Cycle of Infection

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Cycle of Infection

• HST I

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Objectives / Rationale

• Infection Control is an increasingly important
  aspect of health care for the client and the
  health care professional.

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• Upon completion of this lesson, the student will
  be able to
• Identify the cycle of the infectious process
• Investigate ways to protect themselves and
  patients from infection and
• Research common human pathogens.

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Infections and diseases are classified as

• Endogenous it originates within. Includes
  metabolic disorders, congenital abnormalities,
  tumors, infections from microorganism within the
  body.
• Exogenous originates outside the body includes
  invading pathogens, radiation, chemical agents,
  trauma, electric shock, temperature extremes.

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• Nosocomial is one that is acquired in a health
  care facility, which is transmitted by health
  care workers to the patient.
• Opportunistic those that occur when the bodys
  defenses are weak i.e. weakened immune system.

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Infections are also

• Aerobic the organism requires oxygen to live.
• Anaerobic the organism lives and reproduces in
  the absences of oxygen.

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Infection Cycle

• Infective Agent pathogens include bacteria,
  viruses, funguses, rickettsiae, protozoa.
• Reservoir where causative agent can live.
  Includes the human body, animals, environment,
  and fomites or objects contaminated with
  infectious material that contains the pathogens.

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• Portal of exit way for causative agent to
  escape from the reservoir.
• Pathogens can leave the body through urine,
  feces, saliva, blood, tears, mucous discharge,
  sexual secretions, draining wounds.

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• Means of transmission how it is transmitted to
  another host.
• By Direct Contact person to person, physical
  contact, or contact with body secretions
  containing the pathogen.
• Indirect Contact from contaminated sources such
  as food, air, soil, equipment, etc.

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• Indirect contact can include touching
  contaminated equipment or surfaces, breathing in
  droplets carrying airborne pathogens, or
  receiving the bite of an insect carrying the
  pathogen.

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• Portal of entry way to enter a new reservoir or
  host.
• Breaks in the skin or mucous membrane
  respiratory tract digestive tract genitourinary
  tract circulatory system.

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• Susceptible host individual who can contract
  the disease, unless
• Defense mechanisms are intact.
• Immune system is functioning.

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The cycle of infection can be broken

• The infectious agent can be neutralized or
  destroyed by treatment.
• The reservoir host must maintain personal
  hygiene.
• The portal of exit is closed by the use of proper
  attire (gowns, gloves, etc), control of body
  secretions, proper handwashing.

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• The route of transmission is minimized through
  proper handwashing, disinfection, sterilization,
  and proper disposal of contaminated materials.
• The portal of entry is blocked by asepsis,
  disinfection, and sterilization procedures.
• Health and wellness of the individual is
  maintained.

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Microorganisms and Disease

• Microorganism an organism that is too small to
  be seen by the human eye.
• Fungi simple plants such as molds and yeasts
• Protozoa only group classified as an animal.
• Virus cannot be seen by ordinary microscope
  not destroyed by antibiotics.

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• Bacteria classification is determined by the
  shape of the bacteria and whether it grows with
  or without oxygen. Only a few, such as
  staphylococcus and streptococcus cause disease.
• Cocci round includes staphylococci which is in
  clusters like grapes causes boils, impetigo and
  osteomyelitis.

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• Cocci also includes streptococci, round bacteria
  arranged in chains causes rheumatic fever,
  streptococcal pneumonia, and scarlet fever.
• Cocci also includes diplococci, arranged in pairs
  causes gonorrhea and meningitis.

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• Bacilla (i) rod-shaped bacteria.
• Spirilla bacteria shaped like spirals.
• Rickettsiae smaller than bacteria barely
  visible under microscope. Causes typhus, Rocky
  Mountain Spotted Fever.
• Pathogen the term for a disease-causing
  microorganism.

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Vocabulary terms

• Sterile means free from all organisms,
  including spores and viruses.
• Contaminated organisms and pathogens are
  present.

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Asepsis the absence of infection

• Medical Asepsis practices and techniques
  designed to protect individuals from the spread
  of disease.
• Antiseptic substances that inhibit the growth
  of bacteria. Some can be used on the skin.
• Disinfectant cannot be used on skin includes
  chemicals and boiling.

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Sterile absence of all microorganisms

• Surgical asepsis the use of sterile technique
  to handle equipment, maintain sterile fields,
  change dressings, and dispose of contaminated
  materials without introducing harmful
  microorganisms.

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Sterilizing with an Autoclave

• The autoclave is the safest, most efficient
  sterilization method.
• An autoclave is a piece of equipment that uses
  steam under pressure or gas to sterilize
  equipment and supplies.
• It will destroy ALL microorganisms, both
  pathogenic and non-pathogenic, including spores
  and viruses.

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Using an autoclave -

• Items that are to remain sterile must be wrapped
  before they are Items are cleaned and prepared
  before being put in autoclave.
• autoclaved.
• Autoclave indicators are used to insure sterility
  of the item.

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Using chemicals for disinfection -

• Since many chemicals do not kill spores and
  viruses, chemicals are not a method of
  sterilization.
• Chemicals are used to disinfect instruments that
  do not penetrate body tissue.
• Examples 90 isopropyl alcohol,
  formaldehyde-alcohol 10 bleach Lysol, Cidex.

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Epidemiology

• Tracing the occurrence of health related events
  in society.
• Epidemiologist a person who specializes in the
  study of outbreaks of diseases within a
  population group.
• Endemic the ongoing presence of a disease
  within a population, group or area. Example the
  common cold.

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• Epidemic a sudden and widespread outbreak of a
  disease within a population, group or area.
  Example a widespread outbreak of measles or
  influenza.
• Pandemic - an outbreak of a disease occurring
  over a large geographic area, possibly worldwide.
  Ex AIDS, H1N1 flu.