Mycoplasmas are ubiquitous bacteria that differ from other prokaryotes in that they lack a cell wall. Mycoplasma pneumoniae is a common cause of pneumonia, particularly community-acquired. Increasing evidence suggests that M. genitalium and Ureaplasma urealyticum cause some cases of nongonococcal urethritis. They (and M. hominis) are often present in patients with other urogenital infections (eg, vaginitis, cervicitis, pyelonephritis, pelvic inflammatory disease) and some nonurogenital infections, but whether they cause these infections is not clear.

Mycoplasmas are not visible with light microscopy. Culture is technically difficult and often unavailable, but laboratory diagnosis is sometimes possible with DNA probes or by detection of antibodies or antigens; frequently, diagnosis must be clinical.

Macrolides are usually the antimicrobials of choice. Most species are also sensitive to fluoroquinolones and tetracyclines.

Last full review/revision December 2009 by Byron E. Batteiger, MD