Bacterial Agents of Disease

Bacterial Agents of Disease

Pseudomonas

• Pseudomonas aeruginosa:
  • Gram-negative, aerobic, rod-shaped bacterium
  • Opportunistic pathogen, causes infections in immunocompromised individuals
  • Can cause pneumonia, urinary tract infections, and bloodstream infections
  • Produces various virulence factors, including exotoxins and biofilms
  • Multidrug-resistant strains are emerging, making treatment challenging

Leptospira

• Leptospira:
  • Spirochete bacterium, causing Leptospirosis
  • Zoonotic disease, transmitted through contaminated water or direct contact with infected animals
  • Symptoms: fever, headache, muscle aches, vomiting, and diarrhea
  • Can cause kidney and liver failure, meningitis, and respiratory distress
  • Diagnosis: serology, PCR, and culture
  • Treatment: antibiotics, supportive care, and hydration

Brucella

• Brucella:
  • Gram-negative, aerobic, coccobacillus bacterium
  • Causes Brucellosis, a zoonotic disease transmitted through:
    • Direct contact with infected animals (e.g., goats, sheep, cattle)
    • Contaminated milk, cheese, or meat
  • Symptoms: fever, fatigue, muscle and joint pain, and swelling of lymph nodes
  • Can cause chronic infections, leading to complications like arthritis, hepatitis, and meningitis
  • Diagnosis: serology, PCR, and culture
  • Treatment: antibiotics, often in combination with rifampicin and doxycycline

Rickettsia

• Rickettsia:
  • Gram-negative, obligate intracellular bacteria
  • Causes Rickettsioses, a group of diseases transmitted through tick bites or lice
  • Includes diseases like:
    • Rocky Mountain spotted fever (R. rickettsii)
    • Epidemic typhus (R. prowazekii)
    • Murine typhus (R. typhi)
  • Symptoms: fever, headache, rash, and muscle pain
  • Can cause severe complications, such as meningitis, pneumonia, and cardiovascular failure
  • Diagnosis: serology, PCR, and culture
  • Treatment: antibiotics, primarily doxycycline