title: Sewage workers with low antibody responses may be colonized successively by several Tropheryma whipplei strains.
abstract: OBJECTIVE
  Asymptomatic faecal carriage of Tropheryma whipplei, the agent of Whipple's disease, is reported among sewage workers. However, the potential development of such carriage is unknown. A 7-year follow-up of T. whipplei-carrying sewage workers is reported.
  
  
  METHODS
  Nineteen sewage workers previously detected as faecal carriers of T. whipplei were followed to ascertain the chronicity of their carriage. Faeces were tested by molecular assays using quantitative real-time PCR specifically targeting T. whipplei. Serological anti-T. whipplei Western blotting was also performed.
  
  
  RESULTS
  Seventy-nine percent (15/19) of workers exhibited a strong immune response against T. whipplei. Among these, five were followed for more than 1 year. Four maintained a strong response, with three carrying the same strain and one becoming negative. The fifth exhibited a decreased immune response, a negative faeces result, and subsequent carriage of another strain. Three individuals with low immune responses were also followed. Two never developed a response, with one carrying the same strain and one becoming negative and then positive with another strain; the third developed a strong response and became negative.
  
  
  CONCLUSIONS
  Chronic T. whipplei carriers appear to be protected against reinfection, but those with low or decreasing antibody levels may be re-colonized by another strain.
authors.affiliation: Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE) UM63, CNRS 7278, IRD 198, Inserm 1095, 13005 Marseille, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Fenollar
authors.affiliation: Abteilung Innere Medizin, Krankenhaus Maria Hilf, Daun, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Marth
authors.affiliation: Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE) UM63, CNRS 7278, IRD 198, Inserm 1095, 13005 Marseille, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Lagier
authors.affiliation: Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE) UM63, CNRS 7278, IRD 198, Inserm 1095, 13005 Marseille, France.
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Angelakis
authors.affiliation: Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE) UM63, CNRS 7278, IRD 198, Inserm 1095, 13005 Marseille, France. Electronic address: didier.raoult@gmail.com.
authors.forename: Didier
authors.initials: D
authors.lastname: Raoult
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology; D002353:Carrier State / Q000276:immunology / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D006801:Humans; D009784:Occupational Diseases / Q000276:immunology / Q000382:microbiology*; D012722:Sewage; D054851:Tropheryma / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D008061:Whipple Disease / Q000276:immunology / Q000382:microbiology*
chemical_list: D000907:Antibodies, Bacterial; D012722:Sewage
keywords: Asymptomatic carriage; Sewage workers; Tropheryma whipplei; Whipple's disease