title: Analysis of 16S rRNA gene sequences and circulating cell-free DNA from plasma of chronic fatigue syndrome and non-fatigued subjects.
abstract: BACKGROUND
  The association of an infectious agent with chronic fatigue syndrome (CFS) has been difficult and is further complicated by the lack of a known lesion or diseased tissue. Cell-free plasma DNA could serve as a sentinel of infection and disease occurring throughout the body. This type of systemic sample coupled with broad-range amplification of bacterial sequences was used to determine whether a bacterial pathogen was associated with CFS. Plasma DNA from 34 CFS and 55 non-fatigued subjects was assessed to determine plasma DNA concentration and the presence of bacterial 16S ribosomal DNA (rDNA) sequences.
  
  
  RESULTS
  DNA was isolated from 81 (91%) of 89 plasma samples. The 55 non-fatigued subjects had higher plasma DNA concentrations than those with CFS (average 151 versus 91 ng) and more CFS subjects (6/34, 18%) had no detectable plasma DNA than non-fatigued subjects (2/55, 4%), but these differences were not significant. Bacterial sequences were detected in 23 (26%) of 89. Only 4 (14%) CFS subjects had 16S rDNA sequences amplified from plasma compared with 17 (32%) of the non-fatigued (P = 0.03). All but 1 of the 23 16S rDNA amplicon-positive subjects had five or more unique sequences present.
  
  
  CONCLUSIONS
  CFS subjects had slightly lower concentrations or no detectable plasma DNA than non-fatigued subjects. There was a diverse array of 16S rDNA sequences in plasma DNA from both CFS and non-fatigued subjects. There were no unique, previously uncharacterized or predominant 16S rDNA sequences in either CFS or non-fatigued subjects.
authors.affiliation: Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. svernon@cdc.gov
authors.forename: Suzanne D
authors.initials: SD
authors.lastname: Vernon
authors.forename: Sanjay K
authors.initials: SK
authors.lastname: Shukla
authors.forename: Jennifer
authors.initials: J
authors.lastname: Conradt
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Unger
authors.forename: William C
authors.initials: WC
authors.lastname: Reeves
mesh_terms: D004247:DNA / Q000097:blood; D004269:DNA, Bacterial / Q000097:blood*; D015673:Fatigue Syndrome, Chronic / Q000097:blood* / Q000382:microbiology; D006801:Humans; D012336:RNA, Ribosomal, 16S / Q000097:blood* / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D004247:DNA