Displaying publications 41 - 56 of 56 in total

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  1. Alfizah H, Norazah A, Hamizah R, Ramelah M
    J Med Microbiol, 2014 May;63(Pt 5):703-709.
    PMID: 24757218 DOI: 10.1099/jmm.0.069781-0
    Antibiotic resistance is increasing worldwide, and it has been regarded as the main factor reducing the efficacy of Helicobacter pylori therapy. The aim of this study was to determine the phenotype and genotype of antibiotic-resistant strains of H. pylori in the Malaysian population and to evaluate the impact of antibiotic resistance to eradication outcome. One hundred and sixty-one H. pylori isolates were analysed in this study. Metronidazole, clarithromycin, fluoroquinolone, amoxicillin and tetracycline susceptibilities were determined by Etest. PCR followed by DNA sequencing was carried out to determine mutations. The medical records of the patients infected with resistant strains were reviewed to determine the eradication outcome. Metronidazole resistance was encountered in 36.6 % of H. pylori isolates, whereas clarithromycin and fluoroquinolone resistance was observed in 1.2  and 1.9 % of isolates, respectively. All strains tested were susceptible to amoxicillin and tetracycline. Frameshift and nonsense mutations in rdxA and frxA genes resulting in stop codons contributed to metronidazole resistance, which leads to reduced eradication efficacy. A2142G and A2143G mutations of 23S rRNA were identified as causing failure of the eradication therapy. Mutation at either codon 87 or 91 of the gyrA gene was identified in fluoroquinolone-resistant strains. However, the effect of resistance could not be assessed. This study showed that frameshift and nonsense mutations in rdxA or frxA genes and point mutations in the 23S rRNA affected the efficacy of H. pylori eradication therapy.
    Matched MeSH terms: Helicobacter Infections/microbiology*
  2. Ram M R, Teh X, Rajakumar T, Goh KL, Leow AHR, Poh BH, et al.
    J Antimicrob Chemother, 2019 01 01;74(1):11-16.
    PMID: 30403784 DOI: 10.1093/jac/dky401
    Objectives: Eradication of Helicobacter pylori is influenced by susceptibility to antimicrobial agents, elevated bacterial load and degree of acid inhibition, which can be affected by genotypes of drug-metabolizing enzymes [cytochrome P450 (CYP) 2C19 polymorphism]. Theoretically, the choice and dose of proton pump inhibitor may also influence the suppression of H. pylori infection. The CYP2C19 genotype has recently been found to have an impact on peptic ulcer healing, H. pylori eradication and therapeutic efficacy of proton pump inhibitors.

    Methods: Here, we investigated the impact of the CYP2C19 genotype polymorphism and the success of triple therapy (fluoroquinolones/metronidazole/clarithromycin) on antibiotic-resistant strains in eradicating H. pylori in human subjects with non-ulcer dyspepsia (NUD), in human subjects with peptic ulcer disease (PUD) and in asymptomatic human subjects (positive and negative for H. pylori infection).

    Results: Based on the CYP2C19 genotypes, determined by Droplet Digital PCR (ddPCR) analysis, we found 11.2%, 62.5% and 26.3% corresponding to rapid metabolizers, intermediate metabolizers and poor metabolizers, respectively. However, we did not find any significant effect for homozygous ABCB1 or CYP2C19*2 and CYP2C19*3 alleles. We detected several participants heterozygous for both ABCB1 and CYP2C19*2, CYP2C19*3 and CYP2C19*17 loci. The participants heterozygous for both ABCB1 and CYP2C19*2 and *3 loci should be defined as intermediate and poor metabolizers according to the haplotype analysis in the NUD, PUD and asymptomatic subjects.

    Conclusions: Consequently, fluoroquinolones/metronidazole/clarithromycin-based triple therapies can be used to eradicate H. pylori infection, if one does not know the CYP2C19 genotype of the patient.

    Matched MeSH terms: Helicobacter Infections/microbiology
  3. Kuo YT, Liou JM, El-Omar EM, Wu JY, Leow AHR, Goh KL, et al.
    Lancet Gastroenterol Hepatol, 2017 10;2(10):707-715.
    PMID: 28781119 DOI: 10.1016/S2468-1253(17)30219-4
    BACKGROUND: So far, a comprehensive systematic review and meta-analysis has not been done of the prevalence of primary antibiotic resistance in Helicobacter pylori in the Asia-Pacific region. We aimed to assess the trends and regional differences in primary antibiotic resistance to H pylori in the Asia-Pacific region and to examine the relation between resistance and first-line eradication.

    METHODS: We did a systematic review and meta-analysis of primary antibiotic resistance to H pylori and the efficacy of first-line regimens in the Asia-Pacific region. We searched PubMed, Embase, and the Cochrane Library for articles published between Jan 1, 1990, and Sept 30, 2016; we also searched abstracts from international conferences. Both observational studies and randomised controlled trials were eligible for inclusion in the analysis of primary antibiotic resistance, but only randomised controlled trials were eligible for inclusion in the analysis of efficacy of first-line therapies. Meta-analysis was by the random-effects model to account for the substantial variations in resistance across the region. We did subgroup analyses by country and study period (ie, before 2000, 2001-05, 2006-10, and 2011-15) to establish country-specific prevalences of primary antibiotic resistance and first-line eradication rates. This study is registered with PROSPERO, number CRD42017057905.

    FINDINGS: 176 articles from 24 countries were included in our analysis of antibiotic resistance. The overall mean prevalences of primary H pylori resistance were 17% (95% CI 15-18) for clarithromycin, 44% (95% CI 39-48) for metronidazole, 18% (95% CI 15-22) for levofloxacin, 3% (95% CI 2-5) for amoxicillin, and 4% (95% CI 2-5) for tetracycline. Prevalence of resistance to clarithromycin and levofloxacin rose significantly over time during the period investigated, whereas resistance to other antibiotics remained stable. 170 articles from 16 countries were included in analysis of efficacy of first-line therapies. We noted unsatisfactory efficacy (ie, <80%) with clarithromycin-containing regimens in countries where the clarithromycin resistance rates were higher than 20%.

    INTERPRETATION: The prevalence of primary antibiotic resistance varied greatly among countries in the Asia-Pacific region, and thus treatment strategy should be adapted relative to country-specific resistance patterns. Clarithromycin-containing regimens should be avoided in countries where the prevalence of clarithromycin resistance is higher than 20%.

    FUNDING: Ministry of Health and Welfare of Taiwan, Ministry of Science and Technology of Taiwan, and Amity University.

    Matched MeSH terms: Helicobacter Infections/microbiology*
  4. Huang J, Zagai U, Hallmans G, Nyrén O, Engstrand L, Stolzenberg-Solomon R, et al.
    Int J Cancer, 2017 Apr 15;140(8):1727-1735.
    PMID: 28032715 DOI: 10.1002/ijc.30590
    The association between H. pylori infection and pancreatic cancer risk remains controversial. We conducted a nested case-control study with 448 pancreatic cancer cases and their individually matched control subjects, based on the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, to determine whether there was an altered pancreatic cancer risk associated with H. pylori infection and chronic corpus atrophic gastritis. Conditional logistic regression models were applied to calculate odds ratios (ORs) and corresponding 95% confidence intervals (CIs), adjusted for matching factors and other potential confounders. Our results showed that pancreatic cancer risk was neither associated with H. pylori seropositivity (OR = 0.96; 95% CI: 0.70, 1.31) nor CagA seropositivity (OR = 1.07; 95% CI: 0.77, 1.48). We also did not find any excess risk among individuals seropositive for H. pylori but seronegative for CagA, compared with the group seronegative for both antibodies (OR = 0.94; 95% CI: 0.63, 1.38). However, we found that chronic corpus atrophic gastritis was non-significantly associated with an increased pancreatic cancer risk (OR = 1.35; 95% CI: 0.77, 2.37), and although based on small numbers, the excess risk was particularly marked among individuals seronegative for both H. pylori and CagA (OR = 5.66; 95% CI: 1.59, 20.19, p value for interaction 
    Matched MeSH terms: Helicobacter Infections/microbiology*
  5. Amin M, Anwar F, Janjua MRSA, Iqbal MA, Rashid U
    Int J Mol Sci, 2012;13(8):9923-9941.
    PMID: 22949839 DOI: 10.3390/ijms13089923
    A green synthesis route for the production of silver nanoparticles using methanol extract from Solanum xanthocarpum berry (SXE) is reported in the present investigation. Silver nanoparticles (AgNps), having a surface plasmon resonance (SPR) band centered at 406 nm, were synthesized by reacting SXE (as capping as well as reducing agent) with AgNO(3) during a 25 min process at 45 °C. The synthesized AgNps were characterized using UV-Visible spectrophotometry, powdered X-ray diffraction, and transmission electron microscopy (TEM). The results showed that the time of reaction, temperature and volume ratio of SXE to AgNO(3) could accelerate the reduction rate of Ag(+) and affect the AgNps size and shape. The nanoparticles were found to be about 10 nm in size, mono-dispersed in nature, and spherical in shape. In vitro anti-Helicobacter pylori activity of synthesized AgNps was tested against 34 clinical isolates and two reference strains of Helicobacter pylori by the agar dilution method and compared with AgNO(3) and four standard drugs, namely amoxicillin (AMX), clarithromycin (CLA), metronidazole (MNZ) and tetracycline (TET), being used in anti-H. pylori therapy. Typical AgNps sample (S1) effectively inhibited the growth of H. pylori, indicating a stronger anti-H. pylori activity than that of AgNO(3) or MNZ, being almost equally potent to TET and less potent than AMX and CLA. AgNps under study were found to be equally efficient against the antibiotic-resistant and antibiotic-susceptible strains of H. pylori. Besides, in the H. pylori urease inhibitory assay, S1 also exhibited a significant inhibition. Lineweaver-Burk plots revealed that the mechanism of inhibition was noncompetitive.
    Matched MeSH terms: Helicobacter Infections/microbiology
  6. Khalilpour A, Osman S, Yunus MH, Santhanam A, Vellasamy N, Noordin R
    BMC Res Notes, 2014;7:809.
    PMID: 25406411 DOI: 10.1186/1756-0500-7-809
    Helicobacter pylori is a human pathogen and during the process of infection, antigens from the bacterium elicit strong host humoral immune responses. In our previous report, native H. pylori UreG protein showed good reactivity with sera from H. pylori patients. This study was aimed at producing the recombinant form of the protein (rUreG) and determining its seroreactivities.
    Matched MeSH terms: Helicobacter Infections/microbiology*
  7. Alfizah H, Ramelah M, Rizal AM, Anwar AS, Isa MR
    Helicobacter, 2012 Oct;17(5):340-9.
    PMID: 22967117 DOI: 10.1111/j.1523-5378.2012.00956.x
    Polymorphisms of Helicobacter pylori cagA and vacA genes do exist and may contribute to differences in H. pylori infection and gastroduodenal diseases among races in the Malaysian population. This study was conducted to characterize the polymorphisms in H. pylori cagA and vacA in Malaysian population.
    Matched MeSH terms: Helicobacter Infections/microbiology*
  8. Goh KL, Manikam J, Qua CS
    Aliment Pharmacol Ther, 2012 May;35(9):1097-102.
    PMID: 22404486 DOI: 10.1111/j.1365-2036.2012.05054.x
    BACKGROUND:
    H. pylori eradication failures are difficult to treat and rescue therapies often consist of complex treatment regimens.

    AIM:
    To determine an effective and practical rescue therapeutic strategy for H. pylori treatment failures using two consecutive regimens: first rescue therapy - rabeprazole 20 mg t.d.s. and amoxicillin 1 g t.d.s. for 2 weeks and for failures a further second rescue therapy - rabeprazole 20 mg b.d., levofloxacin 500 mg b.d., amoxicillin 1 g b.d. for a further 2 weeks.

    METHODS:
    Consecutive patients who failed the proton pump inhibitor (PPI) 1-week triple therapy were recruited for the study. H. pylori status was determined by a C(13) urea breath test.

    RESULTS:
    One hundred and forty-nine patients received the first rescue therapy. Seven were not compliant to medication/defaulted follow-up. Eradication success- first rescue therapy: per protocol (PP) analysis-107/142 (75.4%) (95% CI (68.3-82.4%) and intention to treat (ITT) analysis-107/149 (71.8%) 95% CI (64.6-79.0%). Thirty-one of 35 patients who failed the first rescue therapy received the second rescue therapy. All were compliant with medications. Eradication success- PP and ITT was 28/31 (90.3%) 95% CI (74.2-98.0%). The cumulative eradication rate using both rescue therapies: PP analysis- 135/138 (97.8%) 95% CI: (93.8-99.6%), ITT analysis- 135/149 (90.6%) 95% CI: (84.7-94.8%).

    CONCLUSIONS:
    A 2-week high dose PPI-amoxicillin dual therapy followed by a PPI-amoxicillin-levofloxacin triple therapy were highly successful in achieving eradication in H. pylori treatment failures.
    Matched MeSH terms: Helicobacter Infections/microbiology
  9. Qua CS, Manikam J, Goh KL
    J Dig Dis, 2010 Aug;11(4):244-8.
    PMID: 20649738 DOI: 10.1111/j.1751-2980.2010.00445.x
    OBJECTIVE:
    To re-examine the efficacy and tolerability of 1-week proton pump inhibitor triple therapy as a first-line Helicobacter pylori (H. pylori) eradication therapy.

    METHODS:
    Consecutive participants with a positive rapid urease test during an outpatient upper endoscopy were included. All participants were given pantoprazole 40 mg b.i.d., amoxycillin 1 g b.i.d. and clarithromycin 500 mg b.i.d. for 1 week. They were asked to return after 1 week to report any side effects related to the medications and to check for compliance. Successful eradication was defined by negative (13)C-urea breath test at least 4 weeks after the completion of therapy.

    RESULTS:
    A total of 191 patients were recruited into the study, of whom 81 were male (42.4%) and 110 female (57.6%), with a mean age of 55.6 (range 21-88) years. Overall 26 patients (13.6%) defaulted follow up and five patients were not compliant (taking less than 85%) with the medications. Per-protocol and intention-to-treat eradication rates were 84.4% (95% CI: 78.6-89.9%) and 71.2% (95% CI: 64.5-77.6%), respectively. Overall 68 participants (42.5%) reported no side effects, followed by 58 (36.3%) with a taste disturbance, 16 (10.0%) with epigastric pain, 15 (9.4%) with diarrhea, 13 (8.1%) with nausea or vomiting, 12 (7.5%) with loss of appetite, nine (5.6%) with dizziness and two (1.3%) with an allergic skin rash, none of which was severe.

    CONCLUSION:
    The current regime using pantoprazole, amoxycillin and clarithromycin is highly tolerable and effective and should continue to be recommended as a first-line therapy for H. pylori eradication in our setting.
    Matched MeSH terms: Helicobacter Infections/microbiology
  10. Yeh LY, Raj M, Hassan S, Aziz SA, Othman NH, Mutum SS, et al.
    Indian J Gastroenterol, 2009 08 21;28(2):49-52.
    PMID: 19696988 DOI: 10.1007/s12664-009-0017-0
    INTRODUCTION: The Northeastern region of Peninsular Malaysia is an area with exceptionally low prevalence for Helicobacter pylori infection. The risk of intestinal metaplasia and dysplasia in patients with chronic atrophic gastritis (CAG) and its association with Helicobacter pylori is unknown in this region.

    METHODS: This was a cross-sectional study on gastric biopsies from 234 consecutive patients (mean age 53.5 [14.8] years) who underwent upper gastrointestinal endoscopy between January 2006 and December 2006.

    RESULTS: There were 137 (59%) men and 185 (79%) Malay patients. Among 234 biopsies, CAG was found in 99 and non-atrophic gastritis in 135. Intestinal metaplasia and dysplasia were detected in 8 and 6 atrophic gastritis biopsies, respectively, and in 10 and 3 of non-atrophic gastritis biopsies, respectively. H. pylori were detected in 16 (9 Malays, 7 non- Malays) biopsies (p=0.024); intestinal metaplasia was detected in 4 biopsies (p=0.3) and dysplasia in 5 biopsies (p=0.3). Of the 218 biopsies negative for H. pylori, intestinal metaplasia was found in 14 and dysplasia in 4. The risk of intestinal metaplasia as well as dysplasia was associated with presence of H. pylori infection (p=0.029 and p<0.001 respectively).

    CONCLUSION: Even in a setting of low prevalence of H. pylori, intestinal metaplasia and dysplasia were significantly associated with H. pylori infection. The frequency of intestinal metaplasia and dysplasia was similar different between biopsies with atrophic gastritis and non-atrophic gastritis.

    Matched MeSH terms: Helicobacter Infections/microbiology
  11. Norazah A, Rasinah WZ, Zaili Z, Aminuddin A, Ramelah M
    Malays J Pathol, 2009 Jun;31(1):29-34.
    PMID: 19694311 MyJurnal
    This study was conducted to determine whether there was any genetic heterogeneity among Helicobacter pylori strains isolated from the antrum and corpus of the same individual in a Malaysian population and to determine the presence of heterogeneous susceptibility of the isolates by comparing PCR-RAPD and antibiotic profiles. Forty-four H. pylori isolates cultured from the antrum and corpus of 22 patients were analyzed. Antibiotic susceptibility testing was carried out by minimum inhibitory concentration determination, using E-Test method strips. PCR-RAPD was carried out on all the strains and the profiles generated were analysed for cluster analysis. Twenty-nine different PCR-RAPD profiles were observed in the 44 isolates. Fifteen pairs of the isolates from the same patients had the same PCR-RAPD patterns while in 7 pairs, the profiles were different. The strains were clustered into 2 separate clusters at a low coefficient of similarity, where most of the strains were in cluster 1. The degree of similarity was very low among most of the isolates. Most of the patients (16 of 22) were infected with strains that have the same antibiotic susceptibility profiles. Out of these, only 10 pairs shared the same PCR-RAPD and antibiotic profiles. Five pairs of isolates with similar PCR-RAPD profiles differed in their antibiotic profiles due to metronidazole resistance in one of the sites. A large degree of genetic heterogeneity was observed among H. pylori strains circulating among Malaysian patients. An individual patient can be infected with multiple strains and the strains can be antibiotic resistant.
    Matched MeSH terms: Helicobacter Infections/microbiology*
  12. Ravishankar Ram M, Goh KL, Leow AH, Poh BH, Loke MF, Harrison R, et al.
    PLoS One, 2015;10(11):e0141865.
    PMID: 26559190 DOI: 10.1371/journal.pone.0141865
    Helicobacter pylori (H. pylori) -induced gastric inflammation impacts the functions of leptin- and ghrelin-producing cells in the gastroduodenum. Inflammation resulting from H. pylori sensing via Toll-like receptors (TLRs) and the associated downstream signaling largely remain ambiguous. Here, we investigated the role of gut hormones, pro-inflammatory cytokines and single nucleotide polymorphisms (SNPs) associated with TLR 4p14 in H. pylori disease in 30 subjects with non-ulcer dyspepsia (NUD), 40 with peptic ulcer disease (PUD) and 15 with gastric cancer (GC) subjects positive and negative for H. pylori infection. The level of pro-inflammatory cytokines was directly proportional to the severity of gastritis, and disease status influenced the levels of gut hormones and pro-inflammatory cytokines. TLR-1 SNPs rs4833095 and TLR-10 SNPs rs10004195 and were directly associated with H. pylori disease, and were up-regulated in the presence of H. pylori in a genotype-independent manner. We concluded that TLR-1 rs4833095 and TLR10 rs10004195 confer susceptibility to development of gastroduodenal disease, especially GC in H.pylori disease.
    Matched MeSH terms: Helicobacter Infections/microbiology
  13. Maran S, Lee YY, Xu S, Rajab NS, Hasan N, Syed Abdul Aziz SH, et al.
    World J Gastroenterol, 2013 Jun 21;19(23):3615-22.
    PMID: 23801863 DOI: 10.3748/wjg.v19.i23.3615
    To identify genes associated with gastric precancerous lesions in Helicobacter pylori (H. pylori)-susceptible ethnic Malays.
    Matched MeSH terms: Helicobacter Infections/microbiology
  14. Fadilah N, Hanafiah A, Razlan H, Wong ZQ, Mohamed Rose I, Rahman MM
    Br J Biomed Sci, 2016 Oct;73(4):180-187.
    PMID: 27922429
    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.

    Matched MeSH terms: Helicobacter Infections/microbiology
  15. Castaño-Rodríguez N, Kaakoush NO, Pardo AL, Goh KL, Fock KM, Mitchell HM
    Hum Immunol, 2014 Aug;75(8):808-15.
    PMID: 24929142 DOI: 10.1016/j.humimm.2014.06.001
    Gastric cancer (GC) is a progressive process initiated by Helicobacter pylori-induced inflammation. Initial recognition of H. pylori involves Toll-like receptors (TLRs), central molecules in the host inflammatory response. Here, we investigated the association between novel polymorphisms in genes involved in the TLR signalling pathway, including TLR2, TLR4, LBP, MD-2, CD14 and TIRAP, and risk of H. pylori infection and related GC.
    Matched MeSH terms: Helicobacter Infections/microbiology
  16. Khalilpour A, Santhanam A, Wei LC, Saadatnia G, Velusamy N, Osman S, et al.
    Asian Pac J Cancer Prev, 2013;14(3):1635-42.
    PMID: 23679248
    Helicobacter pylori antigen was prepared from an isolate from a patient with a duodenal ulcer. Serum samples were obtained from culture-positive H. pylori infected patients with duodenal ulcers, gastric ulcers and gastritis (n=30). As controls, three kinds of sera without detectable H. pylori IgG antibodies were used: 30 from healthy individuals without history of gastric disorders, 30 from patients who were seen in the endoscopy clinic but were H. pylori culture negative and 30 from people with other diseases. OFF-GEL electrophoresis, SDS-PAGE and Western blots of individual serum samples were used to identify protein bands with good sensitivity and specificity when probed with the above sera and HRP-conjugated anti-human IgG. Four H. pylori protein bands showed good (≥ 70%) sensitivity and high specificity (98-100%) towards anti-Helicobacter IgG antibody in culture- positive patients sera and control sera, respectively. The identities of the antigenic proteins were elucidated by mass spectrometry. The relative molecular weights and the identities of the proteins, based on MALDI TOF/ TOF, were as follows: CagI (25 kDa), urease G accessory protein (25 kDa), UreB (63 kDa) and proline/pyrroline- 5-carboxylate dehydrogenase (118 KDa). These identified proteins, singly and/or in combinations, may be useful for diagnosis of H. pylori infection in patients.
    Matched MeSH terms: Helicobacter Infections/microbiology
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