chapter 28 infection and control (learning)

• The relationship between the infection chain and transmission of infection


  Select an intervention to prevent infection for each element of the infection chain
• Infection chain


  The process of how an infection spreads
• Transmission


  Part of the infection chain that explains how germs get around
• Interventions to prevent infection for each element of the infection chain

  • Disinfecting surfaces for infectious agent
  • Control or eliminate sources of bodily fluids for reservoir
  • Standard precautions, proper management with catheters and drainage sets for portal of exit
  • Handwashing for mode of transmission
  • Standard precautions, proper management with catheters and drainage sets for portal of entry
  • Updated vaccines for susceptible host
• Normal defenses of the body against infection


  • Normal flora
  • Body system defenses
  • Inflammation
• Inflammatory response


  1. Cellular response to body injury, infection and irritation

  2. Positive vascular reaction delivering nutrients and blood products to area of injury

  3. Signs of inflammation: redness, swelling, heat, pain

  4. Swelling causes pressure on nerve endings

  5. Platelets form mesh to prevent spread of infection

  6. Tissue repair occurs
• Healthcare-associated infections increase the cost of healthcare, especially in older adults due to chronic disease and aging
• Outcomes of healthcare-associated infections include extended stays, increased disability, increased antibiotic costs, and prolonged recovery times
• Cues from patients most at risk for infection

  • Age
  • Sex
  • Stress
  • Nutritional status
  • Clinical appearance
  • Laboratory data
  • Travel history
  • Medications
  • Risk factors
  • Trauma
• Localized infection


  Involves traumatic wounds, pressure injuries and oral lesions
• Systemic infection


  More generalized with symptoms of nausea, fever and vomiting
• Medical asepsis


  Some microorganisms are killed through hand washing, clothing and linens (sanitation, good hygiene)
• Surgical asepsis


  All germs are killed and eliminated through sterile technique (autoclave)
• Antisepsis


  Using things like rubbing alcohol and iodine to kill microorganisms on the skin
• Standard precautions need to be used for all patients (non-infected and infected) to prevent infection transmission
• Isolation categories


  • Airborne precautions (diseases transmitted by smaller droplets, e.g. measles, chickenpox, TB)
  • Droplet precautions (diseases transmitted by larger droplets, e.g. influenza, streptococcus, mumps)
  • Contact precautions (direct and indirect contact with patients and environment, e.g. MRSA, shigella, scabies)
  • Protective environment (for highly susceptible patients, e.g. stem cell transplant)
• Infection control in the home

  Patients and caregivers lack knowledge on infection control and prevention techniques
• Infection control in the hospital

  Guidelines and efforts to prevent the spread of infection
• Postexposure process for healthcare workers after hepatitis exposure


  Exposed employee must fill out incident report and seek medical attention
• Proper procedure for hand hygiene

  Turn on water, put soap on hands, scrub hands for 20 seconds, dry hands and use napkin to turn off water
• Proper procedure for applying PPE

  Wash hands, put on gown, then mask, then glasses (if needed), then gloves
• Infection


  A pathogen invades tissue and begins to grow within a host
• Colonization


  Presence and growth of microorganisms within a host but without tissue invasion or damage
• Symptomatic


  Individuals have developed symptoms
• Asymptomatic


  Individuals never develop symptoms
• Infectious agents


  • Bacteria
  • Viruses
  • Fungi
  • Protozoa
• Reservoir


  Where the germs live (humans, animals, insects, water, food, healthcare workers, their hands, patients, equipment)
• Aerobic bacteria


  Require oxygen for survival, cause more infections in humans than anaerobic
• Anaerobic bacteria


  Thrive with little to no oxygen
• Portal of exit


  How germs get out (blood, skin, mucus membranes, cuts, respiratory tract, urinary tract, gastrointestinal tract, reproductive tract)
• Modes of transmission


  • Direct (person-to-person, fecal-oral)
  • Indirect (needles, sharp objects, soiled linen, dressings, environment)
  • Droplet (infected person coughs/sneezes, germs land on eyes/nose/mouth)
  • Airborne (organisms carried in droplet or residue, suspended in air)
• Portal of entry


  How germs get in
• Host


  Sick person
• Stages of infection course

  • Incubation period (no symptoms)
  • Prodromal stage (mild symptoms appear)
  • Period of illness (fulminant illness)
  • Period of decline (convalescence, recovery)
• Localized infection


  Affects only one body part or organ
• Systemic infection


  Infection in the bloodstream
• Body's natural defenses against infection

  • Normal flora
  • Body system defenses
  • Inflammation
• Normal flora


  Participate in maintaining health, secrete antibacterial substances, exert protective bactericidal action
• Body system defenses


  Organ systems have unique defenses physiologically suited to their structure and function (e.g. lungs have moist mucous membranes and cilia)
• Inflammation


  Protective vascular reaction that delivers fluid, blood products, and nutrients to an area of injury