T-FORM COLONIES OF PLEUROPNEUMONIALIKE ORGANISMS

Abstract

Minute-colony forms of pleuropneumonialike organisms, designated T-form (tiny) PPLO colonies, are described. These colonies comprised approximately 86% of all PPLO isolations recovered from 74 patients (male) with nongonococcal urethritis at Camp Lejeune, N.C. T-form PPLO colonies appear to represent a distinct group or species of pleuropneumonialike organisms recoverable from the genital tract of men with nongonococcal urethritis. These minute colonies are characterized by their extremely minute size in primary culture in comparison to the familiar, classic-type PPLO colonies observed on the same culture medium. Typical surface growth zones have not been observed in primary culture. The colonies are roughly spherical or irregular in shape and develop downward into the agar medium. The colonies are composed of minute, rather loosely-bound particles of uniform size, suggesting, in many instances, development within a matrix. Young T-form colonies stain bright blue with Dienes'' stain. Older colonies often stain poorly or remain unstained. Two minute-colony forms are described which are believed to be culture variants or precursors of the T-form PPLO colony.