microbiology 2

Question 1

what do gram-ve bacillus tend to cause?

Answer 1

diarrhoea

Question 2

what do gram-ve bacillus contain?

Answer 2

flagella, (helps with movement)

Question 3

explain virulence

Answer 3

ability of microbe to kill host

Question 4

what are commensals?

Answer 4

organisms found in normal flora

Question 5

what are opportunistic pathogens?

Answer 5

organism that is not normally pathogenic but can become when circumstances arise (e.g C diff)

Question 6

what are aerobes?

Answer 6

bacteria that grow in oxygen

Question 7

what are obligate aerobes?

Answer 7

bacteria that require oxygen to survive

Question 8

what are obligate anaerobes?

Answer 8

bacteria that are killed by oxygen

Question 9

what are capnophilics?

Answer 9

bacteria that prefer high levels of carbon dioxide

Question 10

what type of haemolysisis is beta haemolysis? + what colour dopes it appear?

Answer 10

• complete
• appears clear

Question 11

what type of haemolysis is alpha haemolysis? + was colour does it appear?

Answer 11

• partial
• appears green

Question 12

what type pf haemolysis is gamma haemolysis?

Answer 12

• none

Question 13

what do penicillins & cephalosporins do?

Answer 13

• target bacteria cell wall
• beta lactam ring binds to PBP on cell wall bacteria
• prevents addition of peptidglycan layers = KILLING BACTERIA

Question 14

what does Quinolones do?

Answer 14

• target prokaryotic nucleic acid
• inhibit DNA synthesis by preventing DNA “supercoding”

Question 15

what does Trimethoprim do?

Answer 15

• target prokaryotic nucleic acid
• inhibits folic acid synthesis (causes tendonitis)

Question 16

what does Metronidazole do?

Answer 16

• target prokaryotic nucleic acid
• causes DNA structure to unwind
• used against ANAEROBES & PROTAZOA

Question 17

what do Tetracyclines do?
(+ an example of one)

Answer 17

• target bacterial protein synthesis
• bind to 30s submit of ribosomes and stop protein chain elongation
• DOXYCYCLINE

Question 18

what do Macrolides do?
(+ an example of one)

Answer 18

• binds to 50s subunit of ribosomes, interferes with protein synthesis
• ERYTHROMYCIN - safe in pregnancy

Question 19

what do Aminoglysocides do?
(+ an example of one)

Answer 19

• binds to aminoacyl site of 16s within 30s subunit to cause misread of genetic code
• GENTAMICIN

Question 20

examples of gram +ve cocci

Answer 20

• group A strep
• strep pneumonia
• non- haemolytic strep

Question 21

examples of gram +ve bacilli

Answer 21

• C. diff
• spore forming anaerobes (gram +ve)