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Acute gastroenteritis can precipitate irritable bowel syndrome (IBS) in humans. Cytolethal distending toxin is common to all pathogens causing gastroenteritis. Its active subunit, CdtB, is associated with post-infectious bowel changes in a rat model of Campylobacter jejuni infection, including small intestinal bacterial overgrowth (SIBO). To evaluate the role of host antibodies to CdtB in contributing to post-infectious functional sequelae in this rat model. Ileal tissues from non-IBS human subjects, C. jejuni-infected and control rats were immunostained with antibodies to CdtB, c-Kit, S-100, PGP 9.5 and vinculin. Cytosolic and membrane proteins from mouse enteric neuronal cell lysates were immunoprecipitated with anti-CdtB and analyzed by mass spectrometry. ELISAs were performed on rat cardiac serum using CdtB or vinculin as antigens. Anti-CdtB antibodies bound to a cytosolic protein in interstitial cells of Cajal (ICC) and myenteric ganglia in C. jejuni-infected and naive rats and human subjects. Mass spectrometry identified vinculin, confirmed by co-localization and ELISAs. Anti-CdtB antibodies were higher in C. jejuni-infected rats (1.27 ± 0.15) than controls (1.76 ± 0.12) (P

The antibiotic rifaximin is used to treat non-constipated irritable bowel syndrome (IBS). Methane production is associated with constipation and its severity in constipation-predominant IBS (C-IBS). A previous retrospective study suggested that rifaximin and neomycin was superior to neomycin alone in improving symptoms in methane-positive subjects. To determine the effectiveness of neomycin alone or with rifaximin in improving symptoms in methane-positive C-IBS subjects. A double-blind, randomized, placebo-controlled trial was performed from 2010 to 2013 at three tertiary care centers. Subjects aged 18–65 with C-IBS (Rome II criteria) and breath methane (>3 ppm) meeting the inclusion and exclusion criteria were recruited. Subjects completed a baseline symptom questionnaire rating the severity of abdominal and bowel symptoms on a visual analog scale and were randomized to receive neomycin and placebo or neomycin and rifaximin for 14 days. Symptom severity was assessed by weekly questionnaire for 2 weeks of therapy and 4 additional weeks of follow-up. Thirty-one subjects (16 neomycin and placebo, 15 neomycin and rifaximin) were included in the intention-to-treat analysis. Constipation severity was significantly lower in the neomycin and rifaximin group (28.6 ± 30.8) compared to neomycin alone (61.2 ± 24.1) (P = 0.0042), with greater improvement in constipation (P = 0.007), straining (P = 0.017) and bloating (P = 0.020), but not abdominal pain. In the neomycin and rifaximin group, subjects with methane

A growing body of literature suggests an association between methane and constipation. Studies also link degree of methane production to severity of constipation and have shown constipation is improved following antibiotics.We aim to conduct a systematic review and meta-analysis to examine the cumulative evidence regarding the association between methane and constipation.A literature search was performed using MEDLINE and Embase to identify studies where the presence (or absence) of methane was assessed in constipated subjects. Search terms included "methane," "breath test," "constipation," "motility," "transit," "irritable bowel syndrome" and/or "IBS." Pooled odds ratios were generated using a random effects model. In a separate analysis, studies that measured intestinal transit in methane and non-methane subjects were systematically reviewed.Nine studies met inclusion criteria for the meta-analysis. Among these, 1,277 subjects were examined by breath testing (N = 319 methane producers and N = 958 methane non-producers). Pooling all studies, a significant association was found between methane on breath test and constipation (OR = 3.51, CI = 2.00-6.16). Among adults only, methane was significantly associated with constipation (OR = 3.47, CI = 1.84-6.54). Similar results were seen when only examining subjects with IBS (OR = 3.60, CI = 1.61-8.06). The systematic review identified eight additional papers which all demonstrated an association between methane and delayed transit.We demonstrate that methane present on breath testing is significantly associated with constipation in both IBS and functional constipation. These results suggest there may be merit in using breath testing in constipation. Moreover, methane may be used to identify candidates for antibiotic treatment of constipation.

A recent post-infectious rat model with Campylobacter jejuni 81-176 has replicated the events noted in humans with post-infectious irritable bowel syndrome (IBS). In this study, we test whether prophylactic treatment with the antibiotic rifaximin will prevent the development of long-term altered bowel function in this model. Sprague–Dawley rats were divided into two groups. Both groups were gavaged with a 1 mL solution of 108 cfu/mL of C. jejuni. However, one group was also prophylactically gavaged with a solution of rifaximin 200 mg per day for 3 days (the day before gavage, the day of gavage, and the day after gavage with C. jejuni). Fresh stool was collected from rats daily until two consecutive stool cultures were negative for C. jejuni. The rats were then housed for 3 months. At the end of 3 months, fresh stool was collected on three consecutive days to determine stool % wet weight and stool consistency on a stool score. Rats that received rifaximin antibiotic prophylaxis had a greater rate of stool shedding of C. jejuni. However, the mean duration of colonization was shorter in the rifaximin-treated group (10.3 ± 7.1 days) compared to rats receiving no prophylaxis (12.6 ± 5.9 days) (P

Rifaximin is a non-absorbed antibiotic relative of rifampicin. The location of effect and staphylococcal resistance are two recent potential concerns with rifaximin. In this study we evaluate the location of effect of rifaximin as well as the development of staphylococcal rifampicin resistance.Rats were divided into three groups. Group 1 gavaged for 10 days with PBS, group 2 gavaged with rifaximin for 10 days, and group 3 gavaged with rifaximin for 10 days and housed for 30 days. In each group, stool was collected daily for quantitative culture of Staphylococcus spp. and coliforms. After euthanasia luminal bacterial counts were determined at multiple gut locations by qPCR. Rifampicin susceptibility was tested on Staphylococcus pre and post rifaximin.At baseline, rats had a median of 2.90 × 10(6) cfu/ml Staphylococcus spp. in stool. After 10 days of rifaximin, this dropped to 1.20 × 10(5) cfu/ml (P0.01). With coliform counts, rats had a median of 1.86 × 10(4) cfu/ml at baseline which dropped to 2.2 × 10(3) cfu/ml (P0.01) after rifaximin. After cessation of rifaximin, coliform counts recovered within 3 days. When examining the total bacterial counts by qPCR, rifaximin reduced small bowel bacterial levels, but not colon. This reduction was sustained for 30 days. No colonies of Staphylococcus became resistant and only one colony was intermediate. The mean inhibitory concentration for rifampicin was not different before and after rifaximin.Staphylococcal spp. fail to demonstrate resistance to rifampicin after rifaximin. The transient reductions in stool coliform counts recover while rifaximin appears to produce durable reductions in duodenal bacteria.

Among irritable bowel syndrome (IBS) patients, breath methane producers overwhelmingly have constipation predominance (C-IBS). Although the most common methanogen in humans is Methanobrevibacter smithii, incidence and type of methanogenic bacteria in C-IBS patients are unknown.By use of a questionnaire and lactulose breath testing, subjects with Rome II C-IBS and methane (3 ppm) were selected (n = 9). The control group included subjects with IBS who had no breath methane (n = 10). Presence of bacterial DNA was assessed in a stool sample of each subject by quantitative-PCR using universal 16S rDNA primer. M. smithii was quantified by use of a specific rpoB gene primer.M. smithii was detected in both methane and non-methane subjects. However, counts and relative proportion of M. smithii were significantly higher for methane-positive than for methane-negative subjects (1.8 × 10(7) ± 3.0 × 10(7) vs 3.2 × 10(5) ± 7.6 × 10(5) copies/g wet stool, P0.001; and 7.1 ± 6.3 % vs 0.24 ± 0.47 %, P = 0.02 respectively). The minimum threshold of M. smithii resulting in positive lactulose breath testing for methane was 4.2 × 10(5) copies/g wet stool or 1.2 % of total stool bacteria. Finally, area-under-curve for breath methane correlated significantly with both absolute quantity and percentage of M. smithii in stool (R = 0.76; P0.001 and R = 0.77; P0.001 respectively).M. smithii is the predominant methanogen in C-IBS patients with methane on breath testing. The number and proportion of M. smithii in stool correlate well with amount of breath methane.

Campylobacter jejuni has been implicated in the pathogenesis of post-infectious irritable bowel syndrome (PI-IBS) in humans, effects which may be because of cytolethal distending toxin (CDT). In this study, we characterized both acute and chronic-phase histological changes of the small bowel in rats exposed to wild-type C. jejuni 81-176, or a strain that does not produce CDT, by using a validated rat model of PI-IBS.Sprague-Dawley rats were given 1.0 × 10(8) CFU of either wild-type C. jejuni 81-176 (C+, PI/C+) or the CDT-negative strain (CDT-), or vehicle alone (Control). Acute-phase rats (C+, CDT-) were euthanized on days 2, 4, 8, 16, and 32. Chronic-phase rats (PI/C+, Control) were euthanized 3 months after clearing the initial infection. Segments of duodenum, jejunum, and ileum were resected and the contents plated for C. jejuni culture, and tissue sections were stained for histology.We observed preferential infection of the ileum and jejunum by Campylobacter jejuni. Compared with controls, epithelial cell basal membrane ballooning, villous tip disruption, and reduced villous-to-crypt ratios were observed for both C+ and CDT- rats. Villous widening, the only result significantly different in C+ vs. CDT- rats, was greatest at day 4 (134.1 ± 21.12 μm vs. 109.9 ± 10.6 μm for CDT-, P0.01). Little or no cellular inflammatory changes were seen during acute C. jejuni infection. Three months after clearing the initial infection, no histological changes remained.Significant histological changes, with the absence of inflammatory cells, are seen in the duodenum, jejunum, and ileum of rats during acute infection with C. jejuni. These changes occurred irrespective of the presence or absence of the CDT toxin.