Mycoplasmas are the smallest identified free-living organisms that comprise a large group of microorganisms widespread in nature. Found in plants, animals and humans, they cause various ailments or constitute the commensal flora . There are two species which are pathogenic to humans: Mycoplasma and Ureaplasma.
The mycoplasmas isolated from humans tend to inhabit the respiratory and urinary tract mucosa . Three species have been isolated from the surface of the genitourinary tract mucosa: Mycoplasma hominis (M. hominis), Ureaplasma urealyticum(U. urealyticum) and recently discovered Mycoplasma genitalium (M. genitalium). They are referred to as “sexual mycoplasmas", as they cause the infection via sexual contacts. Their pathogenicity is likely to be associated with the ability to adhere to epithelial cells of the genitourinary tract, to erythrocytes and spermatozoa . The involvement of M. hominis and U. urealyticumin the inflammatory conditions of the male genitourinary organ still arouses numerous controversies. Their presence is associated with urethritis and its complications, such as epididymitis, prostatitis or infertility.
2 Morphology and Physiology of Mycoplasma and Ureaplasma
The mycoplasmas are the smallest free-living bacteria. They range from 0.2 - 0.8 micrometers and thus can pass through some filters used to remove bacteria. They have the smallest genome size and, as a result, lack many metabolic pathways and require complex media for their isolation. The mycoplasmas are facultative anaerobes, except for M. pneumoniae, which is a strict aerobe. A characteristic feature that distinguishes the mycoplasmas from other bacteria is the lack of a cell wall. Thus, they can assume multiple shapes including round, pear shaped and even filamentous.
The mycoplasmas grow slowly by binary fission and produce "fried egg" colonies on agar plates; the colonies of M. pneumoniae have a granular appearance. Due to the slow growth of mycoplasmas, the colonies may take up to 3 weeks to develop and are usually very small. The colonies of Ureaplasma are extremely small and thus Ureaplasma are also called T-strains (tiny strains).
The mycoplasma all require sterols for growth and for membrane synthesis. The three species can be differentiated by their ability to metabolize glucose (M. pneumoniae), arginine (M. hominis) or urea (U. urealyticum). The fourth species M. genitalium is extremely difficult to culture
Chlamydia is a sexually transmitted disease (STD) that is caused by bacteria called Chlamydia trachomatis. Although you may not have heard its name, chlamydia is one of the most common STDs. Because there often aren't any symptoms, though, lots of people can have chlamydia and not know it.
The bacteria can move from one person to another through sexual intercourse, and possibly through oral-genital contact. If someone touches bodily fluids that contain the bacteria and then touches his or her eye, a chlamydial eye infection is possible. Chlamydia also can be passed from a mother to her baby while the baby is being delivered. This can cause pneumonia and conjuntivitis, which can become very serious for the baby if it's not treated. You can't catch chlamydia from a towel, doorknob, or toilet seat.
