Mycoplasma is a bacterial genus which contains over 100 species. Most of the species are harmless, but several appear to be virulent, and have been linked with specific medical conditions in humans. These bacteria are extremely small, with a very basic genome which contains only the basic information needed for life. The stripped-down nature of Mycoplasma bacteria forces many of them to be parasitic, because they cannot survive on their own.
These bacteria were first isolated and described in the late 1800s, although early researchers were unable to specifically identify the bacteria in their isolates. However, they knew that the isolated material they had refined in the lab contained bacteria, even if they couldn't see it, and this laid the groundwork for additional research with better microscopes and scientific imaging devices which allowed researchers to eventually identify the bacteria.
One interesting thing about bacteria in this genus is that they have no cell walls. Their lack of cell walls causes them to have a very elastic shape which can vary at any given time, one of the reasons it was so difficult to isolate and confirm the presence of Mycoplasma in the laboratory. These bacteria are also less susceptible to many commonly used drugs, since antibiotics often target the cell wall, and Mycoplasma have no cell walls to grab on to.
These gram negative bacteria often contaminate cell cultures in the laboratory, creating colonies with a distinctive fried-egg appearance caused by a concentration of bacteria in the middle of the colony, and a scattering around the edges. Viewed under the microscope, the dense concentration resembles the yolk of a fried egg, while the thinner population around the edges looks like the white.
One Mycoplasma species, M. pneumoniae, causes atypical pneumonia, also known as walking pneumonia. Other species have been linked with pelvic inflammatory disease, more general respiratory infections, and several chronic diseases. In people with conditions like fibromyalgia and chronic fatigue syndrome, unusually high numbers of Mycoplasma bacteria have been noted, suggesting that the bacteria may be playing a role in the condition. Some research has also implicated the bacteria in autoimmune disorders.
Although these bacteria are not as vulnerable to antibiotics as one might wish, there are several drugs which can be used to treat Mycoplasma infection very successfully. In a mild infection, the body will often fight the bacteria off on its own, requiring little support. For more severe infections, an array of antibiotic drugs are available.