Bacillus

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Bacillus

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~ 60 species; Gram-positive or Gram-variable bacilli Large (0.5 x 1.2 to 2.5 x 10 um) Most are saprophytic contaminants or normal flora Bacillus anthracis is most important member Produce endospores Aerobic or facultatively anaerobic Catalase positive (most) Rapidly differentiates from Clostridium Bacillus spp. are ubiquitous Soil, water, and airborne dust Thermophilic ( < 75°C) and psychrophilic (> 5-8°C) Can flourish at extremes of acidity & alkalinity (pH 2 to 10) General Characteristics of Bacillus

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Diseases Associated with Bacillus

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On blood agar Large, spreading, gray-white colonies, with irregular margins Many are beta-hemolytic (helpful in differentiating various Bacillus species from B. anthracis ) Spores seen after several days of incubation, but not typically in fresh clinical specimens Laboratory Characteristics of Bacillus

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Bacillus anthracis

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Summary of B. anthracis Infections

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Summary of B. anthracis Infections (cont.)

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Epidemiology of Bacillus anthracis Rare in the US (1974-1990, 17 cases reported by CDC) Enzootic in certain foreign countries (e.g., Turkey, Iran, Pakistan,and Sudan) Anthrax spores infectious for decades Biologic warfare experiments (annual tests for 20 years) Gruinard, off western coast of Scotland 4 x 10e14 fully virulent spores exploded Eliminated in 1987 (formaldehyde & seawater) Three well-defined cycles Survival of spores in the soil Animal infection Infection in humans

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Epidemiology of Bacillus anthracis (cont.) Primarily a disease of herbivorous animals Most commonly transmitted to humans by direct contact with animal products (e.g., wool and hair) Also acquired via inhalation & ingestion Increased mortality with these portals of entry Still poses a threat Importing materials contaminated with spores from these countries (e.g., bones, hides, and other materials) Usually encountered as an occupational disease Veterinarians, agricultural workers

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Epidemiology of Anthrax in Animal and Human Hosts

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Clinical Presentation of Anthrax Cutaneous Anthrax 95% human cases are cutaneous infections 1 to 5 days after contact Small, pruritic, non-painful papule at inoculation site Papule develops into hemorrhagic vesicle & ruptures Slow-healing painless ulcer covered with black eschar surrounded by edema Infection may spread to lymphatics w/ local adenopathy Septicemia may develop 20% mortality in untreated cutaneous anthrax

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Clinical Presentation of Anthrax Inhalation Anthrax Virtually 100% fatal (pneumonic) Meningitis may complicate cutaneous and inhalation forms of disease Pharyngeal anthrax Fever Pharyngitis Nneck swelling

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Clinical Presentation of Anthrax Gastrointestinal (Ingestion) Anthrax Virtually 100% fatal Abdominal pain Hemorrhagic ascites Paracentesis fluid may reveal gram-positive rods

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Treatment & Prophylaxis Treatment Penicillin is drug of choice Erythromycin, chloramphenicol acceptable alternatives Doxycycline now commonly recognized as prophylactic Vaccine (controversial) Laboratory workers Employees of mills handling goat hair Active duty military members Potentially entire populace of U.S. for herd immunity

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Characteristic Bacillus anthracis Other Bacillus spp. Hemolysis Neg Pos Motility Neg Pos (usually) Gelatin hydrolysis Neg Pos Salicin fermentation Neg Pos Growth on PEA blood agar Neg Pos Key Characteristics to Distinguish between B. anthracis & Other Species of Bacillus

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Bacillus cereus

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Summary of B. cereus Infections

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Summary of B. cereus Infections (cont.)

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Gram-Variable Stain of B. cereus with Endospores

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Foodborne Diseases of B. cereus (Intoxication) (Foodborne Infection)

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Bacillus thurigensis BT corn; Other GMO’s (genetically modified organisms) Bacillus stearothermophilus Spores used to test efficiency of killing in autoclaves Other Bacillus spp.

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REVIEW Bacillus

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~ 60 species; Gram-positive or Gram-variable bacilli Large (0.5 x 1.2 to 2.5 x 10 um) Most are saprophytic contaminants or normal flora Bacillus anthracis is most important member Produce endospores Aerobic or facultatively anaerobic Catalase positive (most) Rapidly differentiates from Clostridium Bacillus spp. are ubiquitous Soil, water, and airborne dust Thermophilic ( < 75°C) and psychrophilic (> 5-8°C) Can flourish at extremes of acidity & alkalinity (pH 2 to 10) General Characteristics of Bacillus REVIEW

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Diseases Associated with Bacillus REVIEW

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Review of Bacillus anthracis REVIEW

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Bacillus anthracis REVIEW

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Summary of B. anthracis Infections REVIEW

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Summary of B. anthracis Infections (cont.) REVIEW

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Epidemiology of Anthrax in Animal and Human Hosts REVIEW

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Clinical Presentation of Anthrax Cutaneous Anthrax 95% human cases are cutaneous infections 1 to 5 days after contact Small, pruritic, non-painful papule at inoculation site Papule develops into hemorrhagic vesicle & ruptures Slow-healing painless ulcer covered with black eschar surrounded by edema Infection may spread to lymphatics w/ local adenopathy Septicemia may develop 20% mortality in untreated cutaneous anthrax REVIEW

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Clinical Presentation of Anthrax Inhalation Anthrax Virtually 100% fatal (pneumonic) Meningitis may complicate cutaneous and inhalation forms of disease Pharyngeal anthrax Fever Pharyngitis Nneck swelling REVIEW

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Clinical Presentation of Anthrax Gastrointestinal (Ingestion) Anthrax Virtually 100% fatal Abdominal pain Hemorrhagic ascites Paracentesis fluid may reveal gram-positive rods REVIEW

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Treatment & Prophylaxis Treatment Penicillin is drug of choice Erythromycin, chloramphenicol acceptable alternatives Doxycycline now commonly recognized as prophylactic Vaccine (controversial) Laboratory workers Employees of mills handling goat hair Active duty military members Potentially entire populace of U.S. for herd immunity REVIEW

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Review of Bacillus cereus REVIEW

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Summary of B. cereus Infections REVIEW

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Summary of B. cereus Infections (cont.) REVIEW

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Foodborne Diseases of B. cereus (Intoxication) (Foodborne Infection) REVIEW