Infection Control

Asepsis and Infection Control

Introduction to Asepsis

• Asepsis is the state of being free from pathogenic microorganisms, and aims to prevent contamination, protecting both patients and healthcare workers.

• Medical asepsis involves practices to keep areas as clean as possible without making them sterile, reducing the number of microorganisms. This includes using alcohol-based sanitizers, bleach solutions, and regular hand soap.

• Surgical asepsis (sterile asepsis) ensures that items are free of all microbes and spores, maintaining a completely sterile environment. This is crucial during surgeries and invasive procedures to prevent infections.

Types of Microorganisms

• Pathogenic Microorganisms: Cause disease through various mechanisms, including tissue invasion and toxin production.

  • Examples: Bacteria (e.g., Streptococcus), fungi (e.g., Candida).

• Nonpathogenic Microorganisms: Do not cause disease and are part of the normal flora, aiding in digestion and immunity.

  • Examples: Bacteria in the nose or vaginal canal, E. coli in the colon (when in the colon only).

E. Coli as an Example

• In the colon, E. coli is nonpathogenic, aiding in vitamin K production and preventing colonization by harmful bacteria.

• In the digestive system or urethra, it becomes pathogenic, causing diseases like UTIs, gastroenteritis, and even sepsis.

• UTIs are often caused by women wiping the wrong way, transferring E. coli from the colon to the urethra, leading to infection.

Examples of Disease Transmission

• Picking your nose (which contains staph) and then putting your finger in your eye can cause conjunctivitis (pink eye), resulting in inflammation and discharge.

Communicable Diseases

• Communicable diseases must be reported to the National Notifiable Diseases System of the CDC through the local health department to monitor and control outbreaks.

• Examples of communicable diseases:

  • Chickenpox (Varicella)

  • Conjunctivitis (Pinkeye)

  • H Flu (Haemophilus influenzae)

  • Measles (Rubeola)

  • Meningitis (viral or bacterial)

  • MRSA (methicillin-resistant Staphylococcus aureus)

  • Mumps (Infectious Parotitis)

  • Pertussis (Whooping Cough)

  • Rubella (German Measles)

  • Strep Throat (Streptococcal Pharyngitis)

  • VRE (vancomycin-resistant enterococci)

Incubation Period

• Incubation Period: The time interval between exposure to an infection and the appearance of the first symptom, during which the pathogen multiplies without causing noticeable symptoms.

Susceptibility and Vulnerability

• Susceptibility: A person's likelihood of contracting a disease based on their immune system's strength, influenced by genetics and overall health.

  • Factors increasing susceptibility: stress, lack of sleep, poor nutrition, and chronic diseases.

• Vulnerability: Being liable to injury or harm due to weakened immunity or pre-existing conditions such as diabetes, HIV/AIDS, or immunosuppressant medications.

Pathogens and Their Requirements

• Pathogens: Microorganisms that cause disease by invading the host and disrupting normal bodily functions.

• Requirements for growth:

  • Warmth: Optimal temperature for replication.

  • Moisture: Necessary for metabolic processes.

  • Dark environments: Protection from UV radiation.

Normal Flora and Natural Immunity

• Normal flora helps maintain body balance and provides natural immunity against certain infections by competitive exclusion and producing antimicrobial substances.

Environmental Requirements for Microorganisms

• Oxygen: Some microorganisms need oxygen (aerobes) to produce energy through aerobic respiration, while others do not (anaerobes) and use anaerobic respiration.

• pH Levels:

  • Blood pH needs to stay between 4.35 and 4.45. If lower or higher, it can be fatal, leading to acidemia or alkalemia.

  • Bacteria thrive in higher alkalinity, which can disrupt the body's normal pH balance.

  • Ketosis (from not eating) can result in a pH less than 6, causing metabolic acidosis.

• Temperature:

  • Microorganisms grow best at the average body temperature of 98.6 degrees Fahrenheit or 37 degrees Celsius, facilitating rapid replication.

Other Growth Requirements

• Nutrients: Carbon, nitrogen, and other organic compounds.

• Water: Essential for cellular functions and transport.

• A host to inhabit: Provides a suitable environment for survival and reproduction.

Stages of Infection Control: Chain of Infection

• The infection cycle, or chain of infection, illustrates how diseases transmit from one person to another, emphasizing the interconnectedness of factors.

• Breaking the chain through methods like handwashing, sterilization, and proper disposal of contaminated materials is crucial in preventing the spread of infection.

Components of the Chain of Infection

1. Infectious Agent: A pathogen such as:

   • Bacteria: Single-celled organisms that can cause infections like pneumonia and sepsis.

   • Virus: Acellular entities that require a host to replicate, causing diseases like influenza and HIV.

   • Parasite: Organisms that live on or inside a host, causing diseases like malaria and giardiasis.

   • Fungi: Eukaryotic organisms that can cause infections like athlete's foot and candidiasis.

2. Sanitizing, Disinfecting, and Sterilizing are methods to break the chain of infection, reducing the microbial load on surfaces and preventing transmission. Handwashing is also essential.

Bacteria

• Bacteria vary in morphology (form and structure):

  • Spiral (e.g., Spirillum)

  • Round (e.g., Cocci)

  • Rod-shaped (e.g., Bacilli)

• Being present doesn't automatically mean disease; normal flora exists and plays a vital role in maintaining health.

• Single-celled microorganisms lack nuclei or organelles, reproducing through binary fission.

• Examples: E. coli (urinary tract and intestinal infections), Bordetella pertussis (whooping cough), Staphylococcus aureus (skin infections).

Viruses

• Viruses are the smallest microorganisms, viewed only by electron microscopes, consisting of genetic material (DNA or RNA) enclosed in a protein coat.

• Classified by type of DNA or RNA, determining their replication mechanisms and host specificity.

• Reproduce by attaching to a host cell, taking it over, and self-replicating, thus destroying the host cell and releasing new viral particles.

• Examples: HIV/AIDS, herpes, chickenpox, hepatitis, cold, flu, measles, and Zika virus.

• Viral infections must run their course; some viruses stay in the body indefinitely, such as Epstein Barr, causing mononucleosis and potentially leading to other complications.

• HPV (human papillomavirus) has many strains and can come and go, with some strains causing warts and others leading to cervical cancer.

Fungi

• Simple parasitic plants that depend on other life forms for nutrients, obtaining nourishment from living or dead organic matter.

• Molds (multicellular fungi) thrive in warm, dark, humid conditions, producing spores that can cause allergic reactions and respiratory issues.

• Yeast multiplies via budding, especially in sugary mediums, leading to infections like candidiasis.

• Diabetics must be cautious about yeast infections due to sugar in urine, which promotes the growth of Candida albicans.