Bacteria
Bacteria
Bacteria are small, one-celled microorganisms that lack a true nucleus or mechanism to provide metabolism. Some forms of bacteria produce spores, a resistant stage that withstands an unfavorable environment. When proper environmental conditions return, spores germinate and form new cells. Spores are resistant to heat, drying, and disinfectants. Pathogenic bacteria cause a wide range of illnesses including diarrhea, pneumonia, sinusitis, urinary tract infections, and gonorrhea.