Prevalence of small intestinal bacterial overgrowth in intestinal failure syndrome: A systematic review and meta-analysis.

BACKGROUND AND AIM: Patients with intestinal failure (IF) have abnormal intestinal anatomy, secretion, and dysmotility, which impairs intestinal homeostatic mechanisms and may lead to small intestinal bacterial overgrowth (SIBO). We conducted a systematic review and meta-analysis to determine the prevalence of SIBO in patients with IF and to identify risk factors for SIBO. METHODS: MEDLINE (PubMed) and Embase electronic databases were searched from inception to December 2023 for studies that reported the prevalence of SIBO in IF. The prevalence rates, odds ratio (OR), and 95% confidence intervals of SIBO in IF and the risk factors for SIBO in IF were calculated using random effects model. RESULTS: Final dataset included nine studies reporting on 407 patients with IF. The prevalence of SIBO in IF was 57.5% (95% CI 44.6-69.4), with substantial heterogeneity in this analysis (I2 = 80.9, P = 0.0001). SIBO prevalence was sixfold higher in patients with IF who received parenteral nutrition (PN) compared with IF patients not on PN (OR = 6.0, 95% CI 3.0-11.9, P = 0.0001). Overall, the prevalence of SIBO in patients with IF using PPI/acid-suppressing agents (72.0%, 95% CI 57.5-83.8) was numerically higher compared with IF patients not using these agents (47.6%, 95% CI 25.7-70.2). CONCLUSIONS: This systematic review and meta-analysis suggests that there is an increased risk of SIBO in patients with IF and that PN, and potentially, the use of PPI/acid-suppressing agents is risk factors for SIBO development in patients with IF. However, the quality of evidence is low and can be attributed to lack of case-control studies and clinical heterogeneity seen in the studies.

Effect of sleeve gastrectomy on the levels of oral volatile sulfur compounds and halitosis-related bacteria.

Background: The association between sleeve gastrectomy and halitosis remains relatively unknown. Therefore, this study aimed to evaluate the effect of sleeve gastrectomy on halitosis and the oral bacterial species associated with halitosis in patients with obesity. Methods: This was a prospective longitudinal cohort study that examined patients before and after sleeve gastrectomy and followed the patients at three time intervals (1, 3, and 6 months) after sleeve gastrectomy. Clinical periodontal measurements (plaque index [PI], gingival index [GI], and probing depth [PD]) were obtained. In addition, plaque samples were collected for quantification of the periodontopathogenic bacteria: Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Fusobacterium nucleatum using real-time quantitative polymerase chain reaction (qPCR). In addition, breath samples were collected to analyze the concentration of volatile sulfur compounds (VSCs), namely hydrogen sulfide (H2S), methyl mercaptan (CH3SH), and dimethyl sulfide (CH3SCH3), via portable gas chromatography (Oral Chroma™). Results: Of the 43 patients initially included, 39 completed the study, with a mean age of 32.2 ± 10.4 years. For PI and GI repeated measurements one way analysis of variance showed a significant increase (p-value < 0.001 for both) one month after surgery, with mean values of 1.3 and 1.59, respectively, compared to the baseline. During the same period, the number of P. gingivalis increased, with a p-value = 0.04. Similarly, the levels of hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) increased significantly in the first month after surgery (p-value = 0.02 and 0.01, respectively). Conclusion: This study demonstrated that sleeve gastrectomy may lead to increased halitosis one month post-surgery, attributed to elevated and P. gingivalis counts, contributing to the development of gingivitis in obese patients who underwent sleeve gastrectomy. This emphasizes the importance of including oral health professionals in the multidisciplinary team for the management of patients undergoing bariatric surgery.

Fulfilling the Promise of Breathomics: Considerations for the Discovery and Validation of Exhaled Volatile Biomarkers.

The exhaled breath represents an ideal matrix for non-invasive biomarker discovery, and exhaled metabolomics have the potential to be clinically useful in the era of precision medicine. In this concise translational review we will specifically address volatile organic compounds in the breath, with a view towards fulfilling the promise of these as actionable biomarkers, in particular for lung diseases. We review the literature paying attention to seminal work linked to key milestones in breath research; discuss potential applications for breath biomarkers across disease areas and healthcare systems, including the perspectives of industry; and outline critical aspects of study design that will need to be considered for any pivotal research going forward, if breath analysis is to provide robust validated biomarkers that meet the requirements for future clinical implementation.

Bismuth-Based Quadruple Therapy as First-Line Treatment for Clarithromycin-resistant Helicobacter pylori Infection: A Prospective Randomized Comparison of 7- and 14-Day Treatment Regimens.

Background/Aims: : Bismuth-based quadruple therapy (BQT) is a treatment option for clarithromycin-resistant Helicobacter pylori (HP) infection. The aim of this study was to compare the efficacy of 7-day BQT with that of 14-day BQT as first-line treatment for clarithromycin-resistant HP infection. Methods: : A total of 162 treatment-naïve patients with peptic ulcer disease and clarithromycin-resistant HP infection confirmed by real-time polymerase chain reaction (RT-PCR) were enrolled. The enrolled patients were prospectively randomized to receive BQT for either 7 or 14 days of treatment. Eradication of HP infection was assessed using a 13C-urea breath test. Eradication and adverse event rates of the two groups were assessed. Results: : The overall eradication rates in the intention-to-treat (ITT) and per-protocol (PP) analyses were 83.0% (95% confidence interval [CI], 77.2% to 88.9%; 132/159) and 89.8% (95% CI, 84.9% to 94.7%; 132/147), respectively. The eradication rates in the ITT analysis were 79.0% (64/81) in the 7-day group and 87.2% (68/78) in the 14-day group (p=0.170). The eradication rates in the PP analysis were 86.5% (64/74) in the 7-day group and 93.2% (68/73) in the 14-day group (p=0.182). Clinically significant adverse events occurred in 18.2% of patients. There was no statistically significant difference in the rates of individual or all adverse events between the two groups. Conclusions: : Both 7-day and 14-day BQT were effective and safe as first-line therapy for HP infections identified as resistant to clarithromycin by RT-PCR. For clarithromycin-resistant HP infections, 7-day BQT may be sufficient as first-line therapy.

Effect of Trimebutine and Rifaximin on Breath Hydrogen and Methane by Glucose Breath Test in Patients With Functional Bloating: A Randomized Double-blind Clinical Trial.

Background/Aims: Drugs that stabilize intestinal motility may improve the efficacy of nonabsorbable antibiotics, such as rifaximin, against small intestinal bacterial overgrowth (SIBO). We compared the efficacy of rifaximin alone with that of its combination with trimebutine maleate against SIBO. Methods: We performed a randomized double-blind placebo-controlled trial (https://cris.nih.go.kr, no. KCT0004836) that included patients with functional bloating, no constipation, and SIBO using the hydrogen (H2)-methane (CH4) glucose breath test (GBT). Patients were randomized into 2 groups in a 1:1 ratio, namely rifaximin (1200 mg/day) + trimebutine maleate (600 mg/day) group and rifaximin + placebo group, for 2 weeks. Patients completed a symptom questionnaire and underwent a GBT at baseline and at 1 month after treatment withdrawal. The primary outcome was SIBO eradication. The secondary outcomes included changes in the concentrations of exhaled gases, symptoms, and presence of adverse events. Results: The complete eradication rate of SIBO was 35.9% (14/39) in the rifaximin group, and 34.1% (14/41) in the combined group with no significant differences. In both groups, no significant differences were observed in GBT profiles before and after the treatment, respectively. However total breath H2 and CH4 concentration were conspicuously decreased in the combined group after treatment. The combined group exhibited substantial relief of bloating. The adverse events were similar in the 2 groups. Conclusion: While the combination therapy was not superior over rifaximin alone for SIBO eradication, it improves the symptom of bloating with numerically reducing the concentration of breath H2/CH4.

Exhaled Volatile Organic Compounds for Asthma Control Classification in Children with Moderate to Severe Asthma: Results from the SysPharmPediA Study.

RATIONALE: Early identification of children with poorly controlled asthma is imperative for optimizing treatment strategies. The analysis of exhaled volatile organic compounds (VOCs) is an emerging approach to identify prognostic and diagnostic biomarkers in pediatric asthma. OBJECTIVES: To assess the accuracy of gas chromatography-mass spectrometry based exhaled metabolite analysis to differentiate between controlled and uncontrolled pediatric asthma. METHODS: This study encompassed a discovery (SysPharmPediA) and validation phase (U-BIOPRED, PANDA). Firstly, exhaled VOCs that discriminated asthma control levels were identified. Subsequently, outcomes were validated in two independent cohorts. Patients were classified as controlled or uncontrolled, based on asthma control test scores and number of severe attacks in the past year. Additionally, potential of VOCs in predicting two or more future severe asthma attacks in SysPharmPediA was evaluated. MEASUREMENTS AND MAIN RESULTS: Complete data were available for 196 children (SysPharmPediA=100, U-BIOPRED=49, PANDA=47). In SysPharmPediA, after randomly splitting the population into training (n=51) and test sets (n=49), three compounds (acetophenone, ethylbenzene, and styrene) distinguished between uncontrolled and controlled asthmatics. The area under the receiver operating characteristic curve (AUROCC) for training and test sets were respectively: 0.83 (95% CI: 0.65-1.00) and 0.77 (95% CI: 0.58-0.96). Combinations of these VOCs resulted in AUROCCs of 0.74 ±0.06 (UBIOPRED) and 0.68 ±0.05 (PANDA). Attacks prediction tests, resulted in AUROCCs of 0.71 (95% CI 0.51-0.91) and 0.71 (95% CI 0.52-0.90) for training and test sets. CONCLUSIONS: Exhaled metabolites analysis might enable asthma control classification in children. This should stimulate further development of exhaled metabolites-based point-of-care tests in asthma.

Added Value of 13C Analysis in Breath Tests in H2-Negative Subjects to Diagnose Lactose Malabsorption: A Proof of Concept Study.

INTRODUCTION: Diagnosing lactose malabsorption is usually based on hydrogen excretion in breath after a lactose challenge. However, a proportion of subjects with lactose malabsorption will not present a rise in hydrogen. Measuring excretion of methane or stable isotope labeled 13CO2 after ingestion of 13C-lactose has been proposed to mitigate this problem. OBJECTIVE: The aim of the study was to assess the performance of measuring methane and 13CO2 in individuals with normal hydrogen excretion compared to a genetic lactase non-persistence test. METHODS: Individuals referred for lactose breath testing and healthy controls were included. Participants received 13C-enriched lactose, performed breath testing, and underwent genotyping for a marker of lactase non-persistence (13910C*T). Using genotype as gold standard, the performance of measuring methane and 13CO2 excretion was assessed. RESULTS: 151 subjects participated in the study, 50 of which presented a lactase non-persistent genotype. Of these, 72% were correctly diagnosed through hydrogen excretion of ≥ 20 ppm above baseline. In subjects with normal hydrogen excretion, cumulative 13C excretion had an area under the curve (AUC) of the receiver operating characteristics (ROC) curve of 0.852. Sensitivity was 93% and specificity was 51% for the current cutoff of 14.5%. The optimal cutoff was 12.65% (sensitivity 93%, specificity 70%). The ROC curve of peak methane had an AUC of 0.542 (sensitivity of 14%, specificity of 91% for cutoff ≥ 10 ppm). CONCLUSIONS: In individuals with genetically demonstrated lactase non-persistence and negative hydrogen breath test, the use of 13C-lactose with measurement of 13CO2 excretion and hydrogen is a well-performing test to detect the lactose malabsorption and performs better than methane in our cohort.

Role of exhaled hydrogen sulfide in the diagnosis of colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is often accompanied by increased excretion of hydrogen sulfide (H2S). This study aimed to explore the value of exhaled H2S in the diagnosis of CRC. METHODS: A total of 80 people with normal colonoscopy results and 57 patients with CRC were enrolled into the present observational cohort study. Exhaled oral and nasal H2S were detected by Nanocoulomb breath analyser. Results were compared between the two groups. Receiver operating characteristic (ROC) curves were analysed and area under the curves (AUCs) were calculated to assess the diagnostic value of exhaled H2S. Meanwhile, the clinicopathological features, including gender, lesion location and tumour staging of patients with CRC, were also collected and analysed. RESULTS: The amount of exhaled H2S from patients with CRC was significantly higher than that of those with normal colonoscopy results. The ROC curve showed an AUC value of 0.73 and 0.71 based on oral and nasal H2S detection, respectively. The exhaled H2S in patients with CRC was correlated with gender, lesion location and tumour progression, including depth of invasion, lymphatic metastasis and TNM (Tumor, Lymph Nodes, Metastasis) staging. CONCLUSION: Exhaled H2S analysis is a convenient and non-invasive detection method for diagnosing CRC, suggesting a potential role in population screening for CRC.

Symptomatic Response to Antibiotics in Patients With Small Intestinal Bacterial Overgrowth: A Systematic Review and Meta-analysis.

Background/Aims: We performed a systematic review and meta-analysis evaluating the symptomatic response rate to antibiotics in patients with small intestinal bacterial overgrowth (SIBO). Similarly, we performed a meta-analysis on the symptomatic response to antibiotics in irritable bowel syndrome (IBS) patients with and without SIBO. Methods: MEDLINE, EMBASE, Web of Science, and Cochrane databases were searched from inception to March 2021. Randomized controlled trials and prospective studies reporting dichotomous outcomes were included. Results: There were 6 studies included in the first meta-analysis comparing the efficacy of antibiotics to placebo or no antibiotic. This included 196 patients, of whom 101 received antibiotics and 95 received placebo or no antibiotics. Significantly more patients improved with antibiotics (relative risk [95% CI] = 2.46 [1.33-4.55], P = 0.004). There were 4 studies included in the analysis comparing symptomatic response rates in IBS patients with or without SIBO with 266 IBS patients, of whom 172 had SIBO and 94 did not. The pooled response rate for symptomatic response was 51.2% in the SIBO group vs 23.4% in the no SIBO group, respectively. Significantly more IBS patients with SIBO responded to antibiotics compared to those without SIBO (relative risk [95% CI] = 2.07 [1.40-3.08], P = 0.0003). Conclusions: Antibiotics appear to be efficacious in treating SIBO, although small sample sizes and poor data quality limit this interpretation. Symptomatic response rates also appear to be higher in IBS patients with SIBO. This may be the first example of precision medicine in IBS as opposed to our current empiric treatment approach. Large-multicenter studies are needed to verify the results.

Small intestinal bacterial overgrowth in patients with rosacea: prevalence and clinical features / 中华皮肤科杂志

Objective:To investigate the prevalence of small intestinal bacterial overgrowth (SIBO) in patients with rosacea, and to analyze the relationship between breath test results and the occurrence of rosacea.Methods:Patients with rosacea were enrolled from the outpatient department of Xiangya Hospital from March 2022 to June 2023. The methane-hydrogen breath test was used to detect intestinal levels of methane and hydrogen in all patients to investigate the prevalence of SIBO. The basic information, clinical symptoms and severity, quality of life scores, gastrointestinal symptoms, and past medical history of the patients were collected. Statistical analysis was carried out by using the chi-square test, nonparametric test and multivariate logistic regression models to investigate the relationship between SIBO and the occurrence of rosacea.Results:A total of 116 patients with rosacea completed the methane-hydrogen breath test. They were aged 18 to 56 years (median [ Q1, Q3]: 25 [22, 33] years), and included 7 males (6.0%) and 109 females (94.0%) ; there were 43 cases (37.1%) of erythematotelangiectatic rosacea, and 73 (62.9%) of papulopustular rosacea. As the breath test showed, 94 patients were diagnosed with SIBO (81.0%, 95% CI: 72.7% - 87.7%) based on the breath tests, 84 showed positive hydrogen breath test results (72.4%, 95% CI: 63.3% - 80.3%), and 47 had positive methane breath test results (40.5%, 95% CI: 31.5% - 50%). Among the 67 patients with moderate to severe erythema, 33 (49.3%) showed positive methane breath test results, and 14 of 49 (28.6%) patients with mild erythema showed positive methane breath test results, with a rate difference of 20.7% ( P = 0.025, 95% CI: 13.9% - 27.5%) ; there were no significant differences in the positive rates of SIBO and hydrogen breath test results between the patients with moderate to severe erythema and those with mild erythema (both P > 0.05). No significant differences were observed in the age, gender, clinical subtypes, severity of papulopustules, flushing and burning sensation, or rosacea quality of life index scores between the SIBO-positive and -negative groups, between hydrogen-positive and -negative groups, and between methane-positive and -negative groups (all P > 0.05). Multivariate logistic regression analysis showed that methane positivity on breath test was associated with the severity of erythema in rosacea ( OR = 2.495, 95% CI: 1.102 - 5.649, P < 0.05) . Conclusions:The prevalence of SIBO was relatively high in the patients with rosacea. However, only the positive rate of methane breath test differed between the rosacea patients and non-rosacea controls, and there was some correlation between methane positivity on breath test and increased severity of rosacea erythema.

A clinical proteomics study of exhaled breath condensate and biomarkers for pulmonary embolism.

Pulmonary embolism (PE) can be a diagnostic challenge. Current diagnostic markers for PE are unspecific and new diagnostic tools are needed. The air we exhale is a possible new source for biomarkers which can be tapped into by analysing the exhaled breath condensate (EBC). We analysed the EBC from patients with PE and controls to investigate if the EBC is a useful source for new diagnostic biomarkers of PE. We collected and analysed EBC samples from patients with suspected PE and controls matched on age and sex. Patients in whom PE was ruled out after diagnostic work-up were included in the control group to increase the sensitivity and generalizability of the identified markers. EBC samples were collected using an RTube™. The protein composition of the EBCs were analysed using data dependent label-free quantitative nano liquid chromatography-tandem mass spectrometry. EBC samples from 28 patients with confirmed PE, and 49 controls were analysed. A total of 928 EBC proteins were identified in the 77 EBC samples. As expected, a low protein concentration was determined which resulted in many proteins with unmeasurable levels in several samples. The levels of HSPA5, PEBP1 and SFTPA2 were higher and levels of POF1B, EPPK1, PSMA4, ALDOA, and CFL1 were lower in PE compared with controls. In conclusion, the human EBC contained a variety of endogenous proteins and may be a source for new diagnostic markers of PE and other diseases.

Spot Hydrogen Breath Test for Predicting Response to Low Fermentable Oligo-, Di-, Mono-saccharides, and Polyols Dietary Advice in Patients With Bloating.

Background/Aims: An increase in postprandial intestinal gas plays a role in bloating symptoms. We aim to study the utility of spot breath hydrogen (H2) level in predicting the response to a low fermentable oligo-, di-, mono-saccharides, and polyols (FODMAPs) diet. Methods: Patients with functional gastrointestinal disorders diagnosed by Rome IV criteria with bothersome bloating for > 6 months were prospectively enrolled. Patients completed 7-day food diaries and collected a breath sample 2 hours after their usual lunch at baseline and 4 weeks after low FODMAPs dietary advice by a dietitian. The responder was defined as an improvement of ≥ 30% bloating scores in the fourth week. Results: Thirty-eight patients (32 female, 52.6 ± 13.8 years; 22 irritable bowel syndrome) completed the study. Twenty-one patients (55%) were classified as responders. Baseline global gastrointestinal symptoms, bloating, abdominal pain scores, and numbers of high FODMAPs items were similar between responders and non-responders. Both groups significantly decreased high FODMAPs items intake with similar numbers at the follow-up. The area under the curve for predicting low FODMAPs responsiveness using baseline H2 levels was 0.692 (95%CI, 0.51-0.86; P < 0.05), with the best cutoff at 8 parts per million (sensitivity 66.7%, specificity 82.4%). 66% of responders had baseline H2 level > 8 parts per million vs 17% of non-responders (P < 0.05). The baseline spot hydrogen level in responders was 9.5 (3.3-17.3) vs 4.5 (3.3-6.3) in non-responders (P < 0.05). Conclusions: A higher baseline breath hydrogen level was associated with bloating improvement after low FODMAPs dietary advice. A spot breath test after lunch, a simple point-of-care test, is possibly helpful in managing patients with bloating.

Estimation of exocrine pancreatic insufficiency in children with acute pancreatitis using the 13C mixed triglyceride breath test.

BACKGROUND: /Objective: The extent of exocrine pancreatic insufficiency (EPI) in the paediatric population with acute pancreatitis (AP) is unknown. The primary objective was to use a 6 h stable-isotope breath test to determine the prevalence of EPI in children with AP. The secondary objective was to determine the diagnostic ability of a 4 h abbreviated breath test in the detection of EPI. METHODS: 13C-mixed triglyceride (MTG) breath test was used to measure fat digestibility in 12 children with AP and 12 normal children. EPI was diagnosed based on a cumulative dose percentage recovery (cPDR) cut-off value < 26.8% present in literature. To reduce the test burden, the diagnostic accuracy of an abbreviated 4 h test was evaluated, using a cPDR cut-off that was the 2.5th percentile of its distribution in control children. RESULTS: The cPDR of cases was significantly lower than that of controls (27.71 ± 7.88% vs 36.37 ± 4.70%, p = 0.005). The cPDR during acute illness was not significantly different to that at 1 month follow up (24.69 ± 6.83% vs 26.98 ± 11.10%, p = 0.52). The 4 h and 6 h breath test results correlated strongly (r = 0.93, p < 0.001) with each other. The new 4 h test had 87.5% sensitivity and 93.8% specificity for detecting EPI. CONCLUSION: Two-thirds (66.7%) of this sample of children with AP had EPI during admission, which persisted at 1 month follow up. The 4 h abbreviated 13C-MTG breath test has good diagnostic ability to detect EPI in children and may improve its clinical utility in this age group.

Establishing a cell-based screening workflow for determining the efficiency of CYP2C9 metabolism: moving towards the use of breath volatiles in personalised medicine.

The use of volatile biomarkers in exhaled breath as predictors to individual drug response would advance the field of personalised medicine by providing direct information on enzyme activity. This would result in enormous benefits, both for patients and for the healthcare sector. Non-invasive breath tests would also gain a high acceptance by patients. Towards this goal, differences in metabolism resulting from extensive polymorphisms in a major group of drug-metabolizing enzymes, the cytochrome P450 (CYP) family, need to be determined and quantified. CYP2C9 is responsible for metabolising many crucial drugs (e.g., diclofenac) and food ingredients (e.g., limonene). In this paper, we provide a proof-of-concept study that illustrates thein vitrobioconversion of diclofenac in recombinant HEK293T cells overexpressing CYP2C9 to 4'-hydroxydiclofenac. Thisin vitroapproach is a necessary and important first step in the development of breath tests to determine and monitor metabolic processes in the human body. By focusing on the metabolic conversion of diclofenac, we have been able to establish a workflow using a cell-based system for CYP2C9 activity. Furthermore, we illustrate how the bioconversion of diclofenac is limited in the presence of limonene, which is another CYP2C9 metabolising substrate. We show that increasing limonene levels continuously reduce the production of 4'-hydroxydiclofenac. Michaelis-Menten kinetics were performed for the diclofenac 4'-hydroxylation with and without limonene, giving a kinetic constant of the reaction,KM, of 103µM and 94.1µM, respectively, and a maximum reaction rate,Vmax, of 46.8 pmol min-1106cells-1and 56.0 pmol min-1106cells-1with and without the inhibitor, respectively, suggesting a non-competitive or mixed inhibition type. The half-maximal inhibitory concentration value (IC50) for the inhibition of the formation of 4'-hydroxydiclofenace by limonene is determined to be 1413µM.

Assessment of Carbon Monoxide in Exhaled Breath using the Smokerlyzer Handheld Machine: A Cross- Sectional Study.

Introduction: Nicotine dependence is known to be a chronic remitting and relapsing addictive disorder. Among cancer patients who smoke, nicotine addiction has been found to be more when compared with smoking healthy individuals. Smokerlyzer machine can be used to test smoking substance use and de-addiction services can be provided at Preventive Oncology units. The objectives of the study include: (i) To assess eCO using a Smokerlyzer hand-held machine and correlate it with the smoking status, (ii) To assess the cut-off value for smoking use, and discusses the benefits of this method. Methods: In this cross-sectional study, healthy individuals at the workplace were tested for exhaled CO (eCO), which is used as a biological marker for monitoring the tobacco smoking. We discuss the feasibility of testing and its implications for cancer patients. The Bedfont EC50 Smokerlyzer machine was used to measure the concentration of CO in the end-tidal expired air. Results: Among 643 study subjects, we found a statistically significant difference (P < .001) of median (IQR) eCO (measured in ppm) among smokers and non-smokers 2(1,5) vs 1(1,2). A significant and moderate positive correlation (Spearman rank correlation coefficient: .463) was observed between eCO and subjects who used cigarettes (measured in pack years). The ROC curve shows a cut off value for eCO as 2.5 with sensitivity 43.6% and 1 - specificity 2.76% (Specificity: 97.24%), which was rounded to 3. The area under the curve is 74.9%, which indicates a moderate discrimination performance of the test. The diagnostic accuracy of the test is 82.89%, which shows the proportion of correct test results. Conclusion: Estimating eCO in health care settings will enable monitoring the smoking substance use which has important impact on clinical outcomes. In cancer hospitals, when the goal is complete abstinence a stringent CO cutoff in the range of 3-4 ppm should be used.

Eradication rates of Helicobacter pylori in treatment-naive patients following 14-day vonoprazan-amoxicillin dual therapy: A multicenter randomized controlled trial in China.

BACKGROUND: Potassium-competitive acid blockers (P-CAB) are recommended for the treatment of Helicobacter pylori infections, but dual therapy of P-CAB with amoxicillin has been poorly studied. The current study compared the efficacy, adverse reactions, compliance, and effects on gut microbiota of 14-day vonoprazan-amoxicillin (VA) dual therapy with esomeprazole, bismuth potassium citrate, amoxicillin, and metronidazole (EBAM) quadruple therapy in treatment-naive patients with H. pylori. MATERIALS AND METHODS: This was a multicenter, open-label, randomized, and controlled, non-inferiority study. Patients (n = 194) enrolled from six centers were randomly divided into either the VA or EBAM group. H. pylori eradication was determined using 13 C urea breath tests (UBT) 4-6 weeks post-treatment. Fecal samples were collected, and gut microbial populations were analyzed by 16S rDNA and metagenomic sequencing technology. RESULTS: Eradication rates of H. pylori in the VA and EBAM groups were 88.7% and 91.8%, respectively, according to intention-to-treat (ITT) analysis; 95.6% and 96.7% with per-protocol (PP) analysis; and 94.5% and 96.7% with modified ITT (mITT) analysis (all p > 0.05). The incidence of adverse reactions in the VA group was significantly lower compared to the EBAM group, and compliance within both groups was good. There was no difference in α-diversity or microbial composition in the VA and EBAM groups at one-month post-treatment compared to baseline, except for a markedly reduced abundance of Bacteroides in the EBAM group. CONCLUSION: VA therapy achieved excellent eradication rates with low adverse reactions, good compliance, and little impact on gut microbiota. VA therapy should be recommended as a first-line treatment against H. pylori.

Small Intestinal Bacterial Overgrowth Complicating Gastrointestinal Manifestations of Systemic Sclerosis: A Systematic Review and Meta-analysis.

Background/Aims: Systemic sclerosis (SSc) often is complicated by small intestinal bacterial overgrowth (SIBO). A systematic review and meta-analysis thus examined the prevalence of SIBO in SSc (SSc-subtypes), identify risk factors for SIBO in SSc and the effects of concomitant SIBO on gastrointestinal symptoms in SSc. Methods: We searched electronic databases until January-2022 for studies providing prevalence rates of SIBO in SSc. The prevalence rates, odds ratio (OR) and 95% confidence intervals (CI) of SIBO in SSc and controls were calculated. Results: The final dataset comprised 28 studies with 1112 SSc-patients and 335 controls. SIBO prevalence in SSc-patients was 39.9% (95% CI, 33.1-47.1; P = 0.006), with considerable heterogeneity, (I2 = 76.00%, P < 0.001). As compared to controls, there was a 10-fold increased SIBO prevalence in SSc-patients (OR, 9.6; 95% CI, 5.6-16.5; P < 0.001). The prevalence of SIBO was not different in limited cutaneous SSc as compared to diffuse cutaneous SSc (OR, 1.01; 95% CI, 0.46-2.20; P = 0.978). Diarrhea (OR, 5.9; 95% CI, 2.9-16.0; P = 0.001) and the association between SIBO in SSc and proton pump inhibitor use (OR, 2.3; 95% CI, 0.8-6.4; P = 0.105) failed statistical significance. Rifaximin was significantly more effective as compared to rotating antibiotic in eradicating SIBO in SSc-patients (77.8% [95% CI, 64.4-87.9]) vs 44.8% [95% CI, 31.7-58.4]; P < 0.05). Conclusions: There is a 10-fold increased prevalence of SIBO in SSc, with similar SIBO prevalence rates in SSc-subtypes. Antimicrobial therapy of SIBO-positive SSc-patients with diarrhea should be considered. However, the results must be interpreted with caution due to substantial unexplained heterogeneity in the prevalence studies, and the low sensitivity and specificity of the diagnostic tests suggesting that the reliability of the evidence may be low.

Lactase Deficiency Diagnosed by Endoscopic Biopsy-based Method is Associated With Positivity to Glucose Breath Test.

Background/Aims: Lactase deficiency, which has many similarities with small intestinal bacterial overgrowth (SIBO), causes various gastrointestinal symptoms. We estimate the prevalence of SIBO in patients with intestinal symptoms from dairy products and investigate the association between lactase deficiency (LD) and SIBO. Methods: This prospective study included patients with functional intestinal symptoms from dairy product indigestion. A questionnaire on gastrointestinal symptoms, a hydrogen (H2)-methane glucose breath test (GBT) for SIBO, and lactose intolerance quick test (LQT) for LD using upper gastrointestinal endoscopy were performed. Results: A total of 88 patients, 29 (33.0%) with severe and 36 (40.9%) with mild LD were included. Sixteen patients (18.2%) were GBT positive. Patients with LQT negativity indicating severe LD showed a higher positivity to GBT or GBT (H2) than the historic controls (27.6% vs 6.7%, P = 0.032). There was no difference in the items on the symptom questionnaire according to the presence of LD or SIBO, except for higher symptom scores for urgency in GBT-positive patients. There were more LQT-negative patients in the GBT (H2)-positive group than in the other groups (27.6% vs 10.2%, P = 0.036). Moreover, only GBT (H2)-positivity was significantly associated with a higher risk of LQT negativity in multivariate analysis (OR, 4.19; P = 0.029). Conclusions: SIBO producing H2 is common in patients with severe LD suspected lactose intolerance. SIBO may be a new therapeutic target for managing intestinal symptoms in patients with lactose intolerance.

Prevalence of methanogens and associated factors in patients with irritable bowel syndrome and healthy controls in a Southeastern Mexican population.

INTRODUCTION: Methane (CH4) is an inert gas produced by colonic anaerobes and has been associated with different intestinal diseases, including irritable bowel syndrome (IBS). According to geographic region, the prevalence of methanogens varies, being higher in Africa (80%) and lower in the United States (35-40%). In Mexico, the prevalence of methanogens is unknown. AIM: To evaluate the prevalence of CH4 producers and associated factors in a group of patients with IBS and controls in a Mexican population. MATERIALS AND METHODS: A baseline fasting measurement of alveolar H2 and CH4 gas was carried out, by gas chromatography (stationary phase), in consecutive patients diagnosed with IBS and a control group. Subjects with baseline levels of H2 of 0 ppm and CH4 ≥ 5 ppm were classified as methanogenic. RESULTS: A total of 132 controls (53.8% women) and 67 patients with IBS (76% women) were included. The overall prevalence (n = 199) of methanogenic subjects was 38% (n = 76) (95% CI: 0.31-0.45) and they had a greater prevalence of overweight/obesity (56.5 vs 39.8%, P = .028). The prevalence of methanogens in the healthy controls was 41.6% (95% CI: 0.33-0.49), whereas, in the patients with IBS, it was 31.4% (n = 21, 71% IBS-C and 29% IBS-M). CONCLUSIONS: The prevalence of methanogens in our study on a Mexican population was comparable to that reported in other populations and was associated with overweight/obesity. One-third of the patients with IBS presented with methanogens. Said microorganisms were particularlyassociated with the constipation-predominant IBS subtype.

Comparison of different methods of obtaining the rapid shallow breathing index.

OBJECTIVE: To compare the Rapid Shallow Breathing Index (RSBI) obtained by the ventilometer and from mechanical ventilation parameters. METHODS: Randomized crossover trial, including 33 intubated patients, on mechanical ventilation for at least 24 hours, undergoing spontaneous breathing test. Patients were submitted to the measurement of RSBI by four methods: disconnected from the ventilator through the ventilometer; in Pressure Support Ventilation (PSV) mode at a pressure of 7.ßcm H2O; in Continuous Positive Airway Pressure (CPAP) mode at a pressure of 5.ßcmH2O with flow trigger; in CPAP mode at a pressure of 5.ßcmH2O with pressure trigger. RESULTS: No significant difference was detected between the RSBI obtained by the ventilometer and in the CPAP mode with flow and pressure triggers, however, in the PSV mode, the values were lower than in the other measurements (p.ß<.ß0.001). By selecting patients from the sample with higher RSBI (... 80 cycles.min-1.L-1), the value of the index obtained by the ventilometer was higher than that obtained in the three options of ventilation methods. CONCLUSION: The RSBI obtained in the CPAP mode at a pressure of 5.ßcmH2O, in both triggers types, did not differ from that measured by the ventilometer; it is, therefore, an alternative when obtaining it from mechanical ventilation parameters is necessary. However, in the presence of borderline values, the RSBI measured by ventilometer is recommended, as in this method the values are significantly higher than in the three ventilation modalities investigated.