Infectious Agents and Infection Control - Vocabulary Flashcards
Normal Flora, Pathogens, and Infection Basics
Infection definition: an organism that causes disease is a pathogen; when a pathogen invades and causes disease, an infection occurs.
Normal flora: bacteria that naturally live on and in our bodies (skin, mucous membranes, etc.); these organisms help provide initial defense against infection.
Balance and disruption: killing or overcleaning can disrupt normal flora, reducing first line of defense; disruption may allow opportunistic microorganisms to take over.
Opportunistic microorganisms: pathogens that take advantage when normal flora or host defenses are compromised; can cause disease in the right (or wrong) conditions.
Concept of hemostasis disruption by opportunists: when an opportunistic organism hijacks the balance, disease or infection can occur.
Pathogens and quorum: as time passes, more pathogens and viruses are identified; infection risk evolves with new pathogens.
Example reference: emergence and variants (e.g., COVID-19) illustrate how pathogens evolve; even with antibodies, illness can persist or recur due to variants.
Pathogens, Variants, and Vaccination Context
All pathogens are infectious organisms; infection risk grows as new pathogens and variants emerge.
COVID-19 context: notable for multiple variants; antibodies may form but illness can still be experienced with variants.
Influenza context: influenza has numerous variants; vaccination is discussed as a strategy to reduce risk among a population.
Flu shot discussion and policy examples:
Personal stance: some individuals choose not to get flu shots; personal beliefs and medical considerations influence decisions.
Hospital/clinical program implications: in some settings, there are expectations or exemptions considered (e.g., exemption processes for healthcare workers); debates exist about mandates.
Historical note: during the COVID era, vaccine mandates in some workplaces raised questions about legality and individual choice; subsequent changes in policy occurred.
Hepatitis B vaccine for healthcare workers:
Employers are often required to offer the HBV vaccination free of charge or provide the antibody titer to verify immunity.
Rationale: Hepatitis B can be life-threatening, especially for workers exposed to blood.
Personal anecdotes and ethical implications:
Individuals may have strong opinions about vaccines; respect for others’ choices is emphasized.
Real-world implications include balancing personal autonomy with public health safety in clinical environments.
Vaccination decisions and workplace realities:
In some clinical settings, individuals may face choices about vaccination to participate in certain activities (e.g., clinical rotations).
The broader theme is that choices often come with trade-offs (e.g., access to work or program participation).
Personal COVID Experience and Ethical/Practical Implications
Personal COVID illness: significant impact on the speaker’s health and family; experience included severe illness and loss of a spouse.
Impact on work: long recovery and time off; vaccine decisions were framed by the need to continue working and provide for family.
Vaccine decision framing:
In certain circumstances, vaccines were presented as a condition to work or participate in clinical programs.
The speaker emphasizes personal autonomy in choosing whether to vaccinate, while acknowledging the real-world consequences of that choice.
Ethical/practical takeaway:
Balancing individual choice with public health and occupational requirements;
The importance of informed decision-making and access to information.
Healthcare-Associated Infections (HAIs), MRSA, and Clinical Considerations
MRSA (Methicillin-Resistant Staphylococcus aureus): a common hospital-acquired infection; resistant to many antibiotics; requires special precautions.
Colonization vs. infection:
Many individuals may be colonized with MRSA (carrying the bacteria without active infection); colonization can still pose transmission risks.
Percutaneous injury and entry points:
Percutaneous injury = needle-stick injury; skin punctures create portals of infection.
A clean needle can still pose risk if it becomes contaminated during handling.
Portal of infection concept:
Any skin breach (cuts, punctures) can serve as a portal for pathogens to enter the body.
Human bites:
Human bites can transmit pathogens (including HIV if blood is involved); generally more problematic than animal bites.
If a bite occurs in a clinical setting, report and assess the risk and contagion status.
Equipment contamination and transmission risks:
Inadequate cleaning of equipment can transmit pathogens; unseen blood or fluids still pose risk.
Lab scenarios emphasize gloves and proper handling to reduce exposure.
Droplet transmission and TB testing:
Droplet transmission occurs via respiratory droplets expelled by coughing, sneezing, talking.
TB-related testing and precautions are part of infection-control training.
Virus survival on surfaces:
Viruses can survive longer on hard surfaces than many bacteria; reinforces the need for proper disinfection and PPE in labs.
Urine samples and other biohazards:
Handling urine or other body fluids requires gloves and careful handling; sanitize and prevent splashes.
Lab safety practices and PPE usage:
In lab settings: wear gloves, face shields, and sometimes full PPE depending on procedure.
When pouring from uncapped tubes, full-face protection is recommended to prevent splashes.
Portal of Entry, Transmission Pathways, and the Chain of Infection
Chain of infection: three primary elements define the chain at a basic level:
Reservoir: where the pathogen normally lives (ill patient, spill, etc.).
Portal of exit: how the pathogen leaves the reservoir (coughing, vomiting, diarrhea, touching, etc.).
Mode of transmission: how the pathogen moves from reservoir to new host (direct contact, indirect contact, droplets, airborne, common vehicle, vector).
Susceptible host: an individual at risk due to weakened immunity or other factors.
Portal of entry: how the pathogen enters the new host (cuts, nonintact skin, mucous membranes, inhalation, etc.).
Modes of transmission (five main categories):
Direct contact: person-to-person touch.
-Indirect contact: contact with contaminated surfaces or objects.Droplets: large respiratory droplets that travel short distances.
Airborne: small particles that can remain suspended in air and travel longer distances.
Common vehicle: a shared source (contaminated food, water, or other vehicle) that transmits pathogens.
Vector (as described in the lecture): an agent that carries the pathogen; note that textbook definitions distinguish vectors (e.g., mosquitoes) from the pathogen itself.
Common vehicle example:
Shaking hands with someone who is sick can transfer pathogens if hands are contaminated.
Timing of contagion:
People can be contagious several days before symptoms appear in many infections; this complicates control measures.
Hospital-associated infection focus:
Emphasizes preventing transmission through hand hygiene, PPE, isolation, and standard precautions.
Protective Measures: PPE, Hand Hygiene, Isolation, and Precautions
Personal protective equipment (PPE) basics:
Gloves, masks, gowns, hair nets, shoe covers, eye/face protection (goggles or face shields).
In the lab, face shields are used routinely when pouring from uncapped tubes to prevent splashes.
The required PPE depends on the procedure and the expected exposure.
N95 respirators and fit testing:
In clinical settings, proper fit testing for N95 respirators is necessary; the current context notes fit testing may not be performed for non-clinical students.
Standard precautions:
Treat every patient as if they could be infected with something dangerous; applies universally regardless of apparent health status.
Isolation and patient placement:
Isolate patients with infectious diseases (e.g., MRSA) in single rooms with appropriate signs and precautions (gloves, gown, mask as specified on the door).
Isolation also serves to protect vulnerable patients (e.g., those with cancer undergoing chemotherapy) from exposure.
Housekeeping of infection control in clinical areas:
Some individuals may require enhanced precautions (e.g., lice, scabies) with full PPE; examples are given to emphasize strict adherence to isolation protocols.
Common PPE workflow in labs:
Don PPE before handling specimens; change PPE between patients or tasks to prevent cross-contamination.
Lab safety checks and environment:
Standard precautions include never assuming surfaces are clean; gloves are used for contact with potentially contaminated surfaces.
Surfaces and equipment management require careful adherence to safety guidelines.
Sharps and biohazard disposal:
Sharps containers are required for all sharp items; only sharps go into sharps containers.
Improper disposal (e.g., putting gauze in sharps containers) leads to severe fines (example given: $10,000 per item).
Biohazard labeling and proper disposal of all biohazardous waste are mandatory.
Spill response and disinfection:
In the event of a spill of blood or other hazardous material, wear gloves and use a 10% bleach disinfectant or facility-approved agent.
Allow the disinfectant to remain in contact for at least 20\,\text{minutes} to ensure kill-off of pathogens.
OSHA, Bloodborne Pathogens, and Workplace Safety Policies
Written exposure control plan:
Employers must have a written bloodborne exposure plan; if not, the employer is out of compliance.
Vaccination and post-exposure protocols:
Employers must offer the hepatitis B vaccine free of charge or provide post-exposure documentation (titer) to verify immunity.
They must provide free medical follow-up if there is a potential exposure (e.g., needle-stick).
Training and education:
Annual OSHA-compliant training on safety and infectious disease precautions is required.
Labeling and disposal requirements:
All biohazardous materials must be properly labeled and disposed of in appropriate containers (sharps, biohazard bags, etc.).
PPE sizing and accessibility:
Employers must accommodate proper PPE sizes; if only small gloves are available, they must provide medium or appropriate sizes.
Additional Notes on Practice, Exam, and Course Logistics
Exam and assessment context:
Certification tests are typically around 150 questions; content coverage varies by exam; not all topics may appear on every test.
Instructor plans to provide printed notes and slides with notes to help students study; look for alignment between notes and exam emphasis.
Practical lab considerations:
The instructor emphasizes that PPE and safety practices are essential regardless of whether one is in a clinical setting; the same principles apply in the lab.
Final takeaways:
Always wash hands and use PPE appropriately.
Treat all patients as potential infection sources (standard precautions).
Follow the chain of infection framework to understand how infections spread and how to interrupt transmission.
Understand the rationale behind vaccination policies and safety measures, including exemptions and safety protocols, in the healthcare environment.
Key Figures and Concepts to Remember
Pathogen, infection, and disease concepts; role of normal flora as defense.
Opportunistic pathogens and factors that shift the balance (host immunity, microbiome disruption).
Transmission modes: direct contact, indirect contact, droplets, airborne, common vehicle, vector.
Chain of infection components: reservoir, exit, transmission, entry, susceptible host.
PPE and standard precautions as foundational infection control.
MRSA as a major resistant organism in healthcare settings.
Bloodborne pathogens, OSHA requirements, vaccination policies, and post-exposure protocols.
Practical realities of clinical training: PPE availability, fit testing, and policy variations across institutions.
Quick Reference for Formulas and Numeric References
Red blood cells reference: 30{,}000{,}000 cells on the head of a pin (illustrative analogy of cell size and density).
Fever reference: 104^{\circ}\mathrm{F}.
Bleach contact time for disinfection: 20\,\text{minutes}.
Certification exam length reference: 150 questions.
Time-related references: 24\,\text{hours} (example timing in illness trajectory).
Vaccination access and requirements: vaccines can be provided free of charge or via antibody titer verification (HBV example); HAV note in transcripts is mentioned as HAB (likely a transcription error).