Gram stains of different organisms

Question 1

Streptococcus pneumoniae

Answer 1

Gram positive diplococci
Alpha haemolytic - green on blood agar
Facultative anaerobe

Question 2

Streptococcus pyogenes

Answer 2

Gram positive (group A strep) diplococci
Facultative anaerobe

Question 3

Haemophilus influenzae

Answer 3

Gram negative coccobacillus

Facultative anaerobe

Question 4

Moraxella catarrhalis

Answer 4

Gram negative diplococcus

Aerobic

Question 5

Escherichia coli

Answer 5

Gram negative rod

Facultative anaerobe

Question 6

Klebsiella spp.

Answer 6

Gram negative

Facultative anaerobes

Question 7

Corynebacterium diphtheriae

Answer 7

Gram positive rod (bacillus)

Question 8

Neisseria gonorrhoeae

Answer 8

Gram negative coffee-bean shaped diplococcus

Question 9

Bacteroides fragilis

Answer 9

Gram negative bacilli

Anaerobic (dominant gut microbe)

Question 10

Bordetella pertussis

Answer 10

Gram negative rod

Aerobe

Question 11

Campylobacter jejuni

Answer 11

Gram negative rod

Question 12

Chlamydia trachomatis

Answer 12

Gram negative (ovoid shape)
Obligate intracellular bacteria

Question 13

Clostridium difficile

Answer 13

Gram positive

Anaerobe

Question 14

Coliforms

Answer 14

= Gram negative bacteria

Includes - E. coli, Proteus mirabilis, Klebsiella

Question 15

Enterococcus faecalis

Answer 15

Gram positive coccus - single, pair or chains

Aerobe

Question 16

Gardnerella vaginalis

Answer 16

Gram variable - clue cells on Gram stain

Facultative anaerobe

Question 17

Helicobacter pylori

Answer 17

Gram negative rod (curved/spiral shaped)

Question 18

Listeria monocytogenes

Answer 18

Gram positive rod

Question 19

Legionella

Answer 19

Gram negative rod

Question 20

Mycoplasma

Answer 20

No cell wall - don’t hold Gram stain

Question 21

Neisseria meningitidis

Answer 21

Gram negative diplococci (coffee-bean shaped)

Question 22

Peudomonas aeruginosa

Answer 22

Gram negative rod

Question 23

Staphylococcus epidermidis

coagulase?

Answer 23

Gram positive coccus

Coagulase negative

Question 24

Staphylococcus aureus

coagulase?

Answer 24

Gram positive

Coagulase positive

Question 25

Treponema pallidum

Answer 25

Syphilis | Gram negative spirochete (spiral shaped)

Question 26

Streptococcus agalactiae

Answer 26

Gram positive coccus that forms chains | Beta-haemolytic (clear on blood agar)

Question 27

Mycobacterium tuberculosis

Answer 27

Impervious to Gram staining (waxy coat) | Acid-fast bacillus - use Ziehl-Neelsen staining