Microbiology and Parasitology Exam Notes

Branches of Microbiology

• Bacteriology: Study of bacteria - structure, function, biochemistry, classification, genetics, and interactions. Used for disease prevention and treatment.
  • Example Pathogenic Bacteria:
  • Streptococcus: Causes strep throat
  • Staphylococcus aureus: Causes skin infections
  • Escherichia coli: Causes E. coli infections
• Virology: Study of viruses - structure, replication, and disease impact. Types include animal, plant, fungal viruses, and bacteriophages.
• Mycology: Study of fungi (yeasts, molds, mushrooms). Focus on biochemical properties and medical relevance.
• Parasitology: Study of parasites and host interactions, often disease-causing.
• Phycology: Study of algae - photosynthetic organisms in aquatic ecosystems.
• Immunology: Study of the immune system, focusing on disorders like autoimmunity and deficiencies.
• Protozoology: Study of protozoa (single-celled organisms), including amoeba and plasmodium.
• Nematology: Study of nematodes (roundworms), with health implications for humans.

Understanding Bacteria

• Microbiology: Study of microscopic organisms and their roles in health.
• Escherichia coli (E. coli):
  • Domain: Bacteria
  • Kingdom: Eubacteria
  • Phylum: Proteobacteria
  • Importance: Diverse roles in health and disease.

Bacterial Classification

1. Shape:
   • Spherical (cocci), Rod-shaped (bacilli), Spiral (spirochetes)
2. Oxygen Requirement:
   • Aerobic vs. Anaerobic

Gram Staining

• Gram-Positive Bacteria:
  • Stain blue/purple: Corynebacterium, Clostridium, Listeria
• Gram-Negative Bacteria:
  • Stain red/pink: Pseudomonas, Proteus, Klebsiella
  • Require different antibiotics for treatment.

Types of Skin Lesions

Bacterial Skin Infections

1. Staphylococcus aureus
   • Characteristics: Gram-positive cocci; found in skin and nasopharynx
   • Transmission: Direct contact & fomites
   • Laboratory Diagnosis: Gram stain shows Gram+ cocci; culture shows golden yellow colonies
   • Treatment: Beta-lactam antibiotics, drainage of infections.
2. Streptococcus pyogenes
   • Characteristics: Gram-positive cocci in chains; produces enzymes & toxins.
   • Mode of Transmission: Direct contact with infections.
   • Clinical Findings: Various skin infections, risk of complications like glomerulonephritis.

Pathogenesis and Treatment of Bacterial Diseases

• Bacterial Meningitis: Rapid treatment is critical to reduce mortality; empiric therapy may include broad-spectrum antibiotics before pathogen is confirmed.
• Viral Meningitis: Typically mild, self-limiting. Recognize key symptoms and pathogens involved (e.g., enteroviruses).

Other Key Topics

• Fungal Infections: Superficial, cutaneous, and subcutaneous mycoses, detailing their agents and possible treatments.
• Viral Infections of Skin: Including warts (HPV) and herpes simplex virus (HSV), their paths, symptoms, and laboratory diagnostics.
• CNS Infections: Roles of the central and peripheral nervous systems, protective structures and potential complications arising from infections affecting the CNS.