Year 1 Bacterial Classification

Question 1

Rules of bacterial nomenclature?

Answer 1

‘G’enus and ‘s’pecies

e.g. Homo sapiens/H. sapiens

Italics or underlines

Question 2

What are gram-positive bacteria?

Answer 2

Bacteria with thick peptidoglycan cell wall - purple stain

Question 3

What are gram-negative bacteria?

Answer 3

Red/pink stain - thin layer of peptidoglycan, multilayer cell wall

Question 4

Gram-P RODS: BACILLUS

Where are they found?

Characteristics?

Appearance?

Examples?

Answer 4

Found in air, soil and water

Aerobic, spore former

Large rod shape

e.g.
B. anthracis (anthrax)
B. cereus (food poisoning)

Question 5

Gram-P rods: CLOSTRIDIUM

Where are they found?

Characteristics?

Appearance?

Answer 5

Found in soil and water

Anaerobic, spore former, produces gas

Large rod shape

e.g.
C. tetani (tetanus)
C. botulinum (poisoning, botox)

Question 6

Gram-P rods: LISTERIA

Where are they found?

Appearance?

Example?

Answer 6

Common in environment, can grow at fridge temperature

Rod shape

e.g.
L. monocytogenes (listeriosis)

Question 7

Gram-P rods: CORYNEBACTERIUM

Where are they found?

Characteristics?

Appearance?

Example?

Answer 7

Found in air, water and skin

Aerobic

Irregular shaped rods

e.g.
C. diphtheriae (diptheria, exotoxin)
C. glutamicum (makes glutamic acid (MSG)

Question 8

Gram-P COCCI: STAPHYLOCOCCUS

Where are they found?

Characteristics?

Appearance?

Example?

Answer 8

Found in air, soil, skin

Facultative anaerobe, opportunistic pathogen

Small round cell, grape bunch, gather

E.g.
S. aureus (TSS) - resistance (MRSA)
S. epidermidis (medical device infection)

Question 9

Gram-P COCCI: STREPTOCOCCUS

Where are they found?

Characteristics?

Appearance?

Example?

Answer 9

Air, soil, throat

Facultative anaerobe, opportunistic pathogen

Small round cell, chains of cell

e.g.
S. pneumoniae (bacterial pnemonia)
S. pyogenes (sore throat, scarlet fever)

Question 10

Gram-N RODS: Pseudomonas

Where are they found?

Characteristics?

Appearance?

Example?

Answer 10

Ubiquitous

Aerobe, opportunistic pathogen, antibiotic resistant, biochemically versatile

Responsible for 50% G-ve infections

Look like rods

e.g.
P. aeruginosa (cystic fibrosis, UTI, conjunctivitis etc.)

Question 11

Gram-N RODS: Escherichia

Where are they found?

Characteristics?

Appearance?

Example?

Answer 11

Soil, water, vegetation

Facultative aerobe
Enteric (lives in gut)

Rod shaped

e.g.
E. coli (faecal contamination), UTIs, infant enteritis

Question 12

Gram-N COCCI: Neisseria

Where are they found?

Characteristics?

Appearance?

Example?

Answer 12

Throats, air

Facultative anaerobe, strict human pathogen

Diplococci - group in pairs

e.g.
N. meningitidis (bacterial meningitis - high mortality)
N. gonorrhoeae (STD)

Question 13

Types of bacteria that are neither gram positive or negative? (3)

Answer 13

• Mycobacteria
• Mycoplasmas
• Obligate intracellular bacteria

Question 14

What are Mycoplasmas?
Characteristic?
Example?

Answer 14

Smallest free-living organism
No cell wall
Very small genome

e.g.
M. pneumoniae
M. genitalium

Question 15

What are Mycobacteria?
Characteristic?
Example?

Answer 15

Very slow growing
Unusual cell wall structure - contains mycolic acid

e.g.
M. tuberculosis
M. leprae

Question 16

What are Obligately intracellular bacteria? Characteristic?

Example?

Answer 16

Parasitic nature, cultivated in living tissue (live in us), hard to grow

e.g.
C. trachomatis (chlamydia)
R. prowazekii (typhus)
C. burnetti (Q fever)