pt1. 17/18

Key Abbreviations

• AIDS — Acquired immunodeficiency syndrome

• HIV — Human immunodeficiency virus

• C. diff — Clostridioides difficile; Clostridium difficile

• MDRO — Multidrug-resistant organism

• cm — centimeter

• MRSA — Methicillin-resistant Staphylococcus aureus

• EPA — Environmental Protection Agency

• OPIM — Other potentially infectious materials

• GI — Gastro-intestinal

• HAI — Healthcare-associated infection

• OSHA — Occupational Safety and Health Administration

• PPE — Personal protective equipment

• HBV — Hepatitis B virus

• VRE — vancomycin-resistant Enterococci

Infection and Antisepsis

• Infection is a disease state resulting from the invasion and growth of microbes in the body.

• Infection safety and health hazard: minor infections are short-term; some infections are serious and can cause death.

• At-risk groups: Infants, older persons, and disabled persons.

• Infection control: Practices and procedures that prevent the spread of infection; goal is to protect patients, residents, visitors, and staff from infection.

• Antisepsis: Processes, procedures, and chemical treatments that kill microbes or prevent them from causing an infection.

  • Etymology: Anti = against; Sepsis = infection.

Microorganisms

• Microorganism (microbe): a small living thing seen only with a microscope; commonly called germs; microbes are everywhere (mouth, nose, respiratory tract, stomach, intestines, skin, air, soil, water, food, animals, clothing, furniture).

• Pathogens vs non-pathogens:

  • Pathogens cause infection.

  • Non-pathogens do not usually cause infection.

Types of Microbes

• Bacteria: $1$-celled organisms that multiply rapidly; can cause infection in any body system.

• Fungi: Plant-like organisms (mushrooms, yeasts, mold) that can infect mouth, vagina, skin, feet, and other body areas.

• Protozoa: $1$-celled animals; can infect blood, brain, intestines, and other areas.

• Rickettsiae: Found in fleas, lice, ticks, and other insects; transmitted via insect bites (e.g., Rocky Mountain spotted fever causes fever, chills, headache, rash).

• Viruses: Grow in living cells; cause diseases such as the common cold, herpes, AIDS, and hepatitis.

Multidrug-Resistant Organisms (MDROs)

• MDROs are microbes that resist effects of antibiotics; some microbes change their structures and survive in the presence of antibiotics, making infections hard to treat.

• Causes include over-prescribing antibiotics and not completing prescribed courses.

• Common MDROs:

  • MRSA — Methicillin-resistant Staphylococcus aureus: Staph in nose/skin; resistant to many antibiotics; can cause serious wound, bloodstream infections, and pneumonia.

  • VRE — vancomycin-resistant Enterococci: Enterococcus in intestines/feces; transmitted by contaminated hands, toilet seats, care equipment; can cause urinary tract, wound, pelvic infections when not in the intestines; resistant to vancomycin.

Normal Flora

• Normal flora are microbes that inhabit a specific area and are non-pathogenic when in their natural reservoir.

• Example: Escherichia coli (E. coli) normally in the colon; if E. coli enters the urinary system, it can cause an infection.

Requirements of Microbes

• Microbes need a reservoir (host) to live and grow.

• The reservoir is the place where a microbe lives and grows (people, plants, animals, soil, food, water).

• Microbes require water and nourishment from the reservoir; most need oxygen to live; warm and dark environments; grow best at body temperature.

• Microbes are destroyed by heat and light.

The Chain of Infection

• The chain of infection (Fig. 16-1) involves:

  • Source — a pathogen.

  • Reservoir — place where the pathogen grows; a carrier is a human or animal reservoir that does not develop infection; carriers can pass pathogens to others; a vector is a carrier (animal, insect) that transmits disease (examples: dogs carry rabies; mosquitoes carry malaria; ticks carry RMSF; mites cause scabies).

  • Portal of exit — the pathogen leaves the reservoir (respiratory, GI, urinary, reproductive tracts; breaks in the skin; blood).

  • Method of transmission — the pathogen is transmitted to another host (Fig. 16-2, p. 224). A vehicle is any substance that transmits microbes.

  • Portal of entry — the pathogen enters the body (same routes as exit).

  • Susceptible host — the microbe needs a host to grow; susceptible hosts are at risk.

• Susceptible hosts include:

  • Very young or very old individuals

  • People who are ill

  • People exposed to the pathogen

  • People who do not follow infection prevention practices

• Figure reference: FIGURE 16-1 The chain of infection (redrawn and modified from Potter et al., Fundamentals of nursing, ed 9, Elsevier, 2017).

Disinfection, Sterilization, and Aseptic Measures

• Disinfection: Process of killing pathogens; spores are not destroyed.

  • Spores have a hard shell and are killed by very high temperatures.

  • Disinfectants are liquid chemicals that kill many or all pathogens except spores.

  • Used for cleaning: counters, tubs, showers, and re-usable items (blood pressure cuffs, commodes, bedpans, shower chairs, wheelchairs, stretchers, furniture).

  • Related resources: Focus on Long-Term Care and Home Care: Disinfection; Promoting Safety and Comfort: Disinfection.

• Sterilization: Destroys all non-pathogens, pathogens, and spores; uses very high temperatures.

  • Methods include heat, boiling water, radiation, liquid or gas chemicals, dry heat, and steam under pressure.

  • An autoclave is a pressure steam sterilizer (Fig. 16-13).

  • Items typically sterilized: glass, surgical items, and metal items; high temperatures can destroy plastic and rubber items, which are not autoclaved.

  • Related resource: Focus on Long-Term Care and Home Care: Sterilization.

• Other Aseptic Measures: Hand hygiene, cleaning, disinfection, and sterilization are important aseptic measures; Box 16-4 lists additional measures useful in home and health care settings and in everyday life.

Bloodborne Pathogen Standard

• The Bloodborne Pathogen Standard protects health team members from exposure to bloodborne viruses, primarily HIV and HBV.

• It is a regulation of the Occupational Safety and Health Administration (OSHA).

• HIV and HBV exits from the body through blood and spread to others via blood and other potentially infectious materials (OPIM).

• Related references: Focus on Surveys: Bloodborne Pathogen Standard (Laundry); Focus on Long-Term Care and Home Care: Bloodborne Pathogen Standard (Regulated Waste); Promoting Safety and Comfort: Bloodborne Pathogen Standard.

Exposure Incidents

• An exposure incident is any eye, mouth, other mucous membrane, non-intact skin, or parenteral (piercing mucous membranes or skin) contact with blood or OPIM.

• Causes include needle-sticks, human bites, cuts, and abrasions.

• Reporting: Report exposure incidents at once.

• Medical evaluation, follow-up, and testing are provided free of charge.

• Blood testing: Your blood is tested for HIV and HBV; if you refuse testing, the blood sample is kept for at least 90 days; testing can be performed later if you desire.

• Confidentiality is important; you are told about any medical conditions that may need treatment.

• Written medical opinion: You receive a written opinion within 15 days after evaluation is complete.

• The source individual is the person whose blood or body fluids are the source of the exposure incident.

• The agency informs you about laws affecting the source's identity and test results.

• Related references: Law and policy guidance regarding the Bloodborne Pathogen Standard and regulated waste.

Focus on Key Concepts and Real-World Relevance

• Infection control is foundational in nursing and health care to prevent spread of infection to patients, residents, visitors, and staff.

• Understanding MDROs (e.g., MRSA, VRE) is critical for choosing appropriate antibiotic use and infection prevention strategies.

• The chain of infection helps identify intervention points: breaking any link (source, reservoir, exit, transmission, entry, or susceptible host) reduces risk.

• Aseptic technique and proper disinfection/sterilization are central to preventing infection transmission in clinical and home-care settings.

• The Bloodborne Pathogen Standard governs safe handling of blood and OPIM, with procedures for exposure incidents to safeguard workers' health and confidentiality.

Practical Implications and Examples

• Real-world example: E. coli is normal flora in the colon but can cause urinary tract infections if introduced into the urinary system.

• RMSF example: Rocky Mountain spotted fever presents with fever, chills, headache, and rash after a tick bite.

• MDRO prevention: Appropriate antibiotic stewardship reduces selection pressure for resistant organisms.

• Exposure management: Immediate reporting and follow-up testing protect both employee and patient health, with legally defined timelines for documentation (e.g., 15 days for written opinion).