硝化螺旋菌门（Nitrospira）是一类革兰氏阴性细菌。其中的硝化螺旋菌属（Nitrospira）作为硝化细菌（Nitrifier），可将亚硝酸盐氧化成硝酸盐。

• 细菌分类表

Nitrospira is a genus of bacteria in the phylum Nitrospirae. The first member of this genus was described 1986 by Watson et al. isolated from the Gulf of Maine. The bacterium was named Nitrospira marina. The second member of this genus was discovered in 1995 from a corroded iron pipe in a Moscow heating system. The bacterium was named Nitrospira moscoviensis and is a gram-negative nitrite-oxidising organism with a helical to vibroid morphology 0.9-2.2 x 0.2-0.4 micrometres in size. Members of Nitrospira with the capabilities to perform complete nitrification (Comammox bacteria) has also been discovered.