Systematic review and meta-analysis: The incidence and prognosis of post-infectious irritable bowel syndrome.

BACKGROUND: Individual studies suggest that post-infectious irritable bowel syndrome is common, but symptoms gradually improve. AIM: To review evidence for an association between intestinal infection and development of irritable bowel syndrome, assess the prognosis of post-infectious irritable bowel syndrome and explore factors that increase the risk. METHODS: MEDLINE (1966-2007) and EMBASE (1980-2007) databases were searched to identify the studies of post-infectious irritable bowel syndrome epidemiology. Data were extracted by two independent reviewers. Pooled odds ratios (POR) and corresponding 95% CI for incidence of irritable bowel syndrome were estimated among the exposed and unexposed groups. RESULTS: Eighteen of 26 studies identified were eligible for inclusion. Intestinal infection was associated with increased odds of developing irritable bowel syndrome at study end (POR = 5.86; 95% CI: 3.60-9.54). In subgroup analysis, the odds of developing irritable bowel syndrome was increased at 3 months (POR = 7.58; 95% CI: 4.27-13.45), 6 months (POR = 5.18; 95% CI: 3.24-8.26), 12 months (POR = 6.37; 95% CI: 2.63-15.40) and 24-36 months (POR = 3.85; 95% CI: 2.95-5.02). Among all studies (controlled and uncontrolled), the pooled incidence of irritable bowel syndrome at study conclusion was 10% (95% CI: 9.4-85.6). Subjects with post-infectious irritable bowel syndrome were younger and more anxious and depressed than those without post-infectious irritable bowel syndrome. CONCLUSION: The odds of developing irritable bowel syndrome are increased sixfold after acute gastrointestinal infection. Young age, prolonged fever, anxiety and depression are risk factors for post-infectious irritable bowel syndrome.

Sputum versus bronchoscopy for diagnosis of Pseudomonas aeruginosa biofilms in cystic fibrosis.

The present authors hypothesised that bronchoscopy with protected specimen brush may sample biofilm-forming bacteria adherent to the airway wall, whereas traditional sputum collection may not. Pseudomonas aeruginosa obtained from sputum, bronchoalveolar lavage and protected brush, taken from the right upper lung bronchus of 12 adult patients with cystic fibrosis, were compared. Retrieved bacteria were genotyped, and grown in planktonic cultures and as biofilms, and susceptibilities to individual antibiotics and to antibiotic combinations were determined. Bacterial cultures obtained using bronchoscopy did not yield any new strains of bacteria that were not also found in sputum. A total of 10 patients (83%) had a single strain of P. aeruginosa found using sputum, bronchoalveolar lavage and protected brush techniques, and two patients (17%) had two strains recovered in sputum, but only one strain was recovered using bronchoscopic techniques. Susceptibility to single antibiotics and to antibiotic combinations were not different between planktonically or biofilm-grown bacteria derived from sputum, as compared to those obtained by bronchoalveolar lavage and protected brush. In conclusion, sputum collection provides as much information as bronchoscopy for characterising the genotype and antibiotic susceptibility of chronic Pseudomonas aeruginosa infection in patients with stable cystic fibrosis.

Antibody recognition of a conformational epitope in a peptide antigen: Fv-peptide complex of an antibody fragment specific for the mutant EGF receptor, EGFRvIII.

Epitope mapping studies and the determination of the structure to 1.8 A resolution have been carried out for the antigen-binding fragment MR1 in complex with peptide antigen. MR1 is specific for the novel fusion junction of the mutant epidermal growth factor receptor EGFRvIII and has been reported to have a high degree of specificity for the mutant EGFRvIII over the wild-type EGF receptor. The structure of the complex shows that the peptide antigen residue side-chains found by epitope mapping studies to be critical for recognition are accommodated in pockets on the surface of the Fv. However, the most distinctive portion of the peptide antigen, the novel fusion glycine residue, makes no contact to the Fv and does not contribute directly to the epitope. The specificity of MR1 lies in the ability of this glycine residue to assume the restricted conformation needed to form a type II' beta-hairpin turn more easily, and demonstrates that a peptide antigen can be used to generate a conformational epitope.