Uncertain etiology means the cause is unknown.

Pseudomonas is a bacterium. It doesn't have an etiology; it is an etiology. It can cause skin infections, UTIs, and other illnesses.

Etiology is what causes a disease or how it occurs based on studies

Staphylococcus is a bacterium. It doesn't have an etiology, it is an etiology for infections including boils, folliculitis, some UTIs, and impetigo.

That is the correct spelling of "etiology" (study of causation, or especially disease causes).