Prevalence of Helicobacter pylori infection among patients referred for endoscopy: Gender and ethnic differences in Kedah, Malaysia

Development and Validation of Multiplex Quantitative PCR Assay for Detection of Helicobacter pylori and Mutations Conferring Resistance to Clarithromycin and Levofloxacin in Gastric Biopsy

Aims and Objectives

More than half of the world's population is infected with Helicobacter pylori, which can cause chronic gastritis. WHO has regarded clarithromycin-resistant H. pylori as a high priority pathogen. Hence, accurate diagnosis and detection of clarithromycin- and levofloxacin-resistant H. pylori strains is essential for proper management of infection. The objective of this study was to develop and optimize multiplex quantitative PCR assay for detection of mutations associated with clarithromycin and levofloxacin resistance in H. pylori directly from the gastric biopsies.

Materials and Methods

Specific primers and probes were designed to amplify ureA and mutations in 23S rRNA and gyrA genes. Singleplex and triplex qPCR assays were optimized and the assay's sensitivities and specificities were determined. The optimized multiplex qPCR assay was performed on 571 gastric biopsies.

Results

In this study, 14.7% (84/571) of the gastric biopsies were positive for H. pylori by conventional methods and 23.8% (136/571) were positive by the ureA-qPCR with 96.4% sensitivity and 88.5% specificity, while the +LR and -LR were 8.72 and 0.04, respectively. The ureA-positive samples (n=136) were subjected to multiplex qPCR which detected A2142G and A2143G mutations in the 23S rRNA gene (20.6%, 28/136) conferring clarithromycin resistance and gyrA mutations N87K, N87I, D91N, and D91Y (11.8%, 16/136) leading to levofloxacin resistance. The sensitivity and specificity of qPCR of 23S rRNA gene were 100% and 98.7%, respectively, while 100% and 99.8% for qPCR of gyrA, respectively.

Conclusion

The effectiveness of this qPCR is that it is sensitive in detecting low bacterial load and will help in timely detection of clarithromycin- and levofloxacin-resistant strains, especially in case of mixed infections. Since it is culture independent, it can inform clinicians about antibiotics to be included in the first-line therapy, thereby improving the management of H. pylori infection at a much greater pace.

Multiplex PCR for detection of Helicobacter pylori infection in gastric biopsies with lower inflammatory score

BACKGROUND

No gold standard has yet been established for the diagnosis of H. pylori infection. A multiplex polymerase chain reaction (mPCR) was developed in this study for rapid, sensitive and specific detection of H. pylori from gastric biopsies.

METHODS

H. pylori infections were determined by in-house rapid urease test (iRUT), culture, histology and multiplex PCR.

RESULTS

A total of 140 (60.9%) from 230 patients were positive for H. pylori infection. H. pylori were detected in 9.6% (22/230), 17% (39/230), 12.6% (29/230) and 60% (138/230) of biopsy specimens by culture, iRUT, histology and mPCR, respectively. mPCR identified H. pylori infection in 100% of biopsies with positive histology and culture. All biopsies with positive iRUT yielded positive PCR except two cases. mPCR also detected H. pylori in additional 116, 101 and 109 biopsies that were negative by culture, iRUT and histology, respectively. Positive samples by mPCR showed lower average in H. pylori density, activity and inflammation scores. The Indians showed the highest prevalence of H. pylori infection compared to the Chinese and the Malays. In addition, Chinese patients with older age were significantly infected compared to other ethnicities.

CONCLUSION

PCR was able to detect the highest numbers of positive cases although the lowest average scores were recorded in the activity, inflammatory and H. pylori density.

Helicobacter pylori Infection Rates in Patients Undergoing Endoscopy in the Interior of Borneo

INTRODUCTION

Very limited data are available on the Helicobacter pylori infection among the population of interior Borneo. We aimed to investigate the H. pylori infection rate among an endoscoped interior Borneo population and to report the differences between the infected and noninfected patients.

METHODS

We retrospectively analyzed the data of the rapid urease test (RUT) records in Endoscopy Unit Hospital Keningau from January 2009 to May 2014. Student's t-test, chi-square test or Fisher's exact test were used accordingly. Multiple logistic regression analysis was used to identify independent risk factors for H. pylori infection. Birth cohort was analyzed against H. pylori infection rate with chi-square test.

RESULTS

Overall, there were 215 of 774 (27.8%) positive RUTs. Patients with H. pylori infection were younger (47.66 ± 14.93 vs 50.50 ± 15.02 years, p = .019), more likely to be female (OR = 1.54, 95% CI 1.12-2.13, p = .008) and originated from the Pensiangan district (OR = 1.63, 95% CI 1.01-2.64, p = .047). Chinese patients were less likely infected with H. pylori (OR = 0.36, 95% CI 0.16-0.80, p = .013). Birth cohort was significantly associated with H. pylori infection rate (χ(2) (7) = 14.71, p = .040) with an increasing trend of H. pylori infection rate in patients born later (χ(2) (1) = 5.26, p = .022).

CONCLUSION

The overall H. pylori infection rate in this population was unexpectedly low. Accordingly, it may be a recent arrival in this community. Gender, age, dietary practice, socioeconomic status, and ethnicity were among the factors associated with H. pylori infection.

Changes in Metabolic Hormones in Malaysian Young Adults following Helicobacter pylori Eradication

BACKGROUND

More than half of the world's adults carry Helicobacter pylori. The eradication of H. pylori may affect the regulation of human metabolic hormones. The aim of this study was to evaluate the effect of H. pylori eradication on meal-associated changes in appetite-controlled insulinotropic and digestive hormones, and to assess post-eradication changes in body mass index as part of a currently on-going multicentre ESSAY (Eradication Study in Stable Adults/Youths) study.

METHODS

We enrolled 29 H. pylori-positive young adult (18-30 year-old) volunteer subjects to evaluate the effect of H. pylori eradication on meal-associated changes on eight gastrointestinal hormones, using a multiplex bead assay. Changes in body mass index and anthropometric measurements were recorded, pre- and post-eradication therapy.

RESULTS

Pre-prandial active amylin, total peptide YY (PYY) and pancreatic polypeptide (PP) levels were significantly elevated 12 months post-eradication compared with baseline (n = 18; Wilcoxon's signed rank test, p<0.05). Four of the post-prandial gut metabolic hormones levels (GLP-1, total PYY, active amylin, PP) were significantly higher 12 months post-eradication compared to baseline (n = 18; p<0.05). Following H. pylori eradication, the BMI and anthropometric values did not significantly change.

CONCLUSIONS

Our study indicates that H. pylori eradication was associated with long-term disturbance in three hormones (active amylin, PP and total PYY) both pre- and post-prandially and one hormone (GLP-1) post-prandially. Longer post-eradication monitoring is needed to investigate the long-term impact of the observed hormonal changes on metabolic homeostasis.