what type of pathogen is pneumonia
Viruses, bacteria, a fungus, or (in rare cases) parasites or other organisms can cause pneumonia. 1  In most cases, the specific organism (such as bacteria or virus) cannot be identified even with testing.2  When an organism is identified, it is usually the bacteria Streptococcus pneumoniae.iruses, bacteria, a fungus, or (in rare cases) parasites or other organisms can cause pneumonia. 1  In most cases, the specific organism (such as bacteria or virus) cannot be identified even with testing.