Page:Bacteria, why do they make me sick?.pdf/11





Most of the bacteria are harmless to humans or are part of our normal bacterial microbiota, either in the skin or mucosae, protecting us from getting a disease.

Bacteria are classified using different criteria. We can classify them in pathogenic and nonpathogenic; we can also distinguish them based on its morphology, its type of arrangement and also based on its optimal temperature of growth, cell wall and how they respond to oxygen levels. 11