Clostridium (Histotoxic/enterotoxic)

Front 1

What is the gram stain, oxygen requirements, or clostridium?

Back 1

They are anaerobic, gram positive, spore forming rods

Front 2

What are the important histolytic and enterotoxic species of clostridium?

Back 2

Histolytic: C. perfringers and C. difficile; Enterotoxic: C. perfringens

Front 3

Describe the locations where clostridium perfringens is commonly found

Back 3

In the soil, and occasionally in the intestinal tract of humans and animals

Front 4

What phrase is commonly given to describe the appearance of clostridium perfringens?

Back 4

They are big, thick, square bacteria that are often referred to as "box-car"

Front 5

What is significant about the growth of C. perfringens?

Back 5

They produce a large amount of gas during growth that has a foul odor

Front 6

Which strain type of C. perfringens is the major pathogen and which toxin does it produce?

Back 6

The type A strain is the most common human pathogen; it produces the alpha toxin

Front 7

Describe the alpha toxin of C. perfringens

Back 7

It is a phospholipase C which degrades membranes and kills phagocytic, tissue, muscle, and red blood cells

Front 8

Describe the transmission of C. perfringens

Back 8

It can be transmitted by exogenous or endogenous traumatic or non-traumatic infections

Front 9

Describe the exogenous transmission of C. perfringens

Back 9

It commonly occurs from a wound contaminated with dust and dirt from the environment

Front 10

Describe a endogenous traumatic transmission of C. perfringens

Back 10

The intestinal bacteria escapes to other body sites following trauma

Front 11

Describe non-traumatic transmission of C. perfringens

Back 11

It results from the spread of bacteria from the intestinal tract to tissue, peritoneal cavity, and bloodstream

Front 12

What are the two major clinical manifestations of clostridium perfringens?

Back 12

Anaerobic cellulitis and myconecrosis

Front 13

What is anaerobic cellulitis?

Back 13

Germination of spores in anaerobic tissue with growth or spread of bacteria from intestinal tract via bloodstream showing LOCALIZATION and LITTLE INVASION into healthy tissue

Front 14

What is myconecrosis?

Back 14

Germination of spores in anaerobic tissue with spread of bacteria from the intestines showing a NECROTIZING INVASION with production of the alpha toxin; produces a lot of gas

Front 15

What is the best method for diagnosing a C. perfringens infection?

Back 15

Gram stain and anaerobic culture with beta hemolysis on blood agar showing two zones of hemolysins

Front 16

How does a food poisoning by C. perfringens occur?

Back 16

Ingestion of food contaminated with a mixture of organism and the enterotoxin; the organism then produces more enterotoxin in the small bowel

Front 17

What are the symptoms of a clostridium perfringens food poisoning and what is the cause?

Back 17

Diarrhea and fever of short duration are caused by the enterotoxin which stimulates fluid secretion in the intestines

Front 18

What is the cause of pseudomembranous colitis?

Back 18

C. difficile

Front 19

What toxins are produced by C. difficile and how do they work?

Back 19

Toxin A and Toxin B act on intestinal epithelial cells by inhibiting intracellular signaling leading to fluid accumulation, cell death and inflammation

Front 20

What is the significance of the new NAP1 strains of C. difficile?

Back 20

It produces 20 times more of both Toxin A and B and also secretes another toxin called the binary toxin

Front 21

Describe the normal habitats of C. difficile

Back 21

It is found widely distributed in soil and water and as normal flora in infants and a small percentage of healthy adults and those hospitalized

Front 22

How is C. difficile transmitted?

Back 22

It is commonly transmitted as normal flora that overgrows after antibiotic treatment or after the new acquisition of a new strain from the soil, animals, or other people

Front 23

How is antibiotic resistant C. difficile that causes severe disease transmitted?

Back 23

These types are more commonly transmitted via person-person contact and is more likely to be newly acquired strains

Front 24

What are the symptoms of a classical C. difficile infection?

Back 24

Symptoms range in severity from a mild diarrhea to severe, fatal diarrhea and colitis

Front 25

What are risk factors for acquiring a classical D. difficile infection?

Back 25

Recent antibiotic use, long length of stay in a hospital, increasing age, and serious underlying illness

Front 26

What are some characteristics of the new antibiotic resistant severe forms of C. difficile infection?

Back 26

They are resistant to fluoroquinolones and produce higher amounts of A and B toxins along with the production of new toxins; strains can be community acquired and can occur in young, healthy people

Front 27

Describe the clinical manifestations of a C. difficile infection

Back 27

Symptoms appear 3-4 days after infection with pseudomembrane formation, cramps, fever, and mild to severe diarrhea

Front 28

Describe the pathogenesis of a C. difficile infection

Back 28

It adheres to the colonic mucosa and produces toxins causing inflammation and destruction of the epithelium; ulceration can occur if histotoxic

Front 29

What is the best way to diagnose C. difficile infection?

Back 29

Antigen detection kit testing for the A/B toxins in the stool and findings of a pseudomembrane formation

Front 30

What drugs are used to treat C. difficile?

Back 30

Metronidazole and vancomycin (reserved for severe disease)

Front 31

How is the normal flora established after a C. difficile infection caused by antibiotic therapy?

Back 31

Probiotics are given as well as fecal transplantation

Front 32

What antibiotics commonly cause induction of a C difficile infection?

Back 32

Clindamycin, ampicillin/amoxicillin, cephalosporins, and fluoroquinolones