Lecture Notes: Disease Transmission and Nosocomial Infections

Modes of Disease Transmission

• Direct Contact:
  • Example: Being bitten by a rabid animal.
• Indirect Contact (Fomites):
  • Example: Stepping on a rusty nail (tetanus), droplets from someone coughing.
• Vehicles:
  • Waterborne or foodborne transmission.
• Vector Transmission:
  • Mechanical Vectors: Flies picking up parasitic eggs.
  • Biological Vectors: Mosquitoes transmitting malaria (Plasmodium).

Nosocomial Infections

• Definition: Infections acquired in a hospital or medical facility.
• Importance: Major concern in healthcare settings to prevent these infections.
• Common Causes:
  • Medical treatments such as IVs or urinary catheters.
  • Common culprits include: E. coli, Staphylococcus aureus, Streptococcus, Pseudomonas, Klebsiella, Candida, Staphylococcus epidermidis, etc.

Types of Nosocomial Infections

• Exogenous:
  • Caused by organisms entering the patient from the environment.
  • Sources: Other patients, staff, visitors, insects, and fomites.
• Endogenous:
  • Caused by opportunistic microflora from the patient's own body.
  • Example: E. coli from the gut causing a UTI.

Common Nosocomial Infections

• Urinary Tract Infections (UTI):
  • Most common nosocomial infections.
  • Risk factors: Anatomy (urethra's proximity to anus, shorter urethra in females), inability to empty bladder frequently, use of catheters.
• Surgical Wound Infections:
  • Caused by improperly cleaned surgical sites.
• Respiratory Tract Infections:
  • Risk increased due to sedentary state when bedridden.

Preventing Nosocomial Infections

• Hand Hygiene: Proper washing and maintaining sterility.
• Use of Personal Protective Equipment (PPE): Proper donning and discarding of gloves, gowns, etc.
• Avoid Insect Infestation:
• Targeted Antibiotic Use:
  • Avoid depleting patient's microflora and prevent super infections.
  • Use antibiotics only when necessary to prevent resistance.

Case Studies

• E. coli and UTIs:
  • E. coli is the primary causative agent of UTIs and many nosocomial infections.
  • Can be treated with antibiotics if detected early.
  • Complications can arise such as kidney infections (pyelonephritis).
• Real-life Examples:
  • Lecturer's mother-in-law and daughter experienced UTIs, highlighting the risks and necessary treatments.

Conclusion

• Importance of understanding disease transmission and preventing nosocomial infections.
• Practical steps in healthcare settings to reduce infection risks, including hygiene practices and appropriate antibiotic use.