Gram Negative

Question 1

Cultures used to distinguish gram negative cocci

Answer 1

Blood agar

Chocolate agar

Thayer-Martin agar
- isolates N. Gonorrhoeae from N.meningitidis

McConkey: only grows gram (-) and differentiates between Lactose fermentation

Question 2

Neisseria distinction

Answer 2

Oxidase and catalase positive (except for elongata)

Question 3

Clinical relevant gram neg cocci

Answer 3

Neisseria gonorrhoeae and meningitidis

Moraxella catarrhalis

Question 4

E-coli

Answer 4

Common gram neg infection

• causes food poisoning, ITIs and gastroenteritis/meningitis

Question 5

Pseudomonas aeruginosa

Answer 5

Common gram negative infection

Lung and urinary tract infections

Question 6

Klebsiella

Answer 6

Common gram negative infection

Meningitis, lung infections and UTI

Question 7

Acinetobacter baumannii

Answer 7

Common gram neg infection

Various infections

Question 8

Enterobacteriaceae

Answer 8

Common gram neg infection

UTI Lung and blood stream infections

Question 9

Gram neg spiral shaped species

Answer 9

Campylobacteraceae

Helicobacteraceae

Question 10

Moraxella catarrhalis

Answer 10

Gram (-) cocci.

Upper respiratory tract illnesses in both health and COPD adults.

(+) nitrate, nitrite, DNase

Question 10

Serratia marcescens

Answer 10

Facultative anaerobic gram (-) bacillus.

• non lactose fermentation
• (+) catalase, motility and urease
• most common in hospital settings and surgical site infections
• can also cause infective endocarditis through intravenous drug useage