title: Persistence of community-acquired respiratory distress syndrome toxin-producing Mycoplasma pneumoniae in refractory asthma.
abstract: BACKGROUND
  The role of Mycoplasma pneumoniae (Mp) in the initiation and persistence of asthma remains elusive. Mp community-acquired respiratory distress syndrome toxin (CARDS Tx) is a unique virulence factor that induces an intense lymphocytic response and exacerbates asthma in animal models. We sought to determine the incidence of Mp infection and the presence of CARDS Tx in subjects with refractory asthma (RA).
  
  
  METHODS
  We conducted a prospective observational study in 64 subjects with RA. Respiratory secretions (sputum, nasal lavage, and throat swab) and blood were analyzed for the presence of CARDS Tx and P1 adhesin (P1) DNA by polymerase chain reaction (PCR), and CARDS Tx by antigen capture. Serum IgM and IgG antibodies to CARDS Tx were determined by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  Thirty-three of 64 subjects (52%) tested positive for Mp: 29 of 33 by CARDS Tx vs 10 of 33 by P1 assays. Ten subjects followed longitudinally for up to 633 days tested persistently positive for Mp. There were no significant differences in Mp-specific IgG responses between Mp-positive and Mp-negative groups. Eight of 10 subjects who tested persistently positive failed to mount a substantial IgG response to CARDS Tx, and up to 8 weeks of clarithromycin failed to eradicate Mp in five subjects.
  
  
  CONCLUSIONS
  Subjects with RA may be chronically infected with Mp. PCR for CARDS Tx appears to be the most sensitive method of identifying Mp infection. Despite the persistence of Mp in subjects with RA, some subjects failed to mount an IgG response, and macrolide therapy was insufficient to eradicate Mp.
authors.affiliation: Department of Medicine, University of Texas Health Science Center at San Antonio, TX. Electronic address: peters@uthscsa.edu.
authors.forename: Jay
authors.initials: J
authors.lastname: Peters
authors.affiliation: Department of Medicine, University of Texas Health Science Center at San Antonio, TX.
authors.forename: Harjinder
authors.initials: H
authors.lastname: Singh
authors.affiliation: Department of Pediatrics, University of Texas Health Science Center at San Antonio, TX.
authors.forename: Edward G
authors.initials: EG
authors.lastname: Brooks
authors.affiliation: Asthma and Allergy Associates of South Texas, San Antonio, TX.
authors.forename: Joseph
authors.initials: J
authors.lastname: Diaz
authors.affiliation: Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, TX.
authors.forename: Thirumalai R
authors.initials: TR
authors.lastname: Kannan
authors.affiliation: Department of Pathology, University of Texas Health Science Center at San Antonio, TX.
authors.forename: Jacqueline J
authors.initials: JJ
authors.lastname: Coalson
authors.affiliation: Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, TX.
authors.forename: Janet G
authors.initials: JG
authors.lastname: Baseman
authors.affiliation: Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, TX.
authors.forename: Marianna
authors.initials: M
authors.lastname: Cagle
authors.affiliation: Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, TX; Department of Epidemiology, University of Washington School of Public Health, Seattle, WA.
authors.forename: Joel B
authors.initials: JB
authors.lastname: Baseman
mesh_terms: D018829:Adhesins, Bacterial / Q000097:blood; D000328:Adult; D001249:Asthma / Q000150:complications / Q000382:microbiology*; D001426:Bacterial Proteins / Q000378:metabolism*; D001427:Bacterial Toxins / Q000378:metabolism*; D017714:Community-Acquired Infections; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009177:Mycoplasma pneumoniae / Q000378:metabolism*; D017817:Nasal Lavage Fluid; D011019:Pneumonia, Mycoplasma / Q000150:complications* / Q000382:microbiology; D012128:Respiratory Distress Syndrome / Q000150:complications / Q000382:microbiology*; D013183:Sputum / Q000382:microbiology
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins; C546120:CARDS toxin, Mycoplasma pneumoniae; C035471:adhesin, Mycoplasma pneumoniae