Lab manual ID tables

Question 1

How to tell S. bovis and s equinus apart?

Answer 1

both are group D strep (GPC cat NEG, grow on MAC), also both are NEG for PYR and 6.5% salt tolerance.

S bovis is a lactose fermentor while s equinus is a NLF

Question 2

How do we differentiate the Enterococcus sps (all lac pos)? eg faecalis, faecium, durans

Answer 2

By using sugars mannitol arabinose and sorbitol.

E. faecalis is mannitol pos and arabinose NEG
E. faecium is mannitol pos and arabinose POS
E duran is mannitol NEG and arabinose NEG

Question 3

What about strep that doesnt grow on MAC? how to differentiate those with A haemolysis?

Answer 3

A haemolysis can be strep pneumoniae or viridans strep so test using Optochin (BA in CO2)- if S (greater than 14mm diameter) = s pneumoniae, if R perform bile solutibilty.

Bile soluble pos= s pneumonia, if neg= ID viridans strep

Question 4

Strep NG on MAC with B haemolysis how to differentiate?

Answer 4

Group A, B or C,F,G, use Phadebact if available - other wise:
Grp A= Bacitracin pos, hippurate neg, PYR pos, SXT R
Grp B= Bacitracin NEG, hippurate pos, PYR neg, SXT R
Grp C,F,G= Bacitracin R/v, hippurate neg, PYR neg, STX POS

Question 5

What about Strep NG on MAC w gamma haemolysis?

Answer 5

Can be Group B although rare- test w phadebact if not then can be viridans strep so ID.

ONLY group B, group D strep AND enterococci and viridans can be gamma haemolysis

Question 6

GNB or GNCB
1. Cat pos OX NEG growth on MAC
2. cat pos OX POS MAC growth
3. GREEN YELLOW pigments, cat pos majority ox pos, mac growth
4. cat v ox v MAC NEGATIVE growth
5. BA weak or neg GROWTH ON CHOC +++

Answer 6

1. Enterobacterales
2. Aeromonas, Chromobacterium, plesiomonas , vibrio
3. Burkhloderia, Stenotrophamonas, Psuedomonas
4. Acintobacillus, Cardiobacterium, Pasteurella, Eikenella
5. Haemophilus

Question 7

How to identify between acintobacter, pseudomonas and burkholderia and stenotrophomonas?

Answer 7

Acintobacter is coccobacilli and non motile and oxidase neg. grows on MAC
pseudomonas burkholderia is rod that is motile, has green pigment catalase AND ox pos.
stenotrophomonas has lighter yellow green pigment, rod, motile catalase pos OX neg

Question 8

Characteristics of pasteurella

Answer 8

GNB non motile NG on MAC, catalase pos, ox pos

Question 9

Which GN is coccobacillus and likes CO2 doesn’t grow on MAC

Answer 9

Haemophilus

Question 10

WHich enterobacteriacae is h2s pos?

Answer 10

Edwardsiella tarda (urea neg), Salmonella sp, Citrobacter freundii, proteus vulgaris and mirabilis, some morgonella morganii

Question 11

which enterobacteriacae are non motile at 36 degrees?

Answer 11

Klebsiella, Shigella, Yersinia (motile at 22 degrees)

Question 12

Which enterobacteriacea are PYR positive

Answer 12

citrobacter, enterobacter aerogenes and some cloacae, klebsiella, serratia marcescens. yersinia enterocolitica

Question 13

which enterobacteriace are indole pos

Answer 13

Escherichia coli, Citrobacter amalonaticus, Citrobacter koseri (not freundii) Edwardsiella tarda
Klebsiella oxytoca Morganella morganii Proteus vulgaris Providencia species

Question 14

which enterobacteriacea are lac neg and which are lac pos?

Answer 14

lac neg
Edwardsiella Hafnia Morganella Pantoea Proteus Providencia Salmonella Yersinia

lac pos
Escherichia (++++) Klebsiella (++) Enterobacter (++) Citrobacter (+++)

Question 15

how to tell the 3 proteus sp apart?

Answer 15

All swarm and lac neg, P vulgaris is the ONLY indole pos, P mirabilis is indole neg, P penneri is indole neg maltose POS - the rest are neg

Question 16

how can we ID S marcescens and shigella sp?

Answer 16

S marcescens have a red pigment are motile, false pos spot indole due to pigment (indole neg), pyr pos

shigella= lac neg, non motile, spot indole neg, pyr neg (Klebsiella are PYR pos)

Question 17

How to tell the difference between citrobacter sp

Answer 17

C freundii is H2s pos and spot indole neg, C koseri (diversus) is H2s neg and spot indole pos

Question 18

Which Burkolderia sp cannot grow at 42 degrees

Answer 18

B. mallei, B pseudomallei can while cepacia is variable

Question 19

how to diff btween neiserria species

Answer 19

N gonorrhoeae NG on BA and only glucose pos in cta sugars, N meningitidis is weak growth on BA w glucose and maltose pos then lactamica grows on BA and glucose maltose and lactose pos.

Question 20

Which GPB are cat pos

Answer 20

bacillus, listeria, nocardia, diptheroid like cornyebacterium

Question 21

which GPB are cat negative

Answer 21

Clostridium (OA), lactobacillus (medium colony w chaining), erysipelothrox (pleomorphic rod), actinomyces