Impact of Helicobacter pylori virulence markers on clinical outcomes in adult populations

BACKGROUND In recent years,associations between specific virulence markers of Helicobacter pylori(H.pylori)and gastrointestinal disorders have been suggested.AIM To investigate the presence of virulence factors including vacuolating cytotoxin A genotypes(s1m1,s1m2,s2m1,and s2m2),cytotoxin-associated gene A(CagA),and urease activity in H.pylori strains isolated from Arab and Jewish populations in northern Israel and to assess associations between these factors and patients’demographics and clinical outcomes.METHODS Patients(n=108)who underwent gastroscopy at the Baruch Padeh Medical Center,Poriya due to symptomatic gastroduodenal pathologies as part of H.pylori diagnosis were enrolled in the study.Gastric biopsy specimens were collected from the antrum of the stomach.Clinical condition was assessed by clinical pathology tests.Bacteria were isolated on modified BD Helicobacter Agar(BD Diagnostics,Sparks,MD,United States).Bacterial DNA was extracted,and PCR was performed to detect CagA and vacuolating cytotoxin A genes.Urease activity was assessed using a rapid urease test.RESULTS A significant correlation was found between disease severity and patient ethnicity(P=0.002).A significant correlation was found between CagA presence and the s1m1 genotype(P=0.02),which is considered the most virulent genotype.Further,a higher level of urease activity was associated with isolates originating from the Jewish population.Moreover,higher urease activity levels were measured among CagA-/s1m1 and CagA-/s2m2 isolates.CONCLUSION Our study highlights the importance of incorporating molecular methods for detection of virulence markers of H.pylori in order to tailor optimal treatments for each patient.Further investigation should be performed regarding associations between H.pylori virulence factors and ethnicity.

Role of antibiotics for treatment of inflammatory boweldisease

Inflammatory bowel disease is thought to be caused by an aberrant immune response to gut bacteria in a genetically susceptible host. The gut microbiota plays an important role in the pathogenesis and complications of the two main inflammatory bowel diseases: Crohn's disease(CD) and ulcerative colitis. Alterations in gut microbiota, and specifically reduced intestinal microbial diversity, have been found to be associated with chronic gut inflammation in these disorders. Specific bacterial pathogens, such as virulent Escherichia coli strains, Bacteroides spp, and Mycobacterium avium subspecies paratuberculosis, have been linked to the pathogenesis of inflammatory bowel disease. Antibiotics may influence the course of these diseases by decreasing concentrations of bacteria in the gut lumen and altering the composition of intestinal microbiota. Different antibiotics, including ciprofloxacin, metronidazole, the combination of both, rifaximin, and anti-tuberculous regimens have been evaluated in clinical trials for the treatment of inflammatory bowel disease. For the treatment of active luminal CD, antibiotics may have a modest effect in decreasing disease activity and achieving remission, and are more effective in patients with disease involving the colon. Rifamixin, a non absorbable rifamycin has shown promising results. Treatment of suppurative complications of CD such as abscesses and fistulas, includes drainage and antibiotic therapy, most often ciprofloxacin, metronidazole, or a combination of both. Antibiotics might also play a role in maintenance of remission and prevention of post operative recurrence of CD. Data is more sparse for ulcerative colitis, and mostly consists of small trials evaluating ciprofloxacin, metronidazole and rifaximin. Most trials did not show a benefit for the treatment of active ulcerative colitis with antibiotics, though 2 meta-analyses concluded that antibiotic therapy is associated with a modest improvement in clinical symptoms. Antibiotics show a clinical benefit when used for the treatment of pouchitis. The downsides of antibiotic treatment, especially with recurrent or prolonged courses such as used in inflammatory bowel disease, are significant side effects that often cause intolerance to treatment, Clostridium dificile infection, and increasing antibiotic resistance. More studies are needed to define the exact role of antibiotics in inflammatory bowel diseases.

Association of Streptococcus bovis presence in colonic content with advanced colonic lesion

AIM:To prospectively examine the association between presence of Streptococcus bovis(S.bovis)in colonic suction fluid and the endoscopic findings on colonoscopy.METHODS:From May 2012 to March 2013,203 consecutivepatients who underwent colonoscopy for any reason were enrolled in the study.Exclusion criteria included:antibiotic use in the previous month,age younger than18 years,and inadequate preparation for colonoscopy.The colonoscopy was performed for the total length of the colon or to the occluding tumor.The endoscopic findings were registered.Samples were obtained proximal to the colonoscopic part of the suction tube from each patient and sent to the clinical microbiology laboratory for isolation and identification of S.bovis.Samples were incubated in enrichment media with addition of antibiotic disks for inhibition of growth of Gram-negative rods.The samples were seeded on differential growth media;suspected positive colonies were isolated and identified with Gram staining,catalase,and pyrrolidonyl arylamidase tests,and further identified using a VITEK2 system.Statistical analyses were performed using the Student’s t andχ2 tests.RESULTS:Of the 203 patients recruited,49(24%)patients were found to be S.bovis carriers;of them,the endoscopic findings included:17(34.7%)cases with malignant tumors,11(22.4%)with large polyps,5(10.2%)with medium-sized polyps,6(12.2%)with small polyps,4(8.1%)with colitis,and 6(12.2%)normal colonoscopies.Of 154 patients found negative for S.bovis,the endoscopic findings included:none with malignant tumors,9(5.8%)cases with large polyps,11(7.1%)with medium-sized polyps,26(16.9%)with small polyps,7(4.5%)with colitis,and101(65.6%)normal colonoscopies.S.bovis(Grampositive coccus)is considered part of the normal intestinal flora.There is an association between S.bovis bacteremia and colonic neoplasia.It is not well understood whether the bacterium has a pathogenetic role in the development of neoplasia or constitutes an epiphenomenon of colorectal neoplasms.There was a clear relationship between positivity for S.bovis in colonic suction fluid and findings of malignant tumors and large polyps in the colon.CONCLUSION:There is an association between S.bovis bacteremia and malignant colonic lesions;this should prompt for development of a reliable screening method for advanced colonic lesions.