Some bacteria are good for you, including the bacteria in your digestive system, or gut. some bacteria are harmful. If you consume or come in contact with harmful bacteria, they may reproduce in your body and release toxins that can damage your body’s tissues and make you feel ill.


Bacteria are microscopic, single-celled organisms that thrive in diverse environments. These organisms can live in soil, the ocean and inside the human gut.

Some bacterias are beneficial to the human as they help by curdling milk into yogurt or aids in our digestion. However, some bacteria are destructive, causing diseases like pneumonia and methicillin-resistant Staphylococcus aureus (MRSA).

Bacteria (singular: bacterium) are classified as prokaryotes, which are single-celled organisms with a simple internal structure that only contains DNARibosomes are the spherical units in the bacterial cell where proteins are assembled from individual amino acids using the information encoded in ribosomal RNA.

Bacterial cells are generally surrounded by two protective coverings: an outer cell wall and an inner cell membrane. Certain bacteria, like the mycoplasmas, do not have a cell wall at all. 


There are 3 basic bacterial shapes:
  1. Round bacteria called cocci (singular: coccus), cylindrical, capsule-shaped ones known as bacilli (singular: bacillus)
  2. Spiral bacteria, aptly called spirilla (singular: spirillum).

The shapes and configurations of bacteria are often reflected in their names. For example, the milk-curdling Lactobacillus acidophilus are bacilli, and pneumonia-causing S. pneumoniae are a chain of cocci. Some bacteria take other shapes, such as stalked, square or star.

There are 2 basic types of bacteria in terms of how they respond to oxygen
  • Any organisms that does not require oxygen for growth and will dies in an oxygenated environment 
  • Gram-negative bacilli
    1. Haemophilus Influenza
    2. Eischeria Coli
    3. Klebsiella
    4. Eikenella Corrodens
  • Gram-positive cocci
    1. Streptococcus Veridians
    2. Hemolytic
    3. Staphylococcus
  • Any organisms that survives and grows in an oxygenated environment
  • Gram-negative bacilli
    1. Porphyromonas
    2. Prevotella
    3. Fusobacterium
    4. Bacteroids Fragilis
  • Gram-positive cocci
    1. Streptococcus
    2. Peptostreptococcus