Infection Control and Standard Precautions Study Guide

Core Principles of Infection Control

• Organization and Affiliation: Presented by Michael Nuñez, CPT-1, for the UCLA Center for Prehospital Care.
• Presence: Infection control programs are a requirement in every healthcare facility.
• Primary Goal: To reduce the risk of endemic and epidemic infections in patients, personnel, and visitors.
• Body’s Natural Protections:     * Skin serves as a primary physical barrier.     * Mucous membranes provide internal protection.
• Primary Methods of Prevention:     * Hand washing.     * Personal Protective Equipment (PPE).     * Isolation precautions.

Fundamental Microbiology and Pathogens

• Microorganisms: Small, living organisms only visible with a microscope that are capable of causing disease. Categories include:     * Viruses.     * Protozoa.     * Fungi.     * Bacteria.     * Rickettsia.
• Pathogenic Organisms:     * Bloodborne Pathogen: Pathogenic organisms present in human blood that cause disease.     * Infection: The invasion of the body by pathogenic (disease-causing) bacteria, fungi, viruses, protozoa, or parasites.
• Growth Factors for Microorganisms:     * Aerobic vs. Anaerobic: Depends on the organism's need for oxygen.     * Moisture: High moisture areas such as skin, mucous membranes, wet dressings, and wounds facilitate growth.     * Temperature: The optimal temperature for growth is $37^\circ\text{C}$.     * Light: Bacteria generally favor darkness; Ultraviolet (UV) light and direct sunlight can kill bacteria.

Detailed Classification of Microorganisms

• Viruses:     * The smallest known microorganisms.     * Visible only via electron microscope.     * Resistant to chemotherapy treatments.     * Examples: Herpes simplex, Herpes zoster, HIV (Human Immunodeficiency Virus), Hepatitis B Virus (HBV), and Hepatitis C Virus (HCV).     * AIDS: Acquired Immunodeficiency Syndrome is the condition caused by HIV.
• Protozoa:     * Unicellular organisms.     * Move using cilia or "false feet" (pseudopodia).     * Examples: Amoebae ($E. histolytica$, $I. butschlii$, $E. nana$) and Malaria (caused by $Plasmodium vivax$, $ovale$, $malaria$, or $falciparum$).
• Fungi:     * Dimorphic characteristics: Exist as mold at $25^\circ\text{C}$ and as yeast at $37^\circ\text{C}$.     * Reproduction method: Budding.     * Nutrition: Live on other life forms (dead or decaying items) and can feed on antibiotics.     * Examples: $Tinea pedis$ (athlete’s foot) and $Candida albicans$ (candidiasis).
• Bacteria:     * The most numerous organisms, many of which are pathogenic to humans.     * Cocci (spherical):         * Staphylococcus: Associated with boils, acne, and osteomyelitis.         * Streptococcus: Associated with strep throat and scarlet fever.         * Diplococci: Associated with pneumonia and meningitis.     * Bacilli (rod-shaped): Examples include $E. coli$, $P. mirabilis$, $P. aeruginosa$, and Mycobacterium.
• Rickettsia:     * Specifically bacteria transmitted via insects.     * Classification: Gram-negative, coccobacilli.     * Treatment: Susceptible to antibiotics.     * Diseases: Rocky Mountain Spotted Fever and Lyme disease.
• Mycobacterium tuberculosis:     * Bacteria identified using an acid-fast stain (appears as red branching structures on a blue background).     * Cause of TB (Tuberculosis).

Laboratory Identification: The Gram Stain

• Purpose: To identify properties of the cell wall and help classify the organism.
• Gram-Positive Bacteria:     * Stain color: Purple.     * Structure: Thick cell wall.
• Gram-Negative Bacteria:     * Stain color: Pink/Red.     * Structure: Thin cell wall.
• Procedural Key:     1. Application of Crystal Violet (Primary stain).     2. Application of Iodine (Mordant).     3. Alcohol Wash (Decolorization).     4. Application of Safranin (Counterstain).

Infectious Fluids and Clinical Hazards

• Potentially Infectious Materials: Standard precautions apply to the following:     * Cerebrospinal fluid (CSF).     * Synovial fluid.     * Pleural fluid.     * Pericardial fluid.     * Peritoneal fluid.     * Amniotic fluid.     * Saliva in dental procedures.     * Any body fluid visibly contaminated with blood.     * Any unfixed human tissue or organ (living or dead).
• Nosocomial Infection (Healthcare-Associated Infection - HAI):     * An infection acquired after a person enters a healthcare facility (hospital, clinic, nursing home, rehab).     * Caused by the spread of infection from one person to another.     * Common Types:         * Catheter-associated Urinary Tract Infections (CAUTIs) - the most common HAI.         * Central-line associated bloodstream infections (CLABSIs).         * Ventilator-associated events (VAEs).         * Surgical site infections (SSIs).         * MRSA (Methicillin-resistant Staphylococcus aureus).         * $Clostridioides difficile$ ($C. difficile$).

Essential Safety Terms and Training Definitions

• Contaminated Laundry: Laundry soiled with blood or other potentially infectious materials.
• Contaminated Sharps: Any contaminated object capable of penetrating the skin (e.g., needles, scalpels).
• Decontamination: The use of physical or chemical means to remove or destroy bloodborne pathogens on a surface.
• Engineering Control: Protections that isolate or remove bloodborne pathogen hazards from the workplace (e.g., sharps disposal containers, self-sheathing needles).
• Parenteral Contact: Piercing of mucous membranes or the skin barrier through such events as needlesticks, human bites, or cuts.
• Exposure Incident: Specific eye, mouth, nose, mucous membrane, or parenteral contact with blood or infectious material.
• Occupational Exposure: Reasonably anticipated skin, eye, mucous membrane, or parenteral contact with blood/infectious materials during duty.
• Source Individual: Any individual (living or dead) whose blood or fluids may be the source of occupational exposure.
• Regulated Waste: Waste that must be disposed of following specific guidelines using an approved disposal company.

Personal Protective Equipment (PPE) Protocols

• Definition: Specialized clothing or equipment worn for protection against hazards.
• Donning Sequence (Putting On):     1. Gown.     2. Mask/Respirator (Surgical mask or N95 for respiratory protection).     3. Goggles or Face Shield (Eye protection).     4. Gloves (The last item put on).
• Doffing Sequence (Taking Off):     1. Gloves (Considered the most contaminated; removed first).     2. Gown/Face Shield.     3. Mask (Often the last thing removed depending on facility protocol).

Standard and Universal Precautions

• The Concept: All human blood, body fluids, secretions, and excretions (excluding sweat), non-intact skin, and mucous membranes must be treated as if they are infectious for HIV, HBV, HCV, and other pathogens.
• Authority: Established by the CDC (Centers for Disease Control) and enforced by OSHA (Occupational Safety and Health Administration).
• Application: Required for all patients regardless of diagnosis or known infectious status.
• Specific Guidelines:     * Gloves: Wear when drawing blood or exposed to body fluids; change after every patient, every 30 minutes, or if contaminated.     * Body Protection: Wear a gown if splashing is possible; wear a mask for airborne diseases.     * Sharps Safety: Use sharps with extreme care to avoid needlesticks; never recap used needles; dispose of sharps only in designated containers.     * Sanitation: Wash hands/skin immediately if contaminated; use a $1:10$ bleach (Sodium hypochlorite) solution or OSHA-approved disinfectant for surfaces and equipment.     * Workplace Rules: No eating, drinking, smoking, gum chewing, or cosmetic application in laboratory/work areas.

The Chain of Infection

• Components: A cycle of six factors required for an infection to occur. Breaking any link prevents infection.     1. Infectious Agent (Pathogen): Disease-causing organism (Bacteria, Viruses, Fungi, Protozoa, Prions).     2. Reservoir: The source/habitat where the agent lives (Human, Animal, Equipment, Food, Soil, Water).     3. Portal of Exit: Means of escape from the reservoir (Blood, Exudates, Secretions, Excretions, Skin).     4. Mode of Transmission: How the pathogen travels (Physical contact, Airborne, Droplet, Vector, Vehicle).     5. Portal of Entry: Means of entering the host (Body orifices, mucous membranes, respiratory/digestive systems, broken skin).     6. Susceptible Host: An individual unable to fight off the pathogen (Elderly, Newborn, Immunocompromised, Unvaccinated).

Transmission-Based Isolation Types

• Contact Isolation:     * For diseases spread by direct contact (e.g., $C. difficile$, MRSA, Group A Strep, Cutaneous diphtheria).     * Equipment should stay in the room or be disposed of there.
• Droplet Isolation:     * For pathogens spread by droplets $> 5\,\mu\text{m}$.     * Examples: Influenza, Pertussis (Whooping cough), Rubella, Neisseria meningitidis.
• Airborne Isolation:     * For pathogens spread by droplets $< 5\,\mu\text{m}$.     * Requirement: Negative pressure room and N95 respirator.     * Examples: Tuberculosis (TB), Measles, COVID-19, Varicella (Chickenpox).
• Enteric Isolation:     * For intestinal infections (e.g., Salmonella, Shigella, Hepatitis A).
• Protective (Reverse/Neutropenic) Isolation:     * To protect non-infectious, highly susceptible patients from the environment (e.g., Cancer patients).     * Requires sterile gloves and strict PPE.

Regulatory Agencies: OSHA and NIOSH

• OSHA (Occupational Safety and Health Administration):     * A federal agency that mandates and enforces safe working conditions.     * Employer Responsibilities: Provide Hepatitis B vaccinations at no cost; maintain a written Exposure Control Plan.     * Employee Responsibilities: Strictly adhere to OSHA standards and practice universal precautions.     * Needlestick Safety and Prevention Act: OSHA revision requiring employee input on engineering controls and the maintenance of a sharps injury log.
• NIOSH (National Institute for Occupational Safety and Health):     * Federal institute responsible for conducting research and making recommendations for the prevention of work-related injuries.     * Focuses on reducing occupational chronic diseases (cancer, hearing loss, etc.) and promoting healthy work design.
• OSHA Housekeeping Procedures:     * Disinfect all surfaces immediately with $1:10$ bleach after exposure.     * Sharps containers must be closed to the work area, never overfilled, and replaced when $2/3$ full.     * Never remove broken glass with hands; use a dust-pan.     * Contaminated laundry must be bagged separately and not washed with non-contaminated items.

Questions & Discussion

• Q: What is the first action after an accidental needlestick?     * A: Clean the site with soap and water for at least 30 seconds.
• Q: What mask is required for Pulmonary Tuberculosis?     * A: N95 respirator, as it is an airborne disease.
• Q: What is the schedule for the Hepatitis B vaccine?     * A: A first shot, a second shot one month later, and a third shot six months after the first.
• Q: What is the definition of Hemolysis and Hemostasis?     * A: Hemolysis is the breakdown of red blood cells; Hemostasis is the stoppage of blood flow (clotting).
• Q: Identify the largest blood vessels.     * A: The largest artery is the Aorta; the largest veins are the Superior and Inferior Vena Cava.
• Q: What is Proxemics?     * A: The study of an individual’s concept and use of space. The personal "zone of comfort" is a radius of $1.5$ to $4\,\text{ft}$.
• Q: What laboratory department handles blood cultures and parasite testing?     * A: Microbiology.
• Q: What does QNS stand for?     * A: Quantity Not Sufficient.
• Q: What percentage of information used for diagnosis and treatment comes from blood tests?     * A: Approximately $70\%$.
• Q: What is the primary purpose of wearing gloves during phlebotomy?     * A: To protect the phlebotomist from exposure to the patient's blood.
• Q: How should a sharps container be managed?     * A: It should be replaced when it is $2/3$ full.