W04_05 Intro to bacteriology I

Question 1

what gives gram-positive organisms the ability to retain the colour?

Answer 1

1: thicker peptidoglycan layer; 2: magnesium ribonucleate has affinity for crystal violet-iodine complex 3: less lipid in cell walls, so less permeability to decolorizer

Question 2

the presence of what in a sputum sample is cause for rejection of the sample?

Answer 2

squamous epithelial cells. indicates too much oral contamination

Question 3

classify staphylococcus spp

Answer 3

GP, cocci, O2+

Question 4

classify streptococcus spp

Answer 4

GP, cocci, O2+

Question 5

classify enterococcus spp

Answer 5

GP, cocci, O2+

Question 6

classify corynebacterium spp

Answer 6

GP, bacilli, O2+

Question 7

classify bacillus spp

Answer 7

GP, bacilli, O2+

Question 8

classify clostridium spp

Answer 8

GP, bacilli, AnO2

Question 9

classify neisseria spp

Answer 9

GN, cocci, O2+

Question 10

classify haemophilus spp (coccobacilli)

Answer 10

GN, cocci/bacilli, O2+

Question 11

classify e. coli

Answer 11

GN, bacilli, O2+

Question 12

classify bacteroides spp

Answer 12

GN, bacilli, AnO2

Question 13

what is this

Answer 13

staphylococcus spp.

Question 14

name important staphylococcus species

Answer 14

s.aureus

coag-neg staphylococci:

(s. epidermidis, s. lugdunensis, s. saprophyticus)

Question 15

what’s the coagulase test?

Answer 15

sees if the bacteria will cause serum to coagulate

Question 16

what is this

Answer 16

streptococcus spp.

(enterococcus also looks like this)

Question 17

name important streptococci

Answer 17

beta-hemolytic streptococci:

(s. pyogenes (group A strep.), s. agalactiae (group B strep))

alpha-hemolytic streptococci:

(s. pneumoniae, viridans group strep)

Question 18

what’s the difference between beta and alpha hemolysis?

Answer 18

beta is clearer on the blood agar. alpha is greener.

Question 19

what’s this?

Answer 19

viridans group strep. note the long chains.

Question 20

what’s this?

Answer 20

group A strep. note the short chains.

Question 21

what’s this

Answer 21

streptococcus pneumoniae. (gram positive diplococci)

Question 22

what’s this?

Answer 22

enterococcus spp. (gram positive cocci in short chains).

e. faecium and e. faecalis are common species

Question 23

what’s this?

Answer 23

corynebacterium spp.

note the v-shapes and the palisades (lines)

jeikeium, urealyticum and diphtheriae are important.

Question 24

what’s this

Answer 24

bacillus. gram-positive bacilli, typical skin flora

important bacillus: b. anthracis (not common)

Question 25

what’s this?

Answer 25

escherichia coli. gram-negative bacilli. bipolar staining.

important enteric GN: e.coli, salmonella spp., enterobacter spp, etc. etc. refer to 46/61 of slides)

Question 26

what’s this?

Answer 26

haemophilus spp. GN coccobacilli.

important: H. influenzae.

Question 27

what’s this?

Answer 27

neisseria spp. GN diplococci.

important: N. meningitidis, N. gonorrhoeae

Question 28

what’s this?

Answer 28

clostridium spp. GP bacilli. AnO2

important: C. tetani, C. botulinum, C. perfringens, C. difficile

Question 29

what’s this?

Answer 29

bacteroides spp. GN bacilli. AnO2. note they’re scraggly because they’re exposed to air.