General Information: Mycoplasma mobile Strain 163K (ATCC 43663) is the only known strain of the species. It is not pathogenic for humans or animals. However, this organism was originally isolated (1984) from the gills of a fresh-water fish, the tench. It is the first mycoplasmal isolate that colonizes an aquatic organism. The unusual habitat explains lower temperature growth optimum of 20 degrees Celsius. M. mobile can glide at speeds of up to 7 microns/sec, much faster that any other known gliding mycoplasmas. This genus currently comprises more than 120 obligate parasitic species found in a wide spectrum of hosts, including humans, animals, insects and plants. The primary habitats of human and animal mycoplasmas are mucous membranes of the respiratory and urogenital tracts, eyes, mammary glands and the joints. Infection that proceeds through attachment of the bacteria to the host cell via specialized surface proteins, adhesins, and subsequent invasion, results in prolonged intracellular persistence that may cause lethality. Once detected in association with their eukaryotic host tissue, most mycoplasmas can be cultivated in the absence of a host if their extremely fastidious growth requirements are met.