Microthrix parvicella

The purpose of this page is to introduce the characteristics of Microthrix parvicella. Microthrix parvicella can be described as being irregularly curved, appearing like spaghetti. These filaments have a width between 0.6-0.8 µm and a length 0.8-1.0 µm. The filaments can be between 100-400 µm long. When Microthrix is present in activated sludge, the filaments can usually be found outside the floc tangled with other structures. Microthrix parvicella is Gram positive and Neisser negative with occasional Neisser positive granules. There is no attached growth.

Microthrix parvicella 100x (Phase contrast live sample) This photograph displays Microthrix within the floc matrix as well as extending out into the bulk solution.
Microthrix parvicella 100x (Phase contrast live sample) Another view of Microthrix at 100x. A few filaments of Microthrix can be seen in the bulk solution.
Microthrix parvicella 1000x (Phase contrast live sample) Microthrix at 100x. Microthrix is the thinner of the two distinct filaments pictured in this photo. Microthrix filaments in this photo have a particular beaded effect.
Microthrix parvicella 1000x (Brightfield, Gram Stain) Microthrix typically stains Gram positive--purple to dark blue. The distinctive highly curved, sinous morphology of Microthrix is highly evident in this photo.
Microthrix parvicella 1000x (Brightfield, Neisser Stain) Microthrix stain Neisser negative--yellow to light brown. This photo displays Neisser positive filament type 0092 filaments which are shorter and thicker than the curved, yellow Microthrix filaments.