Infection Control Concepts

Infection Cycle

• Components: Infectious agent (bacteria, viruses, fungi), reservoir (natural habitat), portal of exit (escape point), means of transmission (contact, airborne), portal of entry (entry point), susceptible host (overcomes host defenses).

Types of Infectious Agents

• Bacteria: Most common in healthcare settings, significant for infections.
• Virus: Smallest microorganisms, require electron microscope for visualization.
• Fungi: Plant-like organisms, found in various environments (air, soil, water).

Classification of Bacteria

• Shapes: Spherical (cocci), rod-shaped (bacilli), corkscrew (spirochetes).
• Gram Staining: Categorized as gram-positive or gram-negative.
• Oxygen Requirement: Divided into aerobic (requires oxygen) and anaerobic (does not require oxygen).

Infection Factors

• Disease Potential: Influenced by organism number, virulence, immune competence, and contact length/intimacy.

Reservoirs for Microorganisms

• Common reservoirs include other people, animals, soil, food, water, and inanimate objects.

Transmission of Infections

• Contaminated Articles: Influenza can be spread by touching contaminated inanimate objects.

Stages of Infection

• Incubation Period: Organisms grow and multiply.
• Prodromal Stage: Patient is most infectious, displaying vague symptoms.
• Full Illness Stage: Manifestation of specific disease signs and symptoms.
• Convalescent Period: Recovery phase.

Portals of Exit

• Common routes include respiratory, gastrointestinal, genitourinary tracts, skin breaks, and blood/tissue.

Host Susceptibility Factors

• Influencing factors: intact skin and mucous membranes, normal pH levels, immune system status, age, sex, race, immunization history, health status, and use of medical devices.

Infection Control Practices

• Emphasize effective hand hygiene, recognition of infection signs, adequate nutrition, proper disposal of soiled items, cleaning techniques, awareness of immunization, and stress reduction.

Cardinal Signs of Infection

• Key indicators: redness, heat, swelling, pain, loss of function.

Laboratory Indicators of Infection

• Elevated white blood cell count (normal: 5,000-10,000/mm³), specific white blood cell increases, raised erythrocyte sedimentation rates, pathogen presence in cultures.

Hand Hygiene Moments (WHO)

• Five key moments: Before patient contact, before aseptic procedures, after body fluid risk, after patient contact, after touching surroundings.

Types of Bacterial Flora

• Transient Flora: Loosely attached, easily removed.
• Resident Flora: Found in skin creases, requires friction to remove.

Hospital-Acquired Infections (HAIs)

• Four major categories: urinary tract infections, surgical site infections, bloodstream infections, pneumonia.

Risk Factors for VRE

• Includes compromised immune systems, recent surgeries, presence of catheters, prolonged antibiotic use, and lengthy hospital stays.

C. difficile Infection Prevention

• Recommendations include cautious antibiotic prescribing, contact precautions, effective hand hygiene, and thorough cleaning using bleach.

Measures to Reduce Nosocomial Infections

• Strategies: ongoing surveillance, clear infection-prevention guidelines, hand hygiene practices, and maintaining optimal patient health conditions.

Body’s Defenses Against Infection

• Natural Defenses: Normal flora, inflammatory response, and immune response.

Sterilization and Disinfection Considerations

• Factors include organism nature, quantity, equipment type, intended use, available methods, and duration.

Personal Protective Equipment (PPE)

• Key items: gloves, gowns, masks, protective eyewear.

Standard Precautions

• Applicable to all hospitalized patients, covering blood, bodily fluids, non-intact skin, and mucous membranes; now includes respiratory hygiene practices.

Aseptic Techniques

• Methods to prevent infection; includes medical asepsis (clean technique) and surgical asepsis (sterile technique).

Patient Home Teaching

• Emphasizes hand washing, food preparation, safe food storage, and personal hygiene.

Key Definitions

• Asepsis: Absence of disease-causing microorganisms.
• Antibody/Antigen: Immune response components.
• Infection: Disease caused by pathogenic microorganisms.
• Vector: Non-human carriers (e.g., mosquitoes) transmitting organisms.

Infection Stages

• Most contagious during the Prodromal Stage without patient awareness of the contamination.

Test your knowledge on the components of the infection cycle with this quiz. Learn about infectious agents, reservoirs, portals of exit and entry, and how transmission occurs. Perfect for healthcare students or anyone interested in infection control.