Infection Control Concepts - 2021 PDF

Chapter 9 Infection Control Concepts  Key Terms (1 of 2) Acquired resistance Airborne transmission Antibodies Antigens Bacterium (pl. bacteria) Direct contact Droplet contamination Endospore Fomite Fungus (pl. fungi) Health care-associated infection (...

Chapter 9 Infection Control Concepts  Key Terms (1 of 2) Acquired resistance Airborne transmission Antibodies Antigens Bacterium (pl. bacteria) Direct contact Droplet contamination Endospore Fomite Fungus (pl. fungi) Health care-associated infection (HAI) Motile Natural resistance Normal flora Key Terms (2 of 2) Nosocomial infection Opportunistic infection Passive immunity Pathogen Phagocytosis Prion Protozoon (pl. protozoa) Spore Vector Vehicle Virion Virulence factors Microorganisms Bacteria Viruses Fungi Prions Protozoa Cycle of Infection Infectious organisms Reservoir of Infectio Portal of exit Susceptible host Portal of entry Transmission of disease Infectious Organisms Microorganisms capable of causing disease are called pathogens or pathogenic organisms. Virulence factors distinguish pathogens from nonpathogenic organisms and normal flora. Table 8-1 in your textbook lists common pathogens. Reservoir of Infection Place where pathogens can thrive in sufficient numbers to pose a threat Must have:  Moisture  Nutrients  Suitable temperature May be human or nonhuman (e.g., food, water, animals)  Portal of Exit Any route through which blood, body fluids, excretions, or secretions leave the body Examples:  GI tract  Open wound  Respiratory tract  Susceptible Host Patients are often hosts because of a reduced immune system. Nosocomial infection, also called HAI  hospital-acquired infection  health care-associated infection Healthcare workers are also at risk.  Exposure to blood and other bodily fluids  Portal of Entry The route by which microorganisms gain access into the susceptible host Examples:  Respiratory tract  Urinary tract  GI tract  Open wound or break in skin  Mucous membranes of the eyes, nose, or mouth  Bloodstream  Transmission of Disease Most direct way to break the cycle of infection is to prevent transmission of the infectious organism from the reservoir to the susceptible host Six main routes of transmission:  Direct contact  Fomites  Vectors  Vehicles  Airborne  Droplet contamination Direct Contact Infected person must touch susceptible host. Requires the pathogens to be placed in direct contact with susceptible tissue Examples:  Syphilis  HIV infections  Staph infections  Fomites An object that has been in contact with pathogenic organisms Examples:  Contaminated gloves  X-ray table  Positioning sponges  Vectors An arthropod in whose body an infectious organism develops or multiplies before becoming infective to a new host. Transmission occurs when an infected insect bites host. Examples:  Mosquitos—malaria  Ticks—Lyme disease  Vehicles Any medium that transports microorganisms Examples:  Contaminated food, water, drugs, or blood  Droplet Contamination (1 of 2) Occurs when an infectious individual coughs, sneezes, speaks, or sings in the vicinity of a susceptible host Involves contact of the mucous membranes of the eyes, nose, or mouth of a host with large droplets (greater than 5 µm) that contain microorganisms  Droplets do not travel far (3 feet or less)  Droplet Contamination (2 of 2) Examples:  Influenza  Meningitis  Diphtheria  Pertussis  Streptococcal pneumonia Airborne (1 of 2) Occurs from dust that contains spores or by means of droplet nuclei  Droplet nuclei are particles of evaporated droplets containing microorganisms and measuring 5 microns (micrometers, µm, 0.001 mm) or smaller.  Can remain suspended in the air for long periods Airborne (2 of 2) Examples:  TB  Varicella viruses (also transmitted via direct contact) The Body’s Defense Against Infection Natural Resistance  Provided by mechanical barriers of intact skin and mucous membranes Acquired Immunity (long term)  Occurs when an individual develops antibodies to a particular organism as a result of either infection or immunization Passive Immunity  Occurs following an injection of preformed antibodies to a particular infection  Chapter 10 Preventing Disease Transmission Key Terms (1 of 2) Acquired immunodeficiency syndrome (AIDS) Asepsis Disinfection Epidemic Human immunodeficiency virus (HIV) Immunosuppressant Methicillin-resistant Staphylococcus aureus (MRSA) Key Terms (2 of 2) Microbial dilution Opportunistic infection Pandemic Severe acute respiratory syndrome Sharps container Standard precautions Sterilization Tuberculosis (TB) Vancomycin-resistant enterococci (VRE) Infectious Diseases Emerging diseases Healthcare-associated infections Bloodborne pathogens Tuberculosis Emerging Diseases (1 of 2) Emerging diseases are:  New diseases appearing in the population  Existing diseases that are rapidly increasing in incidence or geographic range  Resurgent or recurrent old diseases caused by an old or mutated pathogen Infection-control department of hospital responsible for keeping up- to-date  CDC recommendations  WHO data Emerging Diseases (2 of 2) Disease emergence is precipitated by many factors:  Increased human exposure to vectors in nature  Population growth and migration to crowded cities  Rapid international travel and transportation of goods  Contact with new strains of dangerous pathogens  Pathogen mutation caused by overuse of antimicrobial agents  Breakdown in public health measures  Climate change  Bioterrorism Healthcare-Associated Infections (1 of 2) Those that occur more than 48 hours after patient admitted to the hospital Newer term = healthcare-associated infections (HAI) Of greatest concern are those that are multidrug- resistant  MRSA  VRE Healthcare-Associated Infections (2 of 2) Another very common HAI is Clostridium difficile colitis, a gastrointestinal infection that causes diarrhea. Caused by a Gram-positive bacillus Difficult to control because it cannot be eliminated by routine asepsis methods Patients on antibiotics most susceptible Bloodborne Pathogens HIV AIDS Hepatitis Needle-stick injuries are most common cause of transmission from patients to healthcare workers.  Tuberculosis A contagious, airborne lung disease caused by M. tuberculosis Most patients are homeless, recent immigrants, or immunocompromised. Pre-employment screening required for healthcare workers and after known exposure Preventing Disease Transmission Historical Perspective Standard Precautions OSHA Bloodborne Pathogens Standard Medical Asepsis Handling and Disposal of Contaminated Items and Waste Isolation Technique Historical Perspective (1 of 3) Quarantines were used to contain infectious diseases.  Not allowed to leave the house and no one could enter until all members were well When hospitals were first instituted, infectious patients were isolated to a single ward. Isolation techniques evolved from this practice. Historical Perspective (2 of 3) Isolation no longer commonly used, but still a legal practice of the U.S. Public Health Service for diseases such as  Cholera  Diphtheria  Smallpox  TB  Plague  Yellow fever  SARS Historical Perspective (3 of 3) Protective measures of the past:  Universal Precautions—focused on barriers against bloodborne pathogens  Body Substance Precautions—expanded protection to all moist body secretions Standard Precautions Current infection-control system Designed to reduce risk of transmission of infections from unrecognized sources of bloodborne diseases and from other pathogens in healthcare institutions Includes transmission-based precautions for:  Airborne  Droplet  Contact  OSHA Bloodborne Pathogens Standard Published in 1991 Requires employers to  develop an exposure-control plan for the work site that describes employee protection measures.  include engineering and work-practice controls to ensure the use of personal protective clothing and equipment.  provide signs and labels to identify biohazard materials.  provide annual bloodborne pathogen training, hepatitis B vaccinations, and medical care in the event of occupational exposure.  Medical Asepsis Involves reducing the probability of infectious organisms being transmitted to a susceptible individual Microbial dilution—the process of reducing the number of organisms  Hand hygiene and other cleanliness measures  Disinfection  Sterilization (surgical asepsis) Hand Hygiene Washing for 30–60 seconds with soap and water Alcohol-based rubs  More effective at killing some HAI organisms, such as C. difficile  More convenient than accessing sinks  Box 9-1 provides CDC guidelines for use  Cleaning Techniques Cleaning reduces the incidence of airborne infections and the transfer of pathogens by fomites. Always clean from the least contaminated area toward the more contaminated area and from the top down. Avoid raising dust. Do not contaminate yourself or clean areas. After each use, clean all equipment that comes in contact with patients. Use a cloth moistened with disinfectant.  CDC recommends sodium hypochlorite bleach (Clorox) as an inexpensive, effective disinfectant for preventing the spread of HIV.  Mix bleach in a 1:10 solution daily because its effectiveness declines rapidly when diluted.  Handling and Disposal of Contaminated Items and Waste (1 of 2) Replace linens after each patient. To dispose of contaminated linens  fold edges to the middle without shaking or flapping.  place loosely balled linens in designated hamper. Sharps container is proper disposal for needles. Blood-contaminated items (gauze, bandages) also have designated “Biohazard” disposal containers.  Handling and Disposal of Contaminated Items and Waste (2 of 2) Isolation Technique As a part of Standard Precautions, CDC currently recommends isolating patient based on transmission precautions. Standard Precautions Contact Precautions MRSA VRE continent Shingles Scabies Head lice Strict Contact Precautions VRE (incontinent) Gastroenteritis C. difficile Other selected resistant organisms Droplet Precautions Influenza Pertussis Meningococcal Rubella RSV Airborne Precautions Active Pulmonary TB Measles Chickenpox  Radiography of Isolation Patient Requires two technologists  One has all patient contact.  Other has no patient contact—only handles equipment. Reduces contamination of equipment, which is difficult to disinfect completely When patient is in the department, use sheets to cover table, wheelchair, etc.  Wear appropriate protective apparel. Precautions for Compromised Patients Includes neonates, organ transplants, burn victims, and those receiving chemotherapy Older terminology—protective isolation or reverse isolation May require a modified surgical aseptic technique. Two radiographers are recommended for imaging procedures.