Bacterial taxonomy and stains

Question 1

Define the Gram positive and coccus organisms

Answer 1

• Staphylococcus
• Streptococcus

Question 2

Define Gram negative & coccus

Answer 2

Neisseria

Question 3

Define Gram positive Rods

(six total)

Answer 3

• Clostridium
• Corynebacterium
• Bacillus
• Listeria
• Mycobacterium (acid fast)
• Gardnerella (gram variable)

Question 4

Define the Gram positive & Branching filamentous

Answer 4

• Actinomyces
• Nocardia (weakly acid fast)

Question 5

Define the Gram negative & Pleomorphic

Answer 5

• Rickettsiae (Giemsa)
• Chlamydiae (Giemsa)

Question 6

Define the Gram negative and spiral organisms

Answer 6

• Borrelia (Giemsa)
• Leptospira
• Treponema

Question 7

Define Gram positive with no cell wall

Answer 7

Mycoplasma (does not gram stain)

Question 8

Which bacteria contain sterols and have no cell wall

Answer 8

Mycoplasma

Question 9

Which bacteria contain mycolic acid and have high lipid content?

Answer 9

Mycobacteria

Question 10

Gram stain limitations

​These Microbes May lack real color

• Too thin to be visualized
• High lipid content in cell wall detected by carbofuchsin in acid-fast stain
• no cell wall
• primarily intracellular
• intracellular parasite
• Intracellular parastie, lacks muramic acid in cell wall

Answer 10

• TreponemaToo thin to be visualized
• **Mycobacteria **High lipid content in cell wall detected by carbofuchsin in acid-fast stain
• **Mycoplasma **no cell wall
• **Legionella **primarily intracellular
• **rickettsia **intracellular parasite
• **Chlamydia **Intracellular parastie, lacks muramic acid in cell wall

Question 11

Stains

• Chlamydia, Borrelia, Rickettsiae, Trapanosomes, Plasmodium
• Stains glycogen, mucopolysaccharides, (used to diagnosis whipple disease (Tropheryma whipplei)
• Acid-fast organisms (Nocardia, Mycobacterium)
• Cryptococcus neoformans (mucicarmine can also be used to stain thick polysaccharide capsule rod)
• Fungi (e.g. Pneumocystis, Legionella, Helicobacteri pylori)

Answer 11

• GiemsaChlamydia, Borrelia, Rickettsiae, Trapanosomes, Plasmodium
• **PAS (periodic acid-schiff) **Stains glycogen, mucopolysaccharides, (used to diagnosis whipple disease (Tropheryma whipplei)
• **Ziehl-Neelsen (carbol fuchsin) **Acid-fast organisms (Nocardia, Mycobacterium)
• India ink Cryptococcus neoformans (mucicarmine can also be used to stain thick polysaccharide capsule rod)
• **Silver stain **Fungi (e.g. Pneumocystis, Legionella, Helicobacteri pylori)