Robert Fox, MD


November 09, 2000


I have a patient who believes that her chronic fatigue syndrome is caused by an occult infection by Mycoplasma fermentans. She has found information to support this idea on the Internet. What would you tell her?

Mark E. Spencer, MD

Response from Robert Fox, MD

The potential role of Mycoplasma organisms in the etiology of autoimmune diseases (particularly rheumatoid arthritis) was postulated decades ago, but these microorganisms could not be consistently isolated from blood or tissue fluids. Nevertheless, the role of Mycoplasma was not totally discarded and thousands of patients have been treated with antibiotics to elimate the potential infections.

More recently, a role for M fermentans was postulated on the basis of an increased finding of M fermentans DNA using polymerase chain reaction (PCR) methods.[1] Although these findings are intriguing, the results must still be considered preliminary.

First, the DNA is detected by an extraordinarily sensitive method, and the organism still cannot be cultured from the blood or tissues of the chronic fatigue patients.[1] Thus, it remains possible that our bodies contain tiny remnants of multiple past infections and that the presence of a tiny amount of DNA (and in the absence of infectious organisms) does not mean that the Mycoplasma are stimulating the immune response. The DNA of other species of Mycoplasma (M pneumoniae, M hominis, and M penetrans) were also detected by PCR.[2]

It would be expected that antibodies to M fermentans would be present if an immune response were responsible for the chronic fatigue and a search for such antibodies was negative.[3] In a separate study using synthetic peptides derived from M fermentans, low levels of antibodies could be detected, but they correlated more closely with the detected copy number than with symptoms of chronic fatigue.[1]

Secondly, DNA from multiple different strains of Mycoplasma (including M fermentans) were detected in blood from persons without chronic fatigue, although at a slightly lower frequency and a slightly lower copy number than in the chronic fatigue patients. These results demonstrated that the finding of M fermentans was neither particularly sensitive nor specific for the diagnosis of chronic fatigue syndrome.[2] This suggests that the weakened state of the chronic fatigue patient (due to whatever neural imbalance has triggered the syndrome) might lead to a greater likelihood of exposure to the organism. In this scenario, the infection with Mycoplasma (and other organisms) might reflect nutritional and other factors that would predispose to infection.


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