Biochemical Test of Haemophilus parainfluenzae 50 FAQs and 30 MCQs
Biochemical Test of Haemophilus parainfluenzae 50 FAQs
What is Haemophilus parainfluenzae?
A Gram-negative, pleomorphic, facultatively anaerobic bacterium, part of the normal upper respiratory flora, capable of opportunistic infections.
What is the Gram stain result for H. parainfluenzae?
Gram-negative.
What shape does H. parainfluenzae have?
Small, pleomorphic rods, often appearing as long filamentous forms, pairs, or short chains.
Is H. parainfluenzae motile?
No, it is non-motile.
Does H. parainfluenzae have a capsule?
Capsule presence is variable among strains.
What growth factors does H. parainfluenzae require?
It requires V factor (NAD) but does not require X factor (hemin).
What is the V factor for H. parainfluenzae?
Nicotinamide adenine dinucleotide (NAD).
What is the X factor requirement for H. parainfluenzae?
It does not require X factor (hemin).
What type of agar is commonly used to grow H. parainfluenzae?
What type of agar is commonly used to grow H. parainfluenzae?
What is the oxidase test result for H. parainfluenzae?
Positive.
What is the catalase test result for H. parainfluenzae?
Variable
Does H. parainfluenzae produce hemolysis on blood agar?
No, it is non-hemolytic (Negative).
What is the urease test result for H. parainfluenzae?
Variable (can be positive or negative).
What is the indole production test result for H. parainfluenzae?
Typically Negative
Can H. parainfluenzae reduce nitrate?
Yes, Nitrate Reduction is Positive.
Can H. parainfluenzae reduce nitrite?
Yes, Nitrite Reduction is Positive.
What is the ornithine decarboxylase test result for H. parainfluenzae?
Positive
What is the lysine decarboxylase test result for H. parainfluenzae?
Variable.
What is the arginine dihydrolase test result for H. parainfluenzae?
Negative.
Does H. parainfluenzae ferment glucose?
Yes, Positive with acid production.
Does H. parainfluenzae ferment sucrose?
Yes, Positive with acid production.
Does H. parainfluenzae ferment lactose?
No, Negative.
Does H. parainfluenzae ferment maltose?
Yes, Positive.
Does H. parainfluenzae ferment mannose?
Yes, Positive.
Does H. parainfluenzae ferment fructose?
Yes, Positive
Does H. parainfluenzae ferment galactose?
Yes, Positive.
Does H. parainfluenzae ferment xylose?
No, Negative.
Does H. parainfluenzae ferment mannitol?
No, Negative.
Does H. parainfluenzae ferment sorbitol?
No, Negative.
Does H. parainfluenzae ferment inositol?
No, Negative.
Does H. parainfluenzae ferment adonitol?
No, Negative.
Does H. parainfluenzae ferment arabinose?
No, Negative.
Does H. parainfluenzae ferment cellobiose?
No, Negative.
Does H. parainfluenzae ferment dulcitol?
No, Negative.
Does H. parainfluenzae ferment erythritol?
No, Negative.
Does H. parainfluenzae ferment glycerol?
Variable.
Does H. parainfluenzae ferment inulin?
No, Negative.
Does H. parainfluenzae ferment melibiose?
No, Negative.
Does H. parainfluenzae ferment raffinose?
Variable.
Does H. parainfluenzae ferment rhamnose?
No, Negative.
Does H. parainfluenzae ferment salicin?
No, Negative.
Does H. parainfluenzae ferment sorbose?
No, Negative.
Does H. parainfluenzae ferment trehalose?
No, Negative.
What is the alkaline phosphatase test result for H. parainfluenzae?
Positive.
What is the esculin hydrolysis test result for H. parainfluenzae?
Negative.
What is the fucosidase test result for H. parainfluenzae?
Negative.
What is the IgA1 protease test result for H. parainfluenzae?
Negative.
What is the ONPG (β-galactosidase) test result for H. parainfluenzae?
Variable.
Does H. parainfluenzae produce H2S?
Yes, Positive.
How is H. parainfluenzae distinguished from other Haemophilus species?
Primarily by its requirement for V factor (NAD) but not X factor (hemin), combined with its biochemical profile (e.g., positive oxidase, catalase variable/positive, nitrate reduction positive, fermentation of glucose/sucrose but not lactose, ornithine decarboxylase positive, non-hemolytic).
Biochemical Test of Haemophilus parainfluenzae 30 MCQs
- What is the Gram stain reaction of Haemophilus parainfluenzae?
a) Gram-positive
b) Gram-negative✔
c) Acid-fast
d) Cannot be determined - The characteristic shape of H. parainfluenzae under the microscope is best described as:
a) Large, uniform bacilli
b) Small, pleomorphic rods, often filamentous✔
c) Cocci in clusters
d) Spirochetes - Which growth factor is absolutely REQUIRED by H. parainfluenzae?
a) X Factor (Hemin)
b) V Factor (NAD)✔
c) Both X and V Factors
d) Neither X nor V Factor - On which type of media is H. parainfluenzae most likely to grow well?
a) MacConkey Agar
b) Mannitol Salt Agar
c) Chocolate Agar✔
d) TCBS Agar - What is the result of the Oxidase test for H. parainfluenzae?
a) Positive✔
b) Negative
c) Variable
d) Not Tested - According to Article 2, what is the Catalase test result for H. parainfluenzae?
a) Positive✔
b) Negative
c) Variable
d) Weakly Positive - What is the typical hemolytic pattern of H. parainfluenzae on horse blood agar?
a) Alpha-hemolysis
b) Beta-hemolysis
c) Gamma-hemolysis (Non-hemolytic)✔
d) Double-zone hemolysis - The Urease test result for H. parainfluenzae is:
a) Always Positive
b) Always Negative
c) Variable✔
d) Positive only on specific media - What is the typical result of the Indole production test for H. parainfluenzae?
a) Positive
b) Negative✔
c) Variable
d) Positive only with added tryptophan - Which of the following tests is POSITIVE for H. parainfluenzae?
a) Nitrate Reduction✔
b) Arginine Dihydrolase
c) Esculin Hydrolysis
d) Lactose Fermentation - H. parainfluenzae ferments which of the following carbohydrates?
a) Lactose
b) Sucrose✔
c) Mannitol
d) Xylose - H. parainfluenzae does NOT ferment which carbohydrate?
a) Glucose
b) Fructose
c) Maltose
d) Lactose✔ - According to Article 2, what is the result of the Ornithine Decarboxylase test for H. parainfluenzae?
a) Positive✔
b) Negative
c) Variable
d) Not Mentioned - Which of the following is a key characteristic that helps differentiate H. parainfluenzae from H. influenzae?
a) Requires X Factor (Hemin)✔
b) Requires V Factor (NAD)
c) Is Gram-negative
d) Is Oxidase Positive - The Alkaline Phosphatase test for H. parainfluenzae is:
a) Positive✔
b) Negative
c) Variable
d) Not Mentioned - What is the result of the ONPG (β-galactosidase) test for H. parainfluenzae?
a) Positive
b) Negative
c) Variable✔
d) Positive only at high temperatures - H. parainfluenzae produces which of the following enzymes?
a) IgA1 protease
b) Fucosidase
c) Catalase✔
d) Arginine Dihydrolase - The Lysine Decarboxylase test result for H. parainfluenzae is:
a) Positive
b) Negative
c) Variable✔
d) Not Tested - What is the result of the H2S production test for H. parainfluenzae?
a) Positive✔
b) Negative
c) Variable
d) Not Mentioned - Where is Haemophilus parainfluenzae commonly found as part of the normal flora?
a) Gastrointestinal tract
b) Skin
c) Upper respiratory tract✔
d) Genitourinary tract - Which type of infections is H. parainfluenzae MOST associated with?
a) Primary pathogens causing severe epidemics
b) Opportunistic infections in compromised hosts✔
c) Foodborne illnesses
d) Sexually transmitted infections - Which specific enzymatic reaction is used to confirm nitrate reduction?
a) Oxidase
b) Catalase
c) Nitrate Reductase✔
d) Urease - The motility of H. parainfluenzae is:
a) Motile with flagella
b) Non-motile✔
c) Gliding motility
d) Variable motility - Fermentation of which carbohydrate by H. parainfluenzae is listed as Variable?
a) Glucose
b) Sucrose
c) Glycerol✔
d) Lactose - A gram-negative, pleomorphic rod grows on Chocolate agar but not on Blood agar without supplements. It ferments sucrose but not lactose, is oxidase positive, and reduces nitrate. The MOST likely organism is:
a) Escherichia coli
b) Neisseria meningitidis
c) Haemophilus influenzae
d) Haemophilus parainfluenzae✔ - The presence of which factor allows differentiation of H. parainfluenzae from Haemophilus aphrophilus in basic lab settings?
a) Gram stain
b) X Factor requirement
c) V Factor requirement✔
d) Hemolysis pattern - Which test result is typically NEGATIVE and helps differentiate H. parainfluenzae from some Actinobacillus species?
a) Oxidase
b) Esculin Hydrolysis✔
c) Nitrate Reduction
d) Glucose Fermentation - For the Hemolysis test, H. parainfluenzae is specifically described on which type of blood agar?
a) Sheep Blood Agar
b) Human Blood Agar
c) Horse Blood Agar✔
d) Rabbit Blood Agar - The Nitrite Reduction test for H. parainfluenzae is:
a) Positive✔
b) Negative
c) Variable
d) Not Mentioned - Which of the following is NOT a characteristic biochemical feature of Haemophilus parainfluenzae?
a) Requires V factor (NAD)
b) Ferments Glucose
c) Produces Indole✔
d) Positive Ornithine Decarboxylase (per Article 2)
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