GRAM POS

Question 1

Gram-positive cocci in grape-like clusters
• Catalase positive
• Coagulase positive
• β-hemolytic
• Yellow or golden colonies on
blood agar (staphyloxanthin)
• Ferments mannitol

Answer 1

Staphylococcus aureus

Question 2

Gram-positive cocci in clusters
• Catalase–positive
• Coagulase-negative
• Novobiocin sensitive
• Whitish, non-hemolytic
colonies on blood agar

Answer 2

Staphylococcus epidermidis

Question 3

Catalase-positive
• Coagulase-negative
• Novobiocin resistant
• Whitish, non-hemolytic
colonies on blood agar

Answer 3

Staphylococcus saprophyticus

Question 4

Sheep blood agar: large; entire very glossy, smooth, opaque butyrous, convex;
usually white but colonies can be yellow to orange

Answer 4

Staphylococcus saprophyticus

Question 5

Sheep blood agar: small to medium; opaque, gray-white colonies; most colonies are nonhemolytic; slime-producing strains are extremely sticky and adhere to agar surfaces

Answer 5

Staphylococcus epidermidis

Question 6

Sheep blood agar: round, smooth, white or pigmented (yellow-orange) and β- hemolytic

Answer 6

Staphylococcus aureus

Question 7

Lancefield group A

Answer 7

Streptococcus pyogenes

Question 8

Bacitracin sensitive
PYR test positive

Answer 8

Streptococcus pyogenes

Question 9

Bacitracin resistant
• CAMP test positive
• PYR negative
• Hippurate hydrolysis
positive
• Resistant to SXT

Answer 9

Streptococcus agalactiae

Question 10

Lancefield group B

Answer 10

Streptococcus agalactiae

Question 11

Blood agar: grayish-white mucoid colonies surrounded by a small zone of β-
hemolysis

Answer 11

Streptococcus agalactiae

Question 12

Gram-positive “lancet-shaped” cocci
• Alpha-hemolytic
• Bile solubility
sensitive
• Optochin sensitive
• Positive Quellung
reaction

Answer 12

Streptococcus pneumoniae

Question 13

Previously classified as Group D
• PYR positive
• Posses group D antigen
• Grows in 6.5% NaCl
• LAP positive

Answer 13

Enterococcus

Question 14

Alpha-hemolysis or no hemolysis (greening) on sheep blood agar
• Butterscotch smell especially on chocolate agar

Answer 14

Viridans streptococci

Question 15

Nonhemolytic ”comet tail or Medusa head”or ground glass colonies on 5% sheep blood agar

Answer 15

Bacillus anthracis

Question 16

• Gram-positive box
car-like rods

Answer 16

Bacillus anthracis

Question 17

Colonies (BA): medium-large, gray, flat irregular with swirling projections
(Medusa head or comet tail) or ground grass appearance, nonhemolytic

Answer 17

Bacillus anthracis

Question 18

Bacteria foundd contaminated rice

Answer 18

Bacillus cereus

Question 19

Spore forming rods

Answer 19

Bacilli

Question 20

Only carried by humans; Primary mode of transmission: respiratory secretions or exudates from skin lesions

Answer 20

Corynebacterium diphtheriae

Question 21

produces halo on both media; presumptively identified by brown-black colonies with a gray-brown halo on Tinsdale agar

Answer 21

C. diphtheriae

Question 22

Umbrella-shaped pattern: overnight incubation at room temperature into semisolid
agar
o Ferments glucose
o Vogues-Proskauer positive
o Esculin positive
o CAMP positive

Answer 22

Listeria monocytogenes

Question 23

Pleomorphic, gram-positive bacillus that often forms long filaments
o Catalase-negative, forms hydrogen sulfide
o Non-motile but produces a characteristic ”bottlebrush” extension laterally from the
streak line in soft gelatin agar

Answer 23

Erysipelothrix spp.

Question 24

Important for maintaining the proper pH balance in vaginal secretion
o Frequently associated with dental caries

Answer 24

Lactobacillus spp.

Question 25

Infections are associated with individuals employed in occupations such as fish handlers, farmers, slaughterhouse workers, food preparation workers, and veterinarians

Answer 25

Erysipelothrix

Question 26

primarily associated with pharyngitis in human infections with mild to severe symptoms

Answer 26

Arcanobacterium haemolyticum

Question 27

receoveredinblood,abscess,urinarytract,joints,eyes,andwounds; necrotizing fasciitis

Answer 27

T.bernerdiae

Question 28

isolated from infections in patients in rural environments and has been identified in abscesses, wounds, and blood infections

Answer 28

Trueperella spp.

Question 29

medium for isolation of G. vaginalis from female genital tract

Answer 29

Human blood bilayer Tween agar (HBT)

Question 30

multiple colonial morphologies, ranging from pinpoint, alpha- hemolytic colonies resembling streptococci to rough, gray colonies

Answer 30

Lactobacillus

Question 31

small, gray, opaque colonies surrounded by a diffuse zone of beta-hemolysis; with clue cells

Answer 31

Gardnerella vaginalis

Question 32

Gram-positive (often with a beaded appearance) Variably acid fast Catalase positive Strictly aerobic Saprophytes Pulmonary cutaneous infection in humans

Answer 32

Nocardia

Question 33

Pleomorphic and partially acid fast Slow growing (up to 6 weeks): dry and heaped colonial morphology similar to fungus Soil or musty basement odor Exudates: sulfur granules

Answer 33

N. asteroides

Question 34

Etiologic agent of mycetoma Not acid fast Similar microscopic and macroscopic morphology to Nocardi

Answer 34

Actinomadura

Question 35

Primarily saprophytes: soil organisms Opportunistic infections similar to other actinomycetes

Answer 35

Streptomyces