Exam 11 - Asepsis and Infection Control

Chain of Infection

• Six elements: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host.
• Must be interrupted to prevent transmission of infection.

Infectious Agent

• Pathogenic microorganisms.

Reservoir

• Where the pathogen can grow and multiply.
• Examples: humans, animals, plants, soil, and water.

Portal of Exit

• Exit route from the reservoir.
• Examples: respiratory tract, gastrointestinal tract, skin, mucous membranes, blood, and bodily fluids.

Mode of Transmission

• Method or vehicle of transportation for the pathogen.
• Direct transmission: occurs when the pathogen is transferred directly from one person to another.
• Indirect transmission: occurs through a contaminated vehicle.
  • Vector: living vehicle such as an insect.
  • Fomite: inanimate object such as a stethoscope or medical chart.

Portal of Entry

• Entrance through the skin, mucous membranes, or mouth.
• Similar to portal of exit.

Susceptible Host

• Another person or animal that is susceptible to the pathogen.
• Factors affecting susceptibility:
  • Chemotherapy
  • Diagnostic procedures
  • Disease processes
  • Environmental factors
  • Fatigue
  • Hereditary factors
  • Age (very young or old)
  • Lifestyle
  • Medical therapy
  • Nutritional status
  • Occupation
  • Radiation exposure
  • Stress
  • Trauma
  • Travel

Immunity

• Immunizations are effective in reducing susceptibility to some infectious diseases.
• Body's natural defense mechanisms:
  • Skin: intact multilayered surface, shedding of outer layer, sebum production.
  • Gastrointestinal tract: intact mucosa, saliva, gastric secretions, peristalsis.
  • Eyes: tearing and blinking.
  • Respiratory tract: cilia and mucus.
  • Genitourinary tract: urine flow, vaginal flora.

Stages of the Infectious Process

• Incubation period: time between pathogen entry and first symptoms.
• Prodromal stage: time from onset of nonspecific symptoms to more specific symptoms.
• Acute stage: time when specific symptoms develop; most contagious.
• Convalescence: time when acute symptoms disappear; recovery period.

Inflammation

• Body's response to injury or infection.
• Signs of Localized Inflammation: edema, erythema, heat, pain or tenderness, loss of function.
• Signs of Systemic Inflammation: fever, leukocytosis, malaise, anorexia, nausea, vomiting, lymph node enlargement.

Health Care-Associated Infections (HAIs)

• Previously known as nosocomial infections.
• Acquired by patients during medical treatment in health care facilities.
• Examples: CLABSI, CAUTI, SSI, VAP.
• More common due to virulent microorganisms present in hospitals and weakened immune systems of hospitalized patients.
• Exogenous HAIs: caused by microorganisms from another person.
• Endogenous HAIs: caused by the patient's own microorganisms.

Prevention of HAIs

• Standard precautions:
  • Hand hygiene: single most important preventative measure; wash for minimum 20 seconds with soap and water.
  • Gloves: wear gloves when handling potentially infectious materials; change gloves between patients and after contact with infectious material.
  • Masks: wear a mask when there is a risk of airborne or droplet transmission.
  • Eye protection: wear eye protection when there is a risk of splashes.
  • Gowns: wear a gown when there is a risk of contact with potentially infectious materials.
• Transmission Categories:
  • Airborne: use negative pressure rooms, N-95 respirators, and limit patient transport.
  • Droplet: use private rooms, masks, and limit transport.
  • Contact: use private rooms, gloves, gowns, and limit transport.
• Protective precautions: used for immunocompromised patients to prevent infection from external sources.

Nursing Care for Infections

• Administration of prescribed antimicrobial agents.
• Monitoring patient response to therapies.
• Providing adequate nutrition.
• Allowing for rest.
• Minimizing spread of infection.

Chain of Infection

• Six elements are required for the development of an infection: Infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and host.
• The chain must be interrupted to prevent the spread of infection.

Modes of Transmission

• A contaminated vehicle carries microorganisms to the next host after leaving the reservoir.
• Contamination refers to exposure to harmful agents, making an object potentially unsafe.
• A living vehicle is known as a vector, while an inanimate vehicle is called a fomite.
• Examples of fomites in healthcare facilities include computers, medical records, stethoscopes, thermometers, and soiled dressings.
• Transmission can be direct or indirect.
• Indirect transmission occurs when the host contacts a fomite or vector.
• Direct transmission happens when a nurse, for example, uses poor hand hygiene and then touches a patient.
• To prevent the spread of microorganisms through the environment, do not shake linens when making a bed, use a dampened cloth when dusting, and avoid touching anything on the floor.

Portal of Entry

• Microorganisms must find a way to enter the host after exiting the reservoir and being transmitted.
• Many entrance and exit routes are similar, and methods for prevention are also similar.
• Skin is the first line of defense against infection and should be kept intact, lubricated, and clean.
• Injury from sharp objects, such as needles or scalpels, should be reported immediately to prevent infections.
• Punctured skin provides a portal of entry for microorganisms into the bloodstream.
• Indwelling urinary catheters and drainage equipment can also provide an entrance point for microorganisms.
• Gloves should be worn when handling areas of open skin or mucous membranes.

Host

• A host is an organism that nourishes and harbors another organism.
• Susceptibility to infection is determined by the host's resistance to the pathogen.
• Factors affecting host immunologic resistance include chemotherapy, diagnostic procedures, disease processes, environmental factors, fatigue, hereditary factors, age, lifestyle, medical therapy, nutritional status, occupation, radiation exposure, stress, trauma, and travel.
• Immunizations, alongside normal defense mechanisms, effectively reduce susceptibility to certain infectious diseases.

Natural Defense Mechanisms

• The body has several natural defense mechanisms that protect against infection.
• Skin: intact skin acts as a barrier, shedding removes organisms, sebum kills bacteria.
• Gastrointestinal tract: intact mucosa provides a barrier, saliva inhibits microbes, gastric secretions destroy microorganisms, peristalsis prevents bacterial retention.
• Eyes: tearing and blinking remove pathogens.
• Respiratory tract: cilia trap and remove microbes, alveolar cells engulf and destroy microorganisms.
• Genitourinary tract: urine flow washes away microbes, vaginal flora inhibits microbial growth at puberty.

Stages of Infectious Process

• The infectious process is the progression of stages an infection goes through, whether localized or systemic.
• Incubation period: time between pathogen entry and symptom appearance.
• Prodromal stage: onset of nonspecific symptoms followed by more specific ones.
• Acute stage: manifestation of specific signs and symptoms, often the most contagious period.
• Convalescence: disappearance of acute symptoms.
• The severity of illness depends on infection extent, microorganism virulence, and host susceptibility.

Nursing Care for Infection

• Nursing care for infection includes administering antimicrobial agents, monitoring patient response (vital signs, laboratory values, subjective data), providing adequate nutrition, allowing for rest, and minimizing spread.

Inflammation

• The body's response to injury or infection at the cellular level.
• A protective vascular reaction delivering fluid, blood products, and nutrients to the injured area.
• Signs of localized inflammation: edema, erythema, heat, pain, loss of function.
• Signs of systemic inflammation: fever, leukocytosis, malaise, anorexia, nausea, vomiting, lymph node enlargement.
• Triggered by physical, chemical, or microbial agents, and can occur without infection.

Healthcare-Associated Infections (HAIs)

• Infections acquired by patients during medical treatment in healthcare facilities.
• Examples include CLABSI, CAUTI, SSI, and VAP.
• Hospitals harbor highly virulent microorganisms, and hospitalized patients are often immunosuppressed, making them susceptible.
• Detrimental effects of HAIs include: prolonged hospital stays, increased costs, potential for disability or death.
• HAIs are commonly transmitted through direct contact between healthcare workers and patients or from patient to patient.
• Exogenous infections are caused by microorganisms from another person, while endogenous infections are caused by the patient's own microorganisms.
• Strong emphasis is placed on preventing transmission through measures like hand hygiene and environmental cleaning.

Standard Precautions

• Aim to interrupt the chain of infection and reduce the transmission of bloodborne pathogens and other potentially infectious materials.
• Include the use of masks, eye protection, gowns, and hand hygiene.

Hand Hygiene

• The single most important preventive technique for interrupting the infectious process.
• Standard cleansing practice requires handwashing for a minimum of 20 seconds with facility-approved soap and running water.
• Handwashing is required before and after patient care, after touching blood/fluids, at the beginning/end of shifts, immediately after removing gloves, between patient contacts, before/after eating, before/after using the toilet, before dressing changes, before preparing/administering medications, before invasive procedures, when hands are visibly soiled, between tasks on the same patient, when caring for patients with C. difficile or exposed to B. anthracis.
• Alcohol-based hand sanitizer has proven more effective than plain handwashing for reducing HAIs and should be used before/after patient contact, before donning sterile gloves for central line insertion, before nonsurgical invasive procedures, after contact with body fluids/fluids/membranes/wounds, if moving from a contaminated to clean body site, after contact with inanimate objects, and after removing gloves.
• Only natural nails, no longer than ¼ inch, should be worn in the healthcare setting.

Gloves

• Don gloves if there is any possibility of contact with infectious material.
• Wear gloves only once and dispose of them appropriately.
• Perform hand hygiene after removing gloves.

Isolation Precautions

• Additional precautions used in addition to standard precautions for patients with specific infections.
• Categories include airborne, droplet, and contact precautions.
• Airborne: measles, varicella, TB, private room with negative-pressure airflow, health care workers wear N-95 respirator or PAPR, patient wears a mask when transported.
• Droplet: influenza, meningitidis, pertussis, rubella, private room or 3 feet from others, health care workers wear a mask, patient wears a mask when transported.
• Contact: C. difficile, RSV, impetigo, MRSA, private room, health care workers wear gloves and a gown, noncritical equipment is disposable or patient-dedicated, patient transport limited, infected areas covered.
• Protective: for immunocompromised patients at risk for infections, private room, health care workers wear gloves, gown, mask, and eye protection.
• Basic principles for all isolation techniques:
  • Thorough hand hygiene before and after patient care
  • Understanding of the disease process and transmission method
  • Safe disposal of contaminated equipment
  • Safe transport procedures for patients.

Chain of Infection

• Six elements are necessary for the development of an infection, referred to as the chain of infection.
• The chain of infection must be interrupted to prevent the transmission of an infection.
• Infectious agent: A pathogen is any microorganism that has the potential to cause disease.
• Reservoir: Where the pathogen can grow and multiply.
• Portal of exit: How the pathogen leaves the reservoir.
• Mode of transmission: Method or vehicle of transportation of the pathogen.
• Portal of entry: Entrance through the skin, mucous lining, or mouth.
• Host: Another person or animal that is susceptible to the pathogen.

Mode of Transmission

• A contaminated vehicle is the means by which microorganisms are carried about and transported to the next host after leaving the reservoir
• Contamination: Condition of being soiled, stained, touched by, or otherwise exposed to harmful agents, which makes an object potentially unsafe for use
• Living vehicle: A vector
• Inanimate vehicle: A fomite
• Fomites in health care facilities include computers, medical records and charts, stethoscopes, thermometers, bandage scissors, used tissues, drinking glasses, needles, and soiled dressings
• Direct transmission is possible, such as when the nurse uses poor hand hygiene and then touches a patient while providing care.
• Indirect transmission is more common, occurring when the host comes into contact with a fomite or vector.

Portal of Entry

• Skin: The first line of defense against infection.
• Indwelling urinary catheters and other drainage equipment also provide an entrance for microorganisms.
• Gloves should be worn when handling areas of open skin or mucous membranes.

Host

• Host - an organism in which another organism is nourished and harbored.
• Susceptibility to infection is defined by the amount of resistance that the host can exhibit against the pathogen.
• Factors that affect host immunologic resistance include:
  • Chemotherapy
  • Diagnostic procedures
  • Disease processes
  • Environmental factors
  • Fatigue
  • Hereditary factors
  • Very young or old in age
  • Lifestyle
  • Medical therapy
  • Nutritional status
  • Occupation
  • Radiation exposure
  • Stress
  • Trauma
  • Travel
• Immunizations have proven effective in reducing susceptibility to some types of infectious diseases.

Natural Defense Mechanisms

• Skin:
  • Intact and multilayered provides a barrier to microorganisms.
  • Shedding of the outer layer of skin removes organisms that adhere to the skin’s outer layers.
  • Sebum contains fatty acid that kills some bacteria.
• Gastrointestinal tract:
  • Intact multilayered mucosa of the mouth provides a mechanical barrier to microorganisms.
  • Saliva contains microbial inhibitors and washes away particles that contain microorganisms.
  • The acidity of gastric secretions chemically destroys microorganisms.
  • Rapid peristalsis in the small intestine prevents the retention of bacterial contents.
• Eyes:
  • Tearing and blinking provide mechanisms to reduce entry or to assist in washing away particles that contain pathogens.
• Respiratory tract:
  • Cilia lining the upper airway, coated by mucus, trap inhaled microbes and sweep them outward in mucus to be expectorated or swallowed.
• Genitourinary tract:
  • The flushing action of urine flow washes away microorganisms on the lining of the bladder and urethra.
  • At puberty, normal vaginal flora causes vaginal secretions to achieve a low pH, inhibiting the growth of many microorganisms.

Stages of the Infectious Process

• Incubation period: Interval between the entrance of a pathogen into the body and the appearance of the first symptoms.
• Prodromal stage: Interval from the onset of nonspecific signs and symptoms to more specific symptoms.
• Acute stage: Interval when the patient manifests signs and symptoms specific to the type of infection.
• Convalescence: Interval when acute symptoms of infection disappear.

Inflammation

• The body’s response to injury or infection at the cellular level.
• A protective vascular reaction that delivers fluid, blood products, and nutrients to interstitial tissues in the area of injury.
• Signs of localized inflammation:
  • Edema
  • Erythema
  • Heat
  • Pain or tenderness
  • Loss of function in the affected part
• Signs of systemic inflammation:
  • Fever
  • Leukocytosis
  • Malaise
  • Anorexia
  • Nausea
  • Vomiting
  • Lymph node enlargement
• The inflammatory response is triggered by physical agents, chemical agents, or microorganisms.

Healthcare-Associated Infections (HAI)

• Previously referred to as nosocomial infections.
• Infections acquired by patients when undergoing medical treatment in a health care facility.
• Common HAIs:
  • Central-line associated bloodstream infection (CLABSI)
  • Catheter-associated urinary tract infection (CAUTI)
  • Surgical site infection (SSI)
  • Ventilator-associated pneumonia (VAP)
• Hospitals harbor microorganisms that are often highly virulent.
• The hospitalized patient’s immune system is probably already weakened from disease or invasive procedures, making them more susceptible to these pathogens.
• Detrimental effects of HAIs:
  • Longer hospital stays for the patient
  • Increased cost for the patient, hospital, and funding bodies
  • Possibility of disability or death.

Transmission of HAIs

• HAIs are most commonly transmitted via direct contact between health care workers and patients or from patient to patient.
• Exogenous infections: Caused by microorganisms from another person.
• Endogenous infections: Caused by the patient’s own normal microorganisms, which become altered and overgrow or are transferred from one body site to another.
• Strong emphasis must be placed on the prevention of transmission with measures such as hand hygiene and environmental cleaning.

Standard Precautions

• Aim to interrupt the chain of infection and reduce transmission of bloodborne pathogens and other potentially infectious materials.
• Standard precautions include the following, as applicable to the patient situation:
  • Masks
  • Eye protection
  • Gowns
  • Hand hygiene
• Hand hygiene is the single most important and basic preventive technique that health care workers can use to interrupt the infectious process.
  • Standard cleansing practice requires handwashing for a minimum of 20 seconds with facility-approved soap, running hands under water.
  • Hand washing is required (regardless of whether gloves are worn):
    • Before and after patient care
    • After touching blood, body fluids, secretions, excretions, and contaminated items
    • At the beginning and end of each shift
    • Immediately after gloves are removed
    • Between patient contacts
    • Before and after eating
    • Before and after using the toilet
    • Before changing and dressing or having contact with open wounds
    • Before preparing and administering medications
    • In preparation for an invasive procedure
    • When hands are visible soiled
    • Between tasks or procedures on the same patient to prevent cross-contamination of different body sites
    • When caring for a patient with Clostridium difficile or exposed to Bacillus anthracis (spores are not killed by alcohol-based hand sanitizer)
    • When otherwise indicated to prevent transfer of microorganism to other patients or environments
• The use of alcohol-based hand sanitizer has proven more effective in reducing HAIs than plain hand washing and therefore should be used:
  • Before and after patient contact
  • Before donning sterile gloves when inserting central intravascular catheters
  • Before performing nonsurgical invasive procedures
  • After contact with body fluids, excretions, mucous membranes, nonintact skin, and wound dressings
  • If moving from a contaminated body site to a clean body site during patient care
  • After contact with inanimate objects in the immediate vicinity of the patient
  • After removing gloves
• Note: Only natural nails, no longer than ¼ inch, should be worn in the health care setting.

Gloves

• Nurses and other health care personnel should don gloves if any possibility exists of contact with infectious material with their hands.
• CDC guidance for gloving includes:
  • Wear gloves only once, then place them into the appropriate waste containers for safe disposal
  • If you have not completed patient care but have come into contact with infectious material, change the gloves before continuing the patient’s care
  • Because of the risk of perforating the gloves during use, perform hand hygiene after removing gloves

Latex Allergies

• A latex allergy should be suspected and evaluated when anyone develops red, watery, itchy eyes; sinus or nasal congestion; tachycardia; or hypotension after exposure to latex.
• Anaphylaxis is possible.
• To avoid developing a latex allergy:
  • Whenever possible, wear powder-free gloves since they are lower in protein allergies
  • Wear gloves that are appropriate for the task
  • Wash with a pH-balanced soap immediately after removing gloves
  • Apply only non-oil-based hand care products (oil-based products break down latex)
  • If a reaction or dermatitis occurs, seek medical treatment immediately

Transmission-Based Precautions

• In addition to standard precautions, the CDC condensed disease-specific approaches to isolation into transmission categories: airborne, droplet, and contact precautions.
• These precautions are designed to be used in the care of patients with a specific type of confirmed or suspected infection.
• Isolation precautions are implemented in addition to standard precautions.

Basic Principles of Isolation

• Perform thorough hand hygiene before and after caring for a patient
• Have an adequate understanding of the disease process and method of transmission of the infectious microorganism to help determine which protective barriers to use
• Dispose of contaminated equipment and articles in a safe and effective manner to prevent transmission of pathogens to other individuals
• If the patient is to be transported to other areas in the agency (away from the isolation room), take necessary measures to protect those who potentially will be exposed. The patient should be transported in accordance with hospital protocol.

Airborne Precautions

• Examples of illnesses requiring airborne precautions:
  • Measles
  • Varicella zoster virus
  • Tuberculosis
• Requirements:
  • Private patient room
  • Negative-pressure airflow with 6-12 air exchanges per hour, vented to the outside
  • Health care workers are required to wear an N-95 or higher particulate respirator mask or a powered air purifying respiratory (PAPR) when entering an isolation room
  • Patient transport should be limited to medically necessary purposes
  • Patient must wear a surgical mask when out of isolation room and observe respiratory hygiene etiquette

Droplet Precautions

• Examples of illnesses requiring droplet precautions:
  • Haemophilus influenzae
  • Neisseria meningitidis
  • Pertussis
  • Rubella
• Requirements:
  • Private patient room, cohort, or maintain minimum of 3 feet from other patients and visitors
  • Health care workers are required to wear a mask when entering an isolation room
  • Patient transport should be limited to medically necessary purposes
  • Patient must wear a surgical mask when out of isolation room and observe respiratory hygiene etiquette

Contact Precautions

• Examples of illnesses requiring contact precautions:
  • Clostridium difficile
  • Respiratory syncytial virus
  • Impetigo
  • Methicillin-resistant Staphylococcus aureus (MRSA)
• Requirements:
  • Private patient room
  • Health care workers are required to wear gloves and a gown upon entering an isolation room
  • Noncritical patient care equipment should be disposable or designated for patient-dedicated use only
  • Patient transport should be limited to medically necessary purposes
  • Infected or colonized areas of the patient’s body should be contained and covered
  • Remove contaminated personal protective equipment (PPE) and perform hand hygiene prior to transporting patients
  • Don clean PPE to handle the patient at the transport destination

Protective Precautions

• Protective precautions are used for patients with immunocompromising conditions.
• These patients are generally at increased risk for bacterial, fungal, parasitic, and viral infections from endogenous and exogenous sources.

This quiz covers the essential elements of the chain of infection, including the infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host. Understanding these components is crucial for preventing the transmission of infections in various settings.