chap 12

• Healthcare epidemiology


  The study of the occurrence, determinants, and distribution of health and disease within healthcare settings facilities

  
• Healthcare epidemiology


  • The primary focus is on infection control and the prevention of healthcare-associated infections
  • Includes any activities designed to study and improve patient care outcomes

  
• Healthcare-associated infections (HAIs)


  Infectious diseases acquired within healthcare facilities

  
• Community-acquired infections


  Infectious diseases acquired outside of healthcare facilities
• Of approximately 40 million hospitalizations per year in the U.S., an estimated 2 million patients (~5% of the total) acquire HAIs
• Pathogens most often involved in HAIs


  • Gram-positive cocci: Staphylococcus aureus, coagulase-negative staphylococci, and Enterococcus spp.
  • Gram-negative bacilli: Escherichia coli, Pseudomonas aeruginosa, Enterobacter spp., and Klebsiella spp.
• The sources of these pathogens are healthcare professionals, other healthcare workers, visitors, and the patients themselves
• Approximately 70% of HAIs involve drug-resistant bacteria
• Most common types of HAIs

  • Urinary tract infections (UTIs)
  • Surgical site infections (also referred to as postsurgical wound infections)
  • Lower respiratory infections (primarily pneumonia)
  • Bloodstream infections (septicemia)
• Other types of HAIs

  • Gastrointestinal diseases caused by Clostridium difficile (referred to as Clostridium difficile-associated diseases)
• Patients most likely to develop HAIs

  • Elderly patients
  • Women in labor and delivery
  • Premature infants and newborns
  • Surgical and burn patients
  • Diabetic and cancer patients
  • Patients receiving treatment with steroids, anticancer drugs, antilymphocyte serum, and radiation
  • Immunosuppressed patients
  • Patients who are paralyzed or are undergoing renal dialysis or catheterization
• Major factors contributing to HAIs

  • An ever-increasing number of drug-resistant pathogens
  • The failure of healthcare personnel to follow infection control guidelines
  • An increased number of immunocompromised patients
• Additional factors contributing to HAIs

  • Overcrowding of hospitals and shortages of healthcare staff
  • The indiscriminate use of antimicrobial agents
  • A false sense of security about antimicrobial agents
  • Lengthy and more complicated types of surgery
  • Increased use of less-highly trained healthcare workers
  • Increased use of anti-inflammatory and immunosuppressant agents
  • Overuse and improper use of indwelling devices

  
• What can be done to reduce the number of HAIs?


  • Strict compliance with infection control guidelines
  • Handwashing is the single most important measure to reduce the risks of transmitting pathogens
  • Disinfection and sterilization techniques, air filtration, use of ultraviolet lights, isolation of especially infectious patients, and wearing gloves, masks, and gowns whenever appropriate
• Handwashing is the most important and most basic technique in preventing and controlling infections and preventing the transmission of pathogens
• Asepsis


  Without infection
• Types of asepsis


  • Medical asepsis - Precautionary measures necessary to prevent direct and indirect transfer of pathogens
  • Surgical asepsis or sterile technique - Practices used to render and keep objects and areas sterile
• Medical asepsis


  A clean technique with the goal of excluding pathogens
• Surgical asepsis


  A sterile technique with the goal of excluding all microorganisms
• Standard Precautions


  Infection control guidelines to be applied to the care of ALL patients in ALL healthcare settings, regardless of the suspected or confirmed presence of an infectious agent

  
• What Standard Precautions include

  • Hand hygiene
  • Wearing of gloves, masks, eye protection, and gowns
  • Respiratory hygiene/cough etiquette
  • Safe injection practices
  • Lumbar puncture
  • Cleaning of patient-care equipment
  • Environmental control
  • Handling of soiled linens
  • Resuscitation devices
  • Patient placement
  • Disposal of used needles and other sharps
• Transmission-Based Precautions are used for patients who are known or suspected to be infected or colonized with highly transmissible or epidemiologically important pathogens
• Types of Transmission-Based Precautions

  • Contact Precautions
  • Droplet Precautions
  • Airborne Precautions
• Contact transmission


  Direct-contact (transfer of microorganisms by body surface-to-body surface) and indirect contact (transfer of microorganisms by a contaminated intermediate object)
• Examples of diseases requiring Contact Precautions

  • Acute viral (hemorrhagic) conjunctivitis
  • Acute respiratory infectious diseases or aseptic meningitis in children
• Transmission-Based Precautions


  Used for patients who are known or suspected to be infected or colonized with highly transmissible or epidemiologically important pathogens for which additional safety precautions beyond Standard Precautions are required to interrupt transmission within healthcare settings

  
• Types of Transmission-Based Precautions

  • Contact Precautions
  • Droplet Precautions
  • Airborne Precautions
• Contact transmission


  Divided into direct-contact (transfer of microorganisms by body surface-to-body surface) and indirect contact (transfer of microorganisms by a contaminated intermediate object)
• Diseases requiring Contact Precautions

  • Acute viral (hemorrhagic) conjunctivitis; acute respiratory infectious diseases or aseptic meningitis in infants and young children; chickenpox; cutaneous diphtheria; disseminated shingles; extrapulmonary tuberculosis with draining lesion; gastroenteritis in diapered or incontinent persons; impetigo; infection or colonization with multidrug-resistant organisms; major draining abscesses or wound infections; monkeypox; poliomyelitis; severe mucocutaneous herpes simplex infections; smallpox; staphylococcal scalded skin syndrome; major staphylococcal or streptococcal disease of skin, wounds, or burns; viral hemorrhagic fevers due to Lassa, Ebola, Marburg, or Crimean-Congo fever viruses
• Diseases requiring Droplet Precautions

  • Adenovirus infection in infants and young children; adenovirus pneumonia; epiglottitis or meningitis caused by Haemophilus influenzae type b; major skin, wound, or burn infections due to group A streptococcus; scarlet fever in infants and young children; influenza; meningitis or pneumonia caused by Neisseria meningitidis; mumps; Mycoplasma pneumonia; parvovirus B19 skin infection; whooping cough; pharyngeal diphtheria; pneumonic plague; German measles; severe acute respiratory syndrome (SARS); strep throat in infants and young children; rhinovirus infection; viral hemorrhagic fevers due to Lassa, Ebola, Marburg, or Crimean-Congo fever viruses
• Diseases requiring Airborne Precautions

  • Chickenpox; confirmed or suspected pulmonary or laryngeal tuberculosis; extrapulmonary tuberculosis with draining lesions; disseminated shingles in any patient; localized shingles in immunocompromised patients; measles; monkeypox; severe acute respiratory syndrome (SARS); smallpox
• Some diseases require a combination of Droplet Precautions and/or Contact Precautions in addition to Airborne Precautions
• N95 respirator


  Used when Airborne Precautions are indicated
• Airborne Infection Isolation Room (AIIR)


  • Preferred placement for patients requiring Airborne Precautions
  • Under negative pressure to prevent room air from entering the corridor
  • Air evacuated from the AIIR passes through a HEPA filter
• Protective Environment


  • Used for patients who are especially vulnerable to infection, such as those with severe burns, leukemia, transplants, immunosuppression, radiation treatment, leukopenia, or premature infants
  • Room is under positive pressure and air entering the room passes through HEPA filters
• Regulations for safe handling of food and eating utensils

  • Using high-quality, fresh food
  • Properly refrigerating and storing food
  • Properly washing, preparing, and cooking food
  • Properly disposing of uneaten food
  • Covering hair and wearing clean clothes and aprons
  • Thoroughly washing hands and nails before handling foods
  • Keeping all cutting boards and other surfaces scrupulously clean
  • Washing cooking and eating utensils in a dishwasher with a water temperature > 80oC
• Fomites


  Nonliving, inanimate objects, other than food, that may harbor and transmit microbes
• Rules for preventing transmission of pathogens by fomites

  • Use disposable equipment and supplies whenever possible
  • Disinfect or sterilize equipment soon after use
  • Use individual equipment for each patient
  • Use disposable thermometers or thermometer covers
• General regulations for medical waste disposal

  • Follow OSHA standards
• Regulations for disposal of sharps

  • Sharps should be handled and disposed of properly
  • Dispose of sharps in specifically designed puncture-resistant containers ("sharps containers")