Gram positive rod

Question 1

What are the gram positive rod species?

Answer 1

Bacillus spp
Clostridium spp
Corynebacterium diphtheriae
Listeria monocytogenes

Question 2

Gram positive
Rod shaped
Spore-forming bacteria
Found in soil, water, wool, hair, air, and on vegetation

Answer 2

Bacillus

Question 3

What are the two species under Bacillus?

Answer 3

Bacillus anthracis (encapsulated)
Bacillus cereus (motile and non capsulated)

Question 4

Gram positive rod
spore forming
non motile
non haemolytic
depends on bacterial capsule and anthrax toxin complex

Answer 4

B. anthracis

Question 5

Bacterial capsule - protects against phagocytosis and lysis
Anthrax toxin complex
a. Protective Antigen (PA) - entry of bacteria into host cell. binds to receptor on macrophage surface
b. Edema Factor (EF) - causes cellular edema within the target tissue and also inhibits neutrophil function
Lethal Factor (LF) - release of tumor necrosis factor-alpha and interleukin-1 by macrophages

Answer 5

Virulence factors of B.anthracis

Question 6

What is the combination of oedema toxin?

Answer 6

PA and EF

Question 7

What is the combination of lethal toxin?

Answer 7

PA and LF

Question 8

Causes an increase in the cellular CAMP levels leading to cellular oedema within the target tissues

Answer 8

Edema toxin

Question 9

Zinc metalloprotease inactivates mitogen-activated protein kinase (MAPK), causing impaired proliferation, survival, and inflammation in all cell types. Leads to multisystem dysfunction in the host.

Answer 9

Lethal toxin

Question 10

What is oedema?

Answer 10

Small blood vessels leak fluid into nearby tissues.
Pitting is when it takes a long time for the skin to bounce back

Question 11

Anthrax is a zoonic infection and is transmitted by inoculation, ingestion, and inhalation.

Answer 11

B. anthracis

Question 12

Entry of spores through the skin or through fly bites.
Papule, vesicle, eschar.
Commonly found in farmers and in persons handling infected carcasses

Answer 12

Cutaneous anthrax

Question 13

Ingestion of undercooked meat containing spores.
Abdominal pain and fever are the first symptoms, followed by nausea, vomiting, and diarrhea.
Very rare

Answer 13

Gastrointestinal anthrax

Question 14

Wool sorters disease
Spores are ingested by alveolar macrophages and are carried to the mediastinal lymph nodes
Does not cause pneumonia, but it causes haemorrhagic mediastinitis and pulmonary oedema
High fatality rate

Answer 14

Inhalational anthrax

Question 15

Spore forming, motile, gram positive rods
normal inhabitants in soil, regularly isolated from foods such as grains, spices and dairy products

Answer 15

B. cereus

Question 16

Most important pathogen known to cause food poisoning, “fried rice syndrome” due to improper storage after cooking.

Answer 16

B. cereus

Question 17

Cytotoxic enzymes (cereolysin and phospholipase C) - tissue destruction
Heat stable and heat labile enterotoxin - emetic and diarrheal forms of food poisoning

Answer 17

B. cereus

Question 18

How can Bacillus species be differentiated?

Answer 18

B. cereus agar

Question 19

Resistance to Polymyxin B
Mannitol negative - blue colonies
Lecithinase positive - zone of precipitate around colonies

Answer 19

B. cereus

Question 20

Gram positive spore-forming rods
Found as harmless saprophytes in the soil, water, and sewage
Normal enteric flora of humans and animals
Ability to produce endospores and produce potent exotoxin
Anaerobes but aerotolerant

Answer 20

Clostridium

Question 21

What are the Clostridium species?

Answer 21

C. botulinum - motile
C. perfringens - non-motile
C. difficile - motile
C. tetani - motile

Question 22

Causing gas gangrene and produces toxins and enzymes that lyse blood cells and destroy tissues, leading to soft tissue infections including cellulitis, fasciitis or supportive myositis.

Answer 22

C. perfringens

Question 23

Produces a heat-sensitive enterotoxin that binds to receptors on the epithelium of the small intestine, leading to clostridial food poisoning intense diarrhea

Answer 23

C. perfringens

Question 24

Produces necrotizing enteritis
Necrosis of the intestine, leading to bloody diarrhea, shock, and death

Answer 24

C.perfringens

Question 25

May occur in hospitals
antibiotic associated diarrhea
pseudomembranous colitis
profuse diarrhea, foul-smelling, abdominal cramping, and fever
whitish plaques (pseudomembranes) form over intact colonic tissue
Faecal transplant

Answer 25

C. difficile

Question 26

Toxin A - potent enterotoxin with slight cytotoxic activity
Toxin B - potent cytotoxic (cytopathic)

Answer 26

C. difficile

Question 27

Fastidious, strict anaerobe, spore forming, Gram positive rods
Causative agent of botulism due to food poisoning
Flaccid paralysis - respiratory paralysis is the most common cause of death

Answer 27

C. botulinum

Question 28

• week and dizzy
• blurred vision with fixed and dilated pupil
• diplopia (double vision)
• dysphagia (difficult to swallow), dry mouth
• weakness and inability to breathe
• constipation and abdominal pain
• death due to respiratory paralysis

Answer 28

C. botulinum

Question 29

• classic or food botulism
• wound botulism
• infant botulism (milk powder / honey)
• inhalation botulism

Answer 29

C. botulinum

Question 30

Strict anaerobes and forms bulging spore that appears as drumstick.

Answer 30

C. tetani

Question 31

Tetanospasmin - potent heat labile toxin, prevents the release of neurotransmitter
Tetanolysin - heat stable haemolysin
Neurotoxin

Answer 31

Virulence factor of C. tetani

Question 32

What is the difference between botulinum and tetanus toxin?

Answer 32

botulinum toxin: flaccid paralysis (stops muscle contraction)
tetanus toxin: spastic paralysis (uncontrollable muscle contraction)

Question 33

An increased muscle tone and spasms, caused by the release of a neurotoxin called tetanospasmin

Answer 33

Tetanus

Question 34

A spasm in which the head and heels are bent backwards and the body bowed forward. Deaths results from inability to breathe.

Answer 34

Opisthotonos

Question 35

Seen in newborns when the mother lacks immunity and the umbilical stamp becomes contaminated with C. tetani spores.

Answer 35

Neonatal tetanus

Question 36

Causes lockjaw

Answer 36

C. tetani

Question 37

Gram positive pleomorphic rods, non-motile, and non-sporing that form angles with each other/club shaped, looking like Chinese letters arrangement. Aerobic or facultatively anaerobic

Answer 37

Corynebacterium diphtheria

Question 38

Diptheria toxin (DT) - inhibits protein synthesis

Answer 38

Corynebacterium diphtheria

Question 39

Causes diphteria, an acute upper respiratory illness

Answer 39

Corynebacterium diphtheria

Question 40

Transmitted via airborne, site of infection on the epithelial cells of the tonsils and oropharynx, pathogenesis involves the diphtheria toxin that causes cell damage or death or necrosis and subsequent inflammation leading to thick, gray, adherent pseudomembrane over the tonsil and throat.

Answer 40

Diphtheria infection

Question 41

Bull’s neck, conjunctivitis, severe myocarditis, and pharyngeal membane

Answer 41

Diphtheria

Question 42

Gram positive short rods, singly or in pairs, facultative anaerobes, catalase positive, oxidase negative, and non-sporing. Motile by peritrichous flagella. Capable of growing and reproducing in host cells. Exhibit a narrow zone of Beta-haemolytic on blood agar.

Answer 42

Listeria monocytogenes

Question 43

Cell attachment factors
Haemolysins
A protein that mediates actin-directed intracellular motility

Answer 43

L. monocytogenes virulence factor

Question 44

causes neonatal disease can result in utero death or multiorgan abscesses
causes meningitis and septicemia in patients and pregnant woman with defects in cell-mediated immunity
influenza-like symptoms, and self limited gastroenteritis in healthy adult

Answer 44

L. monocytogenes