bacteriology

Question 1

give three examples of gram positive cocci

Answer 1

streptococcus
enterococcus
staphylococcus

Question 2

what do streptococcus and enterococcus have in common ?

Answer 2

aerobic
cocci chains

Question 3

describe staphylococcus

Answer 3

cocci clusters

Question 4

how does a fever occur ?

Answer 4

• Antigen attacks macrophage
• Releases cytokines
• Travel to anterior hypothalamus of the brain
• Stimulates production of prostaglandin E
• Resets body’s thermal set point
• Body perceives it is cold, shivers to conserve heat
• FEVER

Question 5

describe gram negative cocci

Answer 5

diplococci
aerobic

Question 6

what can gram negative cocci cause ?

Answer 6

Neisseria gonorrhoea
Neisseria meningitidis

Question 7

coliforms

Answer 7

• Gram negative bacilli
• Aerobic but can also be anaerobic
• Gut commensals (E coli, Klebsiella, Proteus )
• Gut pathogens (Salmonella, Shigella, E coli O157)
• Gentamicin is first line antibiotic

Question 8

strict aerobes

Answer 8

Gram negative bacilli
examples - Pseudomonas aeruginosa
Legionella pneumophilia

Question 9

what are examples of spiral or curved gram negative bacilli

Answer 9

• Campylobacter – food poisoning
• Helicobacter pylori – gastritis

Question 10

Haemophilus Influenzae

Answer 10

• Small gram negative bacillus
• Common cause of chest infection, especially in COPD exacerbations

Question 11

Gram positive anaerobic bacilli

Answer 11

• Clostridium spp.
• Part of normal bowel flora
• Produces spores
• Produce exotoxin that cause severe tissue damage

Question 12

Gram negative anaerobic bacilli

Answer 12

• Bacteroides spp.
• Normal gut commensals, only pathogenic when found in other sites
• Metronidazole is first line treatment for infections caused by anaerobes

Question 13

Mycobacteria

Answer 13

• Thick waxy outer coat
• Acid fast bacilli or Ziehl Neelson stain
• TB

Question 14

what do bacteria have regarding their genetics ?

Answer 14

chromosome and plasma

Question 15

what are the stages of gene transfer in bacteria ?

Answer 15

transformation
conjugation
transduction

Question 16

what happens during transformation ?

Answer 16

DNA from dead bacteria taken up by living bacteria and incorporated in plasmids or the bacterial chromosome

Question 17

what happens during conjugation ?

Answer 17

Sex pilus (fimbria) produced by one bacteria through which plasmid DNA can be transferred