Anaerobes Flashcards by Danielle Himelfarb

What is the proper way to get Anaerobic cultures?

Collect in STERILE manner! Can’t be contaminated with normal flora
(Can’t swab, need aspirate/surgical specimen/biopsy)

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What is the morphology of Peptostreptococcus?

Gram positive cocci

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What is the morphology of Clostridium?

Gram positive rod (spore forming)

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What is the morphology of Actinomyces?

Gram positive rod

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What is the morphology of Lactobacillus?

Gram positive rod

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What is the morphology of Bacteroides?

Gram negative rod

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What is the morphology of Fusobacterium?

Gram negative rod

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What is the morphology of Mobiluncus?

Gram positive rod

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What is the morphology of Propionibacterium?

Gram positive rod

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What diseases are caused by Peptostreptococcus (gram positive cocci)?

Polymicrobial (lots of other bacteria involved)

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What diseases are caused by Actinomyces (Gram pos rod)?

Acinomycosis - chronic lesions associated with abscess

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What is a sign of actinomycosis?

“sulfur granules” in abscess material

- Often get mistaken for malignancies, hard and fibrous

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How does Actinomyces appear in culture?

“molar tooth” colonies

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What is the treatment for Actinomyces?

Penicillin

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What diseases are caused by Lactobacillus?

Septicemia in immunocompromised patients

Endocarditis in persons with underlying valve abnormalities

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What is the treatment for Lactobacillus?

Penicillin or combo with aminoglycoside

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What diseases are caused by Mobiluncus?

Bacterial vaginosis

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What diseases are caused by Propionibacterium?

Acne

Opportunistic infections of prosthetic device

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What is the major virulence factor in Bacteroides fragilis?

Polysaccharide capsule

What diseases are caused by Bacteroides fragilis?

Abscess formation

What is the treatment of Bacteroides fragilis?

Metronidazole

Resistant to penicillins

What is the treatment of Mobiluncus?

Penicillin

Resistant to metronidazole, so probably not cause of bacterial vaginosis since metronidazole treats that

What diseases are caused by Fusobacterium?

Oropharyngeal infections

Gingivitis - trench mouth
Pharyngitis
Jugular venous thrombophleitis - Lemierre’s syndrome

What is Lemierre’s syndrome?

Pharyngitis due to Fusobacterium -> peritonsillar abscess -> spread of bacteria through parapharyngeal spaces -> thrombophlebitis of internal jugular vein
(Clots can embolize)

What is treatment of Fusobacterium?

Beta lactam-beta lactamase inhibitor | Ampicillin-sulbactam

What characterizes Clostridium?

Spore-producing

What is the toxin released by Clostridium tetani?

Tetanospasmin

What is the mechanism of action of Tetanospasmin?

Gets internalized into motor neurons and cleaves proteins necessary for release of inhibitory transmitters Hence, stay in state of excitatory synaptic activity (constant contraction = tetanus)

What are the four forms of tetanus?

Generalized tetanus Localized tetanus Cephalic tetanus Neonatal tetanus

What are some major clinical presentations of tetanus?

Spastic paralysis Trismus (inability to open mouth due to masseter contraction) Opisthotonos (contraction of back muscles) Apnea (contraction of pharyngeal muscles)

What is the treatment for C. tetani?

Metronidazole (don't use Penicillin, can theoretically worsen muscle issues) Vaccination Ventilation support

What diseases are caused by Clostridium botulinum?

Botulism from release of botulinum toxin

What are the forms of botulism?

Foodborne (usually home canned vegetables or fermented tofu) Wound Infant Inhalation (biological weapon)

What is the mechanism of action of botulinum toxin?

Inhibits release of acetylcholine at neuromuscular junctions, so don't get any excitatory input. Results in flaccid paralysis (opposite of tetanus)

What is the major clinical presentation of botulism?

Cranial neuropathies with DESCENDING paralysis (in contrast to Guillain-Barre syndrome caused by Campylobacter), progressing to respiratory failure No major sensory deficits or unresponsiveness (also unlike Guillain-Barre)

What is the treatment of botulism?

Metronidazole Trivalent botulinum antitoxin (anti-A,B,E) to bind circulating toxin Ventilation support

How do Clostridium perfingens colonies appear when plated?

Double zone of hemolysis

What toxins are produced by C. perfingens?

"Lethal" toxins: alpha, beta, epsilon, iota | Enterotoxin

What diseases are caused by Clostridium perfingens?

Food poisoning Soft tissue infections (classically myonecrosis [gas gangrene]) Bacteremia

What is the treatment of Clostridium perfingens?

For serious infection, need surgery and debridement | Penicillin + clindamycin

What toxins are produced by Clostridium difficile?

Enterotoxin | Cytotoxin

What diseases are caused by C. diff?

Range from diarrhea to pseudo-membranous collitis, can progress to toxic megacolon Usually from suppression of normal flora due to antibiotics

Which antibiotics are most commonly implicated in C. diff infection?

CLINDAMYCIN

How does pseudomembranous colitis appear on histo?

Denuded epithelium | Psuedoplaque

How can you test for C. diff infection (not just colonization)?

PCR amplification of toxin genes | Can't do culture

What is the treatment for C. diff colitis?

Metronidazole + vancomycin