The following microbes are also known to convert ammonia into nitrites: Nitrosospira, Nitrosouva, Nitrosolobus, Streptomyces, and Nocardia (our favorite activated sludge foam causing microbe).
NOTE: these organisms are chemo-autotrophs, growing with ammonia as the energy substrate and CO2 as the main carbon source. Generally, the optimum growth temperature is 30 degrees C and the optimum pH is between 7.5 and 8.0.