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bacterial infections - Coggle Diagram

- - - - located throughout the world
      - mechanism of transmission isn't fully verified
        
        transmission requires. prolonged contact with an infected person
      - not highly virulent; appears tha health and living conditions influence susceptibility and course of the disease
      - Course of Infection and Disease
        
        Macrophages phagocytize the bacilli, but a weakened macrophage or slow T cell response may not kill bacillus
        
        Incubation from 2-5 years; if untreated, bacilli grow slowly in the skin macrophages and Schwann cells of peripheral nerves
        
        2 forms possible:
        
        Tuberculoid
        
        asymmetrical, shallow lesions, damage nerves – results in local loss of pain reception
        
        Lepromatous
        
        a deeply nodular infection that causes severe disfigurement of the face and extremities, widespread dissemination
    - - Combination of symptomology, microscopic examination of lesions, and patient history
      - Numbness in hands and feet, loss of heat and cold sensitivity, muscle weakness, thickened earlobes, chronic stuffy nose
      - Detection of acid-fast bacilli in skin lesions, nasal discharges, and tissue samples
    - - treatment by long-term combined therapy
      - prevention requires constant surveillance of high risk populations
      - WHO sponsoring a trail vaccine.
- - - - b-hemolytic S. pyogenes
        
        Most serious streptococcal pathogen
        
        Strict parasite
        
        Inhabits throat, nasopharynx, occasionally skin
      - Virulence factors
        
        produces surface antigens-
        
        C substance(carbohydrates)- protect against lysosome
        
        Fimbriae- adherence
        
        M-protein-contibutes to resistance to phasecytosis
        
        Capsule-provokes no immune response
        
        Extracellular toxins:
        
        Streptolysins – hemolysins; cause cell and tissue injury
        
        Erythrogenic toxin (pyrogenic) –nduces fever and typical red rash
        
        Superantigens- strong monocyte and lymphocyte stimulants;
        
        extracelylar enzymes
        
        streptokinase-digest fibrin clots
        
        hyalurinidase-breaks down connective tissue
  - - - contact, droplets,food,fomites
    - - children predominant group affected for cutaneous and throat
    - - and progressive sequela possible if untreated
- - - - preventing sebun formation
      - accurate
      - antibiotics
      - benzoyl peroxide to loosen clogged follicles
      - visible(blue)light(kills P. acnes)
- - - - Enzymes
        
        coagulase- coagulates plasma and blood; produced by 97% of human isolates.
        
        Hyaluronidase- digest connective tissue
        
        staphylokinase- digest blood clots
        
        penicillinase- inactivates penicillin
      - Toxins
        
        hemolysins- (α or alpha toxin) – lyse red blood cells
        
        Leukocidin – lyses neutrophils and macrophages
        
        Enterotoxin – induce gastrointestinal distress
        diahrea
        
        Exfoliative toxin – separates the epidermis from the dermis
        
        Toxic shock syndrome toxin (TSST) – induces fever, vomiting, shock, systemic organ damage
    - - Localized cutaneous infections
        
        folliculitis-superficial inflammation of hair follicle
        
        Furuncle-boil;inflamation of hair follicle or sebaceous gland processes into abscess
        
        How to treat it- has to be surgically perforated
        
        carbuncle-deeper and larger lesion created by aggregation and interconnection of cluster of furuncles
        
        impetigo-bubble-like swellings that can break and peel away; common in new borns, very contagious.
      - Systemic infections
        
        osteomyelitis-infection is established in the metaphysis;absess forms
        
        bacteriemia-primary organ is bacteria from infected site or medical devices; endocarditis possible
        
        How to treat- require intensive lengthy therapy
      - Toxigenic diseases
        
        food intoxication-ingestion of heat stable entertains; gastrointestinal distress, upset stomach and the runs.
        
        staphylococcal scalded skin syndrome- toxin induces bright red flush, blisters,then desquamation of epidermis
        
        toxic shock syndrome- toxemia leading to shock and organ failure
      - MRSA – methicillin-resistant S. aureus – carry multiple resistance
        
        Healthcare-associated MRSA (HA-MRSA)-infections occur in people who are or have recently been in a hospital or other health-care facility.
        
        Community-associated MRSA (CA-MRSA) -CA-MRSA is more severe and is increasing in incidence, it’s also taking over the HA-MRSA in the hospitals!
- - - - bacillus anthracis
        
        large, blocked-shaped rods
        
        central spores that develop under all conditions except in the living body
        
        virulence factors
        
        polypeptide capsule and exotoxins
        
        Anthrax forms
        
        Cutaneous anthrax
        
        90% of cases
        
        Endospores enter through minor cut
        
        20% mortality
        
        Gastrointestinal anthrax
        
        Ingestion of undercooked, contaminated food
        
        50% mortality
        
        Inhalational (pulmonary) anthrax
        
        Inhalation of endospores
        
        100% mortality
        
        How to control/treat Anthrax:
        
        cattle routinely vaccinated
        
        treated with ciprofloxacin or doxycycline
        
        vaccines
        
        live spores and toxin to protect livestock
        
        purified taxied; for high risk occupations and military personnel;taxoid 6 intoculations over 1.5 years; annual boosters
      - bacillus cereus
- - - - gangrene -death of soft tissue
        
        gas gangrene- Clostridium perfringens, gram-positive, endospore-forming anaerobic rod, grows in necrotic tissue
        
        predisposing factors- surgical incisions, diabetic ulcers, septic abortions,puncture wounds, gunshot wounds
        
        virulence factors
        
        toxins-
        
        causes RBC rupture, edema, and tissue destruction
        
        collagenase
        
        hyaluronidasee
        
        what happens?
        
        1.Not highly invasive; requires damaged and dead tissue and anaerobic conditions
        
        2.Conditions stimulate spore germination, vegetative growth and release of exotoxins, and other virulence factors
        
        3.Fermentation of muscle carbohydrates results in the formation of gas and further destruction of tissue
        
        How to treat it and prevent it?
        
        Immediate cleansing of dirty wounds, deep wounds, compound fractures, and infected incisions
        
        Debridement of disease tissue
        
        Large doses of cephalosporin or penicillin
        
        Hyperbaric oxygen therapy
        
        No vaccines available