ENTERO + BIOCHEMICAL

Providencia rettgeri

Which of the following organisms can be used as a positive control for deaminase reactions?

Purple butt due to formation of cadaverine

What is the positive result for decarboxylase reactions using LIA?

• Differentiates S. pyogenes from other β-hemolytic streptococci

• Tests for susceptibility to 0.04 U Bacitracin

• Has a zone of inhibition as its positive result

Taxo P:

Blueing of the medium

Positive result/s for citrate utilization test:

EDTA; because presence of citrate-utilizing bacteria can cause false-positive results if citrated plasma is used.

What is the preferred anticoagulant for rabbit plasma to be used for tube coagulase test? Why?

Incubate further and reread results after 24 hours

In case an orange color is observed after 48 hours of incubation for MR test, what should be done?

Tryptophan : p-dimethylaminobenzaldehyde

Which of the following is a correct combination of substrate and indicator for the indole test?

Yellow butt : sucrose fermenter

Which of the following combinations is not correct for result and interpretation using TSI medium?

A/K, H₂S(+)

Which of the following is not a possible result using TSI medium?

Ratio of lactose to glucose

KIA differs from TSI in the:

Yersinia enterocolitica

Which of the following organism will have a K/A reaction on KIA but weak A/A on TSI?

Lactose, indole, ONPG, motility

Which of the following tests best differentiates Shigella species from Escherichia coli?

Shigella, Yersinia, Klebsiella

Which of the following are usually non-motile at 37°C incubation?

Escherichia coli

Identify the organism with the following biochemical result:
TSI= A/A gas (+), VP= neg, H₂S= neg, Urease= neg, PAD= neg, Indole= pos, MR= pos, Citrate= neg

Proteus vulgaris

Identify the organism with the following biochemical result:
TSI= K/A + H₂S, MR= pos, Indole= Pos, LIA= R/A + H₂S, Gelatin Hydrolysis= pos, Citrate= neg, VP= neg

Yersinia enterocolitica

The organism demonstrates “bull’s eye” colonies on CIN after 48 hours of incubation period:

Enterobacter species

Which of the following demonstrates the characteristic “fish-eye colonies” on EMB?

Acetylmethylcarbinol

KOH and Alpha-naphthol are the reagents used for the detection of:

Glucose, lysine, amino acid, bromcresol purple

Components of the medium used that detects the ability of an organism to remove the carboxyl group from a specific amino acid:

Lysine: Cadaverine

Which of the following carboxyl group and amino acid used correctly match for the decarboxylation reaction?

Moeller’s decarboxylase

Differential medium for lactose fermenters with bromcresol purple as the indicator:

Reagent used for the test is p-phenylenediamine hydrochloride in DMSO

Which of the following is true regarding Modified Oxidase Test?

Ferrous sulfate

In the carbohydrate fermentation test, the blackening of the media is due to the presence of what indicator?

Fermenters

Organisms that produce acid in both aerobic and anaerobic tubes are considered:

• Beta-galactosidase

• Galactoside permease

The enzyme responsible for lactose fermentation:

Deaminase

A test that is used to detect the presence of enzymes that break down amino acid:

Urease

Enzyme that is a characteristic of Proteus:

5%

In preparing blood agar plates, % blood is added to the melted agar?

--++

Klebsiella produces what reaction to IMViC?

Phenol red

Indicator used in TSI:

No sugars fermented

Alkaline over alkaline or red over red indicates on KIA:

Cadaverine

Process of decarboxylation of amino acid lysine produces _____ as end product:

Ferric Chloride

Indicator used in PAD medium for the detection of deamination:

It detects lactose from non-lactose fermenters

The MacConkey agar is considered as a differential media because:

It detects lactose from non-lactose fermenters

The MacConkey agar is considered as a differential media because:

Haemophilus influenzae

Satellite phenomenon on Chocolate agar plate is a characteristic of which organism?

4.4

At what pH does MR test become positive?

Ammonium carbonate

In the test for urease production, ammonia reacts to form which product?

Griffith

This classification of Streptococci is based on the ability of the organism to produce hemolysis on blood agar:

Glucose

A red slant and yellow butt in TSI indicate fermentation of:

Lactose

A yellow butt and yellow slant in a TSI tube indicates fermentation of:

Swarming

Chloral hydrate may be added to avoid:

E. coli

An oxidase-negative Gram-negative rod that grows on EMB and ferments glucose most likely:

Serratia marcescens

Red pigmented colonies on clear medium is usually caused by:

Gram positive

Sodium desoxycholate and other bile salt will inhibit:

Anaerobic respiration

Synonym for Fermentation:

4.5

At which pH does methyl red test become positive:

Anthrax infection

The Ascoli thermoprecipitation test may be used to determine:

Endotoxin

A toxin which is considered a part of the bacterial cell substance:

• Gram (+) organism

• Gram (–) organism

• Fungi

Brain-heart infusion broth is for cultivation of: