Diagnostic strategy of irritable bowel syndrome: a low- and middle-income country perspective.

Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder associated with substantial impairment which considerably burdens healthcare systems worldwide. Research on IBS has largely been conducted in high-income countries posing barriers to the application of diagnostic strategies in low- and middle-income countries (LMICs) due to differences in disease characteristics, healthcare resources, and socioeconomic factors. This review discusses the diagnostic issues associated with LMICs. We present a concise overview of the relevant approaches and propose a diagnostic strategy based on the latest evidence. A positive diagnostic strategy that relies on appropriate symptom-based criteria is crucial within the diagnostic framework. A combination of complete blood count, fecal occult blood test, and complete stool test may reliably identify individuals with suspected IBS who are more likely to have organic diseases, thus justifying the necessity for a colonoscopy. Eventually, we developed a diagnostic algorithm based on a limited setting perspective that summarizes the available evidence and may be applied in LMICs.

Comparison of RDQ and GERDQ for Predicting Erosive Esophagitis in Patients with Typical GERD Symptoms.

Background/Aims: The management decisions regarding gastroesophageal reflux disease (GERD) may differ according to the presence of erosive esophagitis. On the other hand, the availability of upper endoscopy in Indonesia is relatively limited. This study compared the Reflux Disease Questionnaire (RDQ) and the GERD questionnaire (GERDQ) performance in predicting the presence of clinically significant erosive esophagitis and determined the validity and reliability of the Indonesian-translated version of RDQ. Methods: Ninety-two adults with GERD suspicion were recruited. All patients completed RDQ and GERDQ. Receiver operating curve analysis was conducted on RDQ and GERDQ to evaluate their performance in discriminating LA GERD B or higher esophagitis from others. The translated RDQ preserved its main structure and was culturally adapted. Results: The patients were 66.3% female and 73.9% Javanese. Only 22 (23.9%) patients presented with LA grade B or higher erosive esophagitis. The RDQ showed a higher AUC than the GERDQ (0.602 vs. 0.589). A cutoff point of 20 was selected for the RDQ with sensitivity and specificity of 73% and 50%, respectively, whereas the optimal cutoff point of GERDQ was 8, with a sensitivity and specificity of 77% and 43%, respectively. The r-value greater than the critical value table (r>0.205, p<0.01) confirmed the construct validity of our translated RDQ. The questionnaire also demonstrated excellent reliability (α=0.900) and moderate similarity with the Indonesian version of GERDQ (κ=0.459, p<0.01). Conclusions: The RDQ is slightly superior to GERDQ in predicting the presence of clinically significant erosive esophagitis (LA grade B or higher). The Indonesian-translated RDQ is valid and reliable.

Validity and Reliability of the Reflux Symptoms Index Translated into Indonesian: The Role of Upper Endoscopy in Assessing Extra-Esophageal Gastroesophageal Reflux Disease Symptoms.

Background/Aims: The Reflux Symptom Index (RSI) is a questionnaire that evaluates the severity of extra-esophageal symptoms and is one of the most widely used measures to evaluate LPR. This study assessed the validity and reliability of the RSI questionnaire in Bahasa Indonesia and investigated the association between each extra-esophageal symptom reported in the questionnaire and the severity of erosive esophagitis as determined by endoscopic findings. Methods: 85 adult patients with GERD symptoms had an upper endoscopy examination and were asked to complete the translated RSI. The validity and reliability of the questionnaire were assessed. Results: The construct validity of the RSI translated into Bahasa Indonesia was verified with the r value of each question being higher than the crucial table value (r>0.213, p<0.05). Our questionnaire had a Cronbach alpha value of 0.81, which indicates an acceptable level of internal consistency. At least one extra-esophageal symptom was seen in 91.7% of patients with Los Angeles (LA) grade B or higher-grade esophagitis. In addition, the presence of extra-esophageal symptoms was associated with significant mucosal erosion (p=0.20). The symptoms of cough after eating or lying down and chronic cough were associated with the severity of esophageal mucosal erosion (p<0.05). Conclusions: The version of RSI translated into Bahasa Indonesia is a valid and reliable tool for assessing extra-esophageal GERD symptoms. The occurrence of extra-esophageal symptoms in patients with typical GERD symptoms is associated with endoscopic findings of LA grade B or erosive esophagitis of higher severity.

Genetic determinants of Biofilm formation of Helicobacter pylori using whole-genome sequencing.

BACKGROUND: Infection with Helicobacter pylori as the cause of gastric cancer is a global public health concern. In addition to protecting germs from antibiotics, biofilms reduce the efficacy of H. pylori eradication therapy. The nucleotide polymorphisms (SNPs) related with the biofilm forming phenotype of Helicobacter pylori were studied. RESULTS: Fifty-six H. pylori isolate from Bangladeshi patients were included in this cross-sectional study. Crystal violet assay was used to quantify biofilm amount, and the strains were classified into high- and low-biofilm formers As a result, strains were classified as 19.6% high- and 81.4% low-biofilm formers. These phenotypes were not related to specific clades in the phylogenetic analysis. The accessories genes associated with biofilm from whole-genome sequences were extracted and analysed, and SNPs among the previously reported biofilm-related genes were analysed. Biofilm formation was significantly associated with SNPs of alpA, alpB, cagE, cgt, csd4, csd5, futB, gluP, homD, and murF (P < 0.05). Among the SNPs reported in alpB, strains encoding the N156K, G160S, and A223V mutations were high-biofilm formers. CONCLUSIONS: This study revealed the potential role of SNPs in biofilm formation and proposed a method to detect mutation in biofilm from whole-genome sequences.

Mutations Related to Antibiotics Resistance in Helicobacter pylori Clinical Isolates from Bangladesh.

Current management of gastric inflammation involves the eradication of Helicobacter pylori. However, the effectiveness of commonly used antibiotics against H. pylori infection has decreased due to antibiotic resistance. Phenotypic-based diagnostics are laborious and finding the cause of resistance can be difficult. Therefore, early detection and understanding of the underlying mechanism of this resistance are necessary. This study evaluated the mutations in the genes related to the Antimicrobial Resistance (AMR) of the clinical isolates from Bangladeshi subjects. Whole-genome sequencing was performed on 56 isolates and the genes (such as pbp1a, rdxA, ribF, fur, gyrA, gyrB, 23S rRNA, and infB) were extracted. The reads were assembled, and the SNPs were extracted by the latest pipeline for antibiotic mutation analysis, ARIBA. The mutations and the association with the antibiotic phenotypes were evaluated using Fisher's exact test. In this study, the clarithromycin resistance rate was high, 39.3% (22/56), with the median MIC 24 mg/L ranging from 2 to 128 mg/L. The mutation of A2147G was significantly associated with resistance (p = 0.000018) but not in locus A2146G (p = 0.056). Levofloxacin also posed a high resistance. We observed that the mutation of D91N (but not D91Y) (p = 0.002) and N87K (p = 0.002) of gyrA was associated with levofloxacin resistance. Mutations in locus A343V (p = 0.041) of gyrB also showed a significant association. Meanwhile, in the pbp1a gene, several mutations might explain the resistance; they were G594fs (p = 0.036), K306R (p = 0.036), N562Y (p = 0.0006), and V45I (p = 0.018). The prevalence of metronidazole was exceptionally high (96.4%), and numerous mutations occurred in rdxA genes, including the truncation of genes. These results imply that the mutation in genes encoding the target protein of antibiotics remains the critical resistance mechanism in H. pylori.

Emerging inflammatory bowel disease demographics, phenotype, and treatment in South Asia, South-East Asia, and Middle East: Preliminary findings from the Inflammatory Bowel Disease-Emerging Nations' Consortium.

BACKGROUND AND AIM: Inflammatory bowel disease (IBD) is emerging in the newly industrialized countries of South Asia, South-East Asia, and the Middle East, yet epidemiological data are scarce. METHODS: We performed a cross-sectional study of IBD demographics, disease phenotype, and treatment across 38 centers in 15 countries of South Asia, South-East Asia, and Middle East. Intergroup comparisons included gross national income (GNI) per capita. RESULTS: Among 10 400 patients, ulcerative colitis (UC) was twice as common as Crohn's disease (CD), with a male predominance (UC 6678, CD 3495, IBD unclassified 227, and 58% male). Peak age of onset was in the third decade, with a low proportion of elderly-onset IBD (5% age > 60). Familial IBD was rare (5%). The extent of UC was predominantly distal (proctitis/left sided 67%), with most being treated with mesalamine (94%), steroids (54%), or immunomodulators (31%). Ileocolic CD (43%) was the commonest, with low rates of perianal disease (8%) and only 6% smokers. Diagnostic delay for CD was common (median 12 months; interquartile range 5-30). Treatment of CD included mesalamine, steroids, and immunomodulators (61%, 51%, and 56%, respectively), but a fifth received empirical antitubercular therapy. Treatment with biologics was uncommon (4% UC and 13% CD), which increased in countries with higher GNI per capita. Surgery rates were 0.1 (UC) and 2 (CD) per 100 patients per year. CONCLUSIONS: The IBD-ENC cohort provides insight into IBD in South-East Asia and the Middle East, but is not yet population based. UC is twice as common as CD, familial disease is uncommon, and rates of surgery are low. Biologic use correlates with per capita GNI.

Serum Helicobacter pylori antibody reactivity in seven Asian countries using an automated latex aggregation turbidity assay.

BACKGROUND AND AIM: To determine the application range of diagnostic kits utilizing anti-Helicobacter pylori antibody, we tested a newly developed latex aggregation turbidity assay (latex) and a conventional enzyme-linked immunosorbent assay (E-plate), both containing Japanese H. pylori protein lysates as antigens, using sera from seven Asian countries. METHODS: Serum samples (1797) were obtained, and standard H. pylori infection status and atrophy status were determined by culture and histology (immunohistochemistry) using gastric biopsy samples from the same individuals. The two tests (enzyme-linked immunosorbent assay and latex) were applied, and receiver operating characteristics analysis was performed. RESULTS: Area under the curve (AUC) from the receiver operating characteristic of E-plate and latex curves were almost the same and the highest in Vietnam. The latex AUC was slightly lower than the E-plate AUC in other countries, and the difference became statistically significant in Myanmar and then Bangladesh as the lowest. To consider past infection cases, atrophy was additionally evaluated. Most of the AUCs decreased using this atrophy-evaluated status; however, the difference between the two kits was not significant in each country, but the latex AUC was better using all samples. Practical cut-off values were 3.0 U/mL in the E-test and 3.5 U/mL in the latex test, to avoid missing gastric cancer patients to the greatest extent possible. CONCLUSIONS: The kits were applicable in all countries, but new kits using regional H. pylori strains are recommended for Myanmar and Bangladesh. Use of a cut-off value lower than the best cut-off value is essential for screening gastric cancer patients.

Serum pepsinogens as a gastric cancer and gastritis biomarker in South and Southeast Asian populations.

Serum pepsinogens have been widely acknowledged as gastric mucosal biomarkers; however, a multicountry report on the benefits of pepsinogens as biomarkers has not yet been published. We analyzed 1,206 sera and gastric mucosal samples collected from Bangladesh, Bhutan, Indonesia, Myanmar, Nepal and Thailand then assessed the association between gastric mucosal changes and Helicobacter pylori infection. The new cutoff values for serum pepsinogen values were evaluated using a receiver operating characteristic analysis. The participants with H. pylori infection had significantly lower pepsinogen I and higher pepsinogen II values, but a lower pepsinogen I/II ratio than participants without the infection (all P < .001). The pepsinogen I and pepsinogen I/II values were significantly higher and lower, respectively, in individuals with atrophic gastritis than in those without (both P < .001). Among uninfected individuals, only the pepsinogen I/II ratio was significantly lower in atrophic individuals. Pepsinogen I/II ratio also were significantly different between disease among H. pylori-positive and H. pylori-negative individuals, suggesting the pepsinogen I/II ratio is a robust biomarker for determining both chronic and atrophic gastritis. The cutoffs for detecting chronic and atrophic gastritis for the pepsinogen I/II ratio were 4.65 and 4.95, respectively. In conclusion, pepsinogen levels are useful biomarker for both chronic gastritis and atrophic gastritis, but they should be used with caution. Population-based validation is necessary to determine the best cutoff values. Among all pepsinogen values, the pepsinogen I/II ratio was the most reliable gastric mucosal-change biomarker.

Characterization of a novel Helicobacter pylori East Asian-type CagA ELISA for detecting patients infected with various cagA genotypes.

Currently, Western-type CagA is used in most commercial Helicobacter pylori CagA ELISA kits for CagA detection rather than East Asian-type CagA. We evaluated the ability of the East Asian-type CagA ELISA developed by our group to detect anti-CagA antibody in patients infected with different cagA genotypes of H. pylori from four different countries in South Asia and Southeast Asia. The recombinant CagA protein was expressed and later purified using GST-tag affinity chromatography. The East Asian-type CagA-immobilized ELISA was used to measure the levels of anti-CagA antibody in 750 serum samples from Bhutan, Indonesia, Myanmar, and Bangladesh. The cutoff value of the serum antibody in each country was determined via Receiver-Operating Characteristic (ROC) analysis. The cutoff values were different among the four countries studied (Bhutan, 18.16 U/mL; Indonesia, 6.01 U/mL; Myanmar, 10.57 U/mL; and Bangladesh, 6.19 U/mL). Our ELISA had better sensitivity, specificity, and accuracy of anti-CagA antibody detection in subjects predominantly infected with East Asian-type CagA H. pylori (Bhutan and Indonesia) than in those infected with Western-type CagA H. pylori predominant (Myanmar and Bangladesh). We found positive correlations between the anti-CagA antibody and antral monocyte infiltration in subjects from all four countries. There was no significant association between bacterial density and the anti-CagA antibody in the antrum or the corpus. The East Asian-type CagA ELISA had improved detection of the anti-CagA antibody in subjects infected with East Asian-type CagA H. pylori. The East Asian-type CagA ELISA should, therefore, be used in populations predominantly infected with East Asian-type CagA.

Effective therapeutic regimens in two South Asian countries with high resistance to major Helicobacter pylori antibiotics.

Background: Nepal and Bangladesh have a high prevalence of Helicobacter pylori with high resistance rates to clarithromycin, metronidazole, and levofloxacin. Here, we evaluated the susceptibility and genetic mutations of 5 alternative antibiotics against isolates from both countries to obtain an effective treatment regimen for H. pylori eradication. Methods: We used the agar dilution method to determine the minimal inhibitory concentration of 5 alternative antibiotics against 42 strains from Nepal and 56 from Bangladesh and performed whole genome mutation analysis. Results: No resistance to furazolidone or rifabutin and a high susceptibility of sitafloxacin (95.2% in Nepal and 98.2% in Bangladesh) were observed. In contrast, resistance to rifaximin (52.4% in Nepal and 64.3% in Bangladesh) was high. Moreover, resistance to garenoxacin was higher in Bangladesh (51.6%) than in Nepal (28.6%, P = 0.041), most likely due to its correlation with levofloxacin resistance (P = 0.03). Garenoxacin and rifaximin were significantly correlated in Bangladesh (P = 0.014) and occurred together with all sitafloxacin-resistant strains. Mutations of gyrA could play a significant role in garenoxacin resistance, and double mutations of A87 and D91 were associated with sitafloxacin resistance. Analysis of the rpoB gene demonstrated well-known mutations, such as V657I, and several novel mutations, including I2619V, V2592 L, T2537A, and F2538 L. Conclusions: Rifabutin can be cautiously implemented as therapy for H. pylori infection due to its interaction with the tuberculosis endemic in Bangladesh. The high susceptibility of furazolidone and sitafloxacin suggests their possible future application in Nepal and Bangladesh.

Validation of diagnostic tests and epidemiology of Helicobacter pylori infection in Bangladesh.

INTRODUCTION: Helicobacter pylori infection is associated with gastritis, peptic ulcer, and gastric cancer. We conducted a cross-sectional study to compare five diagnostic tests for H. pylori infection and studied the epidemiology of the infection in Bangladesh. METHODOLOGY: Bangladeshi patients with dyspeptic symptoms referred for endoscopic examination were enrolled in this study. Each patient underwent upper endoscopic examination and four gastric biopsy specimens were taken. We used 5 tests for the diagnosis of H. pylori; culture, histology confirmed by immunohistochemistry, rapid urease test (RUT), urinary and serological test. Demographic and environmental variables were collected. RESULTS: A total of 133 patients participated in the study, 61 males and mean age 37.3 ± 12.3 years. We used the culture and/or histology results as the gold standard to estimate the sensitivity, specificity, positive and negative predictive values for the studied diagnostic tests. RUT, culture and histology had high sensitivity and specificity with moderate positive and negative likelihood ratio, whereas urine test and serology showed a good sensitivity and specificity but poor likelihood ratio. The overall prevalence of H. pylori among study subjects was 47% with no difference between gender and age groups. CONCLUSIONS: The invasive tests showed better performance than noninvasive tests among Bangladeshi population. The overall prevalence of H. pylori was less than the previously reported in the region with no difference among all age groups.

Helicobacter pylori bab characterization in clinical isolates from Bhutan, Myanmar, Nepal and Bangladesh.

BACKGROUND: Helicobacter pylori BabA is an important outer membrane protein that involves in the attachment to the gastric mucosa and enhances the virulence property of the bacterium. This study was aimed to characterize the bab genotypes, to evaluate its association with cagA, vacA and clinical diseases as well as degree of gastric inflammation. METHODS: H. pylori isolates from four countries were subjected for the characterization of bab. The locus specific forward and bab specific reverse primers were used to get the specific products by PCR, which could distinguish the three locus (A, B and C). The histological activities were evaluated according to the Updated Sydney system. RESULT: In patients from high risk countries (Bhutan and Myanmar) relatively higher frequencies of strains with babA-positivity (91.8% and 90.7%, respectively), babA at locus A (98% and 91.2%, respectively) and with single babA (96.8% and 91.2%, respectively) were found. Strains with two loci occupied were the most prevalent in Bhutan (84.6%), Myanmar (74.7%), Nepal (58.3%) and Bangladesh (56.9%). The genotype babA at locus A/babB at locus B/bab-negative at locus C (babA/babB/-) was the most common genotype isolated from Bhutan (82.7%), Myanmar (58.7%), Nepal (32%) and Bangladesh (31.4%) among all genotypes assessed. This genotype was also associated with the peptic ulcer disease (P = 0.013) when compared to gastritis. babA-positive characteristics and the genotype babA/babB/- exhibited the enhanced histological activities. CONCLUSIONS: The higher prevalence of virulence associated babA-positive characteristics and enhanced histological activities in Bhutan than in Myanmar, Nepal and Bangladesh might partly explain why the peoples in Bhutan are at higher risk for developing severe gastric complications.

Two populations of less-virulent Helicobacter pylori genotypes in Bangladesh.

Bangladesh has a population with a low gastric cancer risk but high prevalence of Helicobacter pylori infection. Several studies have examined virulence genes in H. pylori from Bangladesh. We analyzed cagA and vacA subtypes and their association with severe histology phenotypes, and analyzed population types among Bangladeshi strains. We included patients who underwent endoscopy in Dhaka. Sequences of virulence genes and seven housekeeping genes were obtained by next generation sequencing and confirmed by Sanger sequencing. We isolated 56 H. pylori strains from 133 patients, of which 73.2% carried cagA, and all were considered Western-type. Patients infected with cagA-positive strains had more severe histological scores than patients infected with cagA-negative strains. Among vacA s1 and m1 genotypes, the s1a (97.8%, 43/44) and m1c (28/30, 93.3%) genotypes were predominant. All strains containing s1 and m1 (30/56, 53.6%) also had i1, d1, and c1. In contrast, all strains containing the less-virulent genotypes s2 and m2 (12/56, 21.4%) also possessed i2, d2, and c2. Multivariate analysis indicated that subjects infected with vacA m1-genotype strains only had a significantly higher risk of antrum atrophy than patients infected with m2-genotype strains. Of the two main H. pylori populations in this study, hpAsia2 strains were associated with higher activity and inflammation in the antrum compared to hpEurope strains; however, only vacA s1m1i1d1c1 strains, independent of population type, were significantly associated with inflammation in the antrum, unlike the s2m2i2d2c2 genotype. In conclusion, Bangladeshi strains were divided into two main populations of different genotypes. The low incidence of gastric cancer in Bangladesh might be attributable to the high proportion of less-virulent genotypes, which may be a better predictor of gastric cancer risk than the ancestral origin of the H. pylori strains. Finally, the vacA m region may be a better virulence marker than other regions.

Helicobacter pylori antibiotic susceptibility patterns in Bangladesh: Emerging levofloxacin resistance.

INTRODUCTION: The most recent study to report Helicobacter pylori antibiotic resistance rates in Bangladesh was published 15 years ago and did not include levofloxacin. We therefore aimed to determine the current antibiotic susceptibility of H. pylori to amoxicillin, clarithromycin, metronidazole, tetracycline and levofloxacin in Bangladesh. METHODOLOGY: This study included 133 consecutive patients who underwent endoscopy examination at Dhaka Medical College in November 2014. The serial two-fold agar dilution method was used to determine the minimum inhibitory concentrations of the five antibiotics. RESULTS: Among 56 cultured strains, H. pylori showed high rates of resistance to clarithromycin and metronidazole (39.3% and 94.6%, respectively). Moreover, levofloxacin showed an emerging antimicrobial resistance pattern (66.1%), which was higher in patients with gastritis than that in those with peptic ulcers (p = 0.02). The resistance rate of levofloxacin was significantly higher in patients living in Dhaka city compared to those living in the village (p = 0.049). However, amoxicillin and tetracycline resistance rates were very low. Resistance to both metronidazole and levofloxacin was most commonly observed. CONCLUSIONS: The rates of resistance to clarithromycin, metronidazole, and levofloxacin were high in Bangladesh, which suggests that triple therapy based on these drugs may not be useful as first-line therapies in Bangladesh. Alternative strategies such as furazolidone-based triple therapy, bismuth-based quadruple therapies, or sequential therapy may be more effective for patients in in Bangladesh.

Observation of gastric mucosa in Bangladesh, the country with the lowest incidence of gastric cancer, and Japan, the country with the highest incidence.

BACKGROUND: The prevalence of Helicobacter pylori (H. pylori) infection is high, but the incidence of gastric cancer is low in natives of Bangladesh. The gastric mucosa was observed in Bangladeshi patients to investigate the differences between Bangladeshis and Japanese. MATERIALS AND METHODS: The study involved 418 Bangladeshi and 2356 Japanese patients with abdominal complaints who underwent endoscopy examinations and had no history of H. pylori eradication. The prevalence of H. pylori infection and the gastric mucosa in H. pylori-positive patients were compared between age-, gender-, and endoscopic diagnosis-matched Bangladeshi and Japanese subjects. RESULTS: The prevalence of H. pylori infection was higher in Bangladeshi than in Japanese subjects (60.2 and 45.1%, respectively). All the scores for chronic inflammation, neutrophil activity, glandular atrophy, and intestinal metaplasia were significantly lower in H. pylori-positive Bangladeshis than in H. pylori-positive Japanese. The ratio of the corpus gastritis score (C) to the antrum gastritis score (A) (C/A ratio) was <1 (antrum-predominant gastritis) in all age groups of Bangladeshi subjects, whereas the C/A ratio changed from <1 to more than 1 (corpus-predominant gastritis) with aging in Japanese subjects. CONCLUSIONS: The scores for glandular atrophy and intestinal metaplasia in H. pylori-positive Bangladeshis were significantly lower than those in Japanese. All age groups of Bangladeshis had antrum-predominant gastritis, whereas corpus-predominant gastritis was more common than antrum-predominant gastritis in older Japanese age groups. These results may explain the low incidence of gastric cancer in Bangladeshis and the high incidence in Japanese.