Foundations of Medic-s2-full

Introduction

• Overview of microbial growth control discussed in previous lectures.

• Importance and context of microbial control in various environments.

Methods of Controlling Microbial Growth

Overview

• Control strategies ranked from least effective to most effective.

Cleaning

• Basic cleaning methods involve the use of water and detergents.

• Effectively removes visible dirt

• Does not typically kill microorganisms but reduces their numbers.

Sanitization

• Sanitization actively reduces viable microbial numbers on clean surfaces.

• Methods include:

  • Steam (moist heat)

  • Chemical agents (e.g., chlorine)

• Effectiveness can be inhibited by dirt or residue on surfaces.

Disinfection

• Disinfection aims to kill pathogens on surfaces or body sites.

• Uses germicides for inanimate objects, referred to as disinfectants.

• Antiseptics are used for surfaces in contact with living tissue (e.g., skin).

• Methods:

  • Heat (e.g., pasteurization at 60-80 degrees Celsius)

  • Radiation (e.g., UV, ionizing radiation)

  • Chemicals (e.g., alcohol, chlorine)

Sterilization

• Complete removal of all microbes, including spores.

• Methods include:

  • Autoclaving (moist heat under pressure)

  • Gas sterilization (e.g., ethylene oxide)

  • Filtration of liquids and air.

• Critical for medical equipment and environment.

Pasteurization

Definition

• Process developed by Louis Pasteur to prevent spoilage.

• Basics:

  • Low-temperature long time (LTLT) or high-temperature short time (HTST).

• Used extensively in food processing to extend shelf life by reducing spoilage microorganisms.

Radiation as a Disinfection Method

Types of Radiation

• UV Radiation:

  • Used for sterilizing surfaces and air but not effective for penetrating materials.

• Ionizing Radiation:

  • Suitable for food and certain medical products.

  • Effectively damages DNA in microorganisms.

Chemical Agents in Microbial Control

Types and Modes of Action

• Alcohol: Commonly used in sanitizers.

• Aldehydes (e.g., formaldehyde): Highly effective for surfaces.

• Halogens (e.g., chlorine): Broad-spectrum disinfectants but can be corrosive.

• Heavy Metals: Used with caution due to toxicity risks.

Organic Matter's Impact on Disinfection

• Organic materials can inhibit the effectiveness of disinfectants.

• Mechanisms include:

  • Forming precipitates,

  • Reacting with disinfectants to form non-effective byproducts,

  • Creating protective barriers around microbes.

Guidelines for Using Disinfectants

• Best Practices:

  • Clean before disinfecting to remove organic debris.

  • Follow manufacturer's concentration recommendations.

  • Allow sufficient exposure time.

  • Rinse after use to avoid chemical residue on surfaces.

Factors Affecting Efficacy

• Microbial population size, concentration of disinfectant, exposure time, temperature, and pH all affect control methods.

• Specific organism characteristics can impact susceptibility to control methods.

Asepsis in Clinical Practice

• Effective handwashing techniques are paramount in preventing infection spread.

• Importance of proper personal protective equipment (PPE) in clinical settings.

• Regular disinfection of surfaces and equipment.

Hand Hygiene

Compliance and Techniques

• **World Health Organization (WHO) recommends five moments for hand hygiene:

  1. Before patient contact

  2. Before procedures

  3. After potential exposure to body fluids

  4. After patient contact

  5. After contact with patient surroundings**

• Handwashing with soap is highly recommended, with alcohol-based sanitizers being effective alternatives.

Understanding Antibiotics

Types of Antibiotics

• Bactericidal: Kill bacteria.

• Bacteriostatic: Inhibit bacterial growth.

• Beta-lactams: Most common group (e.g., penicillins, cephalosporins) targeting cell wall synthesis.

Resistance Issues

• Antibiotic resistance increases due to overprescription and selective pressures from antibiotic use.

• Importance of judicious antibiotic use and adherence to treatment guidelines.

• Developing synergy and antagonism in treatment strategies.

Emerging Treatments

Phage Therapy

• Bacteriophages target and kill specific bacteria, presenting a promising alternative to antibiotics for resistant infections.

• Specificity to bacteria pairs well with fewer side effects for patients.

Fungal and Antiviral Treatments

• Antifungal agents required due to eukaryotic nature impacting host cells.

• Difficulties in treating viral infections due to intracellular hiding in host cells.

Conclusion

• Importance of a comprehensive control strategy against microbes in healthcare and daily environments, integrating hygiene practices, physical disinfection, chemical controls, and potential future treatments.