39-Clostridia

Question 1

What are the 4 characteristics of clostridia?

Answer 1

• Gram Positive
• Obligate anaerobes
• Capable of producing endospores – can allow it to survive harsh climates for extended periods
• Rod Shaped

Question 2

C. difficile- diseases

Answer 2

Antibiotic-associated Diarrhea, Pseudomembranous Colitis

Question 3

C. difficile- clinical Sx

Answer 3

Profuse foul smelling green mucoid diarrhea, abdominal cramping, fever, whitish plaques (pseudomembranes) over intact colonic tissue seen on colonoscopy

Question 4

C. difficile- lab tests

Answer 4

Confirmed by detection of cytotoxin or enterotoxin in patients feces

Question 5

C. difficile- epidemiology

Answer 5

Colonize the intestines of 5% of healthy individuals and can overgrow with exposure to antibiotics. Spores can be detected in hospital rooms of infected patients and can be an exogenous source of infection

Question 6

C. difficile- pathogenesis

Answer 6

Enterotoxin attracts neutrophils to infiltrate the ileum and it also disrupts tight cell junction causing diarrhea. Cytotoxin causes the destruction of actin in the cytoskeleton

Question 7

C. perfrigens- diseases

Answer 7

Soft-tissue Infections, Food Poisoning, Enteritis Necroticans, Septicemia

Question 8

C. perfrigens- clinical Sx

Answer 8

Localized edema and erythema with gas formation in the soft tissue, accumulation of pus in muscle planes, rapid destruction of muscle tissue, gastroenteritis, food poisoning, necrotizing destruction of the jejunum with abdominal pain, vomiting, bloody diarrhea and peritonitis

Question 9

C. perfrigens- lab tests

Answer 9

Large gram positive rods that grows rapidly in culture

Question 10

C. perfrigens- epidemilogy

Answer 10

Widely distributed in soil and water contaminated with feces. Spores are formed under adverse environmental conditions and can survive for prolonged periods

Question 11

C. perfrigens- pathogenesis

Answer 11

Organisms multiply rapidly in culture and in patients. Lyse blood cells and destroy tissues, leading to diseases such as overwhelming sepsis, massive hemolysis and myonecrosis. It also produces a enterotoxin that binds to receptors on the small intestine, leading to a loss of fluids and ions

Question 12

C. Septicum- diseases

Answer 12

Gas Gangrene, Septicemia

Question 13

C. septicum- clinical Sx

Answer 13

Associated with sepsis and a high mortality after 1-2 days

Question 14

C. septicum- epidemiology

Answer 14

Exists in patients with occult colon cancer, acute leukemia or diabetes

Question 15

C. septicum- pathogenesis

Answer 15

Causes nontraumatic myonecrosis. If integrity of bowel mucosa is compromises and immunity is down, it can spread into tissue and rapidly proliferate causing tissue destruction

Question 16

C. botulinum- diseases

Answer 16

Botulism

Question 17

C. botulinum- clinical Sx

Answer 17

Blurred vision, dry mouth, constipation, abdominal pain, bilateral descending weakness of peripheral muscles with flaccid paralysis. Respiratory arrent in infants. Inhalation has high mortality.

Question 18

C. botulinum- lab tests

Answer 18

Toxin activity demonstrated in implicated food, patient’s serum, feces or gastric fluid

Question 19

C. botulinum- epidemiology

Answer 19

Spores are found in soil worlwide

Question 20

C. botulinum- pathogenesis

Answer 20

Botulinum toxin prevents release of neurotrasmitter Ach, thus blocking neurotransmission at peripheral cholinergic synapses, leading to a flaccid paralysis

Question 21

C. tetani- diseases

Answer 21

Tetanus

Question 22

C. tetani- clinical Sx

Answer 22

Generalized or localized musculature spasms that have high mortality in neonates

Question 23

C. tetani- lab tests

Answer 23

Microscopy and culture are insensitive, and neither tetanus toxin nor antibodies are typically detected. Diagnosis based on clinical presentation

Question 24

C. tetani- epidemiology

Answer 24

Spores are found in most soils and can colonize the gastrointestinal tracts of humans and animals. Risk is greatest for people with inadequate immunity.

Question 25

C. tetani- pathogenesis

Answer 25

Primary virulence factor is teanospasmin which blocks the release of neurotransmitters for inhibitory synapses