Unit 11: Anaerobes GPB Spores

Clostridium

Anaerobic / Microaerophilic Gram positive bacilli that most produce spores anaerobically and some exotoxins pathogenic to man, often found in wounds.

C. botulinum

Causes Botulism, is world-wide in distribution (soil), and is characterized as Gram positive bacilli that are straight rods occurring singly or in pairs with spores usually subterminal, resembling a 'tennis racket'.

Clostridium botulinum

A strict anaerobe that cannot tolerate oxygen, is lipase positive, associated with food poisoning, and produces a neurotoxin which is an exotoxin.

Botulism

A deadly food poisoning caused by the ingestion of a very potent heat-labile toxin produced by Clostridium botulinum, leading to respiratory paralysis.

Infant botulism

Occurs when Clostridium botulinum makes the toxin inside the baby's body, with symptoms that appear slowly and worsen gradually.

Symptoms of Infant Botulism

Include constipation (usually first sign), listlessness, difficulty in sucking and swallowing, altered cry, muscle weakness, and a 'floppy' appearance.

Clostridium tetani

Causes Tetanus 'lock-jaw', is widely distributed in nature, especially in cultivated soil, and shows a Gram positive bacilli appearance in stain but may appear Gram-negative after 24 hours of incubation.

Tetanus

A condition caused by Clostridium tetani characterized by constant skeletal muscle contraction, leading to respiratory failure if untreated.

Clostridium perfringens

Now called Clostridioides perfringens, it is the most common Clostridia encountered in labs, characterized by straight parallel sides and box car shaped Gram positive bacilli.

Myonecrosis

Known as gas gangrene, it is a rapid tissue death and gas production in infected areas caused by Clostridium perfringens.

Double zone of hemolysis

A characteristic of Clostridium perfringens observed in culture media.

Reverse CAMP test

A test that is positive for Clostridium perfringens and Beta Strep Group B.

C. difficile

A species of Clostridium that is pathogenic and often associated with antibiotic-associated diarrhea.

C. tetani spores

Oval and terminal or subterminal with a drumstick or tennis racket appearance.

Immunization for Tetanus

Prevention of Tetanus through booster shots given every ten years, known as Tdap.

Clostridium botulinum spores

Can be airborne and sometimes find their way into foods that will be placed in anaerobic storage such as cans or jars.

Anti-toxin for Botulism

Must be administered quickly for any chance of survival in cases of botulism.

Respiratory arrest in Infant Botulism

Can occur and may require respiratory therapy; a small number of infants have died from this condition.

What is Infant Botulism

The most common source of spores that germinate in a child's intestinal tract (from honey)

C. perfringens exotoxins

Many strains produce exotoxins responsible for myonecrosis infections in wounds and food poisoning.

Ana-BAP

A type of culture medium where Clostridium species can be observed, showing specific characteristics such as color and hemolysis.

Clostridioides difficile

A bacterium that causes antibiotic-associated pseudomembranous colitis, characterized by severe diarrhea, dehydration, and fever.

CCFA Medium

A culture medium used for the selective growth of C. difficile, containing antibiotics that inhibit normal fecal flora.

Toxins produced by C. diff

Enterotoxin-Toxin A and Cytotoxin-Toxin B

Gold Standard for C. diff

Cytotoxic Assay: A test used to detect the cytotoxins produced by Clostridioides difficile.

When do patients become susceptible to C. diff

Patients who are at risk for C. difficile infection, often due to long-term antibiotic therapy.

Bacteroides fragilis group

The most isolated anaerobe in clinical labs, known for causing abscesses and tissue destruction.

Bacteroides fragilis group reactions

Includes growth in 20% bile, hydrolyzing esculin, and being catalase positive or negative.

Prevotella

A genus of pigmented saccharolytic gram-negative bacilli that ferment glucose and are part of the normal flora.

Prevotella melaninogenica

A species within the Prevotella genus that is bile sensitive and produces brown/black pigment.

Fusobacterium

A genus of non-spore forming, strict anaerobes with spindle-shaped cells.

Fusobacterium nucleatum

The most common species of Fusobacterium, often involved in pleuropulmonary infections.

Fusobacterium necrophorum

A species associated with virulent infections, including septicemia and abscesses.