Gram Stain

Question 1

Gram (+) cocci clusters

Answer 1

Staphylococcus spp.

Including MRSA, MSSA

Question 2

Gram (+) cocci pair & chains

Answer 2

Strep. pneumoniae (diplococci)
Streptococcus spp. (including Strep, pyogenes)
Enterococcus spp. (including VRE)

Question 3

Gram (+) Rods

Answer 3

Listeria monocytogenes

Corynebacterium spp.

Question 4

Gram (+) Anaerobes

Answer 4

Peptostreptococcus
Propionibacterium acnes
Clostridioides (previously Clostridium) spp.

Question 5

Atypicals

do not Gram stain well

Answer 5

Chlamydia spp.
Legionella spp.
Mycoplasma pneumoniae
Mycobacterium tuberculosis

Question 6

Gram (-) Cocci

Answer 6

Neisseria spp.

Question 7

Gram (-) Anaerobes

Answer 7

Bacteroides fragiiis

Prevoteila spp.

Question 8

Gram (-) Coccobacilll

Answer 8

Acinetobacter baumannii
Bordeteila pertussis
Moraxella catarrhalis

Question 9

Gram (-) Rods

Colonize gut “enteric”

Answer 9

Proteus mirabilis
Escherichia coli
Klebsiella spp,
Serratia spp.
Enterobacter cloacae
Citrobacter spp.

Question 10

Gram (-) Rods

Do not colonize gut

Answer 10

Pseudomonas aeruginosa
Haemophilus influenzae
Providencia spp.

Question 11

Gram (-) Rods

Curved or spiral shaped

Answer 11

H. pylori, 
Campylobacter spp., 
Treponema spp,
Borrelia spp., 
Leptospira spp.