title: Possible role of Escherichia coli in propagation and perpetuation of chronic inflammation in ulcerative colitis.
abstract: BACKGROUND
  This study investigated a possible role of Escherichia coli in propagation and perpetuation of the chronic inflammation in ulcerative colitis (UC). The lesions of UC are located superficially on the rectal and/or colonic mucosa. It is suggested that the commensal bacteria of the digestive tract may play a role in the pathogenesis of UC. Several studies have demonstrated proliferation of E. coli in the gut of UC patients. An increase in the number of E. coli in the inflamed tissue is most probably related to the abundance of iron ions produced by the bacteria.
  
  
  METHODS
  Colon mucosal biopsies were collected from 30 patients with acute-phase UC, both from tissues with inflammatory changes (n = 30) and unchanged tissue with no inflammatory changes (n = 30) from the same patient. Biopsies were also taken from 16 patients with irritable bowel syndrome diarrhea who comprised the control group. Quantitative and qualitative analysis of the biopsy specimens was performed using culture methods and real-time polymerase chain reaction (PCR). Genotyping of the E. coli isolates was done using pulsed-field gel electrophoresis. Multiplex PCR was used to compare the E. coli strains for the presence of genes responsible for synthesis of iron acquisition proteins: iroN, iutA, iha, ireA, chuA, and hlyA.
  
  
  RESULTS
  We demonstrated that there was a significant increase in the number of E. coli at the sites of inflammation in patients with UC compared to the control group (P = 0.031). Comparative analysis of the restriction patterns of E. coli isolated from inflammatory and unchanged tissues showed that the local inflammatory changes did not promote specific E. coli strains. There was a significant difference in the frequency of the iroN gene in E. coli isolated from patients with UC as compared to the control group.
  
  
  CONCLUSIONS
  The increase in the numbers of E. coli in the inflammatory tissues is related to the presence of chuA and iutA genes, which facilitate iron acquisition during chronic intestinal inflammatory processes.
authors.affiliation: Department of Microbiology, Jagiellonian University Medical College, Czysta 18 Street, Cracow, 31-121, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Pilarczyk-Zurek
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Chmielarczyk
authors.forename: Tomasz
authors.initials: T
authors.lastname: Gosiewski
authors.forename: Anna
authors.initials: A
authors.lastname: Tomusiak
authors.forename: Pawel
authors.initials: P
authors.lastname: Adamski
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Zwolinska-Wcislo
authors.forename: Tomasz
authors.initials: T
authors.lastname: Mach
authors.forename: Piotr B
authors.initials: PB
authors.lastname: Heczko
authors.forename: Magdalena
authors.initials: M
authors.lastname: Strus
mesh_terms: D000328:Adult; D003093:Colitis, Ulcerative / Q000382:microbiology* / Q000473:pathology; D003106:Colon / Q000382:microbiology* / Q000473:pathology; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D004927:Escherichia coli Infections / Q000150:complications* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology* / Q000473:pathology; D007501:Iron / Q000378:metabolism; D043183:Irritable Bowel Syndrome / Q000382:microbiology; D008875:Middle Aged
chemical_list: D029968:Escherichia coli Proteins; D007501:Iron