The evolution of Mycoplasma genitalium

Mycoplasma genitalium is the smallest microorganism capable of self-replication. With its small genome, M. genitalium is the best representative of a minimal cell. The comparison of genome evolution among the three urogenital mycoplasmas, M. genitalium, M. hominis, and Ureaplasma parvum, not only indicated that they share a core genome of ~250 protein-encoding genes that correspond to their basic cell metabolism, but also showed a striking difference in their energy-generating pathways. M. genitalium is a sexually transmitted organism associated with nongonococcal urethritis in men and several inflammatory reproductive tract syndromes in women, such as cervicitis, pelvic inflammatory disease, and infertility. The treatment of M. genitalium infections has not yet been standardized. Macrolides are recommended, especially single-dose azithromycin; tetracyclines are responsible for a large number of therapeutic failures without any acquired resistance demonstrated. Acquired resistance to macrolides and fluoroquinolones leading to therapeutic failure has been described.