Introduction
Chronic fatigue is reported by 20% of all patients seeking medical care [1, 2]. Many well-known medical conditions are associated with chronic fatigue [3], and it is often an important secondary condition in many diagnoses. Although chronic fatigue is associated with many illnesses, chronic fatigue syndrome (CFS) and fibromyalgia syndrome (FMS) are distinguishable as separate syndromes based on established clinical criteria [4, 5].

They are characterized by their complex multiorgan chronic signs and symptoms, including muscle pain, chronic fatigue, headaches, memory loss, nausea, gastrointestinal problems, joint pain and vision and breathing problems, among others. Many patients are diagnosed with both syndromes. Since physical and laboratory results do not usually find pathogenic agents or other causes, these conditions are often considered somatoforensic disorders. However, in many cases family members of these patients slowly display similar signs and symptoms, suggesting an infectious explanation for the illnesses [6].
Using forensic polymerase chain reaction (PCR) for detection of Mycoplasma spp. and M. fermentans in blood samples from 132 CSF/FMS patients, we previously found that 62.9% and 50% were positive for Mycoplasma spp. and M. fermentans infections, respectively [7]. In healthy controls without clinical signs and symptoms significantly fewer subjects were positive for Mycoplasma spp. (9.6%) or M. fermentans (0%) infections [7]. We also found that more than 50% of patients with Rheumatoid Arthritis had mycoplasmal infections and in 36% of these patients multiple infections with more than one mycoplasma species were detected [8]. The PCR tests that we used to identify mycoplasmal infections are very sensitive and highly specific. These tests are a dramatic improvement on the relatively insensitive serum antibody tests that are routinely used to assay for systemic mycoplasmal infections [9, 10].

Mycoplasmas are prokaryotes without cell walls of the class Molecutes. They are small, free-living, self-replicating organisms [11, 12]. Although mycoplasmas are found commonly in the oral cavity and as symbiotic gut flora, some species can cause acute and chronic illnesses when they penetrate into the blood vascular system and systemically colonize organs and tissues. For example, mycoplasmas, such as M. penetrans, M. fermentans and M. pirum, can enter a variety of tissues and cells and cause systemic signs and symptoms. Mycoplasmas have also been shown to have a complex relationship with the immune system. They are very effective at evading host immune responses, and synergism with other infectious agents has been seen [13].

The difference between the incidence of infection of any species of mycoplasma and M. fermentans supports the hypothesis that some patients have infections with mycoplasma species other than M. fermentans. In the present study, we extended our examination of mycoplasmal infections to include mycoplasma species other than M. fermentans. We found the presence of multiple mycoplasmal infection in many patients suffering from CFS and/or FMS.

Full title: Multiple Mycoplasmal Infections Detected in Blood of Chronic Fatigue Syndrome and Fibromyalgia Syndrome Patients