Background and Objectives: Municipal solid waste workers (MSWWs) are important in the city’s waste management. With these vital contributions, they face unique occupational hazards and health risks. This study aims to determine the prevalence of occupational infections, such as soil-transmitted helminth infections (STHI) and hepatitis A virus (HAV), as well as the occurrence of Helicobacter pylori infection among the MSWWs of Baguio City. Methods: This cross-sectional analytic study collected data from volunteer MSWWs using a questionnaire to gather information on age, duration of employment, use of gloves in the workplace, and hand hygiene practices. Stool samples were obtained from participants and were analyzed for STHI using the Formalin Ether Concentration Technique (FECT). H. pylori infection was detected using the SD Bioline rapid antigen test kit on stool samples while blood samples were collected and tested for HAV antibodies using the Aria IgG/IgM rapid test kit. Results: Of the 44 volunteer MSWWs tested, 25 were infected with hazardous pathogens. Specifically, six workers (13.6%) were infected with STHI, four (9.1%) were infected with HAV and 15 (34.1%) were infected with H. pylori. Among those infected with STHI, Ascaris lumbricoides and Endolimax nana were the predominant species, each with a prevalence rate of 33.3%. In contrast, Blastocystis hominis and hookworm infections each had a prevalence rate of 16.7%. A significant association was found between STHI prevalence and the preference for alcohol hand rubs over hand washing, with a p-value of 0.008. Conclusion The analysis revealed a significant associat ion between the prevalence of STHI and the preference for alcohol hand rubs over hand washing, suggesting that MSWWs may have a false sense of security regarding their hygiene practices. The findings revealed the critical importance of proper hand washing in preventing STHI. Future research should expand data collection to encompass a broader range of socio-demographic, environmental, and lifestyle factors that may influence infection rates. Additionally, including a control group of individuals not exposed to waste management could help differentiate between factors specific to waste handling and those related to other occupations. This study emphasizes the need for collaborative efforts among researchers, public health authorities, and waste management agencies to enhance the health and safety of MSWWs while addressing broader public health concerns related to waste management practices.
Human ; Hepatitis A virus (HAV) ; Helicobacter pylori

BACKGROUND: Given the general unavailability, common adverse effects, and complicated administration of tetracycline, the clinical application of classic bismuth quadruple therapy (BQT) is greatly limited. Whether minocycline can replace tetracycline for Helicobacter pylori ( H . pylori ) eradication is unknown. We aimed to compare the eradication rate, safety, and compliance between minocycline- and tetracycline-containing BQT as first-line regimens. METHODS: This randomized controlled trial was conducted on 434 naïve patients with H . pylori infection. The participants were randomly assigned to 14-day minocycline-containing BQT group (bismuth potassium citrate 110 mg q.i.d., esomeprazole 20 mg b.i.d., metronidazole 400 mg q.i.d., and minocycline 100 mg b.i.d.) and tetracycline-containing BQT group (bismuth potassium citrate/esomeprazole/metronidazole with doses same as above and tetracycline 500 mg q.i.d.). Safety and compliance were assessed within 3 days after eradication. Urea breath test was performed at 4-8 weeks after eradication to evaluate outcome. We used a noninferiority test to compare the eradication rates of the two groups. The intergroup differences were evaluated using Pearson chi-squared or Fisher's exact test for categorical variables and Student's t -test for continuous variables. RESULTS: As for the eradication rates of minocycline- and tetracycline-containing BQT, the results of both intention-to-treat (ITT) and per-protocol (PP) analyses showed that the difference rate of lower limit of 95% confidence interval (CI) was >-10.0% (ITT analysis: 181/217 [83.4%] vs . 180/217 [82.9%], with a rate difference of 0.5% [-6.9% to 7.9%]; PP analysis: 177/193 [91.7%] vs . 176/191 [92.1%], with a rate difference of -0.4% [-5.6% to 6.4%]). Except for dizziness more common (35/215 [16.3%] vs . 13/214 [6.1%], P = 0.001) in minocycline-containing therapy groups, the incidences of adverse events (75/215 [34.9%] vs . 88/214 [41.1%]) and compliance (195/215 [90.7%] vs . 192/214 [89.7%]) were similar between the two groups. CONCLUSION: The eradication efficacy of minocycline-containing BQT was noninferior to tetracycline-containing BQT as first-line regimen for H . pylori eradication with similar safety and compliance. TRIAL REGISTRATION ClinicalTrials.gov, ChiCTR 1900023646.
Humans ; Bismuth/therapeutic use* ; Metronidazole/therapeutic use* ; Esomeprazole/pharmacology* ; Minocycline/pharmacology* ; Helicobacter pylori ; Potassium Citrate/therapeutic use* ; Anti-Bacterial Agents ; Tetracycline/adverse effects* ; Helicobacter Infections/drug therapy* ; Drug Therapy, Combination ; Amoxicillin

BACKGROUND: With the development of traditional Chinese medicine research, berberine has shown good efficacy and safety in the eradication of Helicobacter pylori (H. pylori). The present study aimed to evaluate the efficacy and safety of triple therapy containing berberine, amoxicillin, and vonoprazan for the initial treatment of H. pylori. METHODS: This study was a single-center, open-label, parallel, randomized controlled clinical trial. Patients with H. pylori infection were randomly (1:1:1) assigned to receive berberine triple therapy (berberine 500 mg, amoxicillin 1000 mg, vonoprazan 20 mg, A group), vonoprazan quadruple therapy (vonoprazan 20 mg, amoxicillin 1000 mg, clarithromycin 500 mg, colloidal bismuth tartrate 220 mg, B group), or rabeprazole quadruple therapy (rabeprazole 10 mg, amoxicillin 1000 mg, clarithromycin 500 mg, colloidal bismuth tartrate 220 mg, C group). The drugs were taken twice daily for 14 days. The main outcome was the H. pylori eradication rate. The secondary outcomes were symptom improvement rate, patient compliance, and incidence of adverse events. Furthermore, factors affecting the eradication rate of H. pylori were further analyzed. RESULTS: A total of 300 H. pylori-infected patients were included in this study, and 263 patients completed the study. An intention-to-treat (ITT) analysis showed that the eradication rates of H. pylori in berberine triple therapy, vonoprazan quadruple therapy, and rabeprazole quadruple therapy were 70.0% (70/100), 77.0% (77/100), and 69.0% (69/100), respectively. The per-protocol (PP) analysis showed that the eradication rates of H. pylori in these three groups were 81.4% (70/86), 86.5% (77/89), and 78.4% (69/88), respectively. Both ITT analysis and PP analysis showed that the H. pylori eradication rate did not significantly differ among the three groups (P >0.05). In addition, the symptom improvement rate, overall adverse reaction rate, and patient compliance were similar among the three groups (P >0.05). CONCLUSIONS The efficacy of berberine triple therapy for H. pylori initial treatment was comparable to that of vonoprazan quadruple therapy and rabeprazole quadruple therapy, and it was well tolerated. It could be used as one choice of H. pylori initial treatment.
Humans ; Amoxicillin/therapeutic use* ; Helicobacter pylori ; Anti-Bacterial Agents ; Clarithromycin/therapeutic use* ; Rabeprazole/therapeutic use* ; Berberine/therapeutic use* ; Bismuth ; Helicobacter Infections/drug therapy* ; Drug Therapy, Combination ; Treatment Outcome ; Proton Pump Inhibitors/therapeutic use*

Background: Helicobacter pylori is acknowledged to cause chronic gastritis and peptic ulcer disease and is also implicated in gastric carcinoma and B cell mucosa-associated lymphoid tissue (MALT) lymphoma development. It has infected at least half of the world’s population. Proton Pump Inhibitors (PPIs) have been the conventional antacid of choice for H. pylori eradication triple therapy, while vonoprazan is a novel drug of its class that was recently studied but is limited to an oral form which makes it less feasible in cases of acute gastrointestinal bleeding. According to several systematic reviews and meta-analyses, the vonoprazan-based triple therapy regimen for H. pylori eradication is a non-inferior treatment to traditional PPI-based treatment when given in 1 week for patients having no active gastrointestinal bleeding. Likewise, a safety profile has been established with its use, offering an alternative treatment option. Objectives: The research aims to identify the H. pylori eradication rate among H. pylori-positive patients who received a vonoprazan-based triple therapy regimen as outpatients, describe their clinicodemographic profile, and identify potential side effects associated with the treatment. Methods: This study utilized a cross-sectional study design in a single tertiary institution from January 2018 to December 2020. Descriptive and inferential statistics were used in data analysis. Frequency and percentage were utilized to determine the success and failure rates of H. pylori eradication, describe the clinicodemographic profile of patients who underwent vonoprazan-based triple therapy, and the potential side effects with treatment. The chi-square test of independence was applied to assess the significant difference in the successful and failed eradication rates across the clinicodemographic profile. A P-value of <0.05 was considered statistically significant, and statistical analyses were conducted using SPSS version 20.0. Results: 32 (91%) had successful H. pylori eradication, with the majority of them determined by a negative 13C-UBT result (62.8%) and the rest with a negative H. pylori stool antigen test (28.6%). The majority of patients undergoing H. pylori eradication using a vonoprazan-based regimen with documented successful eradication belonged to the 19 to 39 years old group (50%), clerical support workers (40.63%), with a chief complaint of abdominal pain (46.88%), with no known co- morbid illness (75%), and with endoscopic finding limited to antral gastritis alone (46.88%). This study described only two documented side effects of treatment: diarrhea and abdominal pain (2.9%). Conclusion Vonoprazan-based triple therapy, given at 20 mg twice daily for 7 days, has shown a high H. pylori eradication rate among hemodynamically stable patients, without active bleeding, and treated on an outpatient basis. There was a significant difference in eradication success and failure across co-morbidities, with a higher success rate in those without co-morbid illness. A high success rate was also seen in patients <40 years of age, with a single chief complaint, and with antral gastritis as the sole endoscopic finding.
Helicobacter pylori

Objective: To investigate the association between Helicobacter pylori (Hp) virulence factor genotypes and the degree and activity of gastric mucosa pathological changes in pediatric gastroduodenal diseases. Methods: This retrospective cohort study was conducted from May 2020 to October 2020. The frozen strains of Hp, which were cultured with the gastric mucosa of 68 children with gastroscopy confirmed gastroduodenal diseases who visited the children's hospital of Zhejiang University School of Medicine from April 2012 to December 2014, were resuscitated. After extracting DNA from these Hp strains, PCR amplification and agarose gel electrophoresis were performed to determine the detection rate of cytotoxin-associated protein A (cagA),vacuolating cytotoxin A (vacA)(s1a、s1b/s2,m1/m2), outer inflammatory protein A (oipA),blood group antigen binding adhesin (babA),duodenal ulcer promoting protein A (dupA) genes; oipA genes were sequenced to determine the gene status. The patients were divided into different groups according to the findings of gastroscopy and gastric mucosa pathology. The detection rates of various virulence factor genotypes among different groups were compared using χ² tests or Fisher's exact tests. Results: The 68 Hp strains all completed genetic testing. According to the diagnostic findings of gastroscopy, the 68 cases were divided into 47 cases of superficial gastritis and 21 cases of peptic ulcer. Regarding the pathological changes of gastric mucosa, 8 cases were mild, and 60 cases were moderate and severe according to the degree of inflammation; 61 cases were active and 7 cases inactive according to the activity of inflammation. The overall detection rates of cagA, vacA, vacA s1/m2, functional oipA, babA2, and dupA virulence factor genes were 100% (68/68), 100% (68/68), 94% (64/68), 99% (67/68), 82% (56/68), and 71% (48/68), respectively. In the superficial gastritis group, their detection rates were 100% (47/47), 100% (47/47), 96% (45/47), 98% (46/47), 81% (38/47), and 70% (33/47), respectively; in the peptic ulcer group, their detection rates were 100% (21/21), 100% (21/21), 90% (19/21), 100% (21/21), 86% (18/21), and 71% (15/21), respectively. There was no statistically significant difference between the two groups (all P>0.05). In the mild gastric mucosa inflammation group, the detection rates of the above six genotypes were 8/8, 8/8, 8/8, 7/8, 7/8, and 5/8, respectively; and in the moderate to severe inflammation groups, the detection rates were 100% (60/60), 100% (60/60), 93% (56/60), 100% (60/60), 82% (49/60), and 72% (43/60), respectively, with no statistically significant difference between the two groups (all P>0.05). In the active inflammation group, the detection rate of six genotypes were 100% (61/61), 100% (61/61), 93% (57/61), 98% (60/61), 82% (50/61), and 72% (44/61), respectively; and in the inactive inflammation group, they were 7/7, 7/7, 7/7, 7/7, 6/7, and 4/7, respectively. Again, there was no statistically significant difference between the two groups (all P>0.05). There was no statistically significant difference in the detection rate of combinations of 4 or 5 virulence factor genes among the different groups (all P>0.05). Conclusions: CagA, vacA, vacA s1/m2, functional oipA, babA2, and dupA genes are not associated with superficial gastritis and peptic ulcer in children, or with the degree and activity of gastric mucosa pathological inflammation. Different gene combinations of cagA, vacA, oipA, babA2, and dupA have no significant effects on predicting the clinical outcome of Hp infection in children.
Humans ; Child ; Helicobacter pylori/genetics* ; Retrospective Studies ; Genotype ; Inflammation ; Gastritis ; Cytotoxins

OBJECTIVE: Agar dilution method (ADM) was used as the golden standard to evaluate the consistency of Epsilometer test (E-test) in detecting the sensitivity of Helicobacter pylori (H. pylori) to metronidazole. METHODS: From August 2018 to July 2020, patients with H. pylori infection treated for the first time in Peking University Third Hospital for gastroscopy due to dyspepsia were included in this study. Gastric mucosas were taken from the patients with H. pylori infection. H. pylori culture was performed. Both the ADM and E-test were applied to the antibiotic susceptibility of H. pylori to metro-nidazole, and the consistency and correlation between the two methods were validated. RESULTS: In the study, 105 clinical isolates of H. pylori were successfully cultured, and the minimum inhibitory concentration ≥ 8 mg/L was defined as drug resistance. Both ADM and the E-test showed high resistance rates to metronidazole, 64.8% and 62.9%, respectively. Among them, 66 drug-resistant strains were detected by ADM and E-test, and 37 were sensitive strains, so the consistency rate was 98.1%. Two strains were evaluated as drug resistance by ADM, but sensitive by the E-test, with a very major error rate of 1.9%. There was zero strain sensitive according to ADM but assessed as resistant by the E-test, so the major error rate was 0%. Taking ADM as the gold standard, the sensitivity of E-test in the detection of metronidazole susceptibility was 97.1% (95%CI: 0.888-0.995), and the specificity was 100% (95%CI: 0.883-1.000). Cohen's kappa analysis showed substantial agreement, and kappa coefficient was 0.959 (95%CI: 0.902-1.016, P < 0.001). Spearmans correlation analysis confirmed this correlation was significant (r=0.807, P < 0.001). The consistency evaluation of Bland-Altman method indicated that it was good, and there was no measured value outside the consistency interval. In this study, cost analysis, including materials and labor, showed a 32.2% higher cost per analyte for ADM as compared with the E-test (356.6 yuan vs. 269.8 yuan). CONCLUSION The susceptibility test of H. pylori to metronidazole by E-test presents better agreement with ADM. Because it is less expensive, less labor intensive, and more rapid, it is an easy and reliable method for H. pylori susceptibility testing.
Humans ; Metronidazole/therapeutic use* ; Helicobacter pylori ; Agar/therapeutic use* ; Disk Diffusion Antimicrobial Tests ; Microbial Sensitivity Tests ; Helicobacter Infections/drug therapy* ; Anti-Bacterial Agents/therapeutic use*

Objective To explore the inhibitory effects and mechanisms of benzodiazepines on Helicobacter pylori (Hp).Methods The Hp international standard strain ATCC43504 was treated with benzodiazepines diazepam,midazolam,and remimazolam,respectively.The treatments with amoxicillin and clarithromycin were taken as the positive controls,and that with water for injection as the negative control.The inhibition zone of each drug was measured by the disk diffusion method.The minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of each drug against Hp were determined.Hp suspension was configured and treated with diazepam and midazolam,respectively.The bacterial suspension without drug added was used as the control group.The concentration of K⁺ in each bacterial suspension was measured by an automatic biochemical analyzer before drug intervention(T₀)and 1(T₁),2(T₂),3(T₃),4(T₄),5(T₅),6(T₆),and 7 h(T₇)after intervention.Hp urease was extracted and treated with 1/2 MIC diazepam,1 MIC diazepam,2 MIC diazepam,1/2 MIC midazolam,1 MIC midazolam,2 MIC midazolam,1 mg/ml acetohydroxamic acid,and water for injection,respectively.The time required for the rise from pH 6.8 to pH 7.7 in each group was determined by the phenol red coloring method.Results The inhibition zones of diazepam,midazolam,remimazolam,amoxicillin,clarithromycin,and water for injection against Hp were 52.3,42.7,6.0,72.3,60.8,and 6.0 mm,respectively.Diazepam and midazolam showed the MIC of 12.5 μg/ml and 25.0 μg/ml and the MBC of 25 μg/ml and 50 μg/ml,respectively,to Hp.The concentrations of K⁺ in the diazepam,midazolam,and control groups increased during T₁-T₇ compared with those at T₀(all P<0.01).The concentration of K⁺ in diazepam and midazolam groups during T₁-T₄ was higher than that in the control group(all P<0.01).The time of inhibiting urease activity in the 1/2 MIC diazepam,1 MIC diazepam,2 MIC diazepam,1/2 MIC midazolam,1 MIC midazolam,and 2 MIC midazolam groups was(39.86±5.11),(36.52±6.65),(38.58±4.83),(39.25±6.19),(36.36±4.61),and(35.81±6.18)min,respectively,which were shorter than that in the acetohydroxamic acid group(all P<0.01)and had no significance differences from that in the water for injection group(all P>0.05).Conclusion Diazepam and midazolam exerted inhibitory effects on Hp,which may be related to the cleavage of Hp cells rather than inhibiting urease.
Midazolam ; Helicobacter pylori ; Urease ; Clarithromycin/pharmacology* ; Benzodiazepines/pharmacology* ; Diazepam/pharmacology* ; Amoxicillin ; Water ; Anti-Bacterial Agents/pharmacology*

Objective To explore the aptamer specific binding blood group antigen-binding adhesin (BabA) of Helicobacter pylori (H.pylori) for blocking of H.pylori adhering host cell. Methods H.pylori strain was cultured and its genome was extracted as templates to amplify the BabA gene by PCR with designed primers. The BabA gene obtained was cloned and constructed into prokaryotic expression plasmid, which was induced by isopropyl beta-D-galactoside (IPTG) and purified as target. The single stranded DNA (ssDNA) aptamers that specifically bind to BabA were screened by SELEX. Enzyme-linked oligonucleotide assay (ELONA) was used to detect and evaluate the characteristics of candidate aptamers. The blocking effect of ssDNA aptamers on H.pylori adhesion was subsequently verified by flow cytometry and colony counting at the cell level in vitro and in mouse model of infection, respectively. Meanwhile, the levels of cytokines, interleukin 6 (IL-6), IL-8, tumor necrosis factor α (TNF-α), IL-10 and IL-4 in the homogenate of mouse gastric mucosa cells were detected by ELISA. Results The genome of H.pylori ATCC 43504 strains was extracted and the recombinant plasmid pET32a-BabA was constructed. After induction and purification, the relative molecular mass (M_r) of the recombinant BabA protein was about 39 000. The amino acid sequence of recombinent protein was consistent with BabA protein by peptide mass fingerprint (PMF). Five candidate aptamers were selected to bind to the above recombinent BabA protein by SELEX. The aptamers A10, A30 and A42 identified the same site, while A3, A16 and the above three aptamers identified different sites respectively. The aptamer significantly blocked the adhesion of H.pylori in vitro. Animal model experiments showed that the aptamers can block the colonization of H.pylori in gastric mucosa by intragastric injection and reduce the inflammatory response. The levels of IL-4, IL-6, IL-8 and TNF-α in gastric mucosal homogenates in the model group with aptamer treatment were lower than that of model group without treatment. Conclusion Aptamers can reduce the colonization of H.pylori in gastric mucosa via binding BabA to block the adhesion between H.pylori and gastric mucosal epithelial cells.
Animals ; Mice ; Helicobacter pylori/genetics* ; Interleukin-4 ; Interleukin-6 ; Interleukin-8 ; Tumor Necrosis Factor-alpha ; Stomach ; Oligonucleotides ; Adhesins, Bacterial/genetics* ; Blood Group Antigens

Bismuth-containing quadruple therapy (BQT) has long been recommended for Helicobacter pylori ( H. pylori ) eradication in China. Meanwhile, in the latest national consensus in China, dual therapy (DT) comprising an acid suppressor and amoxicillin has also been recommended. In recent years, the eradication rate of H. pylori has reached >90% using DT, which has been used not only as a first-line treatment but also as a rescue treatment. Compared with BQT, DT has great potential for H. pylori eradication; however, it has some limitations. This review summarizes the development of DT and its application in H. pylori eradication. The H. pylori eradication rates of DT were comparable to or even higher than those of BQT or standard triple therapy, especially in the first-line treatment. The incidence of adverse events associated with DT was lower than that with other therapies. Furthermore, there were no significant differences in the effects of dual and quadruple therapies on gastrointestinal microecology. In the short term, H. pylori eradication causes certain fluctuations in the gastrointestinal microbiota; however, in the long term, the gastrointestinal microbiota eventually returns to its normal state. In the penicillin-naïve population, patients receiving DT have a high eradiation rate, better compliance, lower incidence of adverse reactions, and lower primary and secondary resistance to amoxicillin. These findings suggest the safety, efficacy, and potential of DT for H. pylori eradication.
Humans ; Helicobacter Infections/drug therapy* ; Anti-Bacterial Agents/pharmacology* ; Helicobacter pylori ; Proton Pump Inhibitors ; Drug Therapy, Combination ; Amoxicillin/therapeutic use* ; Treatment Outcome

Objective: To investigate the characteristics of duodenal bulbar microbiota in children with duodenal ulcer and Helicobacter pylori (Hp) infection. Methods: This prospective cohort study enrolled 23 children with duodenal ulcers diagnosed by gastroscopy who were admitted to the Children's Hospital of Zhejiang University School of Medicine due to abdominal pain, abdominal distension, and vomiting from January 2018 to August 2018. They were divided into Hp-positive and Hp-negative groups according to the presence or absence of Hp infection. Duodenal bulbar mucosa was sampled to detect the bacterial DNA by high-throughput sequencing. The statistical difference in α diversity and β diversity, and the relative abundance in taxonomic level between the two groups were compared. Microbial functions were predicted using the software PICRUSt. T-test, Rank sum test or χ² test were used for comparison between the two groups. Results: A total of 23 children diagnosed with duodenal ulcer were enrolled in this study, including 15 cases with Hp infection ((11.2±3.3) years of age, 11 males and 4 females) and 8 cases without Hp infection ((10.1±4.4) years of age, 6 males and 2 females). Compared with Hp-negative group, the Hp-positive group had higher Helicobacter abundance (0.551% (0.258%, 5.368%) vs. 0.143% (0.039%, 0.762%), Z=2.00, P=0.045) and lower abundance of Fusobacterium, Streptococcus and unclassified- Comamonadaceae (0.010% (0.001%, 0.031%) vs. 0.049% (0.011%, 0.310%), Z=-2.24, P=0.025; 0.031% (0.015%, 0.092%) vs. 0.118% (0.046%, 0.410%), Z=-2.10, P=0.036; 0.046% (0.036%, 0.062%) vs. 0.110% (0.045%, 0.176%), Z=-2.01, P=0.045). Linear discriminant analysis (LDA) effect sized showed that at the genus level, only Helicobacter was significantly enriched in Hp-positive group (LDA=4.89, P=0.045), while Streptococcus and Fusobacterium significantly enriched in Hp-negative group (LDA=3.28, 3.11;P=0.036,0.025, respectively). PICRUSt microbial function prediction showed that the expression of oxidative phosphorylation and disease-related pathways (pathways in cancer, renal cell carcinoma, amoebiasis, type 1 diabetes mellitus) in Hp-positive group were significantly higher than that in Hp-negative group (all P<0.05), while the expression of pathways such as energy metabolism and phosphotransferase system pathways were significantly lower than that in Hp-negative group (all P<0.05). Conclusion: In children with Hp-infected duodenal ulcers, the mucosal microbiota of the duodenal bulb is altered, characterized by an increased abundance of Helicobacter and a decreased abundance of Clostridium and Streptococcus, and possibly alters the biological function of the commensal microbiota through specific metabolic pathways.
Male ; Female ; Humans ; Child ; Duodenal Ulcer/diagnosis* ; Helicobacter Infections/complications* ; Helicobacter pylori/genetics* ; Prospective Studies ; Microbiota