Infectious Diseases and Infection Control

Antonie van Leeuwenhoek's Observations

• Leeuwenhoek observed microorganisms he called "wee animacules" over 300 years ago.
• His work laid the foundation for microbiology, crucial for understanding infectious diseases today.

Major Causes of Death in Early 20th Century

• Common causes included microbial infections such as pneumonia, tuberculosis, gastroenteritis, and diphtheria.
• Compared to modern times where many of these diseases can be treated effectively, understanding their historic impact is essential.

Importance of Understanding Infectious Diseases

• Health practitioners need to comprehend infectious diseases to prevent their spread, protect patients, themselves, and their families.
• Awareness and compliance with infection control procedures are critical as healthcare workers encounter infectious agents daily.

Definitions

• Infection: Establishment and growth of a microorganism in or on a host organism.
• Pathogen: Microorganism that can cause disease.
• Pathogens may multiply, cause tissue damage, or secrete exotoxins with symptoms like fever, shock, nausea.
• Four basic categories of infectious agents: bacteria, viruses, fungi, protozoan parasites.

Pathway of Infectious Disease Establishment

1. Encounter: Pathogen meets host.
2. Entry: Pathogen enters the host.
3. Spread: Pathogen disperses within host.
4. Multiplication: Incubation period where pathogens reproduce.
5. Damage: Host can experience direct or indirect damage due to pathogen activity.
6. Outcome:
   • Host can eliminate the pathogen.
   • Infection can overpower the host leading to disease.
   • Host and pathogen can coexist without causing symptomatic disease.

Avenues of Pathogen Transmission

• Reservoir: Environment where pathogens reside (e.g., urinary bladder for E. coli).
• Modes of Transmission:
• Exogenous: Infection from external sources (e.g., contaminated objects).
• Endogenous: Infection from internal sources (e.g., flora out of balance leading to UTIs).
• Direct Transmission: Contact (e.g., kissing).
• Indirect Transmission: Vectors (organisms that carry pathogens) or fomites (inanimate objects).

Preventing Nosocomial Infections (Hospital-acquired infections)

• Educate and adhere to infection control protocols.
• Iatrogenic Infections: Infections acquired due to medical procedures or healthcare environment.
• Patients with compromised immune systems are at higher risk for both nosocomial and iatrogenic infections.

Infection Control Practices

• Standard Precautions: Basic infection prevention protocols applied to all patients regardless of known infection status.
• Personal Protective Equipment (PPE): Essential for protecting healthcare workers and patients from infection.
• Hand Hygiene:
• Most effective method for preventing infection transmission.
• Requires both chemical (soap) and physical (rubbing hands) processes.
• Effective handwashing takes 7-8 minutes, though a minimum of 20 seconds is recommended for clinical practice.
• Isolation Precautions: Different precautions based on how infections spread through airborne, droplet, or contact.
• Cohorting: Placing multiple patients with similar infections in adjacent rooms to prevent broader spread and ease monitoring.

Aseptic Techniques

• Medical Asepsis: Reduction of pathogens (e.g., handwashing, disinfecting surfaces).
• Surgical Asepsis: Complete removal of pathogens (e.g., sterilizing instruments).

Chemical and Physical Methods

• Use of disinfectants and antiseptics to manage infections.
• Bacteriostatic agents inhibit growth, while Bactericidal agents kill bacteria.
• Steam sterilization (moist heat) is the most effective method of sterilization.

Proactive Infection Prevention

• Immune system support through vaccinations and good hygiene is critical.
• Probiotics can help maintain normal flora and support overall health.
• Emphasis on the importance of immunization to prevent outbreaks of vaccine-preventable diseases.

Key Takeaways

• Keep learning and stay updated on infection control practices.
• Regularly review infection prevention strategies, especially as new pathogens emerge.