Medical Microbiology: Gram Positive Rods MCQs

Multiple Choice Questions on Gram Positive Rods

1) All are general characteristics of Bacilli, except
a) Anaerobes
b) Gram-positive
c) Spore-forming
d) Ubiquitous

2) Which one of the following Bacillus spp is NOT a medically important pathogenic bacteria?
a) Bacillus cereus
b) Bacillus thuringiensis
c) Bacillus thermophilus
d) Bacillus anthracis

3) Bacillus.............is commonly found in soil and is an insect pathogen which can infect humans also. This organism is often used as pest control in insecticidal products.
a) thuringiensis
b) subtilis
c) anthracis
d) cereus


4) Most of the species of Bacilli and Clostridia are.............., which means they obtain their nutrients from dead or organic matter.
a) Parasites
b) Saprophytes
c) Symbiotic
d) Mutualistic

5) Bacillus anthracis is a principle pathogen of a disease known as "anthrax" which primarily infects animals like goats and cattle and is transmitted to humans through ingestion or inhalation of spores. What are the two important virulence factors of this organism?
a) Capsule and enterotoxins
b) Exotoxins and enterotoxins
c) Endotoxins and capsule
d) Capsule and exotoxins

6) Bacillus cereus causes two types of foodborne intoxications, known as the emetic type and diarrheal type. What is the incubation period for the onset of symptoms ingestion in the emetic type of food intoxication?
a) 1-12 hours
b) 1-2 days
c) 1-5 hours
d) 1-24 hours

7) Bacillus….......is a common laboratory contaminant and is used as sterility testing. It is an endospore-forming bacteria and resistant to an extreme environmental condition.
a) subtilis
b) thermophilus
c) cereus
d) agalactiae

8) Which of the following species of Clostridia do not have flagella, but rapidly grows on nutrient media and mimics the growth of motile organisms?
a) Clostridium botulinum
b) Clostridium perfringens
c) Clostridium tetani
d) Clostridium difficile

9) All of the following is the type of infections caused by Clostridium perfringens, EXCEPT?
a) Gas gangrene
b) Food poisoning
c) Cellulitis
d) None of the above

10) The AVA BioThrax is the FDA approved vaccines for
a) Bacillus cereus
b) Clostridium tetani
c) Bacillus anthrax
d) Bacillus substilis


11) The shape and position of spores vary in different types of species and is useful in identification of Clostridia. Clostridium perfringens forms subterminal spores whereas Clostridium....... forms terminal spores.
a) tetani
b) botulinum
c) cereus
d) sordellii

12) The bacterial spore of..............can invade human body through a puncture wound and ultimately enter the central nervous system by releasing a potent toxin known as neurotoxins, thus blocking the release of neurotransmitters and resulting in cramping of muscles, causing loc jaw and other muscle related spasms.
a) Bacillus anthracis
b) Clostridium botulinum
c) Clostridium tetani
d) Bacillus subtilis

13) Which is the most common food associated with infant botulism?
a) Maple syrup
b) Honey
c) Canned baby food
d) Corn syrup

14) All of the given species of Clostridia produces botulinum toxins, except
a) Clostridium botulinum
b) Clostridium butyricum
c) Clostridium baratii
d) Clostridium difficile

15) The toxin responsible for food poisoning by Bacillus cereus is
a) Cytotoxins
b) Neurotoxins
c) Enterotoxins
d) None of the above



16) All of the statements given below for Bacillus anthracis are true, EXCEPT
a) Hemolytic colonies on Blood agar
b) Large gram-positive rods
c) Non-motile
d) Capsulated

17) Colony characteristics/characteristic of Clostridia
a) Grow well in Nutrient agar
b) Produce alpha hemolytic colonies
c) Grow under aerobic conditions
d) None of the above

18) Clostridium botulinum associated foodborne illness can occur within 18-24 hours of ingestion of a toxin produced by the bacteria in food. Which of the following is NOT the symptoms associated with C.botulinum toxin?
a) Poor vision
b) Fever
c) Difficulty swallowing
d) Bulbar paralysis

19) All of the following are the preventive measures for Tetanus, EXCEPT
a) Active immunization of toxoids
b) Prophylactic use of antitoxin
c) Administration of Bacitracin
d) None of the above

20) Clostridium perfringens toxins are released only after entering the host cell through wounds or from the intestinal tract, which of the following also known as alpha toxin can damage the cell membranes ultimately resulting in hemolysis and tissue destruction?
a) Lecithinase
b) Enterotoxin
c) Alpha
d) Beta


Multiple Choice Answers
1)- a,
2)-c,
3)-a,
4)-b,
5)-d,
6)-c,
7)-a,
8)-b,
9)-d,
10)-c
11)- a,
12)- c,
13)-b,
14)-d,
15)-c,
16)-a,
17)-d,
18)-b,
19)-c,
20)-a