MYCOPLASMA-IMITANS SP-NOV IS RELATED TO MYCOPLASMA-GALLISEPTICUM AND FOUND IN BIRDS

A mycoplasma designated strain 4229T (T = type strain) was isolated in 1984 from the turbinate of a duck in France, and similar strains were isolated from geese in France and from a partridge in England. All of these strains were originally identified as Mycoplasma gallisepticum by immunofluorescence and growth inhibition tests, but subsequent sero logical and molecular studies indicated only a partial relationship to this species and DNA-DNA hybridization studies revealed only approxim ately 40 to 46% genetic homology with M. gallisepticum PG31T. In this study morphological, cultural, and physical investigations were carrie d out on strain 4229T and partridge strain B2/85, after we first demon strated the similarity between these organisms by performing a restric tion enzyme analysis of their DNAs. Both strains had phenotypic proper ties very similar to M. gallisepticum properties, including the presen ce of an attachment organelle. As a result of these investigations, th e organisms were assigned to the class Mollicutes, the order Mycoplasm atales, and the genus Mycoplasma. They fermented glucose, reduced trip henyl tetrazolium chloride aerobically and anaerobically, and exhibite d hemadsorption and hemagglutination, but other biochemical tests were negative. Apart from a serological cross-reaction with M. galliseptic um, these organisms exhibited no significant relationship with any pre viously described Mycoplasma species as determined by growth inhibitio n or immunofluorescence tests or with a number of additional serovars and unclassified avian strains. This Mycoplasma taxon therefore appear s to be a new species, for which we propose the name Mycoplasma imitan s. The type strain is strain 4229 (= NCTC 11733 = ATCC 51306). The sig nificance of the organism has not been fully investigated, but prelimi nary in vitro and in vivo studies have indicated that it may be pathog enic.