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