spiroplasma mirum spiroplasma mirum spiroplasma mirum is a bacterium in the genus spiroplasma. a strain of it, called spiroplasma mirum strain smca (suckling mouse cataract agent), causes cataracts in suckling mice. spiroplasma mirum scientific classification domain: bacteria phylum: mycoplasmatota class: mollicutes order: mycoplasmatales family: mycoplasmataceae genus: spiroplasma species: s. mirum binomial name spiroplasma mirumtully et al. 1982