Fecal Colonization Research Articles

SYN-004 (Ribaxamase), an Orally Administered β-Lactamase for Prevention of Clostridium Difficile Infection in Patients Treated with Intravenous β-Lactam Antibiotics: A Randomized, Double-Blind, Placebo-Controlled Phase 2b Study

Background: Clostridium difficile infection (CDI) is an urgent public health threat, yet there is no product currently licensed for its prevention. The use of intravenous β-lactam antibiotics are considered high risk for the development of CDI due to their biliary excretion into the GI tract and disruption of the gut microbiome. SYN-004 (ribaxamase) is an orally-administered β-lactamase, designed to be given with IV β-lactam antibiotics to degrade excess antibiotics in the upper GI tract before they can disrupt the gut microbiome leading to CDI. Methods: A parallel-group, double-blind, placebo-controlled, multi-center, study evaluating the effectiveness of ribaxamase for prevention of CDI was conducted in 412 hospitalized patients > 50 years of age who received intravenous ceftriaxone for a lower respiratory tract infection (LRTI). Patients were randomized 1:1 to receive either 150 mg of ribaxamase or placebo four times per day during and for 72 hours after ceftriaxone treatment. The primary endpoint was the incidence of CDI through 4 weeks post-treatment in the ribaxamase vs. the placebo group. Secondary endpoints included resolution of the LRTI, new colonization by certain opportunistic pathogens, and microbiome-focused exploratory endpoints. Findings: Of 412 patients (mean age ~69·5), 206 each received ceftriaxone plus ribaxamase or ceftriaxone plus placebo. By 4 weeks post-antibiotics, the incidence of CDI in the placebo group was 3·4% while the incidence of C. difficile infection in the ribaxamase group was only 1·0% which corresponds to a 71% reduction in the incidence of C. difficile infection (one-sided, P=0·045). Patients who received ribaxamase also had a lower incidence of new fecal colonization with C. difficile and vancomycin resistant enterococci. Interpretation: In patients being treated with intravenous ceftriaxone for a LRTI, oral ribaxamase significantly reduced the incidence of CDI as compared with placebo. Ribaxamase has the potential to become the first product licensed for prevention of CDI. Trial registration number: The trial was registered at clinicaltrials.gov: NCT02563106. Funding: Synthetic Biologics, Inc. Declaration of Interest: All authors are employees or paid consultants of Synthetic Biologics, Inc. Ethical Approval: The study protocol was approved by the appropriate institutional review boards or ethics committees at the corresponding institutions or countries. All study patients provided written informed consent to participate in the study.

Co-production of MCR-1 and NDM-5 in Escherichia coli isolated from a colonization case of inpatient.

Colistin is increasingly used as an antibiotic of last resort for treating carbapenem-resistant Enterobacteriaceae. Mobile colistin resistance gene mcr-1 has been increasingly reported in Enterobacteriaceae around the world. Of particular concern is the spread of mcr-1 into carbapenemase-producing Enterobacteriaceae, which results in highly drug-resistant strains that are potentially untreatable. Notably, such mcr-1-carrying isolates harboring carbapenemase genes have been reported in animals and patients with infection. Here, we report an Escherichia coli strain carrying co-transferable mcr-1-harboring IncX4 and blaNDM-5-harboring IncX3 plasmids, which was recovered in the context of fecal colonization.

High rates of colonisation with ESBL (+) gram negative bacteria in newly admitted neonates in a neonatal care unit, Port au Prince, Haiti

Background Nosocomial invasive Gram negative bacterial (GNB) infections are common causes of mortality in neonatal care units (NCU). Gastrointestinal tracts of hospitalized infants can serve as a reservoir for these infections. We aimed to estimate the faecal colonisation proportion by GNB and ESBL (+) GNB of systematically sampled newly admitted neonates in an NCU in Haiti, to describe the antimicrobial resistance profiles (AMR) of isolated GNB and identify factors associated with colonisation. Materials/methods We included all neonates admitted to the NCU from May to August 2016 who were started on prophylactic antibiotics or treated for infection. Neonates had fecal swabs taken before treatment was initiated; these were tested for GNB, AMR profiles and ESBL status. We calculated adjusted prevalence ratios (aPR) using binomial regression. Results Of the 800 neonates admitted in NCU, 409 were treated with antimicrobials and 78 received second treatment. One hundred and twenty-five out of 279 (45%) screened neonates were colonised by GNB, 85% before the second treatment and 34% before the first treatment (aPR 2.5; 95% CI: 2.0–3.0). Twenty-three percent (52/224) of neonates were colonised by ESBL (+) GNB, 70% (32/46) before the second treatment, 8.8 (95% CI: 5.6–14) times higher than those before first treatment (7.9%; 20/254). Ninety-eight out of 175 (56%) of isolated GNB were Escherichia coli, Klebsiella oxytoca and Klebsiella pneumoniae. Fifty percent of the tested GNB were susceptible to first-line antimicrobials and 99% to second-line antimicrobials; 4% and 35% of isolates indicated intermediate resistance to amikacin and ceftazidime, respectively. Vaginal delivery (aPR 2.1; 95% CI: 1.4–3.2) and length of stay (aPR 1.82; 95% CI: 1.2–2.7) were associated with GNB colonisation among newly admitted neonates. Neonates sampled > 48 h after admission were 19 times more likely to be colonised by ESBL (+) GNB (aPR 19; 95% CI: 8.9–41) than those sampled Conclusions GNB colonisation was high and increased with length of stay. Second line antimicrobial treatment seems still adequate, but signs of intermediate resistance to ceftazidime were observed. We recommend to re-enforce: –surveillance for suspected pathogens of nosocomial infections using blood cultures for septic infants; –monitoring of antimicrobial treatment failure in infants receiving antibiotics.

Pseudomonas aeruginosa Isolates from Spanish Children: Occurrence in Faecal Samples, Antimicrobial Resistance, Virulence, and Molecular Typing.

Pseudomonas aeruginosa is a major opportunistic human pathogen, responsible for nosocomial infections and infections in patients with impaired immune systems. Little data exist about the faecal colonisation by P. aeruginosa isolates in healthy humans. The occurrence, antimicrobial resistance phenotype, virulence genotype, and genetic lineages of P. aeruginosa from faecal samples of children from two different Spanish regions were characterised. Seventy-two P. aeruginosa were isolated from 1,443 faecal samples. Low antimicrobial resistance levels were detected: ceftazidime (8%), cefepime (7%), aztreonam (7%), gentamicin (3%), ciprofloxacin (1%), and imipenem (1%); susceptibility to meropenem, amikacin, tobramycin, levofloxacin, and colistin. Four multidrug-resistant strains were found. Important differences were detected between both geographical regions. Forty-one sequence types were detected among the 48 tested strains. Virulence and quorum sensing genes were analysed and 13 virulotypes were detected, being 26 exoU-positive strains. Alteration in protein OprD showed eight different patterns. The unique imipenem-resistant strain showed a premature stop codon in OprD. Intestinal colonisation by P. aeruginosa, mainly by international clones (as ST244, ST253, and ST274), is an important factor for the systemic infections development and the environmental dissemination. Periodic active surveillance is useful to identify these community human reservoirs and to control the evolution of antibiotic resistance and virulence activity.

Faecal colonization of E. coli and Klebsiella spp. producing extended-spectrum beta-lactamases and plasmid-mediated AmpC in Mozambican university students

BackgroundIn recent years, the world has seen a surge in Enterobacteriaceae resistant to broad-spectrum beta-lactam antibiotics due to the production of extended-spectrum beta-lactamases (ESBLs) or plasmid-mediated AmpC (pAmpC) enzymes. Data on the epidemiology of cephalosporin-resistant Enterobacteriaceae in Sub-Saharan Africa are still limited.MethodsTwo hundred seventy-five non-repetitive stool samples were collected from Mozambican university students of both sexes. Samples were cultured on MacConkey agar with and without ceftriaxone (1 mg/L) for selection of third-generation cephalosporin-resistant isolates, which were subjected to antimicrobial susceptibility testing by disc diffusion, characterization of resistance genes by PCR and ERIC-PCR analysis for strain clonality.ResultsAmong the 275 students, 55 (20%) carried a total of 56 E. coli (n = 35) and Klebsiella spp. (n = 21) isolates resistant to ceftriaxone and phenotypically positive for ESBL- and/or pAmpC-production. Forty-three percent of the isolates (24/56) contained only ESBL genes, 11% (6/56) only pAmpC genes, and 36% (20/56) both ESBL and pAmpC genes. The remaining six isolates were negative for the CTX-M/pAmpC genes included in the test panel. E. coli and Klebsiella spp. combined demonstrated 70% resistance to tetracycline and co-trimoxazole, 63% to ceftazidime and 34% to ciprofloxacin. In total, 89% of ESBL/pAmpC-positive isolates were defined as multi-resistant by being resistant to three or more antibiotic classes. ERIC-PCR fingerprinting demonstrated low similarity among isolates. None of the participants reported recent hospitalization and just 12.5% had taken antibiotics 3 months prior to the study.ConclusionThis study demonstrated 20% colonization with multi-resistant E. coli and Klebsiella spp. among Mozambican students with a diversity of ESBL and pAmpC genes. Colonization was not related to prior hospitalization or antimicrobial consumption.

Subsequent infection with extended-spectrum β-lactamase-producing Enterobacteriaceae in patients with prior infection or fecal colonization.

In clinical practice, there is a growing need to assess the impact of prior colonization or infection with extended-spectrum β-lactamase-producing Enterobacteriaceae (EPE) on new EPE infections. We have investigated the frequency of, and duration to, a subsequent EPE infection in patients with prior fecal carriage or infection with EPE. Culture data for 3272 EPE-positive patients in Western Sweden during 2004-2014 were evaluated. The median follow-up time was 3.7years. The first recorded EPE-positive fecal screen, or clinical (urine, blood) culture, and subsequent EPE-positive clinical samples were analyzed, focusing on the first and last recurrence of EPE infection. ESBL Escherichia coli dominated (95%). Almost all (94%) patients initially positive in fecal screen (n = 1436) and 72 and 71% of those initially positive in urine (n = 1717) and blood (n = 119) had no further EPE clinical isolates. Subsequent EPE bacteremia was only detected in 0.7, 1.6, and 4.2% of the respective patient group. Recurrent EPE-positive urine cultures occurred in 27% (460/1717), most (75%) within 6months, and rarely (13%) after 1year. Repeated EPE-positive clinical samples were significantly (p < 0.01) more common in patients > 65years and in men with ESBL Klebsiella pneumoniae. In our low-endemic setting, subsequent EPE infections in previously colonized patients were rare. On the other hand, in patients previously EPE-positive in urine or blood, subsequent EPE urinary tract infections were common, especially within 6months and in patients > 65years old.

Dietary Magnesium Alleviates Experimental Murine Colitis Through Upregulation of the Transient Receptor Potential Melastatin 6 Channel.

Magnesium (Mg) is essential for human health and is absorbed mainly in the intestine. In view of the likely occurrence of an Mg deficit in inflammatory bowel disease (IBD) and the documented role of Mg in modulating inflammation, the present study addresses whether Mg availability can affect the onset and progression of intestinal inflammation. To study the correlation between Mg status and disease activity, we measured magnesemia by atomic absorption spectroscopy in a cohort of IBD patients. The effects of dietary Mg modulation were assessed in a murine model of dextran sodium sulfate (DSS)-induced colitis by monitoring magnesemia, weight, fecal occult blood, diarrhea, colon length, and histology. Expression of the transient receptor potential melastatin (TRPM) 6 channel was assessed by real-time reverse transcription polymerase chain reaction and immunohistochemistry in murine colon tissues. The effect of Mg on epithelial barrier formation/repair was evaluated in human colon cell lines. Inflammatory bowel disease patients presented with a substantial Mg deficit, and serum Mg levels were inversely correlated with disease activity. In mice, an Mg-deficient diet caused hypomagnesemia and aggravated DSS-induced colitis. Colitis severely compromised intestinal Mg2+ absorption due to mucosal damage and reduction in TRPM6 expression, but Mg supplementation resulted in better restoration of mucosal integrity and channel expression. Our results highlight the importance of evaluating and correcting magnesemia in IBD patients. The murine model suggests that Mg supplementation may represent a safe and cost-effective strategy to reduce inflammation and restore normal mucosal function.

P-296 - High-fat diet and constipation

Background Constipation is one of the most common gastrointestinal complaints with a highly prevalent and is a chronic functional gastrointestinal disorder affecting health-related quality of life. The relationship between constipation and an excessive intake of high-fat diet (HFD) has been speculated. In addition, some anti-oxidants have been reported to improve the state of constipation. However, the mechanism behind these phenomena is not clear yet. Aim The aim of this study is to investigate whether HFD causes constipation and to clarify the mechanism behind this phenomenon, focusing on the involvement of oxidative stress. Method Male 6-week-old C57BL/6 mice were randomly divided into two groups; feeding HFD and normal diet. Fecal pellet numbers, fecal pellet water content and colon transit time were measured to evaluate whether mice are in the state of constipation. Colonic malondialdehyde (MDA) density was measured as oxidative stress marker. Result Compared to mice feeding normal diet, fecal pellet numbers were less, colon transit time was longer, and the MDA density was higher in HFD feeding mice. Conclusion HFD might cause constipation via oxidative stress dependent mechanism, and the therapeutic strategy targeting oxidative stress may be effective.

Evaluation of a therapy for Idiopathic Chronic Enterocolitis in rhesus macaques (Macaca mulatta) and linked microbial community correlates.

Idiopathic chronic enterocolitis (ICE) is one of the most commonly encountered and difficult to manage diseases of captive rhesus macaques (Macaca mulatta). The etiology is not well understood, but perturbations in gut microbial communities have been implicated. Here we evaluated the effects of a 14-day course of vancomycin, neomycin, and fluconazole on animals affected with ICE, comparing treated, untreated, and healthy animals. We performed microbiome analysis on duodenal and colonic mucosal samples and feces in order to probe bacterial and/or fungal taxa potentially associated with ICE. All treated animals showed a significant and long-lasting improvement in stool consistency over time when compared to untreated and healthy controls. Microbiome analysis revealed trends associating bacterial community composition with ICE, particularly lineages of the Lactobacillaceae family. Sequencing of DNA from macaque food biscuits revealed that fungal sequences recovered from stool were dominated by yeast-derived food additives; in contrast, bacteria in stool appeared to be authentic gut residents. In conclusion, while validation in larger cohorts is needed, the treatment described here was associated with significantly improved clinical signs; results suggested possible correlates of microbiome structure with disease, though no strong associations were detected between single microbes and ICE.

Risk factors of fecal colonization with extended-spectrum β-lactamase-producing Enterobacteriaceae in special nursing homes in Japan.

ObjectiveJapanese welfare facilities for the elderly are called as special nursing home (SNH), providing conventional‐type with group care or unit‐type with individual care. We investigated the risk factors of fecal colonization with extended‐spectrum β‐lactamase‐producing Enterobacteriaceae (ESBL‐E) of elderly who required care at SNH in Japan.MethodsThe feces discharged on diaper were obtained from the total of 100 residents with fecal incontinence in 9 SNHs located in Tokyo, Japan. The samples were cultured on ESBL selection agar, and ESBL‐E were determined by the antimicrobial susceptibility test and genetic analysis. The status of the residents and the characteristics of facilities, especially about the incontinence care, were obtained by questionnaire methods. Statistical analysis was performed to determine the factors related to carriage of ESBL‐E.ResultsExtended‐spectrum β‐lactamase‐producing Enterobacteriaceae was isolated from 53 of 100 SNH residents. Risk factors of colonization among the individual residents were not found. The prevalence of ESBL‐E carriage was significantly higher in the 6 conventional‐type facilities than in the 3 unit‐type facilities (P = .015). The cart for diaper exchange was used in 5 of 6 conventional‐type facilities in 9 SNHs, and their residents tended to show high of ESBL‐E colonization rate. The residents living in unit‐type facilities which do not use gloves for changing diaper tended to show high ESBL‐E colonization rate than other 2 facilities using gloves.ConclusionsIt is suggested that using the cart for changing diaper has relation to carry ESBL‐E. In the facilities using cart, revision of their methods of excretion care will be needed.

English

Anti-tumour necrosis factor (TNF) monoclonal antibodies have become an invaluable treatment against chronic inflammatory diseases such as rheumatoid arthritis (RA). However, due to increased risk of opportunistic infections, patients receiving anti-TNF therapy should be closely monitored for serious infections. Here, we describe a case of acute Salmonella_enteritidis infection of a joint arthroplasty that previously was functioning well, in a patient receiving infliximab treatment for RA. After prolonged antimicrobial chemotherapy and interrupted infliximab treatment, reimplantation of a new prosthesis was successfully performed two years after Salmonella septic arthritis. Therefore, because of the possibility of extraintestinal salmonellosis, screening for fecal colonization could be advisable in patients undergoing anti-TNF treatment. Moreover we emphasize the importance of appropriate counselling of these patients concerning food hygiene.

CTX-M ESBL-producing Enterobacteriaceae: estimated prevalence in adults in England in 2014.

BackgroundESBL-producing Enterobacteriaceae (ESBLPE) are increasing in prevalence worldwide and are more difficult to treat than non-ESBLPE. Their prevalence in the UK general population is unknown, as the only previous UK ESBLPE faecal colonization study involved patients with diarrhoea.ObjectivesTo estimate the prevalence of CTX-M ESBLPE faecal colonization in the general adult population of England in 2014, and investigate risk factors.MethodsA stratified random sample of 58 337 registered patients from 16 general practices within four areas of England were invited to participate by returning faeces specimens and self-completed questionnaires. Specimens were tested for ESBLPE and carbapenemase-producing Enterobacteriaceae (CPE).Results2430 individuals participated (4% of those invited). The estimated prevalence of colonization with CTX-M ESBLPE in England was 7.3% (95% CI 5.6%–9.4%) (Shropshire 774 participants, 4.9% colonization; Southampton City 740 participants, 9.2%; Newham 612 participants, 12.7%; Heart of Birmingham 234 individuals, 16.0%) and was particularly high in: those born in Afghanistan (10 participants, 60.0% colonization, 95% CI 29.7%–84.2%); those born on the Indian subcontinent (India, Pakistan, Bangladesh or Sri Lanka) (259 participants, 25.0% colonization, 95% CI 18.5%–32.9%); travellers to South Asia (India, Pakistan, Bangladesh, Sri Lanka or Nepal) in the last year (140 participants, 38.5% colonization, 95% CI 27.8%–50.5%); and healthcare domestics (8 participants, unweighted 37.5% colonization, 95% CI 8.5%–75.5%). Risk factors identified included: being born in the Indian subcontinent (aOR 5.4, 95% CI 3.0–9.7); travel to South Asia (aOR 2.9, 95% CI 1.8–4.8) or to Africa, China, South or Central America, South East or Pacific Asia or Afghanistan (aOR 2.6, 95% CI 1.7–4.1) in the last year; and working as a healthcare domestic (aOR 6.2, 95% CI 1.3–31). None of the 48 participants who took co-amoxiclav in the last year was colonized with CTX-M ESBLPE. blaCTX-M-15 accounted for 66% of CTX-M ESBLPE positives. 0.1% (two participants) were colonized with CPE.ConclusionsCTX-M ESBLPE are established in the general population in England and prevalence is particularly high in people from certain countries of birth or with recent travel. We recommend that these findings be taken into account in guidance on the empirical management of patients presenting with a likely Enterobacteriaceae infection.

What's the risk? Identifying potential human pathogens within grey-headed flying foxes faeces.

Pteropus poliocephalus (grey-headed flying foxes) are recognised vectors for a range of potentially fatal human pathogens. However, to date research has primarily focused on viral disease carriage, overlooking bacterial pathogens, which also represent a significant human disease risk. The current study applied 16S rRNA amplicon sequencing, community analysis and a multi-tiered database OTU picking approach to identify faecal-derived zoonotic bacteria within two colonies of P. poliocephalus from Victoria, Australia. Our data show that sequences associated with Enterobacteriaceae (62.8% ± 24.7%), Pasteurellaceae (19.9% ± 25.7%) and Moraxellaceae (9.4% ± 11.8%) dominate flying fox faeces. Further colony specific differences in bacterial faecal colonisation patterns were also identified. In total, 34 potential pathogens, representing 15 genera, were identified. However, species level definition was only possible for Clostridium perfringens, which likely represents a low infectious risk due to the low proportion observed within the faeces and high infectious dose required for transmission. In contrast, sequences associated with other pathogenic species clusters such as Haemophilus haemolyticus-H. influenzae and Salmonella bongori-S. enterica, were present at high proportions in the faeces, and due to their relatively low infectious doses and modes of transmissions, represent a greater potential human disease risk. These analyses of the microbial community composition of Pteropus poliocephalus have significantly advanced our understanding of the potential bacterial disease risk associated with flying foxes and should direct future epidemiological and quantitative microbial risk assessments to further define the health risks presented by these animals.

Use of Gas Chromatography to Quantify Short Chain Fatty Acids in the Serum, Colonic Luminal Content and Feces of mice.

Short-Chain Fatty Acids (SCFAs) are a product of the fermentation of resistant starches and dietary fibers by the gut microbiota. The most important SCFA are acetate (C2), propionate (C3) and butyrate (C4). These metabolites are formed and absorbed in the colon and then transported through the hepatic vein to the liver. SCFAs are more concentrated in the intestinal lumen than in the serum. Butyrate is largely consumed in the gut epithelium, propionate in the liver and acetate in the periphery. SCFAs act on many cells including components of the immune system and epithelial cells by two main mechanisms: activation of G-protein coupled receptors (GPCRs) and inhibition of histone deacetylase. Considering the association between changes in SCFA concentrations and the development of diseases, methods to quantify these acids in different biological samples are important. In this study, we describe a protocol using gas chromatography to quantify SCFAs in the serum, feces and colonic luminal content. Separation of compounds was performed using a DB-23 column (60 m x 0.25 mm internal diameter [i.d.]) coated with a 0.15 µm thick layer of 80.2% 1-methylnaphatalene. This method has a good linear range (15-10,000 µg/ml). The precision (relative standard deviation [RSD]) is less than 15.0% and the accuracy (error relative [ER]) is within ± 15.0%. The extraction efficiency was higher than 97.0%. Therefore, this is cost effective and reproducible method for SCFA measurement in feces and serum.

Consumption of edible ice contaminated with Acinetobacter, Pseudomonas, and Stenotrophomonas is a risk factor for fecal colonization with extended-spectrum β-lactamase-producing Escherichia coli in Vietnam.

Although Vietnamese residents frequently harbor extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E), it is unclear which foods/beverages are risk factors for acquiring these bacteria. The aim of this study was to evaluate the frequency with which edible ice served in restaurants is contaminated with antibiotic-resistant bacteria, and thereby clarify whether this product poses a risk for ESBL-E carriage in humans. Ice from restaurants in Vietnam and Japan was screened for bacteria capable of growing on agar containing cefotaxime (BG-CTX). Of the 119 BG-CTX strains isolated in Vietnam, 40%, 39%, and 12% were identified as Pseudomonas spp., Acinetobacter spp., and Stenotrophomonas maltophilia, respectively. Meanwhile, of the six such strains isolated in Japan, five were identified as Acinetobacter spp. and one as Pseudomonas spp. More than 10% of the Acinetobacter isolates exhibited cefotaxime, ceftazidime, and sulfa/trimethoprim resistance, while 21% of Pseudomonas and 14% of S. maltophilia isolates exhibited meropenem and sulfa/trimethoprim resistance, respectively. Subsequent multiplex polymerase chain reaction (PCR) analyses detected ESBL-encoding genes in 10% of the BG-CTX. Notably, feces harvested from mice administered water contaminated with BG-CTX contained E. coli harboring the blaCTX-M-9 gene. In conclusion, our findings indicate that consumption of contaminated edible ice is a risk factor for human ESBL-E carriage.

Serum cortisol mediates the relationship between fecal Ruminococcus and brain N-acetylaspartate in the young pig

ABSTRACTA dynamic relationship between the gut microbiota and brain is pivotal in neonatal development. Dysbiosis of the microbiome may result in altered neurodevelopment; however, it is unclear which specific members of microbiota are most influential and what factors might mediate the relationship between the gut and the brain. Twenty-four vaginally-derived male piglets were subjected to magnetic resonance spectroscopy at 30 d of age. Ascending colon contents, feces, and blood were collected and analyzed for volatile fatty acids, microbiota relative abundance by 16s rRNA, and serum metabolites, respectively. A mediation analysis was performed to assess the mediatory effect of serum biomarkers on the relationship between microbiota and neurometabolites. Results indicated fecal Ruminococcus and Butyricimonas predicted brain N-acetylaspartate (NAA). Analysis of serum biomarkers indicated Ruminococcus independently predicted serum serotonin and cortisol. A 3-step mediation indicated: i) Ruminococcus negatively predicted NAA, ii) Ruminococcus negatively predicted cortisol, and iii) a significant indirect effect (i.e., the effect of fecal Ruminococcus through cortisol on NAA) was observed and the direct effect became insignificant. Thus, serum cortisol fully mediated the relationship between fecal Ruminococcus and brain NAA. Using magnetic resonance spectroscopy, this study used a statistical mediation analysis and provides a novel perspective into the potential underlying mechanisms through which the microbiota may shape brain development. This is the first study to link Ruminococcus, cortisol, and NAA in vivo, and these findings are substantiated by previous literature indicating these factors may be influential in the etiology of neurodevelopmental disorders.

Should we consider faecal colonisation with extended-spectrum β-lactamase-producing Enterobacteriaceae in empirical therapy of community-onset sepsis?

In patients colonised with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E), the preference for carbapenems (CRBs) over non-CRB antibiotics for empirical therapy of sepsis is questionable from an ecologic perspective. Moreover, how well colonisation predicts an ESBL-E aetiology of infection has been poorly investigated. The purpose of this retrospective observational study was to determine the positive predictive value (PPV) of ESBL-E faecal colonisation for ESBL-E sepsis aetiology and the impact of empirical therapy on treatment outcome. The study included 653 ESBL-E carriers with community-onset sepsis hospitalised at a single medical centre during a 5-year period. The PPV of ESBL-E colonisation for ESBL-E sepsis aetiology was significantly higher (62.6%) when sepsis originated from a urinary tract infection (UTI) than from a respiratory tract infection (24.5%), other known origins (27.1%) or an unidentified origin (21.4%). Among the 653 patients, 177 (27.1%) received CRBs empirically and 476 received non-CRBs, predominantly β-lactam/β-lactamase inhibitor combinations. Although univariate analysis suggested a higher 30-day mortality in the non-CRB versus CRB group (26.7% vs. 19.2%; OR = 1.53; P = 0.049), the estimated association was much smaller and was not significant (OR = 1.11, 95% CI 0.66–1.87; P = 0.68) in the multiple regression analysis adjusted for age, sex, Charlson comorbidity index, and severity, origin or aetiology of sepsis. The subgroup of 240 patients with unidentified sepsis aetiology also did not benefit from empirical CRB treatment. In non-critically ill ESBL-E carriers with community-onset sepsis, CRB-sparing empirical therapy seems appropriate, particularly if sepsis originates from a site other than a UTI.

Abstract 234: Association between fecal microbiome, diet, and colon adenomas and hyperplastic polyps

Abstract Background: Colorectal cancer arises from adenomatous and serrated colon polyps that are identifiable with colonoscopy. Generally, a healthy gut is characterized by higher fecal microbiota. We conducted a study to determine whether fecal microbiota composition and structure are associated with colon adenomas and hyperplastic polyps in a set of identical (MZ, monozygotic) twins. Methods: We enrolled 83 individual twins from the California Twin Program. Of these, 56 (representing 38 twin pairs) had documented past colonoscopy and no gastrointestinal diseases, cancer or recent antibiotic use. Body mass index (BMI) and food frequency information was collected 15 years before stool collection and again at the time of stool collection. The V4 region of the 16S rRNA gene was sequenced using the HiSeq 2500 system. Alpha diversity measures including number of OTU (operational taxonomic units) and Shannon index were calculated for each sample. Mixed ANOVA models with a random effect accounting for twin pair status, were used to examine the association of alpha diversity with polyp status. Results: Alpha diversity measured by Shannon index and number of unique OTUs was inversely associated with obesity and high beef consumption and positively associated with yogurt consumption. Surprisingly, we found that fecal microbiota alpha diversity was higher in subjects with adenomas and hyperplastic polyps compared to subjects with no polyps. When restricted to subjects with colonoscopy in the 3 years prior to stool collection, differences were stronger and statistically significant (mean OTUs for subjects with adenoma, hyperplastic polyps and no polyps = 908, 850, and 801, respectively; Padenoma vs. no = 0.017, Phyperplastic vs no = 0.007; Plinear trend= 0.018). In order to determine whether diet changes may have played a role, we examined dietary change from food frequency questionnaires collected 15 years apart. We found that subjects with no polyps increased yogurt consumption by 50% over the 15 year period, whereas subjects diagnosed with adenomas and hyperplastic polyps increased their yogurt consumption more (140% and 130%, respectively). Conclusion: Participants diagnosed with adenomas and hyperplastic polyps had higher fecal microbiota alpha diversity compared to those without polyps. The timing of measurement of fecal microbiota years after colonoscopy obscures the causal relationship between adenoma and fecal microbiome. One possibility is that subjects may have increased their yogurt consumption after a polyp diagnosis, resulting in increased fecal alpha diversity, compared to subjects who were not diagnosed with polyps. Alternatively, polyp removal may alter microbial diversity. A third possibility is that polyp susceptibility is associated with an outgrowth of deleterious bacteria, still present after polyp removal, reflected as increased alpha diversity. Twin comparisons will be presented. Citation Format: Yang Yu, Joshua Millstein, Amie E. Hwang, Bing Ma, Guoqin Yu, Laura H. Buchanan, Michael Humphreys, Ann S. Hamilton, John Zadnick, Myles G. Cockburn, James Buxbaum, Heinz-Josef Lenz, Thomas M. Mack, Jacques Ravel, Wendy Cozen. Association between fecal microbiome, diet, and colon adenomas and hyperplastic polyps [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 234. doi:10.1158/1538-7445.AM2017-234

Fecal carriage of extended-spectrum \u03b2-lactamase- and carbapenemase-producing Enterobacteriaceae in Egyptian patients with community-onset gastrointestinal complaints: a hospital -based cross-sectional study

ObjectivesThe aim of this study was to determine the prevalence of extended-spectrum β-lactamase (ESBL) and carbapenemase production among Enterobacteriaceae isolated from ambulatory patients with gastrointestinal complaints admitted to El-Ahrar General Hospital, Zagazig, Egypt in the period between January 2013 and May 2013.MethodsOne hundred and thirteen Enterobacteriaceae isolates were recovered from 100 consecutive Egyptian patients with community–onset gastrointestinal complaints. The fecal samples were plated directly on selective EbSA-ESBL Screening Agar and on MacConkey agar. Isolate identification was performed with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Screening for ESBLs and carbapenemases production was done by both the automated VITEK®2 system with AST N198 and by disk diffusion method. Real-time PCR and sequencing were used to characterize the resistance genes. Phylogroups of the E. coli isolates were determined by a triplex PCR-based method.ResultsOf 100 patients screened for fecal colonization with extended-spectrum β-lactamase -producing Enterobacteriaceae (ESBL-E) and carbapenemase- producing Enterobacteriaceae (CPE), 68 were colonized with ESBL-E whereas five patients were positive for CPE. One hundred and thirteen Enterobacterceae isolates were recovered from 100 fecal samples, they belonged to E. coli (n = 72), Klebsiella pneumoniae (n = 23), Enterobacter cloacae(n = 3), Salmonella spp. (n = 1) and other Enterobacterceae isolates (n = 14). The blaCTX-M gene was detected in 89.04% (65/73) of the ESBL-producing Enterobacteriaceae, whereas blaSHV and blaTEM were detected in 30.14% (22/73) and 19.18% (14/73) respectively. Three out of 5 carbapenem-resistant isolates harbored New Delhi metallo-beta-lactamase (NDM) and 2 produced Verona integron-encoded metallo- beta -lactamase (VIM). Twenty-two (47.83%) of the ESBL positive isolates were multidrug resistant (MDR). Phylogenetic analysis showed that, of the 51 ESBL-EC isolates, 17 belonged to group B2, 13 to group D, 11 to group A and 10 to group B1.ConclusionsNearly two-thirds of the Enterobacteriaceae isolates recovered from feces of ambulatory patients with community–onset gastrointestinal complaints admitted to El-Ahrar General Hospital, Zagazig, Egypt were ESBL producers and one in every 20 patients included in our study was colonized by carbapenemase-producing Enterobacteriaceae. These high colonization rates are worrying, therefore prudent antimicrobial use should be adopted in Egyptian community settings.

Feed efficiency phenotypes in lambs involve changes in ruminal, colonic, and small-intestine-located microbiota.

Several studies have revealed differences in rumen-located microbes between greatly efficient and inefficient animals; however, how the microbiota vary in the hind gastrointestinal tract (GIT) has only been sparsely explored and how they vary in the small intestine remains to be determined. We therefore sampled the microbiota of the duodenum, jejunum, ileum, colon, and colorectally-obtained feces, in addition to the rumen of 12 lambs that, in a residual feed intake trial, were found to be at either extreme of feed efficiency phenotypes. The 16S rRNA gene (V3-V4 region) profiles of all samples were analyzed and revealed unique microbiota in all GIT locations except the jejunum and ileum (ANOSIM > 0.2, < 0.001). Measures of β-diversity revealed greater dissimilarity between more anatomically distant GIT locations (e.g., Rumen-Duodenum, ANOSIM = 0.365, < 0.001; Rumen-Colon, ANOSIM = 1, < 0.001) with the nearest distal region typically more similar than the nearest proximal location. The relative abundances of 13 operational taxonomic units (OTUs) from the duodenum, jejunum, colon, and feces, as well as the rumen, differed between efficient and inefficient animals (Bonferroni corrected, < 0.05), while another 2 OTUs trended toward significance. These OTUs were classified as taxa with known roles in fibrolysis (Fibrobacteres, Ruminococcaceae, and Saccharofermentans) and others that are commonly associated with health (Bifidobacteriaceae, and Christensenellaceae) and dysbiosis (Proteobacteria). Our findings show biospatial delineations of microbiota throughout the GIT and suggest that feed efficiency extends beyond the rumen, transcending these regions, and involves increases in both rumen- and colon-located fibrolytic taxa, increases in bifidobacterial species in the small intestine, and reductions in small intestine and distal GIT-located Proteobacteria.