Resistotype of Helicobacter pylori isolates: the impact on eradication outcome.

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.

Ethnicity association of Helicobacter pylori virulence genotype and metronidazole susceptibility.

AIM: To characterise the cag pathogenicity island in Helicobacter pylori (H. pylori) isolates by analysing the strains' vacA alleles and metronidazole susceptibilities in light of patient ethnicity and clinical outcome. METHODS: Ninety-five H. pylori clinical isolates obtained from patients with dyspepsia living in Malaysia were analysed in this study. Six genes in the cagPAI region (cagE, cagM, cagT, cag13, cag10 and cag67) and vacA alleles of the H. pylori isolates were identified by polymerase chain reaction. The isolates' metronidazole susceptibility was also determined using the E-test method, and the resistant gene was characterised by sequencing. RESULTS: More than 90% of the tested isolates had at least one gene in the cagPAI region, and cag67 was predominantly detected in the strains isolated from the Chinese patients, compared with the Malay and Indian patients (P < 0.0001). The majority of the isolates (88%) exhibited partial deletion (rearrangement) in the cagPAI region, with nineteen different patterns observed. Strains with intact or deleted cagPAI regions were detected in 3.2% and 8.4% of isolates, respectively. The prevalence of vacA s1m1 was significantly higher in the Malay and Indian isolates, whereas the isolates from the Chinese patients were predominantly genotyped as vacA s1m2 (P = 0.018). Additionally, the isolates from the Chinese patients were more sensitive to metronidazole than the isolates from the Malay and Indian patients (P = 0.047). Although we attempted to relate the cagPAI genotypes, vacA alleles and metronidazole susceptibilities to disease outcome, no association was observed. The vacA alleles were distributed evenly among the strains with intact, partially deleted or deleted cagPAI regions. Interestingly, the strains exhibiting an intact cagPAI region were sensitive to metronidazole, whereas the strains with a deleted cagPAI were more resistant. CONCLUSION: Successful colonisation by different H. pylori genotypes is dependent on the host's genetic makeup and may play an important role in the clinical outcome.

Prevalence of Helicobacter pylori infection in epilepsy patients in a teaching hospital in Malaysia

Background & Objective: Helicobacter pylori infection has been associated with extradigestive diseases including epilepsy. The main aim of the study was to determine the prevalence of Helicobacter pylori using 13C urea breath test (UBT) in epilepsy patients in a teaching hospital in Malaysia and compared to control. Methods: The study subjects were epilepsy patients from the neurology clinic in a teaching hospital. The study was conducted from August 2010 to February 2011. The control consisted of healthy individuals matched for age and gender, not on any acid suppression medications and antibiotics. All subjects underwent UBT as per protocol. Variables such as age, race, household income, types of epilepsy, duration of epilepsy, number of antiepileptic drugs, prognosis were analysed. Good prognosis was defi ned as seizure free for 3 years. Results: Forty eight epilepsy patients and 47 control subjects were studied. Prevalence of H. pylori infection in the epilepsy patients was 37.5% (n=18) and was 36.2% (n=17) in control. There were signifi cantly more subjects in the epilepsy group with lower income. There were also more smokers in the epilepsy group but there was no association between smoking and positive UBT. Epilepsy patients with poor prognosis have a higher UBT positive rate compared to the good prognosis group (64.3% vs 35.7 %). However the difference was not statistically signifi cant. Conclusion: The prevalence of H. pylori infection in epilepsy patients is similar to that of the control in this study involving Malaysian subjects.