IPC-Basic Micro

FETAC Level 5

• Infection Prevention and Control

• Class 1: Basic Microbiology

Unit 1: Basic Microbiology

Cells

• All living organisms made up of structures called cells.

• Most primitive organisms consist of a single cell.

• Higher animals consist of millions of cells grouped to perform particular functions (e.g., muscles, skin, hair).

Structure of Cells

• Cell Wall: Protects the cell and provides structure.

• Cytoplasm: Gel-like substance where cellular processes occur.

• Chromosome (DNA): Contains genetic information.

Micro-organisms

• Micro-organisms (microbes) are tiny living cells, visible only through a microscope.

• They are ubiquitous: found on/in the body, air, soil, water, food, clothing, animals, and furniture.

• Most microbes are harmless and essential for health or beneficial to the environment (e.g., gut bacteria for digestion).

• Resident Bacteria: Prevent growth of harmful bacteria in certain areas of the body; also known as commensals, normal flora, or non-pathogens.

Pathogens

• Some micro-organisms can cause harm by invading and damaging tissue, leading to disease; these are known as pathogens.

• An Infection: A disease resulting from the invasion and growth of pathogens.

Main Types of Pathogenic Micro-organisms

• Bacteria

• Fungi

• Protozoa

• Viruses

• Helminths

Types of Micro-organisms: Bacteria

• Bacteria are single-celled organisms visible through an optical microscope.

• Identified by three different shapes:

  • Cocci: Round-shaped bacteria.

  • Bacilli: Rod-shaped bacteria.

  • Spirella or Spirochetes: Spiral-shaped bacteria.

Specific Bacterial Infections

• Cocci can cause infections such as:

  • Streptococcus (strep throat)

  • Staphylococcus (staph infections)

• Bacilli can cause:

  • Tuberculosis (TB)

• Spirochetes can cause:

  • Syphilis

Types of Micro-organisms: Fungi

• Includes yeasts and moulds.

• Example infections caused by fungi:

  • Ringworm

  • Thrush

  • Athlete's foot

Types of Micro-organisms: Protozoa

• Protozoa are single-celled organisms that often live in water; some are parasites living in animals.

• Examples of diseases caused by protozoa:

  • Malaria

  • Sleeping sickness

Types of Micro-organisms: Viruses

• Viruses are the smallest micro-organisms, not visible with an optical microscope; require an electron microscope.

• Not true living cells; consist of genetic material.

• Cannot reproduce without a host cell.

• Examples of viral infections:

  • Poliomyelitis

  • Influenza

  • Varicella virus (chickenpox)

• Difficult to develop drugs that stop viruses without damaging host cells.

Types of Micro-organisms: Helminths

• Include roundworms, tapeworms, and flukes.

• Commonly found in tropical and subtropical countries.

Growth of Microbes

• Some bacteria grow with minimal nutrients; they produce necessary substances for growth.

• However, most bacteria require an external nutrient source.

Requirements for Microbial Growth

• Microbes need:

  • Water

  • Carbon: Provides energy.

  • Nitrogen: Essential for protein synthesis.

  • Correct Temperature: Optimal is 37°C.

  • pH Level: Neutral or slightly alkaline.

  • Oxygen: Some require it; others (e.g., in intestines) do not.

Microbial Multiplication: Bacteria

• Bacteria multiply through cell division called Binary Fission:

  • Cell grows to about twice its normal length.

  • A cell wall forms in the middle, dividing it into two identical cells.

  • Can divide every 20 minutes under optimal conditions.

Microbial Multiplication: Viruses

• Viruses multiply only in living host cells:

  • Invade a host cell and take control.

  • Host cell is forced to produce new virus particles.

  • Eventually, the host cell dies, releasing new virus particles.

Microbial Multiplication: Fungi & Yeasts

• Fungi multiply by producing spores that germinate and grow into new fungi (e.g., ringworm).

• Yeasts multiply by forming a bud, which grows larger and breaks off to become a new cell (e.g., Candida/thrush).

Spreading of Micro-organisms

• Primary infection spread methods:

  • Airborne Transmission: Inhalation via breathing, coughing, sneezing.

  • Touch: Transfer from one individual to another.

  • Absorption: Through skin or breaks in the skin.

  • Injection: Via pin pricks or insect bites.

Direct and Indirect Contact

• Terms: Define how micro-organisms are passed from one person to another (transmission method).

Direct Contact Transmission

• Involves skin-to-skin contact:

  • Physical transfer of microbes during care, e.g., bathing.

  • STDs and infections from mother to child during birth (e.g., rubella).

Indirect Contact Transmission

• Spread from one individual to another via contaminated objects:

  • Carried through air (dust, respiratory droplets).

  • Contaminated surfaces and equipment.

  • Spread via vectors such as insects.

Chain of Infection

• Source: The pathogen (harmful micro-organism).

• Reservoir: Where the pathogen can grow; generally in humans or animals.

• Portal of Exit: How the pathogen leaves the reservoir (e.g., through skin or bodily fluids).

• Method of Transmission: How the pathogen is transmitted to another host.

• Portal of Entry: How the pathogen enters the new host.

• Susceptible Host: An individual with a risk of infection.

Vulnerability to Infection

• Factors influencing vulnerability include:

  • Age: Very young or old individuals.

  • Nutrition: Poor nutrition status.

  • Stress and Fatigue: Decrease immune response.

  • Health Conditions: Existing diseases and medications affecting immunity.

  • Open Wounds: Provide entry points for pathogens.

Healthcare Clients

• Healthcare clients are particularly vulnerable; therefore, safe practices must be employed at all times.

Breaking the Chain of Infection

• Identify the chain components attributed to specific pathogens, reservoirs, portals, transmission methods, and vulnerable hosts.

Task

• Identify sources of potential infection in your workplace.

• Work in groups to describe these potential sources.