title: Human inflammatory bowel disease does not associate with Lawsonia intracellularis infection.
abstract: BACKGROUND
  There is increasing evidence that bacterial infection of the intestinal mucosa may contribute to the pathogenesis of inflammatory bowel diseases (IBD). In pigs, an obligate intracellular bacterium, Lawsonia intracellularis (LI), was shown to cause proliferative enteropathy (PE) of which some forms display histological and clinical similarities to human IBD. Since LI-similar Desulfovibrio spp. may infect human cells, we hypothesized that LI might be associated with the development of human IBD.
  
  
  RESULTS
  In human intestinal tissue samples, PCR using LLG, 50SL27, LSA and strictly LI-specific 16SII primers, yielded either no amplicons or products with weak homology to human genomic sequences. Sequencing of these amplicons revealed no specificity for LI. However, amplification of DNA with less specific 16SI primers resulted in products bearing homology to certain Streptococcus species. These 16SI-amplified products were present in healthy and diseased specimens, without obvious prevalence.
  
  
  CONCLUSIONS
  LI is not associated with the pathogenesis of UC or CD. Whether an immunologic response to commensal bacteria such as streptococci may contribute to the chronic inflammatory condition in IBD, remained to be determined.
authors.affiliation: Department of General Surgery, University of Heidelberg, Im Neuenheimer Feld 110, D-69210 Heidelberg, Germany. christoph.michalski@med.uni-heidelberg.de
authors.forename: Christoph W
authors.initials: CW
authors.lastname: Michalski
authors.forename: Fabio Francesco
authors.initials: FF
authors.lastname: Di Mola
authors.forename: Klaus
authors.initials: K
authors.lastname: Kümmel
authors.forename: Michael
authors.initials: M
authors.lastname: Wendt
authors.forename: Jörg S
authors.initials: JS
authors.lastname: Köninger
authors.forename: Thomas
authors.initials: T
authors.lastname: Giese
authors.forename: Nathalia A
authors.initials: NA
authors.lastname: Giese
authors.forename: Helmut
authors.initials: H
authors.lastname: Friess
mesh_terms: D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D045824:Desulfovibrionaceae Infections / Q000150:complications / Q000382:microbiology* / Q000473:pathology; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000209:etiology / Q000382:microbiology* / Q000473:pathology; D007413:Intestinal Mucosa / Q000382:microbiology / Q000473:pathology; D020639:Lawsonia Bacteria / Q000235:genetics* / Q000254:growth & development; D016133:Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial