Makindo Medical Notes

🦠 The Chain of Infection

Infection spreads through a predictable chain of six links. Breaking any one link can stop transmission and protect patients and staff. 💪

• 🧫 Infectious Agent — bacteria, viruses, fungi, or parasites. Control: hand hygiene, cleaning, disinfection, sterilisation, and antimicrobial therapy.
• 🏥 Reservoir — where the pathogen lives: people, animals, equipment, food, water, soil, or environmental surfaces (including sinks!). Control: environmental cleaning, safe equipment storage, and staff health screening.
• 🚪 Portal of Exit — how the agent leaves the reservoir: via the nose 👃, mouth 👄, stool 💩, blood 🩸, or skin. Control: source isolation, respiratory etiquette, waste and linen management.
• 🔄 Mode of Transmission — direct contact 🤝, indirect contact 🧽, droplet 💦, airborne 🌫️, or via contaminated food/water 🍲💧. Control: hand hygiene, PPE, ventilation, and cleaning shared equipment.
• 🩹 Portal of Entry — where infection enters: breaks in skin, mucous membranes, medical devices, ingestion, inhalation, or sexual contact. Control: aseptic technique, device care, and skin protection.
• 🧍‍♀️ Susceptible Host — individuals at higher risk due to:
  • 🧒 very young or 👵 very old age
  • 💊 low immunity or immunosuppressive drugs
  • 🍽️ malnutrition
  • 🫁 underlying disease or surgery
  • 🩼 indwelling medical devices
  • 🧬 genetic or chronic health conditions
  Control: vaccination, good nutrition, early mobilisation, and reducing invasive devices.

💩 Clostridioides difficile (C. diff) Infection

C. difficile infection occurs when the natural gut flora is disrupted, allowing C. difficile spores to multiply. Transmission happens via ingestion of spores shed in faeces. Highest risk is among older adults and those recently on antibiotics. ⚠️

🔬 Pathogenesis

• Antibiotics (especially cefuroxime, ciprofloxacin, or co-amoxiclav) reduce protective gut bacteria.
• Other risks: older age, weakened immunity, recent surgery, hospital stays, proton pump inhibitor use, chronic illness.
• C. difficile produces toxins that damage the gut lining, leading to illness ranging from mild diarrhoea to life-threatening colitis.
• 💡 Up to 5% of healthy adults carry it without symptoms.

🩸 Gram-negative Bloodstream Infections (GNBSIs)

Serious infections caused by bacteria such as E. coli, Klebsiella, and Pseudomonas. These can cause severe sepsis, especially in vulnerable patients. Many strains show antibiotic resistance. 🧬

🚨 Risk Factors

• Indwelling devices (catheters, IV lines)
• Recent invasive procedures or surgery
• Hospital admission or antibiotic use in past 28 days
• Neutropenia or immune suppression
• Colonisation with resistant Gram-negatives

🧼 Prevention

• Strict hand hygiene and aseptic technique
• Timely removal of unnecessary devices
• Antimicrobial stewardship
• Active infection surveillance
• Staff education and training

🧫 Carbapenemase-Producing Enterobacterales (CPE)

CPE are bacteria resistant to carbapenems — powerful last-line antibiotics. They may live harmlessly in the gut but can cause serious infection if they spread to other body sites. 🧯

⚠️ Who Is at Risk?

• Recent or overseas hospital stay 🏥
• Use of medical devices (catheters, IV lines)
• Frequent antibiotic exposure 💊
• Close contact with someone who has CPE
• Long-term healthcare exposure 🧓

🧍‍♀️ Infection Control Measures

• 🧴 Standard Precautions: hand hygiene, safe waste handling, PPE use
• 🧤 Contact Precautions: gloves and aprons for all contact
• 🚪 Isolation: single room with en-suite if possible
• 🧽 Dedicated Equipment: avoid sharing between patients
• ✨ Enhanced Cleaning: focus on high-touch surfaces and sinks

🩸 Bloodborne Viruses (BBVs)

Includes HIV, Hepatitis B (HBV), and Hepatitis C (HCV). These spread via blood and certain body fluids. Some people remain asymptomatic, increasing risk of unnoticed transmission. 💉

• HIV: damages the immune system; treated with antiretrovirals (ART) that suppress viral load to undetectable levels.
• HBV: may be acute or chronic; prevented by vaccination 💉.
• HCV: curable in >90% with modern antivirals.

⚕️ Reduce Risk

• Use PPE appropriately 🧤
• Cover wounds with waterproof dressings 🩹
• Use eye/face protection if splashing possible 👓
• Dispose of sharps safely 🩸

🧽 Cleaning, Disinfection, and Sterilisation

• 🧼 Cleaning: removes dirt and organic matter; microorganisms are removed, not killed.
• 🧴 Disinfection: reduces or eliminates harmful microbes on surfaces.
• 🔥 Sterilisation: destroys all microorganisms; for instruments entering sterile tissues.
• ♻️ Decontamination: an umbrella term including cleaning, disinfection, and sterilisation.

Routine cleaning uses neutral detergent and disposable cloths. ‘Deep cleaning’ after outbreaks may use hydrogen peroxide vapour or UV light. Colour-coded cleaning tools help prevent cross-contamination. 🎨

😷 Transmission-Based Precautions (TBPs)

• 🧤 Contact: for infections spread by touch (most common)
• 💦 Droplet: for infections spread over short distances via coughs/sneezes
• 🌫️ Airborne: for aerosol-transmitted diseases (e.g. TB, measles)

Isolation, correct PPE, and enhanced cleaning are key to preventing spread. 🧼

🧪 Specimen Collection

Collect only when clinically indicated, using aseptic technique and correct PPE. Accurate sampling supports targeted antimicrobial therapy and reduces unnecessary antibiotic use. 🎯

🧤 Personal Protective Equipment (PPE)

• Located near the point of use 🧰
• Single-use unless specified otherwise
• Changed between patients or tasks
• Disposed of safely into correct waste stream 🚮

Examples

• 🧤 Gloves: for contact with blood, body fluids, or non-intact skin
• 🩺 Aprons: to protect clothing from contamination
• 👓 Eye/Face Protection: for splash risk
• 😷 Masks: FRSM Type IIR for droplet protection
• 🥾 Footwear: clean, closed, and non-slip
• 🧢 Headwear: theatre use only; must cover all hair

🧬 Principles of Asepsis (ANTT®)

Aseptic Non-Touch Technique (ANTT) ensures only uncontaminated equipment contacts sterile or susceptible body sites. Used for IV therapy, catheterisation, wound care, and invasive lines. 🧴

• 🖐️ Hand hygiene before and after every procedure
• 🚫 Non-touch technique: only handle non-key parts
• 🧤 Use sterile gloves for key parts if touching is unavoidable
• 🧰 Prepare an aseptic field and maintain sterility throughout

💊 Antimicrobial Resistance (AMR)

AMR occurs when microorganisms evolve to resist antimicrobial drugs. It leads to treatment failure, prolonged illness, and increased mortality. 🧬

• Apply infection prevention principles from the NIPCM for England
• Assess infection severity and risk of resistance
• Avoid unnecessary antibiotic prescriptions 🚫
• Take cultures before starting treatment 🧪
• Switch IV → oral early when appropriate
• Prescribe the shortest effective course ⏱️

Carbapenems (e.g. meropenem) are often last-line drugs; resistance is rising. Good stewardship preserves their effectiveness. 💚