Complete genome sequence of the Crohn's disease-associated adherent-invasive Escherichia coli strain HM605.

Adherent-invasive Escherichia coli strains are increasingly being associated with intestinal pathologies. Here we present the genome sequence of E. coli HM605, a strain isolated from colonic biopsy specimens of a patient with Crohn's disease.

A subset of mucosa-associated Escherichia coli isolates from patients with colon cancer, but not Crohn's disease, share pathogenicity islands with urinary pathogenic E. coli.

Adherent and invasive mucosa-associated Escherichia coli have been implicated in the pathogenesis of colon cancer and inflammatory bowel diseases. It has been reported that such isolates share features of extraintestinal E. coli (ExPEC) and particularly uropathogenic E. coli (UPEC). We used suppression subtractive hybridization (SSH) to subtract the genome of E. coli K-12 from that of a colon cancer mucosal E. coli isolate. Of the subtracted sequences, 53 % were present in the genomes of one or more of three sequenced UPEC strains but absent from the genome of an enterohaemorrhagic E. coli (EHEC) strain. Of the subtracted sequences, 80 % matched at least one UPEC genome, whereas only 4 % were absent from the UPEC genomes but present in the genome of the EHEC strain. A further genomic subtraction against the UPEC strain 536 enriched for sequences matching mobile genetic elements, other ExPEC strains, and other UPEC strains or commensals, rather than strains associated with gastrointestinal disease. We analysed the distribution of selected subtracted sequences and UPEC-associated pathogenicity islands (PAIs) amongst a panel of mucosa-associated E. coli isolated from colonoscopic biopsies of patients with colon cancer, patients with Crohn's disease and controls. This enabled us to identify a group of isolates from colon cancer (30-40 %) carrying multiple genes previously categorized as UPEC-specific and implicated in virulence.

Replication of Colonic Crohn's Disease Mucosal Escherichia coli Isolates within Macrophages and Their Susceptibility to Antibiotics.

There is increasing evidence that Escherichia coli organisms are important in Crohn's disease (CD) pathogenesis. In CD tissue they are found within macrophages, and the adherent-invasive CD ileal E. coli isolate LF82 can replicate inside macrophage phagolysosomes. This study investigates replication and antibiotic susceptibility of CD colonic E. coli isolates inside macrophages. Replication of CD colonic E. coli within J774-A1 murine macrophages and human monocyte-derived macrophages (HMDM) was assessed by culture and lysis after gentamicin killing of noninternalized bacteria and verified by electron microscopy (EM). All seven CD colonic isolates tested replicated within J774-A1 macrophages by 3 h (6.36-fold +/- 0.7-fold increase; n = 7 isolates) to a similar extent to CD ileal E. coli LF82 (6.8-fold +/- 0.8-fold) but significantly more than control patient isolates (5.2-fold +/- 0.25-fold; n = 6; P = 0.006) and E. coli K-12 (1.0-fold +/- 0.1-fold; P < 0.0001). Replication of CD E. coli HM605 within HMDM (3.9-fold +/- 0.7-fold) exceeded that for K-12 (1.4-fold +/- 0.2-fold; P = 0.03). EM showed replicating E. coli within macrophage vacuoles. Killing of HM605 within J774-A1 macrophages following a 3-h incubation with antibiotics at published peak serum concentrations (C(max)) was as follows: for ciprofloxacin, 99.5% +/- 0.2%; rifampin, 85.1% +/- 6.6%; tetracycline, 62.8% +/- 6.1%; clarithromycin, 62.1% +/- 5.6% (all P < 0.0001); sulfamethoxazole, 61.3% +/- 7.0% (P = 0.0007); trimethoprim, 56.3% +/- 3.4% (P < 0.0001); and azithromycin, 41.0% +/- 10.5% (P = 0.03). Ampicillin was not effective against intracellular E. coli. Triple antibiotic combinations were assessed at 10% C(max), with ciprofloxacin, tetracycline, and trimethoprim causing 97% +/- 0.0% killing versus 86% +/- 2.0% for ciprofloxacin alone. Colonic mucosa-associated E. coli, particularly CD isolates, replicate within macrophages. Clinical trials are indicated to assess the efficacy of a combination antibiotic therapy targeting intramacrophage E. coli.

Family history in pediatric primary care.

The family history is a critical element in pediatric medicine and represents the gateway to the molecular age of medicine for both pediatric clinicians and their patients. The pediatric clinician has several opportunities to obtain a family history and multiple clinical and educational uses for that information. Available methods include paper and digital forms, classical pedigrees, online programs, and focused family history at the time of a new diagnosis or problem. Numerous barriers impede the application of family history information to primary pediatric practice. The most common barrier is the limited amount of time the typical primary care encounter allows for its collection. The family history can be used in many facets of pediatric practice: (1) as a diagnostic tool and guide to testing and evaluation; (2) to identify patterns of inheritance; and (3) as a patient-education tool. The most exciting future use of family history is as a tool for public health and preventive medicine. More accurately identifying children at risk for common chronic conditions such as diabetes, asthma, and cardiovascular disease could change the primary care clinician's approach to pediatric medicine.

Enhanced Escherichia coli adherence and invasion in Crohn's disease and colon cancer.

BACKGROUND & AIMS: Altered mucosal glycosylation in inflammatory bowel disease and colon cancer could affect mucosal bacterial adherence. This study aimed to quantify and characterize mucosa-associated and intramucosal bacteria, particularly Escherichia coli, in these conditions. METHODS: Mucosa-associated bacteria were isolated, after dithiothreitol mucolysis, from biopsy samples obtained at colonoscopy (Crohn's disease, n = 14 patients; ulcerative colitis, n = 21; noninflamed controls, n = 24) and at surgical resection (colon cancer, n = 21). Intramucosal bacteria were grown after gentamicin treatment followed by hypotonic lysis. RESULTS: Mucosa-associated and intramucosal bacteria were cultured more commonly in Crohn's disease (79%, P = 0.03; and 71%, P < 0.01, respectively), but not ulcerative colitis (38% and 48%), than in noninflamed controls (42% and 29%) and were commonly cultured from colon cancers (71% and 57%). Mucosa-associated E. coli, which accounted for 53% of isolates, were more common in Crohn's disease (6/14; 43%) than in noninflamed controls (4/24, 17%), as also were intramucosal E. coli: Crohn's disease, 29%; controls, 9%. E. coli expressed hemagglutinins in 39% of Crohn's cases and 38% of cancers but only 4% of controls, and this correlated (P = 0.01) with adherence to the I407 and HT29 cell lines. Invasion was cell-line dependent. E. coli, including nonadherent isolates, induced interleukin-8 release from the cell lines. E. coli adhesins showed no blood group specificity, excepting 1 cancer isolate (HM44) with specificity for the Thomsen-Friedenreich antigen, but they could be blocked by soluble plantain fiber. CONCLUSIONS: These studies support a central role for mucosally adherent bacteria in the pathogenesis of Crohn's disease and colon cancer. Soluble plant fibers that inhibit their adherence have therapeutic potential.