Gram Stain Interpretation And Correlates

Question 1

Gram positive cocci in clusters

Answer 1

Staphylococcus spp.

Question 2

Large, “boxcar” shaped, gram positive bacilli, with or without spores evident

Answer 2

Bacillus spp; Clostridium spp.

Question 3

Gram positive, beaded, bacilli without branching

Answer 3

Mycobacterium spp.

Question 4

Gram positive, beaded, branching bacilli

Answer 4

Nocardia spp.

Question 5

Narrow-diameter, gram-positive bacilli

Answer 5

Listeria; Lactobacillus

Question 6

Gram-positive cocci in chains

Answer 6

Streptococcus spp. other than S. pneumoniae; Enterococcus

Question 7

Gram-positive diplococci

Answer 7

Streptococcus pneumoniae

Question 8

“Plump” gram-negative bacilli

Answer 8

Enterobacteriaceae, such as E. coli

Question 9

“Narrow Diameter” gram-negative bacilli

Answer 9

Pseudomonas aeruginosa

Question 10

Tapered, fusiform-shaped gram-negative bacteria

Answer 10

Fusobacterium nucleatum; Capnocytophaga spp., Leptotrichia spp.

Question 11

Gram negative diplococci

Answer 11

Neisseria spp; Moraxella catarrhalis

Question 12

Gram negative coccobacilli

Answer 12

Heamophilus spp; Actinetobacter spp, Moraxella spp.

Question 13

Curved, gram-negative bacteria

Answer 13

Campylobacter spp; Vibrio spp

Question 14

Yeast

Answer 14

Candida spp, Cryptococcus spp, Geotrichium, Trichosporon