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What Gram Positive Rods are "Non-spore forming?"
What animals/species do Bacillus anthracis affect?
-Herbivorous ANIMALS (sheep, goats, cattle)
-HUMANS (contact with animals)
How do herbivores get Bacillus anthracis?
Herbivores come into contact with the SPORES or BACTERIA in the soil, which can last there for months/years
Describe the pathogenesis of Anthrax
1. Spores are DEPOSITED in skin, respiratory or GI mucosa
2. Spores then GERMINATE in tissues
3. Bacteria MULTIPLY and PRODUCE TOXINS
4. Toxins cause TISSUE NECROSIS
5. Anthrax toxins DISSEMINATE through bloodstream and lymphatics
6. Anthrax causes systemic toxicity and DEATH
What toxins are produced by anthrax?
1. Lethal toxin
2. Edema toxin
CAPSULE blocks phagocytosis and toxins inhibit neutrophil function (oxidative burst) & induce cytotoxic effects
How does Cutaneous Anthrax manifest clinically?
Pruritic papules on exposed skin
-Enlarges over several days, progressing to an ulcer with/without surround vesicles
-CENTER is BLACK and NECROTIC
-EDEMA surrounds the lesion
-Often painless, regional lymphadenopathy
After germination and transport via the lymphatics, where do the Respiratory anthrax spores go to?
Hilar/mediastinal lymph nodes
What are the symptoms of respiratory anthrax?
Substernal pain and cough
Signs of stridor (noisy breathing) on exam
Neck and mediastinal edema
How many phases are there to respiratory anthrax? What are they?
1. Initial phase (1-3 days)
Malaise, fever, dry cough, sub-sternal pain
2. Secondary Phase
Sudden onset, rapid progression to death in 1-2 DAYS!!
Dyspnea, stridor, high fever, diaphoresis
Mortality high, over 90% (difficult to diagnose!)
How is respiratory anthrax diagnosed?
Chest X-ray with Widened mediastinum!
-Bloody pleural tap
-Culture blood, pleural fluid or CSF for Gram Positive Rods
How does Gastrointestinal Anthrax present?
One of TWO forms:
1. Oropharyngeal Anthrax (hard palate, postpharynx)
2. Abdominal Anthrax (Large bowel, cecal lesions)
How do you diagnose someone with Anthrax?
High Clinical Suspicion
-Must be able to recognize clinical syndromes
Bacillus cereus pathogenesis
1. Enzymes destroy tissue
2. Toxins cause diarrhea/emesis
3. Anti-microbial agents produced by bacteria help the bacteria to compete
What are the two types of food poisoning?
1. Emetic form
vomiting predominate feature
2. Diarrhea form
cramps, nausea, watery stools
What are examples of foods that cause the diarrheal form of food poisoning?
Contaminated MEATS (turkey) or VEGETABLES
How long does it take for Bacillus cereus to incubate in the diarrheal form?
10-12 hours, improved in 24
What is the virulence factor that is responsible for Bacillus cereus food poisoning?
How are bacillus ocular infections usually caused?
-Trauma (soil exposure)
-Foreign body (particles of dust, soil or shrapnel)
-IV drug abuse
How long does it take for Bacillus cereus to cause damage to the eye
RAPID: 12-48 hours
-pain, redness, visual changes
What are important Corynebacterial Infections?
1. C. diphtheriae
2. C. jeikeium
3. Arcanobacterium haemolyticum
4. Rhodococcus equi
What does C. jeikeium cause?
Bacteremia in IMMUNOCOMPROMISED PATIENTS/NEUTROPENIA, HOSPITAL ACQUIRED INFECTIONS (IV CATHETERS)
What does C. diptheriae's virulence factor do?
-Inhibits protein synthesis
-Responsible fo tonsilar/pharyngeal exudate that characteristics of diptheri
How is diptheria transmitted?
Transmission through bacteria in AIRBORNE droplets or CONTACT with secretions/exudate
Who is at risk for diptheria today?
Children <15 yo if unvaccinated
Unimmunized or unboosted adolescents/adults (urban poor, those with no access to health care, IV drug users)
What does the diptheria exudate consist of?
Necrotic collection of cells, fibrin, dead respiratory epithelial cells, RBCs, WBCs and bacteria
Besides the exudate, how does someone with diptheria usually present in the clinic?
-Fever, sore throat and membrane development (tonsils, posterior pharynx)
-Cervical lymph nodes common
-Systemic effects on tissues at distant sites
-Cardiac toxicity (myocarditis)
Paralysis of palate, hoarseness or stridor
What general foods can harbor Listeria monocytogenes?
Raw vegetables, raw milk , raw fish, meants and poultry
What are specific examples of foods that can harbor Listeria monocytogenes?
-Unpasteurized soft cheeses
Who is most at risk for Listeria monocytogenes?
-Neonates and elderly
-Impaired cell-mediated immunity, immunosuppressed
What promotes Listeria monocytogenes infection?
-H2 blockers (stomach pH increased)
What is the pathogenesis of Listeria monocytogenes?
-Binds epithelial cells
-Escapes host's ability to kill the organism
What are the clinical diseases caused by Listeria?
4. Neonatal infection
What does Listeria meningitis cause in patients?
Seizures, 30% CSF samples have monocyte predominance
How can Listeria affect neonates?
1. Granulomatosis Infantiseptica
2. Meningitis 2 weeks after birth or immediate Sepsis after delivery
What happens to pregnant women when they get Listeria during prenancy?
Major decline in cell-mediated immunity
How does a human become infected by Erysipelothrix rhusiopathiae?
DIRECT cutaneous contact
-Occupational exposures: fishermen, butchers, veterinarians
What are the 3 clinical syndromes associated with Erysipelothrix rhysiopathiae infection?
1. Erysipeloid skin lesion
2. Diffuse skin rash/systemic
Describe an Erysipeloid skin lesion
Violaceous, raised and well defined lesion, usually associated with lymphadenopathy
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