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Analysis of antibiotic susceptibility patterns of Helicobacter pylori isolates from Malaysia

Ahmad N, Zakaria WR, Mohamed R

Helicobacter, 2011 Feb;16(1):47-51.
PMID: 21241412 DOI: 10.1111/j.1523-5378.2010.00816.x

The prevalence of antibiotic resistance varies in geographic areas. The information on the antibiotic susceptibility patterns of Helicobacter pylori (H. pylori) in our local setting is therefore relevant as a guide for the treatment options.

Matched MeSH terms: Helicobacter pylori/isolation & purification
Association of Malaysian Helicobacter pylori virulence polymorphisms with severity of gastritis and patients' ethnicity

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 pylori/isolation & purification
Resistotype of Helicobacter pylori isolates: the impact on eradication outcome

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 pylori/isolation & purification
Evaluation of the monoclonal stool antigen test for Helicobacter pylori in an Asian population with dyspepsia

Bhewa Y, Hilmi I, Cheah PL, Navaratnam P, Goh KL

J Dig Dis, 2007 Nov;8(4):207-10.
PMID: 17970878

Although well established in the West, stool antigen tests (SAT) are not widely used in Asia. Data on the accuracy of this test in Asia is sparse and, to date, there have been no studies looking at the more refined monoclonal SAT. The aim of this study is to validate the diagnostic accuracy of a stool antigen test, Hp STAR, for the detection of Helicobacter pylori.

Matched MeSH terms: Helicobacter pylori/isolation & purification*
Seroprevalence of Helicobacter pylori infection in Malaysian children: evidence for ethnic differences in childhood

Boey CC, Goh KL, Lee WS, Parasakthi N

J Paediatr Child Health, 1999 Apr;35(2):151-2.
PMID: 10365351

OBJECTIVES: To determine the prevalence of Helicobacter pylori (H. pylori) in healthy Malaysian children and to discover whether differences exist among children of different races.
METHODS: Serum samples from asymptomatic children tested for H. pylori seropositivity using an ELISA test.
RESULTS: Five hundred and fourteen healthy urban Malaysian children aged 0.5 to 17 (mean 5.9) years from three different racial groups had their blood tested for H. pylori antibodies. The overall prevalence was 10.3%. There was no significant difference in the prevalence of infection between boys and girls, but a significant rise was noted with increasing age (P = 0.009). Seropositivity was most common in the Indians and lowest in the Malays (P = 0.001). Father's level of education did not affect the child's rate of H. pylori seropositivity.
CONCLUSION: The prevalence of H. pylori seropositivity among asymptomatic urban Malaysian children is lowest in Malays. Intermediate in Chinese and highest in Indians. The racial differences found in children are consistent with those found in Malaysian adults.

Matched MeSH terms: Helicobacter pylori/isolation & purification*
Fulltext Biofilm Formation and Antibiotic Resistance Phenotype of Helicobacter pylori Clinical Isolates

Fauzia KA, Miftahussurur M, Syam AF, Waskito LA, Doohan D, Rezkitha YAA, et al.

Toxins (Basel), 2020 07 24;12(8).
PMID: 32722296 DOI: 10.3390/toxins12080473

We evaluated biofilm formation of clinical Helicobacter pylori isolates from Indonesia and its relation to antibiotic resistance. We determined the minimum inhibition concentration (MIC) of amoxicillin, clarithromycin, levofloxacin, metronidazole and tetracycline by the Etest to measure the planktonic susceptibility of 101 H. pylori strains. Biofilms were quantified by the crystal violet method. The minimum biofilm eradication concentration (MBEC) was obtained by measuring the survival of bacteria in a biofilm after exposure to antibiotics. The majority of the strains formed a biofilm (93.1% (94/101)), including weak (75.5%) and strong (24.5%) biofilm-formers. Planktonic resistant and sensitive strains produced relatively equal amounts of biofilms. The resistance proportion, shown by the MBEC measurement, was higher in the strong biofilm group for all antibiotics compared to the weak biofilm group, especially for clarithromycin (p = 0.002). Several cases showed sensitivity by the MIC measurement, but resistance according to the MBEC measurements (amoxicillin, 47.6%; tetracycline, 57.1%; clarithromycin, 19.0%; levofloxacin, 38.1%; and metronidazole 38.1%). Thus, biofilm formation may increase the survival of H. pylori and its resistance to antibiotics. Biofilm-related antibiotic resistance should be evaluated with antibiotic susceptibility.

Matched MeSH terms: Helicobacter pylori/isolation & purification
Fulltext Functional dyspepsia

Ford AC, Mahadeva S, Carbone MF, Lacy BE, Talley NJ

Lancet, 2020 11 21;396(10263):1689-1702.
PMID: 33049222 DOI: 10.1016/S0140-6736(20)30469-4

Dyspepsia is a complex of symptoms referable to the gastroduodenal region of the gastrointestinal tract and includes epigastric pain or burning, postprandial fullness, or early satiety. Approximately 80% of individuals with dyspepsia have no structural explanation for their symptoms and have functional dyspepsia. Functional dyspepsia affects up to 16% of otherwise healthy individuals in the general population. Risk factors include psychological comorbidity, acute gastroenteritis, female sex, smoking, use of non-steroidal anti-inflammatory drugs, and Helicobacter pylori infection. The pathophysiology remains incompletely understood, but it is probably related to disordered communication between the gut and the brain, leading to motility disturbances, visceral hypersensitivity, and alterations in gastrointestinal microbiota, mucosal and immune function, and CNS processing. Although technically a normal endoscopy is required to diagnose functional dyspepsia, the utility of endoscopy in all patients with typical symptoms is minimal; its use should be restricted to people aged 55 years and older, or to those with concerning features, such as weight loss or vomiting. As a result of our incomplete understanding of its pathophysiology, functional dyspepsia is difficult to treat and, in most patients, the condition is chronic and the natural history is one of fluctuating symptoms. Eradication therapy should be offered to patients with functional dyspepsia who test positive for Helicobacter pylori. Other therapies with evidence of effectiveness include proton pump inhibitors, histamine-2 receptor antagonists, prokinetics, and central neuromodulators. The role of psychological therapies is uncertain. As our understanding of the pathophysiology of functional dyspepsia increases, it is probable that the next decade will see the emergence of truly disease-modifying therapies for the first time.

Matched MeSH terms: Helicobacter pylori/isolation & purification
Fulltext Commentary: changing aetiology of peptic ulcers

Goh KL, Chan WK

Aliment Pharmacol Ther, 2012 Aug;36(3):291-2; discussion 292-3.
PMID: 22747451 DOI: 10.1111/j.1365-2036.2012.05164.x
Matched MeSH terms: Helicobacter pylori/isolation & purification*
Fulltext High-dose rabeprazole-amoxicillin dual therapy and rabeprazole triple therapy with amoxicillin and levofloxacin for 2 weeks as first and second line rescue therapies for Helicobacter pylori treatment failures

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 pylori/isolation & purification
Fulltext Epidemiology of Helicobacter pylori infection and public health implications

Goh KL, Chan WK, Shiota S, Yamaoka Y

Helicobacter, 2011 Sep;16 Suppl 1:1-9.
PMID: 21896079 DOI: 10.1111/j.1523-5378.2011.00874.x

This review summarizes studies on the epidemiology and public health implications of Helicobacter pylori published in peer-reviewed journals from April 2010 through March 2011. Prevalence rates vary widely between different geographical regions and ethnic groups. An interesting study from the USA identified the degree of African ancestry as an independent predictor of H. pylori infection. Two studies have demonstrated early childhood as the period of transmission of infection and identified an infected sibling as an important risk factor. An oral-oral route of spread has been substantiated with several studies showing the presence of H. pylori in the oral cavity. Studies have shown the presence of H. pylori in drinking water and the role of poor living conditions and sanitation in H. pylori infection, supporting an oral-fecal route of spread. Screening for H. pylori as a gastric cancer pre-screening strategy has been described in Japan, and the importance of H. pylori eradication as a gastric cancer-prevention strategy has now been further emphasized in Japanese guidelines. Two studies have shown a decrease in the burden of dyspepsia and peptic ulcer disease with H. pylori eradication.

Matched MeSH terms: Helicobacter pylori/isolation & purification
Comparison of two 1-week low-dose omeprazole triple therapies--optimal treatment for Helicobacter pylori infection?

Goh KL, Parasakthi N, Chuah SY, Cheah PL, Lo YL, Chin SC

Aliment Pharmacol Ther, 1997 Dec;11(6):1115-8.
PMID: 9663838

OBJECTIVES: To determine and compare the efficacy and tolerability of two 1-week regimen comprising omeprazole, clarithromycin and amoxycillin or metronidazole in the eradication of Helicobacter pylori, and to determine the influence of bacterial resistance to metronidazole and clarithromycin on the outcome of treatment.
PATIENTS AND METHODS: Patients with unequivocal evidence of H. pylori infection based on culture, histology and rapid urease test of both antrum and corpus biopsies were recruited for the study. The study was a randomized, investigator-blind, comparative study. Patients received either omeprazole 20 mg o.m., clarithromycin 250 mg b.d. and amoxycillin 500 mg b.d. (OAC) or omeprazole 20 mg o.m., metronidazole 400 mg b.d. and clarithromycin 250 mg b.d. (OMC) for 1 week. Patients were assessed for successful eradication, which was defined as absence of bacteria in all tests (culture, histology and urease test on both antral and corpus biopsies), at least 4 weeks after completion of therapy.
RESULTS: Eighty-two patients were recruited for the study. Eradication rates on intention-to-treat analysis were--OAC: 36/41 (87.8%, 95% CI: 73.8, 95.9); OMC: 33/41 (80.5%, 95% CI: 65.1, 91.2). On per protocol analysis were--OAC: 36/40 (90%, 95% CI: 76.3, 97.2); OMC: 32/38 (84.2%, 95% CI: 68.7, 94.0). All side-effects encountered were mild and no patient discontinued treatment because of intolerance to medications. The most common side-effects were altered taste (OAC 31.7%, OMC 53.7%) and lethargy (OAC 14.6%, OMC 19.5%). Pre-treatment metronidazole resistance was encountered in 34/63 (54.0%) patients. No bacterial strains were found with primary resistance to clarithromycin. Metronidazole resistance did not significantly affect eradication rates. Emergence of resistance to clarithromycin was not seen post-therapy.
CONCLUSIONS: Both the OAC and the OMC regimens were convenient and well-tolerated treatments for H. pylori. However, eradication rates were lower than anticipated.

Matched MeSH terms: Helicobacter pylori/isolation & purification*
Campylobacter pylori infection: experience in a multiracial population

Goh KL, Peh SC, Wong NW, Parasakthi N, Puthucheary SD

J Gastroenterol Hepatol, 1990 5 1;5(3):277-80.
PMID: 2103410

Over a 15-month period, 399 patients with dyspepsia were investigated for the presence of Campylobacter pylori infection. Half of the patients (50.6%) had Campylobacter organisms in the antrum of the stomach. C. pylori was found in 96.1% of patients with histological changes of chronic active gastritis in the antrum. Of patients with duodenal and gastric ulcers, 87.8% and 87.5%, respectively, had Campylobacter organisms, as did 39.3% of patients with non-ulcer dyspepsia. C. pylori infection was most commonly found in Chinese and Indians. Although the prevalence of infection appeared to increase with age, there was an equal distribution amongst the sexes.

Matched MeSH terms: Helicobacter pylori/isolation & purification*
Draft genome sequences of Helicobacter pylori isolates from Malaysia, cultured from patients with functional dyspepsia and gastric cancer

Gunaletchumy SP, Teh X, Khosravi Y, Ramli NS, Chua EG, Kavitha T, et al.

J Bacteriol, 2012 Oct;194(20):5695-6.
PMID: 23012278

Helicobacter pylori is the main bacterial causative agent of gastroduodenal disorders and a risk factor for gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. The draft genomes of 10 closely related H. pylori isolates from the multiracial Malaysian population will provide an insight into the genetic diversity of isolates in Southeast Asia. These isolates were cultured from gastric biopsy samples from patients with functional dyspepsia and gastric cancer. The availability of this genomic information will provide an opportunity for examining the evolution and population structure of H. pylori isolates from Southeast Asia, where the East meets the West.

Matched MeSH terms: Helicobacter pylori/isolation & purification
Fulltext Helicobacter pylori infection, chronic corpus atrophic gastritis and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort: A nested case-control study

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 pylori infection and pancreatic cancer risk in western European populations. However, the suggested association between chronic corpus atrophic gastritis and pancreatic cancer risk warrants independent verification in future studies, and, if confirmed, further studies on the underlying mechanisms.

Matched MeSH terms: Helicobacter pylori/isolation & purification*
Prevalence and predictors of Helicobacter pylori infection in children and adults from the Penan ethnic minority of Malaysian Borneo

Huang SS, Hassan AK, Choo KE, Ibrahim MI, Davis TM

Am J Trop Med Hyg, 2004 Oct;71(4):444-50.
PMID: 15516641

To determine the prevalence of Helicobacter pylori antigen carriage in stool in the Penan ethnic minority in Malaysian Borneo, we studied 295 Penans 0.6-89.0 years of age from 1) the remote Limbang Division, 2) Mulu regional center, and 3) Belaga village. Overall, 37.7% of the subjects tested positive. Peak prevalence was reached by 10 years of age. There were no differences in age, sex, body mass index, and socioeconomic/domestic variables between antigen-positive and antigen-negative subjects. In a logistic regression analysis, subjects from Limbang were least likely to be antigen-positive (odds ratio [OR] = 0.23, 95% confidence interval [CI] = 0.12-0.44 versus other sites, P < 0.001). Availability of a flushing toilet was protective against H. pylori carriage (OR = 0.51, 95% CI = 0.27-0.95, P = 0.031). Infection with H. pylori among the Penan was less than reported in other low socioeconomic groups. The lowest prevalence in the most remote setting suggests that the infection has been a recent arrival in previously isolated communities.

Matched MeSH terms: Helicobacter pylori/isolation & purification*
Application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the study of Helicobacter pylori

Ilina EN, Borovskaya AD, Serebryakova MV, Chelysheva VV, Momynaliev KT, Maier T, et al.

Rapid Commun Mass Spectrom, 2010 Feb;24(3):328-34.
PMID: 20049887 DOI: 10.1002/rcm.4394

The characteristics of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry based investigation of extremely variable bacteria such as Helicobacter pylori were studied. H. pylori possesses a very high natural variability. Accurate tools for species identification and epidemiological characterization could help the scientific community to better understand the transmission pathways and virulence mechanisms of these bacteria. Seventeen clinical as well as two laboratory strains of H. pylori were analyzed by the MALDI Biotyper method for rapid species identification. Mass spectra collected were found containing 7-13 significant peaks per sample, and only six protein signals were identical for more than half of the strains. Four of them could be assigned to ribosomal proteins RL32, RL33, RL34, and RL36. The reproducible peak with m/z 6948 was identified as a histidine-rich metal-binding polypeptide by tandem mass spectrometry (MS/MS). In spite of the evident protein heterogeneity of H. pylori the mass spectra collected for a particular strain under several cultivations were highly reproducible. Moreover, all clinical strains were perfectly identified as H. pylori species through comparative analysis using the MALDI Biotyper software (Bruker Daltonics, Germany) by pattern matching against a database containing mass spectra from different microbial strains (n = 3287) including H. pylori 26695 and J99. The results of this study allow the conclusion that the MALDI-TOF direct bacterial profiling is suited for H. pylori identification and could be supported by mass spectra fragmentation of the observed polypeptide if necessary.

Matched MeSH terms: Helicobacter pylori/isolation & purification
Racial differences in Helicobacter pylori seroprevalence in Singapore: correlation with differences in peptic ulcer frequency

Kang JY, Yeoh KG, Ho KY, Guan R, Lim TP, Quak SH, et al.

J Gastroenterol Hepatol, 1997 Oct;12(9-10):655-9.
PMID: 9407329

The aim of this study was to determine, first, whether racial differences exist in the seroprevalence of Helicobacter pylori infection in Singapore, and second, whether these differences correlate with racial differences in peptic ulcer frequency. A commercial serological test for immunoglobulin (Ig)G antibody to H. pylori which was 90% sensitive and 83% specific in our population was used to screen 403 adult blood donors of Chinese, Malay and Indian origin, aged between 15-60 years. Serum specimens from 84 paediatric patients admitted to the Paediatrics Department, National University of Singapore, with non-gastroenterological illnesses were also tested. In all three races, seroprevalence of H. pylori increased with age. Indians have the highest prevalence of infection followed by Chinese and Malays. Peptic ulcer prevalences are known to be highest in Chinese, followed by Indians and Malays. The Malays have the lowest prevalence of H. pylori and peptic ulcer among the three races in Singapore. Indians have a higher prevalence of H. pylori antibodies but a lower frequency of peptic ulcer than the Chinese. Racial differences in peptic ulcer frequency between Chinese and Indians are not explained by the prevalence of H. pylori infection; other environmental or genetic factors may be involved.

Matched MeSH terms: Helicobacter pylori/isolation & purification*
Rapid diagnosis of Helicobacter pylori infection in gastric imprint smears

Kaur G, Madhavan M, Basri AH, Sain AH, Hussain MS, Yatiban MK, et al.

Southeast Asian J. Trop. Med. Public Health, 2004 Sep;35(3):676-80.
PMID: 15689086

The objective of this study was to determine the sensitivity, specificity, positive (PPV), and negative predictive values (NPV) of Diff-Quik-stained gastric imprint cytology smears in the detection of H. pylori compared with histology. Air-dried imprint smears of gastric biopsies from 150 patients were stained by the Diff-Quik method in the endoscopy suite and examined for H. pylori, providing results within minutes. The presence of inflammation and intestinal metaplasia were documented. The same biopsy was processed and stained with H&E and Warthin-Starry stains, and reviewed by a different pathologist blind to the imprint cytology results. Ninety-four of the 150 patients were male with a mean age of 50 years. Based on histology, the H. pylori prevalence was very low at 8%. The sensitivity and specificity of imprint cytology in the detection of H. pylori were 83.3% and 100%, respectively. The PPV and NPV were 100% and 98.6%, respectively. There were two false negatives and no false positives. A combination of imprint cytology and histology achieved 100% sensitivity. Imprint smears did not provide added value over histology with regards to inflammation and metaplasia. Gastric imprint smears stained with Diff-Quik method is a rapid, cheap, and reliable method for the detection of H. pylori and have their best results when complemented with histology.

Matched MeSH terms: Helicobacter pylori/isolation & purification*
Fulltext Comparative genomic analysis of Helicobacter pylori from Malaysia identifies three distinct lineages suggestive of differential evolution

Kumar N, Mariappan V, Baddam R, Lankapalli AK, Shaik S, Goh KL, et al.

Nucleic Acids Res, 2015 Jan;43(1):324-35.
PMID: 25452339 DOI: 10.1093/nar/gku1271

The discordant prevalence of Helicobacter pylori and its related diseases, for a long time, fostered certain enigmatic situations observed in the countries of the southern world. Variation in H. pylori infection rates and disease outcomes among different populations in multi-ethnic Malaysia provides a unique opportunity to understand dynamics of host-pathogen interaction and genome evolution. In this study, we extensively analyzed and compared genomes of 27 Malaysian H. pylori isolates and identified three major phylogeographic lineages: hspEastAsia, hpEurope and hpSouthIndia. The analysis of the virulence genes within the core genome, however, revealed a comparable pathogenic potential of the strains. In addition, we identified four genes limited to strains of East-Asian lineage. Our analyses identified a few strain-specific genes encoding restriction modification systems and outlined 311 core genes possibly under differential evolutionary constraints, among the strains representing different ethnic groups. The cagA and vacA genes also showed variations in accordance with the host genetic background of the strains. Moreover, restriction modification genes were found to be significantly enriched in East-Asian strains. An understanding of these variations in the genome content would provide significant insights into various adaptive and host modulation strategies harnessed by H. pylori to effectively persist in a host-specific manner.

Matched MeSH terms: Helicobacter pylori/isolation & purification
Fulltext Elucidation of the Metabolic Network of Helicobacter pylori J99 and Malaysian Clinical Strains by Phenotype Microarray

Lee WC, Goh KL, Loke MF, Vadivelu J

Helicobacter, 2017 Feb;22(1).
PMID: 27258354 DOI: 10.1111/hel.12321

Helicobacter pylori colonizes almost half of the human population worldwide. H. pylori strains are genetically diverse, and the specific genotypes are associated with various clinical manifestations including gastric adenocarcinoma, peptic ulcer disease (PUD), and nonulcer dyspepsia (NUD). However, our current knowledge of the H. pylori metabolism is limited. To understand the metabolic differences among H. pylori strains, we investigated four Malaysian H. pylori clinical strains, which had been previously sequenced, and a standard strain, H. pylori J99, at the phenotypic level.

Matched MeSH terms: Helicobacter pylori/isolation & purification

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