Clostridium

Question 1

anaerobic,
Gram-positive,
endospore-forming bacillus
that is ubiquitous in soil, water, sewage, and the gastrointestinal tracts of animals & humans.

Answer 1

Clostridium

Question 2

Several species of Clostridium are significant human pathogens:

Answer 2

1) Clostridium tetani
2) Clostridium botullinum
3) Clostridium perfringens

Question 3

Small, motile, obligate anaerobe that produces a terminal endospore,
giving the cell a distinctive “lollipop” appearance.

Answer 3

Clostridium tetani

Question 4

extremely sensitive to oxygen and live only in anaerobic environments.
But its endospore survive for years.

Answer 4

Clostridium tetani

Question 5

Clostridium tetani cause what we called

Answer 5

tetanus

Question 6

is a disease caused by the secretion of tetanus toxin
(a potent neurotoxin released by Cl. tetani cells when they die),

Answer 6

Tetanus

Question 7

an aerobic, endospore-forming, Gram-positive bacillus that is common in soil and water worldwide.

Answer 7

Clostridium Botulinum

Question 8

Clostridium Botulinum endospores survive improper canning of food, germinating to produce vegetative cells that grow and release

Answer 8

neurotoxin (botulism toxins)
that cause botulism.

Question 9

neurotoxin (botulism toxins) prevent

Answer 9

muscular contraction, resulting in a flaccid paralysis.

Question 10

Botulism is not an infection, but instead an intoxication (poisoning) caused

Answer 10

by botulism toxin

Question 11

Clinicians recognize three manifestations of botulism:

Answer 11

1- Food borne botulism
2- Infant botulism
3- Wound botulism

Question 12

Food borne botulism is prevented by destroying all endospores in contaminated food by proper techniques, such as

Answer 12

• Preventing endospores from germinating by using
refrigeration

• Establishing an acidic environments (˂pH 4.5)

• Destroying the toxin by heating at least 80°C for 20 min

Question 13

large, rectangular,
Gram-positive bacillus.
Although it is non-motile,
its rapid growth enables it to spread across the surface of laboratory media

Answer 13

Clostridium perfringens

Question 14

Clostridium perfringens produce 11 toxins that

Answer 14

lyse erythrocytes and leucocytes, increase vascular permeability, reduce blood pressure, and kill cells.

Question 15

Cl. perfringens is not invasive, but when some traumatic wound, crushing trauma, or a compound fracture introduces endospores into the body, they can

Answer 15

germinate in the anaerobic environment of deep tissues.

Question 16

The rapidly growing bacteria (Cl. perfringens )can spread in to the surrounding tissues causing

Answer 16

myonecrosis (the death of muscle and connective tissues) “Gas gangrene”.

Question 17

The appearance of gas gangrene is usually diagnostic by itself; through the

Answer 17

the detection of large
Gram-positive bacilli is confirmatory.

Question 18

Cl. perfringens colonies on blood agar surface show double zone of hemolysis

Answer 18

the inner is β- hemolysis (clear zone),
the outer is α- hemolysis green color zone).

Question 19

pleomorphic,
Gram-positive,
Non-endospore-forming bacteria that are ubiquitous on plants and in animals and humans,

Answer 19

Corynebacterium diphtheriae

Question 20

where they
colonize the skin and the respiratory, gastrointestinal, urinary, and genital tracts.

Answer 20

Corynebacterium diphtheriae

Question 21

Corynebacterium diphtheriae divided via a type of binary fission called

Answer 21

snapping division,

Question 22

Corynebacterium diphtheriae appear in short chains” V or Y configurations” resembling

Answer 22

Chinese letters

Question 23

Corynebacterium diphtheriae has granules which composed of

Answer 23

polymetaphosphate
and show bluish purple
when stained with methylene blue.

Question 24

Corymebacterium diphtheriae is transmitted from person to person via

Answer 24

respiratory droplets or skin contact.

Question 25

Corymebacterium diphtheriae contain diphtheria toxin which responsible for

Answer 25

signs and symptoms of diphtheria such as
fever, sore throat, pharyngitis, blood clotting factors,

Question 26

Initial diagnosis (Corynebacterium diphtheriae )is based on the presence of a

Answer 26

a pseudomembrane

Question 27

The most effective way to prevent diphtheria is immunization. It is

Answer 27

It is DPT
vaccine Which combines diphtheria, pertussis, and tetanus.

Question 28

kills the Corymebacterium diphtheriae, preventing the synthesis of more toxin.

Answer 28

Penicillin. Erythromycin

Question 29

Gram-positive,
non-sporeforming coccobacillus, has tumbling motility at 20-25°C due to peritrichous flagella,
found in soil, water, mammals, birds, fish

Answer 29

Listeria monocytogenes

Question 30

Listeria monocytogenes cause

Answer 30

Listeriosis

Question 31

Listeria monocytogenes produce a pore-forming protein called

Answer 31

listeriolysin O

help the bacterium to grow,
and reproduces in the cytosol.

Question 32

Listeria is rarely pathogenic in healthy adults. In contrast, infection in

Answer 32

pregnant women, fetuses, newborns, the elderly (aged 65)

• In pregnant women can cause: placentitis, abortion.
• In non-pregnant humans can cause: meningitis, encephalitis.

Question 33

Listeria can be cultured from

Answer 33

blood or CSF fluid.

Question 34

Listeria monocytogenes show* on blood agar and * in semisolid medium, both are useful for identification.

Answer 34

• β-hemolysis
• motility

Question 35

Ampicillin & Erythromycin is the best oral antibiotics for

Answer 35

Listeria infection.

Question 36

To reduce the risk for Listeriosis:

Answer 36

• Cook thoroughly raw food from animal sources, such as beef.
• Wash raw vegetables
• Avoid unpasteurized milk

Question 37

Mycobacterium tuberculosis, also known as* , is a species of pathogenic bacteria in the family * and the causative agent of *.

Answer 37

• Koch’s bacillus
• Mycobacteriaceae
• tuberculosis

Question 38

usually attack the lungs, but TB bacteria can attack

Answer 38

can attack any part of the body such as the kidney, spine, and brain.

Question 39

M. tuberculosis has an unusual, waxy coating on its cell surface primarily due

Answer 39

due to the presence of mycolic acid.

Question 40

Types of tuberculosis

Answer 40

• PulmonaryTuberculosis
• Pleural Tuberculosis
• Skeletal Tuberculosis
• Brain Tuberculosis
• Bladder and Kidney Tuberculosis
• Joint Tuberculosis
•Gastrointestinal Tract Tuberculosis
• Miliary Tuberculosis