Bacteria Phyla and Classification

Major Groups of Bacteria

• Bacteria are divided into several phyla, including Proteobacteria, Chlamydia, Spirochetes, Gram+ bacteria, and Cyanobacteria.

Proteobacteria

• Alpha Proteobacteria: many species have eukaryotic hosts through symbiosis; mitochondria evolved from aerobic alpha proteobacteria through endosymbiosis.
• Beta Proteobacteria:
  • Pathogenic species include Neisseria meningitidis (causes meningococcal meningitis), Neisseria gonorrhoeae (causes gonococcal urethritis), and Bordetella pertussis (causes whooping cough).
• Gamma Proteobacteria:
  • Opportunistic pathogens, normally non-pathogenic but can cause infections in certain circumstances (immunosuppressed).
  • Examples include Escherichia coli, which is part of normal intestine flora but can cause opportunistic infections, and is used in gene cloning.
  • Pathogenic species include Vibrio cholerae (causes cholera), Legionella, and Salmonella.
• Epsilon Proteobacteria:
  • Many species are pathogens, including Campylobacter (causes food poisoning) and Helicobacter pylori (causes stomach ulcers, gastric cancer, and gastritis).

Chlamydia

• Chlamydia trachomatis causes non-gonococcal urethritis (STD).

Spirochetes

• Treponema pallidum causes syphilis (STD).
• Borrelia burgdorferi causes Lyme disease (Borreliose).
• Leptospira causes Leptospirosis.

Gram+ Bacteria

• Actinomycetes can cause Actinomycoses (skin infection).
• Bacillus anthracis causes Anthrax.
• Bacillus cereus causes Gastroenteritis.
• Corynebacterium diphtheriae causes Diphtheria, which can lead to upper respiratory tract infection and tissue damage due to inhibition of protein synthesis by diphtheria toxin.
• Clostridium botulinum causes botulism, which can be fatal due to respiratory muscle failure.
• Clostridium tetani causes Tetanus, which leads to muscle spasms and paralysis due to toxin production.
• Staphylococcus aureus causes toxic shock syndrome, food poisoning (gastroenteritis), and pneumonia.
• Streptococcus pneumoniae causes Pneumococcal meningitis.
• Mycobacteria:
  • Mycobacterium tuberculosis causes Tuberculosis, a chronic cough with blood-containing sputum.
  • Mycobacterium leprae causes Leprosy.
• Mycoplasma:
  • Mycoplasma hominis and Ureaplasma urealyticum cause Non-gonococcal urethritis (STD).

Vaccines

• DTP vaccine is an anti-bacterial vaccine that protects against Diphtheria, Tetanus, and Pertussis.