2 hours is:

Answer 9

Listeria monocytogenes

Question 10

The CAMP factor is produced by:

Answer 10

Streptococcus agalactiae

Question 11

Micrococcus luteus will produce which of the following results when a modified oxidase test is performed:

Answer 11

blue/purple color

Question 12

Patients who are immunocompromised and pregnant women should avoid eating soft cheeses such as Mexican-style, feta, brie, Camembert and blue veined cheese to prevent:

Answer 12

foodborne listeriosis

Question 13

An organism recovered from a case of pharyngitis (sore throat) in an 8 year old child is beta hemolytic, catalase negative and has a gram positive cocci chain gram stain. Which test would be performed next to further identify this organism?

Answer 13

Lancefield grouping by latex agglutination

Question 14

S. saprophyticus is best differentiated from S. epidermidis by resistance to:

Answer 14

Novobiocin

Question 15

All of these organisms are associated with gastrointestinal infections except:
Bacillus anthracis
Listeria monocytogenes
Staphylococcus aureus
Streptococcus pyogenes

Answer 15

Streptococcus pyogenes

Question 16

A wet mount and gram stain of vaginal secretions of a patient with bacterial vaginosis caused by Gardnerella vaginalis will likely reveal:

Answer 16

Large squamous epithelial cells with numerous attached gram variable or gram negative coccobacilli and rods

Question 17

True or False?

Sodium desoxycholate will not dissolve colonies of viridans streptococci on sheep blood agar.

Answer 17

True

Question 18

The bacterial species that can be described as able to grow in 6.5% NaCL and 40% bile and hydrolyze esculin, is part of the normal gastrointestinal flora of animals and humans, frequently nonhemolytic, and is a major cause of nosocomial infections is:

Answer 18

E. faecalis

Question 19

True or False?
Lancefield group testing by latex agglutination is appropriate for alpha heolytic, catalase negative, gram positive cocci.

Answer 19

False

Question 20

This aerobic gram positive rod may cause conjuctivitis, gastroenteritis, meningitis and neonatal sepsis.

Answer 20

Listeria monocytogenes

Question 21

Gram positive rods that are palisading and are typical of:

Answer 21

Corynebacterium diptheriae

Question 22

This alpha hemolytic gram positive rod is frequently considered a contaminant and is normal flora of the human mouth and female genital tract. It is:

Answer 22

Lactobacillus sp.

Question 23

The tube coagulase test:

Answer 23

detects extracellular coagulase (free coagulase)

Question 24

The first identification test performed on a clinical isolate of a gram-positive cocci that is catalase-positive would likely be the:

Answer 24

coagulase test

Question 25

The optochin test causes a zone of greater than 14mm with which organism?

Answer 25

S. pneumoniae

Question 26

A patient has several bloodstream cultures growing beta hemolytic, catalase positive, gram positive cocci. It is coagulase negative by the slide coagulase test. What is the most appropriate action to identify this organism?

Answer 26

do a tube coagulase to confirm the slide test

Question 27

This organism is not considered to be part of the normal flora of humans:

Answer 27

S. pyogenes

Question 28

An organism that has a gram stain of gram positive cocci in pairs is most likely:

Answer 28

S. pneumoniae

Question 29

What type of motility reaction, associated with Listeria, is known as:

Answer 29

Umbrella

Question 30

The gram stain of LIsteria monocytogenes may be confused with streptococci, the organisms are rapidly differentiate by this test:

Answer 30

Catalase

Question 31

What mode of transmission has not been associated with B. anthracis infection?

Answer 31

Person to person

Question 32

True or False? | Group A Streptococcus is PYR positive and CAMP postive.

Answer 32

False

Question 33

A non-spore forming, catalase negative, gram positive rod that produced hydrogen sulfide was isolated from a finger abcess of a farm worker. The organism is likely:

Answer 33

Erysipelothrix rhusiopathiae

Question 34

A 3 day old infant is symptomatic of meningitis, which organism is most likely the cause?

Answer 34

Streptococcus agalactiae

Question 35

``` Which of the following infections is least likely to be associated with S. aureus? Neonatal Sepsis Osteomyelitis Foodpoisoning Toxic Shock Syndrome ```

Answer 35

Neonatal Sepsis

Question 36

The gram stain morphology of Staphylococcus epidermidis is typically:

Answer 36

Gram positive cocci in clusters

Question 37

Optochin, bile solubility, bile esculin, and 6.5% NaCl are tests most likely performed on:

Answer 37

alpha-hemolytic streptococcus

Question 38

The catalase test is used to differentiate which groups of organisms?

Answer 38

Staphylococcus from Streptococcus

Question 39

``` A patient is admitted to the hospital with a persistent cough, fever and chills. Sputum cultures were collected and subsequently grew and organism with the following results: blood agar - mucoid, alpha hemolytic colonies chocolate - growth MacConkey - no growth PEA - light growth Gram stain - gram pos cocci in pairs (diplococci) catalase - neg bile esculin - negative 6.5% salt - negative bile solubility - lysis of the colony Optochin zone - 16mm The most likely identification is: ```

Answer 39

Streptococcus pneumoniae

Question 40

``` An oncology patient receiving chemotherapy was seen by her physician for a soft tissue infection of her lower leg. A routine culture grew the folowing: blood agar - beta hemolytic colonies PEA and Thioglycollate - growth MacConkey - no growth Gram stain - gram positive cocci catalase - negative PYR - negative Motility negative CAMP test - positive Bile esculin - negative What is the most likely presumptive ID? ```

Answer 40

Streptococcus agalactiae

Question 41

An organism was recovered from a blood culture of a 41 year old female cattle rancher from South America. The patient was in acute respiratory distress and experiencing multiple organ failure. The lab results were: Gram stain - large gram positive rods with spores The plates were than handled using special precautions. Colonies on aerobic blood agar plate are nonhemolytic with swirling progections. PEA - growth MacConkey - no growth H2S negative Motility - negative The organism was sent to the Virginia Consolidated labs for further ID. What is the expected ID of this organism?

Answer 41

Bacillus anthracis

Question 42

``` A wound culture of a 17 year old football player is growing a pure culture of an organism with the following results: blood agar - cream colored, beta hemolytic colonies growth on PEA no growth on MacConkey Gram stain - GPC in clusters Catalase - positive CAMP - negative PYR Test - negative Slide coagulase - negative Novobiocin - sensitive Tube coagulase - positive ```

Answer 42

S. aureus

Question 43

``` Heavy growth of a bacteria was recovered from a urine culture of a 29 year old female. The following results were observed: blood agar - pure culture of a white non hemolytic colony PEA - growth MacConkey - no growth Gram stain - GPC Catalase - positive Slide coagulase - negative Tube coagulase - negative Novobiocin - resistant Modified oxidase - neg ```

Answer 43

Staphylococcus saprophyticus

Question 44

Match the organism with the appropriate disease or infection: Severe conjuctivitis, corneal ulceration

Answer 44

Listeria monocytogenes

Question 45

Match the organism with the appropriate disease or infection: Otitis media

Answer 45

Streptococcus pneumoniae

Question 46

Match the organism with the appropriate disease or infection: Nosocomial UTI

Answer 46

Enterococcus faecalis

Question 47

Match the organism with the appropriate disease or infection: Carbuncles

Answer 47

Staphylococcus aureus

Question 48

Match the organism with the appropriate disease or infection: Bacterial vaginosis

Answer 48

Gardnerella vaginalis

Question 49

Match the organism with the appropriate disease or infection: Scarlet fever

Answer 49

Streptococcus pyogenes

Question 50

Match the organism with the appropriate disease or infection: Cellulitis in butchers

Answer 50

Erysipelothrix rhusopathiae

Question 51

Match the organism with the appropriate disease or infection: Wool sorter's disease

Answer 51

Bacillus anthracis

Question 52

Match the organism to the appropriate media: | PLAT

Answer 52

Bacillus anthracis

Question 53

Match the organism to the appropriate media: | Cysteine tellurite

Answer 53

Corynebacterium diphtheriae

Question 54

Match the organism to the appropriate media: | Oxford

Answer 54

Listeria monocytogenes

Question 55

Match the organism to the appropriate media: | Human blood bilayer tween

Answer 55

Garderella vaginalis

Question 56

The red line alert test is an immunochromatographic test that will presumptively identify:

Answer 56

Bacillus anthracis

Question 57

Stabbing the loop into the blood agar after streaking could allow colonies to display hemolysis caused by:

Answer 57

Streptolysin O