Jacob Yahav

Relationship between Helicobacter pylori CagA status and colorectal cancer

OBJECTIVES:Infection with Helicobacter pylori, particularly with strains positive for CagA protein, increases the risk of gastric adenocarcinoma. Few studies have explored the possible association between H. pylori infection and colorectal cancer. This study evaluated whether the seroprevalence of CagA in H. pylori-infected patients affected risk for colorectal cancer independently of H. pylori status.METHODS:In this study, we tested serum IgG antibodies against H. pylori (ELISA) and CagA protein (Western blot assay) in 67 patients with colorectal adenocarcinoma, 36 with gastric adenocarcinoma, 47 with other malignancies (cancer controls), and 45 hospitalized for transesophageal echocardiography (TEE controls). Colonic cancer and gastric cancer patients with H. pylori infection were compared to each control group and to the pooled controls using simple and adjusted analyses.RESULTS:H. pylori infection was noted in 50 colon cancer patients, 31 gastric cancer patients, 31 cancer controls, and 32 TEE controls. In all, 41 (82%), 29 (94%), 11 (35%), and 13 (41%), respectively, of these H. pylori-positive sera expressed CagA reactivity (p < 0.001 for all pairwise comparisons between cases and controls). In the adjusted analysis, infection with H. pylori CagA+ compared to H. pylori CagA− was associated with increased risk for colorectal adenocarcinoma (odds ratio = 10.6; 95% CI = 2.7–41.3; p = 0.001) and gastric adenocarcinoma (odds ratio = 88.1; 95% CI = 6.3–1229.2; p = 0.001).CONCLUSIONS:Among patients infected with H. pylori, CagA+ seropositivity is associated with increased risk for both gastric and colonic cancer. This finding should stimulate additional research into the role of cagA+ H. pylori infection in the development of colorectal cancer.

Antibiotic Prophylaxis of Bacterial Infections in Cirrhotic Inpatients: a Meta-Analysis of Randomized Controlled Trials

Background: Antibiotic prophylaxis has been reported to decrease bacterial infections and fatality rates in inpatients with cirrhosis. We performed a systematic review to evaluate the efficacy of antibiotic prophylaxis in inpatients with cirrhosis, regardless of the underlying risk factors that led to hospital admission. Methods: A comprehensive literature search strategy was performed including the Cochrane Library, Embase, Medline, a manual search of bibliographic references, and contacting the authors of each included trial. We included any randomized clinical trial comparing different types of antibiotic prophylaxis with placebo or no intervention in inpatients with cirrhosis. Two reviewers independently applied the selection criteria to all identified references, appraised the methodological quality of each trial and extracted the relevant data. Relative risks and 95% confidence intervals were estimated using the fixed effect model. A test of heterogeneity and a funnel plot were performed and an intention-to-treat approach was used for the outcome measures. Results: Nineteen randomized trials were identified, 13 of which were included in the review. A significant beneficial effect on mortality (RR: 0.70; 95% CI: 0.56, 0.89) and prevention of bacterial infections (RR: 0.39; 95% CI: 0.32, 0.48) was observed, regardless of the underlying risk factors. Few adverse events were reported and there was no heterogeneity between studies. We identified a funnel plot asymmetry for the included trials. Conclusions: Antibiotic prophylaxis for inpatients with cirrhosis is efficacious in reducing the number of deaths and bacterial infections regardless of the underlying risk factors.

Helicobacter pylori and Clostridium difficile in Cystic Fibrosis Patients

We describe the prevalence of H. pylori and toxigenic Clostridium difficile (CD) infection and its relationship with gastrointestinal symptoms and pancreatic sufficiency (PS) or insufficiency (PI) in cystic fibrosis (CF) patients. Stool specimens from 30 consecutive patients with CF, aged 1–44, and from 30 healthy similarly aged subjects were tested for the H. pylori antigen by specific monoclonal antibodies and for CD toxins by Tox A/B assay and Tox A assay. CF patients were assessed clinically and tested for specific H. pylori serum antibodies and for mutations. In CF patients, the prevalence of H. pylori antigen was 16.6% (5/30), compared to 30% (9/30) in controls. Of the 26 CF patients with PI, only 2 (7.6%) were infected by H. pylori, compared with 3 of the 4 (75%) patients with PS (P=0.001). H. pylori infection was diagnosed in 3 of 5 (60%) CF patients carrying mild mutations, compared to 1 of 25 (4%) CF patients carrying severe mutations (P=0.01). Fourteen of 30 (46.6%) stool specimens from CF patients tested positive in the ToxA/B assay, and 3 of 14 tested positive for ToxA. No significant differences in antibiotic use, severity of lung disease, PI, chronic abdominal pain, or genotype were found between the two groups. None of the controls was positive for CD toxins. Prevalence of H. pylori infection in CF patients was lower than in similarly aged non-CF controls. CF patients with PI or a history of distal intestinal obstruction syndrome and those carrying mutations associated with a severe phenotype were protected against H. pylori infection. Almost half of the CF patients were asymptomatic carriers of CD producing mostly toxin B. More studies are needed to confirm our results in a larger group of CF patients.

Antibiotic resistance of Helicobacter pylori in Israeli children

Abstract Objectives. To determine the antibiotic susceptibility of Helicobacter pylori isolates from Israeli children; assess the role of previous antibiotic use in the development of antibiotic resistance and examine the possibility of simultaneous colonization of strains with different resistance patterns in the same patients. Material and methods. A prospective case-series design was used. The study group included 174 patients aged 1–18 years referred to the Schneider Childrens Medical Center of Israel for gastroscopy over a 2.5-year period. Antibiotic susceptibility to amoxicillin, clarithromycin, metronidazole, tetracycline, and levofloxacin was determined by E-test on gastric biopsies (2 per patient). Clinical and demographic data were obtained by questionnaire. Results. Cultures for H. pylori yielded 55 isolates from 53 children. In treatment-naïve children, the prevalence rate of primary resistance to clarithromycin was 25% and to metronidazole, 19%. Respective rates in children previously treated for H. pylori infection were 42% (p = 0.22) and 52% (p = 0.016). Simultaneous resistance to both drugs was found in 13% of isolates (n = 7), all from children with previous treatment failure. No resistance was found to amoxicillin, tetracycline or levofloxacin. Clarithromycin resistance was associated with macrolide use for any indication during the previous year (p = 0.033). In 2 patients (3.8%), a different H. pylori strain was cultured from each biopsy. Conclusions. H. pylori resistance to clarithromycin and metronidazole is high in Israeli children, particularly in those previously treated for H. pylori infection, in whom culture-based treatment should be considered. The simultaneous colonization of multiple strains in a minority of patients needs to be further characterized.

Helicobacter pylori infection in pediatrics.

The diagnosis of Helicobacter pylori infection continues to challenge practicing physicians around the world. In the last year, several reports from Africa tried to examine the epidemiology of H. pylori infection in nursing babies, while others investigated the association between recurrent abdominal pain symptoms and H. pylori. In the diagnostic arena, attempts were made to improve diagnostic accuracy, mainly by using a new monoclonal version of the stool antigen test, and by applying the urea breath test in smaller children. In the current report, the most important studies on H. pylori infection in children published in the last year are also reviewed.

Association of Helicobacter pylori infection with Shigella gastroenteritis in young children.

OBJECTIVE:Helicobacter pylori infection is acquired mainly in early childhood. Much is unknown about the mode of transmission. The organism can be cultivated from cathartic stools and vomitus and is potentially transmissible during episodes of gastrointestinal tract illness. Because Shigella and Salmonella are common pathogens in enteric infections in children, we examined the association of H. pylori with Shigella and Salmonella infections in pediatric patients.METHODS:The study population included consecutive children aged 2–72 months hospitalized with acute gastroenteritis who had culture-proven shigellosis (N = 78) or salmonellosis (N = 76). Sixty-five healthy similarly aged children with culture-negative stools served as controls. Parents of cases were queried for personal and family characteristics and socioeconomic indicators. The stool specimens from all participants were tested for H. pylori antigen.RESULTS:On univariate analysis, Shigella gastroenteritis was significantly associated with H. pylori positivity (odds ratio, OR: 3.5, 95% confidence interval (CI): 1.5–8.8, P = 0.004) compared to controls. This association remained significant even after adjusting for living conditions, fathers occupation, and fathers education (OR = 3.38, 95% CI: 1.39–8.22, P = 0.007). Salmonella gastroenteritis was not associated with H. pylori positivity (OR = 1.1; 95% CI: 0.4–3.0, P = 0.8).CONCLUSIONS:H. pylori infection in young children is associated with Shigella gastroenteritis. This association warrants further investigation.

Elevated 13C Urea Breath Test Values Females Infected With Helicobacter pylori

Abstract13C-urea breath test (UBT) for the diagnosis of Helicobacter pylori requires a high density and active bacteria and has the potential to provide a noninvasive index of bacterial growth. We describe the gender differences in δ over baseline 13C-UBT values in 7373 patients (4531 females and 2842 males) who underwent 13C-UBT test for the diagnosis of H. pylori infection. A significantly (P<.001) higher mean ± SD excess delta 13CO2 excretion was recorded in females (24.7±17.4) compared to males (17.6±11.8) aged 10–80 years. The age-adjusted difference between sexes was 7.1 (95% confidence interval, 6.4–7.9). Our analysis demonstrates quantitatively for the first time gender associated differences in H. pylori host interaction. This study suggests that infected females have a higher bacterial load and therefore may potentially infect their children at a higher degree than males.

Seven-year study of bacteremia in hospitalized patients on chronic hemodialysis in a single tertiary hospital.

Sixty-seven hospitalized bacteremic patients on chronic hemodialysis were matched with 134 bacteremic controls. Mortality (25% and 28% respectively) was unrelated to dialysis. Predictors of mortality were: advanced age, decreased functional capacity, and malignancies. Most common organisms recovered were Staphylococcus aureus (30%), coagulase negative Staphylococcus (15%), and polymicrobial agents (15%).