Ch. 19
Bacillus cereus
Common airborne and dust-borne; usual methods of disinfection and antisepsis are ineffective Grows in foods, spores survive cooking and reheating Ingestion of toxin-containing food causes nausea, vomiting, abdominal cramps, and diarrhea; 24-hour duration No treatment Increasingly reported in immunosuppressed
- polypeptide capsule and exotoxins (edema,cell death)
Bacillus anthracis Virulence factors
Bacillus cereus,
Bacillus; cause of one type of food poisoning
1. Gram-positive, endospore-forming, motile rods 2. Mostly saprobic 3. Aerobic and catalase positive 4. Versatile in degrading complex macromolecules 5. Source of antibiotics 6. Primary habitat is soil -2 species : anthracis & cereus,
General Characteristics of the Genus Bacillus
Non-acid-fast -Corynebacterium -Propinonibacterium Acid-fast -Mycobacterium Filamentous branching cells -Actinomyces -Nocardia
Gram-Positive Bacilli Irregular shape and staining properties
- Corynebacterium - Propionibacterium - Mycobacterium -Actinomyces -Nocardia
Gram-Positive Irregular Non-Spore- Bacilli Irregular: pleomorphic, Medically important genera:
Listeria monocytogenes Erysipelothrix rhusiopathiae
Gram-Positive Regular Non-Spore- Forming Bacilli Regular: stain uniformly and do not assume pleomorphic shapes Medically important:
Aerobic or facultative anaerobes -Bacillus Obligate anaerobes - Clostridium
Gram-positive rods Endospore formers
Regular shape and staining properties -Listeria -Erysipelothrix
Gram-positive rods Non-endospore formers
dirty wounds, deep wounds, compound fractures, & infected incisions Debridement cephalosporin/penicillin Hyperbaric oxygen No
Immediate cleansing of _____, _____, _____, & ______ _____of disease tissue Large doses of _____ or _____ _____ _____therapy ___ vaccines available
anaerobic cellulitis,
In _____ _____ the bacteria spread within damaged necrotic muscle tissue, producing toxins and but the infection remains gas, localized
Bacillus anthracis
Large, block-shaped angular nonmotile rods (3-5 um long and 1-1.2 um wide) Central spores that develop under all conditions except in the living body
ability to replicate in the cytoplasm of cells after inducing phagocytosis; avoids humoral immune system
Listeria monocytogenes Virulence attributed to
-Non-spore-forming gram-positive -Ranging from coccobacilli to long filaments -1-4 flagella and lack capsules -Resistant to cold, heat, salt, pH extremes, and bile
Listeria monocytogenes characteristics
- - Endospore-formers - - Non-endospore-formers - Irregular shaped and staining properties
Medically Important Gram-Positive Вacilli Can be subdivided into three general groups, based on presence or absence of endospores and acid-fastness Three general groups:
gram- positive,motile, rod- shaped
Most endospore-forming bacteria are ______,_____,______,forms in the genera Bacillus and Clostridium Resistant to heat, drying, radiation, and chemicals, factor for survival, longevity, ecological niche, and pathogenicity of sporeformers
Pos/neg
Motility Clostridium botulinum
Pos/neg
Motility Clostridium difficile
Neg
Motility Clostridium perfringens
Pos
Motility Clostridium tetani
Tetanus,
Neuromuscular disease due to an early effect of the disease on the jaw muscle Produced by Clostridium tetan Spores usually enter the body through accidental puncture wounds, burns, the umbilicus, frostbite, and crushed body parts Anaerobic environment is required for vegetative cells to grow and release toxin
Strict anaerobe
Oxygen Requirements Clostridium botulinum
Strict anaerobe
Oxygen Requirements Clostridium difficile
Strict anaerobe
Oxygen Requirements Clostridium perfringens
Strict anaerobe
Oxygen Requirements Clostridium tetani
Leprosy
Pathogenic Gram-Positive Bacilli Skin/Skeletal Mycobacterium leprae
Septicemia
Pathogenic Gram-Positive Bacilli Cardiovascular/ Lymphatic/Systemic Listeria monocytogenes
Leprosy (lepromatous)
Pathogenic Gram-Positive Bacilli Cardiovascular/ Lymphatic/Systemic Mycobacterium leprae
Extrapulmonary tuberculosis
Pathogenic Gram-Positive Bacilli Cardiovascular/ Lymphatic/Systemic Mycobacterium tuberculosis
Food poisoning
Pathogenic Gram-Positive Bacilli Gastrointestinal Bacillus cereus
C. difficile- associated disease
Pathogenic Gram-Positive Bacilli Gastrointestinal Clostridium difficile
Food poisoning (mild)
Pathogenic Gram-Positive Bacilli Gastrointestinal Clostridium perfringens
Diarrhea
Pathogenic Gram-Positive Bacilli Gastrointestinal Listeria monocytogenes
Botulism (wound, infant, and food- borne)
Pathogenic Gram-Positive Bacilli Nervous/Muscle Clostridium botulinum
Gas gangrene (myonecrosis)
Pathogenic Gram-Positive Bacilli Nervous/Muscle Clostridium perfringens
Tetanus
Pathogenic Gram-Positive Bacilli Nervous/Muscle Clostridium tetani
Meningitis (in immunocompromised hosts)
Pathogenic Gram-Positive Bacilli Nervous/Muscle Listeria monocytogenes
Leprosy (tuberculoid)
Pathogenic Gram-Positive Bacilli Nervous/Muscle Mycobacterium leprae
Recurrent tuberculosis
Pathogenic Gram-Positive Bacilli Nervous/Muscle Mycobacterium tuberculosis
Diphtheria
Pathogenic Gram-Positive Bacilli Respiratory Corynebacterium diphtheriae
Pulmonary anthrax
Pathogenic Gram-Positive Bacilli Respiratory Bacillus anthracis
Sore throat
Pathogenic Gram-Positive Bacilli Respiratory Listeria monocytogenes
Primary tuberculosis
Pathogenic Gram-Positive Bacilli Respiratory Mycobacterium tuberculosis
Cutaneous anthrax
Pathogenic Gram-Positive Bacilli Skin/Skeletal Bacillus anthracis
Wound botulism
Pathogenic Gram-Positive Bacilli Skin/Skeletal Clostridium botulinum
Gas gangrene (myonecrosis)
Pathogenic Gram-Positive Bacilli Skin/Skeletal Clostridium perfringens
Cutaneous diphtheria
Pathogenic Gram-Positive Bacilli Skin/Skeletal Corynebacterium diphtheriae
Erysipelas
Pathogenic Gram-Positive Bacilli Skin/Skeletal Erysipelothrix rhusiopathiae
Acne
Pathogenic Gram-Positive Bacilli Skin/Skeletal Propionibacterium acne
Local infection Diphtherotoxin production and toxemia
Pathology of Diphtheria Two stages of disease:
1. Gram-positive, spore-forming rods 2. Anaerobic and catalase negative 3. 120 species with oval or spherical spores produced only under anaerobic conditions 4. Synthesize organic acids, alcohols, and exotoxins 5. Cause wound infections, tissue infections, and food intoxications
The Genus Clostridium
C
The action of the botulinum toxin is on the: A. Spinal nerves B. Cerebellum C. Neuromuscular junction D. Smooth Muscle
B.
Which of the following is the mode of transmission for Bacillus cereus? A. Inhalation B. Ingestion C. Entry through wounds D. Sexual Contact
True myonecrosis
_____ _____ is more destructive, extensive, mimics some aspects of necrotizing fasciitis
Clostridium botulinum
rare but severe intoxication usually from home canned food
anthrax: Cutaneous
spores enter through skin, black sore- eschar; least dangerous
Bacillus anthracis,
cause of anthrax
Infant botulism
caused by ingested spores that germinate and release toxin Most common type of botulism in the United States, with ~80 to 100 cases reported annually Immature state of the neonatal intestine and resident microbiota allows the spores to gain a foothold, germinate, and produce neurotoxin Results in baby flaccid paralysis "floppy baby syndrome"
Endospore
dense survival unit that develops in a vegetative cell in response to nutrient deprivation
anthrax: Gastrointestinal
ingested spores. Rare, lethal
Botulism
intoxication associated with inadequate food preservation
Clostridium perfringens
mild intestinal illness; second most common form of food poisoning worldwide
Listeriosis
most cases associated with dairy products, poultry, and meat Often mild or subclinical in normal adults Immunocompromised patients, fetuses, and neonates; affects brain and meninges 20% death rate
Clostridium perfringens
most frequent clostridia involved in soft tissue and wound infections Spores found in soil, human skin, intestine, and Predisposing factors - surgical incisions, compound fractures, diabetic ulcers, septic abortions, puncture wounds, gunshot wounds
Tetanospasmin
neurotoxin causes paralysis by binding to motor nerve endings; blocking the release of neurotransmitter for muscular contraction inhibition; muscles contract uncontrollably Death most often due to paralysis of respiratory muscles
anthrax: Pulmonary
-inhalation of from animal spores products or soil
Clostridium botulinum
-spore-forming anaerobe; commonly inhabits soil and water -Spores are present on food when gathered and processed -If reliable temperature and pressure are not achieved air will be evacuated but will spores remain -Anaerobic conditions favor spore germination and vegetative growth Potent toxin, botulinum toxin, is released
Cutaneous Pulmonary Gastrointestinal
3 types of anthrax:
neuromuscular junctions acetylcholine,
Botulinum toxin is carried to _____ _____and blocks the release of _____for muscle contraction necessary to occur Double or blurred vision, difficulty swallowing, neuromuscular symptoms
Clostridial Gastroenteritis
Caused by Clostrium perfringens Spores contaminate food that has not been cooked thoroughly enough Spores germinate and multiply When consumed, toxin is produced in the intestine; acts on epithelial cells, acute abdominal pain, diarrhea, and nausea Rapid recovery
Alpha toxin (RBC rupture, edema, and tissue destruction) Collagenase Hyaluronidase DNase
Clostridium perfringens Virulence factors : (4)
clindamycin, doxycycline, or ciprofloxacin Raxibacumab, Live spores, toxoid Purified toxoid (Biothrax);
Control and Treatment of Anthrax Treated with _____, _____,or _____ Antibiotics are given along with a second drug, _____ that uses monoclonal antibodies that bind one of the toxins and prevent its entry to cells Vaccines _____ _____ & _____to protect livestock _____ for high risk occupations and military personnel; toxoid 6 inoculations over 1.5 years; annual boosters
cold ELISA, immunofluorescence, DNA analysis Ampicillin, trimethoprim/ sulfamethoxazole pasteurization, cooking
Diagnosis and Control of Listeriosis Culture requires lengthy _____ enrichment process Rapid diagnostic tests using ____, _____, and___ _____ _____and _____/_____ Prevention - _____and_____
Pseudomembrane & swelling indicative Stains Conditions, history Serological assay
Diagnostic Methods for Corynebacterium
Food poisoning
Disease In Humans Bacillus cereus
Botulism
Disease In Humans Clostridium botulinum
Antibiotic-associated colitis
Disease In Humans Clostridium difficile
Gas gangrene ;Food poisoning (mild)
Disease In Humans Clostridium perfringens
Tetanus
Disease In Humans Clostridium tetani
Vaccines for high risk
Spore-Forming Pathogens Differentiation Treatment Pulmonary anthrax
Cutaneous ,Pulmonary ,Gastrointestinal anthrax
Spore-Forming Pathogens Differentiation Disease In Humans Bacillus anthracis
Neg
Spore-Forming Pathogens Differentiation Motility Bacillus anthracis
Pos
Spore-Forming Pathogens Differentiation Motility Bacillus cereus
Aerobe
Spore-Forming Pathogens Differentiation Oxygen Requirements Bacillus anthracis
Facultative anaerobe
Spore-Forming Pathogens Differentiation Oxygen Requirements Bacillus cereus
Antibiotics
Spore-Forming Pathogens Differentiation Treatment Bacillus anthracis
Corynebacterium diphtheriae
Straight or somewhat curved rod that tapers at the ends with many pleomorphic variants Reservoir of healthy carriers; potential for diphtheria always present Acquired via respiratory droplets from carriers or infected individuals
None; disease self-limiting
Treatment Bacillus cereus
Antitoxin
Treatment Clostridium botulinum
Withdrawal of antibiotics; administration of probiotics; fecal microbiota transplant
Treatment Clostridium difficile
Debridement; antibiotics; oxygen therapy
Treatment Clostridium perfringens Gas gangrene
None; disease self-limiting
Treatment Clostridium perfringens Food poisoning (mild)
Vaccination; passive immunization
Treatment Clostridium tetani
Antibiotics
Treatment Gastrointestinal anthrax
toxin antitoxin; penicillin
Treatment and Prevention of Botulism Determine presence of _____of in food, intestinal presence contents or feces Administer _____;cardiac and respiratory support Infectious botulism treated with _____ Practice methods of preserving and proper handling canned foods; addition of preservatives
broad- spectrum antibiotics Mild cases Severe infections
Treatment and Prevention of CDI Antibiotic-associated colitis -Relatively non-invasive; treatment with _____ _____ _____kills the other bacteria, allowing C. difficile to overgrow _____ _____respond to fluid and electrolyte replacement and withdrawal of antimicrobials _____ _____treated with oral vancomycin or metronidazole and replacement cultures
toxemia & infection Antitoxin therapy ; human tetanus immune globulin (TIG); penicillin/tetracycline; 10
Treatment and Prevention of Tetanus Treatment aimed at deterring degree of _____ and _____and maintaining homeostasis _____ _____with _____ _____ _____ _____inactivates circulating toxin but does not counteract that which is already bound Control infection with _____or _____and muscle relaxants Vaccine available; booster needed every ___ years
Clostridium botulinum & perfringens
Two Clostridium species are involved in food poisoning
anaerobic cellulitis, True myonecrosis
Two forms of identified: gas gangrene
Local infection by Corynebacterium diphtheriae
Upper respiratory tract inflammation (primary infection) Sore throat, nausea, vomiting, swollen lymph nodes Pseudomembrane formation can cause asphyxiation
