The descending order of resistance of disease agents is:
1-Coccdial oocyst.
2- Spores (i.e. clostridial diseases) and acid-fast bacteria (i.e., Mycobacterium avium).
3- Gram-negative bacteria (i.e., Pseudomonas, E.coli, Salmonella).
4- Fungi (i.e., Candida and Aspergillus).
5- Non-enveloped viruses (i.e.,enterovirus & adenovirus)
6- Gram-positive bacteria (i.e., Staph aureus).
7- Lipid enveloped viruses (i.e., Avian influenza virus)