microbiology

Question 1

what colour do gram +ive stain and why

Answer 1

purple, thick peptidoglycan layer

Question 2

what colour do gram -ive stain and why

Answer 2

pink, think peptidoglycan layer

Question 3

exotoxin is produced by..

Answer 3

gram +ive, produced inside and released

Question 4

endotoxin is produced by…

Answer 4

gram -ive, part of the cell wall

Question 5

what shape is staphylococcus

Answer 5

gram +ive clusters of balls

Question 6

what is the test for staph A

Answer 6

coagulase test, +ive = staph A, -ive = another staph

Question 7

what is streptococcus

Answer 7

gram +ive chain of balls

Question 8

what does alpha heamolysis show

Answer 8

partial, strep pneumonia and viridans

Question 9

what does beta heamolysis show

Answer 9

complete, group A (pyogens) and group B

Question 10

what does gamma heamolysis show

Answer 10

none, is enterococcus

Question 11

what are enterococci

Answer 11

chained cocci, gram +ive, often found in the gut as commensal bacteria but can cause UTI’s

Question 12

descrive gram -ive cocci

Answer 12

diplococci (pairs) and are aerobic

Question 13

what are the 2 main types of -ive cocci

Answer 13

neisseria meningitidis and gonorrhoea

Question 14

describe coliforms of the GI tract

Answer 14

grow best aerobically but can be anaerobic. are gram -ive bacilli commensal bacteria. can cause infection in sterile places eg UTI

Question 15

name common GI coliforms

Answer 15

E. coli, klebsiella, proteus

Question 16

name gut pathogens

Answer 16

salmonella, shigella, E. coli 0157 (verotoxin)

Question 17

what is the antibiotic for GI coliforms and and pathogens

Answer 17

gentamicin

Question 18

what are strict aerobes, name some

Answer 18

need O2, pseudomonas (-ive bacilli), legionella (-ive bacilli)

Question 19

what are strict anaerobes, name some

Answer 19

need CO2: clostridia - produces spores and can cause C diff (+ive bacilli), bacteriodes (-ive bacilli)

Question 20

how do you treat anaerobes

Answer 20

metronidazole

Question 21

name some gram -ive bacilli

Answer 21

camplobacter (food poisoning), H pylori (gastritis), H. influenza

Question 22

what are the 2 types of fungal infections

Answer 22

yeast eg candida, moulds that produce spores eg aspergillus

Question 23

name a protozoan

Answer 23

malaria

Question 24

describe the virus structue

Answer 24

DNA or RNA, protein coat surrounded by envelope with protein spikes

Question 25

describe how viruses infecta cell

Answer 25

virus uncoats and nucleic acid is released to produce viral proteins, they are released via budding or lysis

Question 26

what does cytotoxic T lymphocyte do in virus infection

Answer 26

recognised foreign proteins and induces apoptosis

Question 27

what does IgG and IgM do

Answer 27

neutralise and prevent viruses infecting other cells

Question 28

once viruses had infected can they become reactivated

Answer 28

yes - eg herpes

Question 29

name some common viral infections

Answer 29

HIV, hep C, herpes

Question 30

what do bactericidal drugs do

Answer 30

kill bacteria

Question 31

what do bacteriostatic drugs do

Answer 31

inhibit bacterial growth

Question 32

what antibiotics attack the cell wall

Answer 32

penicillin, cephalosporins, glycopeptides

Question 33

what are the 3 types of penicillin and how must they be administered

Answer 33

``` benzylpenicillin (pen G, IV) phenoxymethyl penicillin (pwn V, oral) benzathine penicillin (IM) ```

Question 34

describe the gram +ive penicillin

Answer 34

flucloxacillin for staph and strep

Question 35

describe the gram +ive/-ive penicillin

Answer 35

amoxicillin (destroyed by B-lactamase) and co-amoxiclav (everything but MRSA and pseudomonas)

Question 36

describe the gram -ive penicillin

Answer 36

temicillin, resistant to B-lactamase, acts on coliforms eg e. coli

Question 37

describe cephlasporins

Answer 37

excreted via kidneys and urine, safe in pregnancy, bactericidal, can promote C diff

Question 38

descrive glycopeptides

Answer 38

excreted in kidneys and kidneys, bactericidal resistant to B-lactamase, gram +ive eg vancomycin

Question 39

describe penicillin

Answer 39

safe in pregnancy, people can be hypersensitive, excreted in kidneys, bactericidal

Question 40

name the 3 antibiotics that attack ribosomes

Answer 40

aminoglycosides, tetracyclines, macrolides

Question 41

describe aminoglycocides

Answer 41

bacteriocidal, gram -ive eg gentamycin, excreted in urine and can damage kidneys, not safe in pregnancy

Question 42

describe tetracyclines

Answer 42

broad spectrum, bacteriostatic

Question 43

describe macrolides

Answer 43

erythrmoycin, clarithromycin, azithromycin, used for pen allergies, excreted via liver, erythromycin safe in pregnancy

Question 44

name the 3 nucleic acid antibiotics

Answer 44

metronidazole, trimethroprim, fluoroquinolones

Question 45

describe metronidazole

Answer 45

anaerobic infections eg clostridium and bacteroides, dafe in pregnancy, bactericidal

Question 46

describe trimethroprim

Answer 46

if you add sulphonamide = co-trimoxazole, can cause UTI's, bacteriostatic

Question 47

describe fluroquinolones

Answer 47

gram +ive or -ive, bacteriocidal, excreted via urine, levofloxacin and ciprofloxacin

Question 48

what 4 C's can cause C diff

Answer 48

co-amoxiclac, cephlosporins, clindomycin and ciprofloxacin

Question 49

what 5 I's spread infection

Answer 49

inhalation, ingestion, intercourse, inoculation, mother to Infant

Question 50

how does the body cause a fever

Answer 50

antigen interacts with macrophages which release cytokines, they travel to hypothalamus and stimulate PGE, PGE increases body temp --> shiver