ENTEROBACTERIACEAE

Question 1

RAPID LACTOSE FERMENTERS

Answer 1

Escherichia coli
Klebsiella spp
Enterobacter spp.

Question 2

NON-LACTOSE FERMENTERS

Answer 2

Salmonella spp except for S. arizonae
Shigella except S. sonnei
Proteus
Providencia
Morganella
Edwardsiella

Question 3

LATE LACTOSE FERMENTERS

Answer 3

Salmonella arizonae
Shigella sonnei
Serratia spp
Hafnia spp
Yersinia spp
Citrobacter

Question 4

Triple Sugar Iron (TSI) pH indicator

Answer 4

Phenol Red

Question 5

TSI H2s indicator

Answer 5

Sodium thiosulfate is reduced to Sulfur Dioxide and Hydrogen Sulfide which reacts with Ferrous Sulfate
to produce black ferric sulfide

Question 6

To determine if a g- bacilli
decarboxylates or
deaminates lysine and forms
H2S

Answer 6

Lysine Iron Agar (LIA)

Question 7

If oxidative deamination of lysine
occurs

Answer 7

it will form a burgundy (red) color on
the slant in the presence of ferric ammonium
citrate and flavin mononucleotide.

Question 8

If deamination does not occur

Answer 8

LIA slant remains purple

Question 9

When glucose is fermented, the butt of
the medium becomes

Answer 9

acidic (yellow)

Question 10

If the organism produces lysine
decarboxylase

Answer 10

cadaverine (purple) is
formed

Question 11

If the decarboxylase is not produced,
the butt remains

Answer 11

acidic (yellow)

Question 12

check organism (+) for
deamination

Answer 12

Slunt part

Question 13

check organism (+) for
deamination

Answer 13

Slunt part

Question 14

check organism (+) for
decarboxylation

Answer 14

Butt part

Question 15

Organisms that involved deamination

Answer 15

Proteus, Morganella and Providencia

Question 16

if the bacteria can produce sulfide
it will result of blackening

Answer 16

SULFIDE (H2S+)

Question 17

INDOLE Result

Answer 17

Pink ring formation (+)
need Kovac’s reagent/Ehrlich’s reagent

Question 18

POSITIVE IN INDOLE

Answer 18

Proteus vulgaris

Question 19

NEGATIVE IN INDOLE

Answer 19

Proteus mirabilis

Question 20

 SIM would have heavy turbidity.
 Can also form a brush like formation.
 If the organism shows this it is
automatically

Answer 20

MOTILITY

Question 21

 To determine if the m/o is capable
of utilizing citrate as its sole source
of carbon.

Answer 21

CITRATE UTILIZATION TEST

Question 22

POSITIVE REACTION FOR CITRATE

Answer 22

BLUE

Question 23

NEGATIVE REACTION FOR CITRATE

Answer 23

GREEN CITRATE

Question 24

Citrate useful in identification of lactose
fermenters

Answer 24

E, K, E

Question 25

Positive organisms in Citrate Utilization Test

Answer 25

Klebsiella and Enterobacter

Question 26

Negative organisms in Citrate Utilization Test

Answer 26

Escherichia coli

Question 27

To identify the rapid urease producers and weak urease producer

Answer 27

Urease Test

Question 28

POSITIVE RESULT FOR UREASE

Answer 28

Pink/Red formation

Question 29

NEGATIVE RESULT FOR UREASE

Answer 29

Yellow color

Question 30

BROTH USE IN UREASE TEST

Answer 30

Christensen's agar/ Stuart broth

Question 31

Rapid Urease producers within 2-4 hrs

Answer 31

Proteus, Providencia and Morganella

Question 32

Weak Urease producers more than 4 hrs

Answer 32

Kleibsiella pneumoniae and Enterobacter spp, Yersinia spp, Serratia and Citrobacter

Question 33

Sugars in TSI

Answer 33

Lactose= 10 Sucrose=10 Glucose=1

Question 34

pH indicator of MacConkey agar

Answer 34

neutral red

Question 35

only media for detecting gram negative in hospital settings  Selective for gram negative organisms  Carbohydrate present: Lactose  Differential media: it differentiate lactose fermenters and non lactose fermenter

Answer 35

MacConkey agar

Question 36

If organism is lactose fermenters

Answer 36

pink colonies

Question 37

ENTEROBACTERIACEAE GENERAL CHARACTERISTICS

Answer 37

Gram (-)  Facultative anaerobic  Glucose fermenters  Oxidase (-)

Question 38

Motile with peritrichous flagella (except

Answer 38

Klebsiella, Shigella, Yersinia

Question 39

Non-encapsulated (except

Answer 39

Klebsiella and Enterobacter)

Question 40

Catalase (+) (except

Answer 40

Salmonella dysenteriae)

Question 41

Nitrate reducers (except

Answer 41

Erwinia and Pantoea agglomerans)

Question 42

Often with Gas production (except

Answer 42

Shigella, Salmonella, Proteus and Providencia)

Question 43

Commensal flora in the intestinal tract (except

Answer 43

Salmonella, Shigella and Yersinia

Question 44

Nonhemolytic except

Answer 44

In BAP: Escherichia coli- beta hemolysis