ch 14

• Microorganisms


  Small, living organisms that must be viewed under a microscope, found in and on the body
• Classes of Microorganisms


  • Bacteria
  • Fungi
  • Rickettsiae
  • Viruses
  • Helminths
• Bacteria: Cocci


  • Sphere shaped
  • Diplococcus - pairs (Ex: gonorrhea, meningitis, pneumonia)
  • Streptococcus - chains (Ex: strep throat, rheumatic fever)
  • Staphylococcus - clusters (Ex: pus-producing boills, UTIs, wound infections, toxic shock)
• Bacteroa: Bacilli


  • Rod shaped
  • Single, in pairs, or in chains
  • Many have flagella for movement
  • Many have spores to survive harsh conditions
  • Ex: Tuberculosis (TB), Tetanus, Pertussis, Botulism
• Bacteria: Spirilla 


  • Spiral, corkscrew, comma
  • Ex: Syphilis, cholera
• Fungi


  • Live on dead organic matter
• FungiExamples


  • Yeast
  • Mold
  • Ringworm
  • Athlete's foot
  • Thrush
• Rickettsiae


  • Parasites that cannot live outside of host
  • Actually a type of bacteria
  • Found in fleas, ticks, lice, etc.
  • Ex: Typhus fever, rocky mountain spotted fever
• Viruses


  • Not cells, no energy, cannot respond, cannot reproduce on own
  • Composed of genetic material (DNA/RNA) inside capsid (protein coat)
  • Have ability to mutate
  • Ex: Common cold, polio, COVID, influenza, herpes
• Helminths


  • Multicellular parasites (worms & flukes)
  • Transmitted through contaminated food/meat
  • Cause intestinal infections & obstructions
• Helminths


  • Hookworms
  • Ascariasis
• Types of Infections


  • Endogenous
  • Exogenous
  • Nosocomial
  • Opportunistic
• Endogenous infection/disease


  Originates in the body (e.g. metabolic disorders, tumors, congenital abnormalities)
• Exogenous infection/disease


  Originates outside the body (e.g. pathogens, radiation, trauma)
• Nosocomial infection


  Acquired in a healthcare facility, usually from worker to patient (e.g. MRSA, staph infections, surgical infections)
• Opportunistic infection


  Occurs when body defenses are weak (not common in healthy patients) (e.g. Kaposi's sarcoma, pneumonia in individuals with AIDS)
• Asepsis


  Absence of disease-producing microorganisms or pathogens
• Sterile


  Free from ALL organisms (pathogenic and non-pathogenic, spores, and viruses)
• Contaminated


  Organisms and/or pathogens are present
• Levels of Aseptic Control


  • Antisepsis
  • Disinfection
  • Sterilization
• Antisepsis


  To prevent or inhibit growth of pathogens (does not work on spores or viruses, safe to use on skin)
• Disinfection


  Destroys or kills pathogens (may not work on spores or viruses, use on objects, not skin)
• Sterilization


  Destroys ALL microorganisms (use on objects)
• Handwashing


  • Regular
  • Antiseptic
  • Antiseptic Hand Rub
• Handwashing Guidelines


  1. Soap must be used: suds trap pathogrens

  2. Warm water: less damage to skin

  3. Friction: helps remove pathogens

  4. All surfaces cleaned: palms, between fingers, front/back of hands

  5. Fingertips pointed downward: prevents re-contamination of hands

  6. Use dry towel to turn faucet: prevents re-contamination of hands
• Endemic disease


  The amount of a particular disease that is usually present in a community (baseline) (Ex: malaria)
• Epidemic


  A sudden increase in the number of cases of a disease above what is normally expected in that population in a specific area ("outbreak") (Ex: smallpox, cholera)
• Pandemic


  An epidemic that has spread over several countries or continents and affects many people
• Pathogenic 


  cause infection & disease
• Non-pathogenic


  beneficial or non-harmful to the body
• Parasites


  cannot live outside of host
• Regular handwashing 


  plain soap & water, routine cleaning when visibly dirty or soiled
• Antiseptic handwashing 


  antimicrobial soap & water, before invasive procedures, critical care units, care for infectious patients
• Antiseptic hand rub


  hand sanitizer, hands not visibily dirty
• Stage 1: Causative Agent

  • pathogen
  • How to break: early recognition, rapid ID of pathogen
• Stage 2: Reservior

  • where causative agent lives (ex: body, environment, fomite (contaminated surfaces like doorknobs))
  • Break the chain: sanitation, aseptic techniques, disinfection
• Stage 3: Portal of Exit

  • how causative agent escapes reservior (ex: urine, feces, saliva, blood, mucus)
  • Break the chain: personal protective equipment (gloves, masks, etc), handwashing, proper trash/waste disposal
• Stage 4: Mode of transmission

  • How causative agent moves to host/other reservior
  • Break the chain: Proper food handling. sterilization, aseptic techniques, disinfection
• Direct mode of transmission 


  Person to person (ex. touch, intercourse, etc.)
• Indirect mode of transmission 


  Environment to person (ex. food, air, insects, clothing, equipment)