CPCT Certification Study Guide: Disease Transmission and Infection Control

Disease Transmission

• To understand standard precautions, one must understand the process of disease transmission.
• There are six links in the chain of infection that must be in place for disease transmission to occur.

Six Links in the Chain of Infection

1. Pathogen (Infectious Agent):

   • A pathogen or infectious agent must be present.
   • These are disease-causing micro-organisms, often in the form of:
     • Virus
       • A micro-organism that causes infections and diseases.
     • Bacteria
       • A single-celled micro-organism that reproduces rapidly and causes many infections.
     • Fungi
       • A micro-organism that grows on or in animals, plants, humans, and food, including yeasts and molds.
     • Protozoa
       • A single-celled parasite that replicates rapidly once inside a living host.

2. Reservoir:

   • An environment conducive to pathogen survival.
   • In a clinical setting, the reservoir is often the patient but can also be inanimate objects, such as medical equipment.
   • The human body is an ideal reservoir due to nutrients, moisture, optimal temperature, and pH levels.

3. Portal of Exit:

   • The passageway the pathogen uses to exit the reservoir.
   • This can be infected body fluids in a patient care setting.

4. Mode of Transmission:

   • Necessary for the cycle to continue once the pathogen exits the reservoir.
   • Direct Transmission:
     • Occurs through contact with the infected person or body fluid carrying the pathogen.
   • Indirect Transmission:
     • Involves an intermediate step between the portal of exit and entry.
     • Fomites: Nonliving objects like medical equipment and supplies that carry infectious organisms.
     • Vectors: Carriers (animals or insects) that transmit disease.
     • Other often-overlooked objects include telephones, doorknobs, computer keyboards, faucets, pens, books, eyeglasses, and laboratory coats.
       • A fomite is any nonliving object (e.g. catheters, tubing, hemostats) or substance capable of carrying infectious organisms.
       • A vector is a carrier (animal or insect) that can transmit disease.

5. Portal of Entry:

   • The means by which the pathogen enters a new host to continue the infectious cycle.
   • Common entry points include open wounds, mouth, nose, eyes, intestines, urinary tract, or reproductive system.

6. Susceptible Host:

   • The final step, where the human body, especially that of an immunocompromised patient, serves as an ideal host.
   • An immunocompromised individual has an impaired immune response, usually resulting from disease, medication therapy, or surgery.

Breaking the Chain

• Breaking any link in the infection cycle stops transmission.
• Effective hand hygiene is the primary method for breaking the chain of infection.
• Clinical facilities employ various isolation practices based on the identified pathogen; if unidentified, the most restrictive isolation is used.

Stages of Infection

• Upon exposure to a pathogen, the body activates the inflammatory response – a series of protective mechanisms.
• Inflammation is characterized by:
  • Erythema (reddening of skin)
  • Edema (excessive buildup of fluid in body tissue).
  • Pain
  • Heat
• When pathogens invade, they damage cells at the invasion site.
• The body responds by sending specific mediators of inflammation to the site:
  • Histamine
  • Kinins
  • Prostaglandins
• These mediators cause specific actions that bring white blood cells (WBCs) to the infected site.
• Blood vessels dilate, causing erythema and heat.
• Blood vessel walls become more permeable, allowing WBCs to reach the site and form a capsule to protect surrounding areas.
• Plasma enters the site, causing edema, which exerts pressure on nerves, leading to pain.
• Blood brings clotting factors to stop bleeding and proteins to repair damaged cells.
• WBCs engage in phagocytosis (eating and digesting bacteria), destroying pathogens and damaged cells.
• The containment of these materials plus WBCs creates pus.

Potential Scenarios Following the Inflammatory Response

1. Local Healing: The infection heals locally due to the inflammatory response.
2. Spread to Lymph Nodes: If the invasion is too strong, the infection spreads to the lymph nodes, increasing WBC count.
3. Spread to Bloodstream (Septicemia): The worst-case scenario, where the infection spreads to the bloodstream, causing a systemic infection that can be fatal without medical treatment (e.g., antibiotics for bacterial infections).
   • An antibiotic is a medication that kills bacteria.

Types of Infection

1. Acute:
   • Symptoms appear suddenly, beginning gradually with initial cell damage and worsening quickly.
   • The body recovers within weeks with a functioning immune system and sometimes medical treatment.
   • Example: common cold.
2. Chronic:
   • Lingers for a long time, sometimes permanently.
   • Symptoms might not last long, but the person can transmit it to others.
   • Example: Hepatitis B virus (HBV), a liver infection.
     • HBV is a liver infection caused by the hepatitis B virus, which is transmitted by blood, semen, or other body fluid from an infected person.
3. Latent:
   • Characterized by periods of remission and relapse.
   • Example: herpes simplex, manifesting as recurrent cold sores.
     • Herpes simplex is a virus that causes blisters around the mouth and lips (cold sores) or genital area.
4. Opportunistic:
   • Occurs in people with weak immune systems.
   • Micro-organisms that usually do not cause disease in healthy individuals can cause serious infections.
   • Example: oral candidiasis in patients with acquired immune deficiency syndrome (AIDS).
     • Oral candidiasis is a fungal infection of the mouth.

Personal Protective Equipment (PPE)

• Employers must provide PPE when there is a potential for exposure to blood or body fluids.
• Employees must use PPE when contact is anticipated.
• PPE use varies based on the patient encounter and identified pathogen.
• Examples of PPE: gloves, goggles, face shields, and gowns.
  • Personal protective equipment (PPE) consists of protective clothing and equipment (gloves, mask, gown, goggles) designed to protect a worker from exposure to chemicals or infectious material.

Gloves

• Usually made of nitrile or vinyl to avoid allergic reactions.
• If latex gloves are used and an employee is allergic to latex or glove पाउडर, the employer must provide hypoallergenic or powder-free gloves at no expense to the employee.

Standard Precautions for Gloves

1. Wash hands before donning gloves and after removing them.
2. Wear gloves when handling body fluids and during procedures (e.g., venipuncture, dermal puncture) with potential blood or body fluid contact.
3. Wear gloves when handling specimen containers (vacuum tubes, urine collection containers).
4. Replace gloves between each patient encounter.
5. Replace gloves when performing different procedures for the same patient, such as wound care.
6. Ensure gloves fit properly.
7. Check gloves for holes or rips before performing procedures.
8. Do not remove the tip of the glove to palpate for a vein during a venipuncture, as this practice is unsafe.

Glove Removal Procedure

1. Grab the glove on the palm of the nondominant hand and pull it off inside out, transferring it to the palm of the dominant gloved hand.
2. Slip the nongloved hand under the cuff of the dominant hand glove, pulling both gloves off together, turning them inside out.
3. Dispose of the single-glove pouch in a trash can designated for biohazardous materials.

Eye Protection

• Use eye protection whenever splashing of infectious material is possible.
• Minimum: goggles or safety glasses.
• Better protection: full-face shield.

Face Mask

• Wear a mask when interacting with patients, depending on the situation.
• Masks should fit well, cover the nose and mouth, and create a tight seal against the face.
• Use disposable masks, replace them between each patient encounter, and do not wear them from room to room.
• When wearing a mask to contain a possible communicable illness, replace it between patients or whenever it becomes wet or otherwise contaminated.

Gown

• When required, ensure it fits well and covers as much of the body as possible.
• Replace gowns between each patient encounter and do not wear them from room to room.
• Put on the gown before donning gloves, then make sure the gloves cover the cuff of the sleeves completely.
• Remove the gown by folding the potentially infected area in and only touching the side that did not come in contact with the patient.

Shoe and Head Covers

• May be needed when working with patients who have extremely communicable infections that require airborne, droplet, or contact precautions.

Types of Precautions

• Health care workers use necessary precautions to reduce the spread of infection for every patient.
• This includes assuming that all patients have the potential to spread a pathogen to another person.
• As a result, you need to be familiar with common pathogens and how to protect yourself and others from these transmissions.

Standard Precautions

• Introduced in 1996 by the CDC (previously known as universal precautions) to reduce the transmission of infectious agents in health care.
• Reduces health care-associated infections (HAIs)
  • A health-care associated infection (HAI) is an infection acquired in a health care setting.
• Applies to every patient.

Standard Precautions Include:

1. Using PPE when handling body fluids, nonintact skin, or mucous membranes.
2. Practicing meticulous hand hygiene before and after contact with each patient.
3. Safely disposing of used equipment, needles, and other sharps.

Droplet Precautions

• Required for patients with infections spread via droplets larger than 5 microns in diameter (e.g., rubella, meningitis, mumps, pertussis, influenza, some respiratory infections).
  • Rubella is a virus that causes fever and a rash and can cause serious harm to the fetus if a person develops this illness during pregnancy; German measles.
  • Meningitis is an infection of the membranes that surround and protect the brain and spinal cord.
• Technicians must wear a mask when interacting with these patients, especially within 3 feet.

Airborne Precautions

• Required for patients with infections spread via droplets smaller than 5 microns in diameter (e.g., varicella, tuberculosis, measles).
  • Varicella is a viral infection that causes a blister-like rash, itching, fatigue, and fever; chicken pox.
  • Tuberculosis is a bacterial infection of the lungs that causes fever, cough, weight loss, chills, and night sweats.
  • Measles is a virus that causes fever, cough, runny nose, blotchy rash, and tiny white spots inside the mouth.
• Airborne transmission is similar to droplet transmission, but airborne particles span a larger distance of potential spread and tend to have a longer time of virility.
• Require patients to be in a negative-pressure room (restricts airflow from the rest of the facility) or airborne infection isolation room (AIIR).
• Most hospitals have a respiratory isolation protocol in place that dictates patient access and exposure.
• These patients should also wear a mask when elsewhere in the facility.

Protective Environment (Reverse Isolation)

• Used for inpatients who are immunocompromised.
• The patient’s disease is not necessarily contagious, but their immune system is weak, and therefore they need protection from potential infectious threats.
• Patients who have cancer, transplant recipients, and others who are immunocompromised are at a higher risk from infection from all sources.
• Critical to prevent transmission of infectious agents by using hand hygiene and wearing PPE.
• Each facility has specific policies and procedures for access to these patients; read all signs outside a reverse isolation room.
• Requirements may include handwashing with a specific cleansing agent and wearing gloves, a gown, and shoe covers.
• PPE is donned before entering the patient’s room and removed after leaving.

General Precautions

• If you have any signs or symptoms of infection, it is in the best interest of the patient for you to stay home.
• If this is not possible, don a mask to prevent infecting patients through droplet or airborne transmission.
• It is unacceptable for a health care worker to transmit an infection to a patient.

Contact Precautions

• Required for patients with infections that spread via direct or indirect contact (contact with the environment).
• Examples: diphtheria, herpes simplex, scabies, hepatitis A, respiratory syncytial virus, wound and skin infections, especially with pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and C. diff.
  • Scabies is an itchy skin rash resulting from mites burrowing under the skin.
• Wear gloves and a gown when handling any items in the patient’s room because patients touch many items in their room.
• It is important to read any sign outside a patient’s room to determine which PPE to don when entering and remove before leaving the room.
• C. diff, MRSA, and VRE are virulent bacteria that are difficult to treat, so preventing any contamination from leaving the room on clothing, shoes, or skin is critical.

Bloodborne Pathogens Standard

• OSHA’s bloodborne pathogens standard requires the implementation of work practices and engineering controls to prevent exposure incidents.
• The bloodborne pathogen standard identifies sharps as any item that can easily break the skin and therefore potentially transmit disease (needles, scalpel blades, broken glass).
  • The bloodborne pathogen standard is an OSHA standard that identifies sharps as any item that can easily break skin and therefore potentially transmit disease.
• The standard provides guidelines for required training for all employees who handle blood and body fluids.
• It also addresses the availability and use of PPE and the availability of the HBV vaccination for all at-risk employees.
• The standard also includes definitions relating to engineering controls, record-keeping requirements, an exposure control plan, and employee engagement.
• It encourages individuals to provide input about safe work practices and engineering controls at their place of employment.

Sharps

• Although you will not be using needles and syringes to administer medications, it is possible to encounter stray or discarded sharps after a procedure.
• If blood or other potentially infectious materials contaminate sharps and a needlestick injury or a cut results, the worker can contract a serious illness, such as hepatitis or human immunodeficiency virus (HIV).
  • Human immunodeficiency virus (HIV) is a retrovirus that invades and inactivates helper T-cells of the immune system and causes AIDS and AIDS-related complex.
• Dispose of sharps immediately by dropping (not pushing) them into a rigid, impenetrable sharps container, which is usually red with a biohazard symbol.
  • A sharps container is a puncture-proof container designed to safely dispose of needles, scalpels, and other sharp disposable medical instruments.
• It must be leakproof on the sides and bottom and not allow retrieval of its contents after disposal.
• Sharps disposal containers must be closable, and they must be upright to keep the sharps and any fluids from spilling out.
• Do not overfill them because that can increase the risk of needlestick injuries and cuts.
• Replace sharps containers regularly.
• Sharps disposal containers must be readily accessible and as close as reasonably possible to the area where staff members use sharps.
• The National Institute for Occupational Safety and Health (NIOSH) annually updates regulations for workplace safety, including the handling and use of sharps containers.
• NIOSH has identified that incorrect sharps disposal is a significant cause of sharps injuries in the workplace and stresses the importance of four criteria.

NIOSH Criteria for Sharps Containers

1. Functionality: Sharps containers must be leak- and puncture-resistant, durable for transport, of the appropriate size and shape, and have a secure closure that protects against exposure during closing.
2. Accessibility: Sharps containers must be upright, easy to operate, within easy reach, below eye level, and located away from obstructive areas, doors, and sinks.
3. Visibility: Sharps containers must have the fill level and biohazard symbol clearly visible.
4. Accommodation: Sharps containers must require minimal training, be easy to operate (facilitating one-handed use), and have a mounting system that is safe, durable, and stable.

Additional Sharps Handling Guidelines

• Never recap, bend, or remove needles from syringes.
• If it is necessary to recap a needle, it should only be done using the one-handed scoop method (using the needle itself to pick up the cap and then pushing the cap against a hard surface to ensure a tight fit).
• Do not clean up any contaminated broken glass with bare hands.
• When a needlestick injury occurs, follow facility protocol for assessment, treatment, and documentation.

Medical and Surgical Asepsis

• All human bodies contain micro-organisms—some are harmless, and some can cause infection.
• Even the usually harmless micro-organisms can cause trouble for people who are immunocompromised.
• Patients in a hospital setting are usually compromised in some way.
  • Immunocompromised means having an impaired immune response, usually as a result of disease, medication therapy, or surgery.
• They might have an open wound, be on a medication that weakens their immune system, or be extremely stressed.
• All of these things can increase the possibility of disease transmission.
• Asepsis is divided into two categories: medical and surgical.
  • Asepsis means being free from pathogenic micro-organisms.
• Technicians use medical asepsis by methods such as washing hands, cleaning surfaces, and disposing of used supplies.
  • Medical asepsis means reducing the number and transfer of pathogens as well as breaking the chain of infection; clean technique.
• Surgical asepsis is used for more invasive tasks, such as assisting with a urinary catheter insertion or changing a surgical dressing.
  • Surgical asepsis means complete removal of micro-organisms and their spores from the surface of an object; sterile technique.

Medical Asepsis (Clean Technique)

• Used in every clinical setting; consists of removing micro-organisms after they leave the body.
• The goal is to reduce the number of micro-organisms and stop their growth.
• Handwashing is a medical aseptic technique that is routinely used to prevent the spread of infection.
• This type of asepsis does not remove all possibility of pathogens.
• However, it greatly reduces their number and ability to multiply or cause further infections.
• Washing hands before and after each patient encounter, ensuring the workspace is clean, using gloves when in contact with body fluids, and properly cleaning supplies are just a few examples of medical asepsis in action.

CDC Hand Hygiene Recommendations

• Hand hygiene is the most effective means of preventing infection.
• Perform hand hygiene at all of the following times:
  • When entering or leaving work areas
  • After any contact with body fluid (even if wearing gloves)
  • Before and after patient procedures, eating, and using the restroom
• Clinical staff are discouraged from wearing jewelry (rings, bracelets).
• These items can harbor pathogens and make asepsis difficult to achieve.
• Artificial nails should not be worn in a clinical setting.

Steps for Washing Hands Using Soap and Water

1. Wet hands with clean, running warm water. Make sure the water is not too cold or too hot. Temperature extremes can lead to drying and chapping of the skin.
2. Apply soap.
3. Rub hands together for at least 20 seconds (as recommended by the CDC), using friction to help lift debris from the skin. Pay attention to all surfaces, including the knuckles, skin between the fingers, and the first 1 inch of the forearm. Microbes tend to concentrate near and under the nails, so give special attention to these areas.
4. Rinse hands thoroughly with running water, taking care to remove all of the soap.
5. Dry with a clean towel or an air dryer. If using a standard faucet, use a paper towel to turn the faucet off once the hands are clean and dry to avoid exposing hands to a contaminated surface.

When to Use Hand Hygiene Even With Gloves

• The combination of water and friction are the most effective means of achieving medical asepsis.
• Proper hand hygiene must be used in the following situations even if disposable gloves are used.
  • Before and after patient contact
  • After contact with contaminated surfaces
  • After contact with blood or other body fluids
  • Before performing an aseptic procedure (blood draw, medication administration)
  • Before and after contact with supplies or equipment near patients
  • After contact with a contaminated body site prior to contact with a clean body site
  • After glove removal

Alcohol-Based Hand Sanitizer

• When hands are not visibly soiled, you may use an alcohol-based hand sanitizer that has at least a 60\% concentration of alcohol.
• Hand sanitizers do not remove all microbes—for example, they do not remove norovirus, Clostridium difficile (C. diff), or Escherichia coli (E. coli).
• Many hospitals, clinics, and other facilities provide wall-mounted or stand-alone sanitizer dispensers to promote regular attention to hand hygiene.

Steps for Using an Alcohol-Based Sanitizer

1. Apply an ample (enough to cover all surfaces) amount of product into the palm of one hand.
2. Rub hands together, creating friction for several seconds.
3. Make sure to cover all surfaces, paying special attention to the nails, nail beds, knuckles, and the skin between the fingers.
4. Continue rubbing until the solution has dried (usually around 20 seconds).

Important Considerations

• Sanitizers can be a good solution in specific circumstances, but they should not be used if hands are visibly dirty.
• Soap and water must be used to remove debris and wash hands.

Biohazard Material Disposal

• OSHA also requires the disposal of infectious and hazardous waste according to safety standards.
• The use of PPE and Safety Data Sheets (SDSs) provide health care workers with the tools and resources to maintain a safe clinical work environment.
• The proper identification and disposal of contaminated material is another step in preventing the spread of infectious material.
• Any item that comes into contact with blood or body fluids must be disposed of properly.
• Needles must not be recapped, but rather placed in a sharps container immediately after use.
• Any item that has sharp edges or blades—such as a scalpel—should also be placed in a sharps container.
• Sharps containers must be made of a puncture-proof, leak-proof material and be labeled with the biohazard symbol.
• When a sharps container is two-thirds full, the container should be sealed and placed in the designated area for disposal.
• Gloves, gauze, bandages, and other items that do not have sharp edges or contain needles should be placed in a biohazard bag, which is leak-proof and labeled with the biohazard symbol.
• All biohazard waste must be contained and identified with the biohazard symbol.
• Bags used to collect infectious material must be made of an impermeable polyethylene or polypropylene material.
• A lid must be present on all boxes or receptacles and replaced after each use.
• All medical facilities have to abide by OSHA standards regarding biohazard material handling and disposal.
  • Safety Data Sheets (SDSs) are documents containing information regarding chemicals in the work environment.

Safety Data Sheets (SDSs)

• OSHA requires that all employers provide SDSs to their employees.
• Any time a new chemical is brought into the work environment, SDS information must accompany the chemical.
• Technicians work with solutions ranging from mild detergents to toxic chemicals.
• The following information must be included on the SDS to communicate the hazards and actions necessary if exposure to the chemical occurs.

Information on the SDS

1. Identification:
   • Product identifier, manufacturer information, recommended use, and restrictions on use
2. Hazard Identification:
   • All hazards related to the chemical including label requirements
3. Composition/Ingredients:
   • Chemical ingredients
4. First-Aid Measures:
   • Symptoms and effects from exposure, including necessary treatment
5. Fire-Fighting Measures:
   • Appropriate extinguishing methods and chemical hazards from fire
6. Accidental Release Measures:
   • Emergency procedures, PPE, containment, and clean-up
7. Handling and Storage:
   • Safe handling and appropriate storage requirements
8. Exposure Controls/Personal Protection:
   • Recommended exposure limits and necessary PPE
9. Physical and Chemical Properties:
   • Chemical characteristics
10. Stability and Reactivity:
    • Chemical stability and potential reactions
11. Toxicological Information:
    • Measures of toxicity, acute and chronic effects, and routes of exposure; ecological, disposal, transport, and regulatory information regarding the chemical
12. Other Information:
    • Additional information, including revision date

Exposure Control Plan

• OSHA requires all health care facilities to develop and annually review an effective Exposure Control Plan specific to the organization.
• At a minimum, the plan must consist of the following.

Components of an Exposure Control Plan

1. Protections in place for jobs with exposure to infectious material
2. Use of PPE
3. Action plans when an exposure incident occurs
4. Labeling of hazardous substances
5. Immunizations offered
6. Record-keeping
7. Training for employees related to bloodborne pathogen standards

Reducing Accidental Exposure

• To reduce accidental exposure, employees must implement infection control practices, use safeties on devices, properly dispose of potentially infectious material, and obtain HBV immunizations.
• All staff should regularly review safety practices and precautions in the workplace safety manual, including clear explanations that describe the steps to take when an incident occurs.
• Examples of accidental exposure are a needlestick with a used needle; a splash into the eyes, nose, or other orifice; or a cut or puncture from a used instrument.

Steps Following an Accidental Needlestick

1. Immediately decontaminate the puncture site with an antiseptic (such as iodine) or soap and water.
2. Notify the immediate supervisor. Provide information such as how the exposure occurred; the department or area where it occurred; and which equipment, PPE, and safety measures were used. Document this information in the sharps injury log and on the facility’s incident report form.
3. Have a medical examination as soon as possible from an urgent care, emergency department, or other available health care support. The provider will ask which vaccines you have had and will likely test for HIV, HBV, and hepatitis C.
4. If the patient has any other infectious disease, you should undergo testing for those diseases as well. The patient should also undergo testing for infections but needs to provide consent for blood tests.
5. If the patient refuses testing, is unavailable for testing, or already has documentation of HIV, HCV, or HBV, you should undergo postexposure prophylaxis.
   • For HIV, the series of injections should begin within 2 hours of exposure.
   • If the patient has HBV, the provider will determine your vaccine status. If you have not had HBV immunization, the postexposure prophylaxis will include that immunization.
   • There is no prophylaxis for HCV, but you should still consult with a health care professional.
6. After the initial evaluation, have follow-up examinations at the discretion of the professional who provided the initial examination.

Steps Following Accidental Fluids Exposure

1. After a splash of a body fluid or contaminated material into the eyes, nose, or mouth, immediately flush the areas with large amounts of water. An eye wash station is preferred, but you may use an accessible sink or a commercially prepared product, which is usually sterile saline solution.
2. Report the exposure to the immediate supervisor. Include information such as how the incident occurred, the time and location of the incident, and the substance involved.
3. Seek emergency medical examination to determine what further testing and treatment are necessary.

Steps Following a Cut

1. If a cut or other break in the skin occurs with a contaminated piece of equipment, flush the area with water and then wash it with soap and water.
2. Notify the immediate supervisor. Include how and where in the facility the cut occurred, the time and date of the incident, and what type of equipment caused the cut.
3. Seek prompt medical assessment and treatment.
4. An incident report should be completed as soon as possible following the exposure.

General Considerations for Accidental Exposure

• Consider any accidental encounter, splash, cut, or puncture involving blood or body fluids a possible source of infection.
• Know the location and have a thorough understanding of the resources you might need before accidental exposure incidents occur.
• Regularly reviewing the facility’s accidental exposure policies and procedures will help you locate necessary supplies and understand the importance of the documentation so you can take the proper steps in the event of an incident.