How many letters does the top answer for “parasitic or free-living bacteria; many pathogenic to humans and other animals” have?

The most common answer is spirochaete (11 letters).

Crossword clue: parasitic or free-living bacteria; many pathogenic to humans and other animals

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

spirochaete 11 letters wn-def

parasitic or free-living bacteria; many pathogenic to humans and other animals

spirochete 10 letters wn-def

parasitic or free-living bacteria; many pathogenic to humans and other animals