Prosthecate bacteria are a non-phylogenetically related group of Gram-negative bacteria that possess appendages, termed prosthecae. These cellular appendages, also known as stalks, are neither pili nor flagella, as they are extensions of the cellular membrane and contain cytosol.[1] One notable group of prosthecates is the genus Caulobacter.
Prosthecates are generally chemoorganotrophic aerobes that can grow in nutrient-poor habitats, being able to survive at nutrient levels on the order of parts-per-million for which reason they are often found in aquatic habitats. These bacteria will attach to surfaces with their prosthecae, allowing a greater surface area with which to take up nutrients (and release waste products).[1][2] Some prosthecates will grow in nutrient-poor soils as aerobic heterotrophs.