The Hungarian epidemiology of clarithromycin resistance in Helicobacter pylori infection

Benign and malignant gastroduodenal diseases associated with Helicobacter pylori: a narrative review and personal remarks in 2018

The subject of Helicobacter pylori continues to elicit worldwide interest in many research fields. Epidemiological data suggest that the prevalence of the infection is decreasing in Western/developed countries and even in some developing regions, but this is masked by the high prevalence in the most populous regions. Chronic gastritis, caused invariably by the bacterium, was again classified in Kyoto and Helicobacter pylori-associated gastritis was included as a distinct entity. The prevalence of peptic ulcers is decreasing, but bleeding ulcers are a challenging problem, with stable mortality levels even in the endoscopic era. With the extended use of endoscopy, gastric polyps (GP) have become more prevalent: some are associated with the infection, some are not. Autoimmune and Helicobacter-induced gastritis can share common pathogenetic mechanisms. Gastric cancer (GC) is ranked highly on mortality lists worldwide. Its surgical treatment has registered some progress though. Little, if any improvement has been achieved in the medical treatment of advanced GC. With proper organization, GC seems a preventable disease. In spite of many guidelines, the Pan-European registry of Helicobacter pylori management shows that eradication rates obtained in many places are suboptimal. A new therapeutic regimen was compiled with promising pilot results. The results obtained with vonaprazan are limited to Asia. New avenues of both antibiotic and non-antibiotic treatments are expected to accelerate the eradication of this ulcerogenic and carcinogenic bacterium.

Standard Triple Therapy versus Sequential Therapy in Helicobacter pylori Eradication: A Double-Blind, Randomized, and Controlled Trial

Aim. To compare 10-day standard triple therapy versus sequential therapy as first-line treatment in patients infected with H. pylori. Methods. One hundred H. pylori positive patients (diagnosed by rapid urease test and histology), with average age of 47.2, M/F = 28/72, were randomized to receive either standard triple treatment (TT) as follows: lansoprazole 30 mg, clarithromycin 500 mg, and amoxicillin 1 g, b.i.d. for ten days, or sequential treatment (ST) as follows: lansoprazole 30 mg, amoxicillin and placebo 1.0 g b.i.d for the first five days, followed by lansoprazole 30 mg, clarithromycin 500 mg, and tinidazole 500 mg b.i.d, for the remaining five days. Eradication rates were determined 60 days after treatment by urease, histology, or ¹³C-urea breath test. Results. In intention to treat (ITT) analysis, the rate of H. pylori eradication in the TT and ST groups was the same for both regimens as follows: 86% (43/50), 95% CI 93,3 to 73.4%. In Per protocol (PP) analysis, the rate of H. pylori eradication in the TT and ST groups was 87.8% (43/49), 95% CI 94,5 to 75.3% and 89.6% (43/48), 95% CI 95,8 to 77.3%, respectively. Conclusions. In Brazil, standard triple therapy is as equally effective as sequential therapy in eradicating Helicobacter pylori patients. This study was registered under Clinical Trials with number ISRCTN62400496.

Geographic map and evolution of primary Helicobacter pylori resistance to antibacterial agents

Antibiotic resistance in Helicobacter pylori is the major cause of eradication failure. Primary H. pylori susceptibility patterns, however, are becoming less predictable. Currently, high (> or =20%) clarithromycin resistance rates have been observed in the USA and in developed countries in Europe and Asia, while the highest (> or =80%) metronidazole-resistance rates have been reported in Africa, Asia and South America. Primary quinolone-resistance rates of 10% or more have already been reported in developed countries in Europe and Asia. Primary amoxicillin resistance has been low (0 to <2%) in Europe but higher (6-59%) in Africa, Asia and South America. Similarly, tetracycline resistance has been absent or low (<5%) in most countries and higher (9-27%) in Asia and South America. The increasing clarithromycin and quinolone resistance, and multidrug resistance detected in 0 to less than 5% in Europe and more often (14.2%) in Brazil are worrying. Growing resistance often parallels national antibiotic consumption and may vary within patient groups according to the geographic region, patient's age and sex, type of disease, birthplace, other infections and other factors. The geographic map and evolution of primary H. pylori resistance are clinically important, should be considered when choosing eradication regimens, and should be monitored constantly at national and global levels in an attempt to reach the recently recommended goal of eradication of more than 95%.

Enzymic colorimetry-based DNA chip: a rapid and accurate assay for detecting mutations for clarithromycin resistance in the 23S rRNA gene of Helicobacter pylori

Macrolide drugs, such as clarithromycin (CAM), are a key component of many combination therapies used to eradicate Helicobacter pylori. However, resistance to CAM is increasing in H. pylori and is becoming a serious problem in H. pylori eradication therapy. CAM resistance in H. pylori is mostly due to point mutations (A2142G/C, A2143G) in the peptidyltransferase-encoding region of the 23S rRNA gene. In this study an enzymic colorimetry-based DNA chip was developed to analyse single-nucleotide polymorphisms of the 23S rRNA gene to determine the prevalence of mutations in CAM-related resistance in H. pylori-positive patients. The results of the colorimetric DNA chip were confirmed by direct DNA sequencing. In 63 samples, the incidence of the A2143G mutation was 17.46 % (11/63). The results of the colorimetric DNA chip were concordant with DNA sequencing in 96.83 % of results (61/63). The colorimetric DNA chip could detect wild-type and mutant signals at every site, even at a DNA concentration of 1.53×102 copies μl−1. Thus, the colorimetric DNA chip is a reliable assay for rapid and accurate detection of mutations in the 23S rRNA gene of H. pylori that lead to CAM-related resistance, directly from gastric tissues.

Evaluation of clinical and socio-demographic risk factors for antibacterial resistance of Helicobacter pylori in Bulgaria

The aim of this study was to assess the clinical and socio-demographic risk factors for primary Helicobacter pylori antibacterial resistance. In total, 266 consecutive H. pylori strains, from untreated symptomatic adult patients who answered a questionnaire, were evaluated. Strain susceptibility to amoxicillin, metronidazole, clarithromycin and tetracycline was tested by a breakpoint susceptibility test. Metronidazole resistance was found in fewer (17.0 %) peptic ulcer patients than in non-ulcer subjects (28.3 %, P=0.037), as well as in fewer patients born in villages (12.7 %) than in those born in towns (27.6 %, P=0.016). Clarithromycin resistance varied from 8.8 to 23.4 % (P=0.009) within the hospital centres. The highest clarithromycin resistance rate was found in hospital centre A (23.4 %) compared to other centres (12.9 %, P=0.041). The factors sex, age, symptom duration, non-steroidal anti-inflammatory drug use, diabetes, type of profession and educational level were not associated with H. pylori resistance. Logistic regression revealed that the risk factors for metronidazole resistance were non-ulcer disease [odds ratio (OR) 1.95, 95 % confidence interval (95 % CI) 1.04-3.65] and a birthplace of a town (OR 2.64, 95 % CI 1.18-5.93). The hospital centre may be a risk factor (OR 2.07, 95 % CI 1.02-4.21) for clarithromycin resistance but further studies are required to verify this suggestion. In conclusion, the knowledge of the risk factors for H. pylori resistance to antibacterials could facilitate the treatment choice for H. pylori eradication.

Liquid culture medium for the rapid cultivation of Helicobacter pylori from biopsy specimens

The goal of this study was to develop a liquid culture medium for the rapid isolation, cultivation, identification and subsequent antibiotics susceptibility testing of Helicobacter pylori directly from biopsy specimens. Five liquid media were tested: Ham's F-12, Brucella broth, tryptic soybroth, brain heart infusion broth and Mueller-Hinton broth. After optimisation of the medium, it was applied in order to investigate biopsy samples from 150 patients with gastro-duodenal disorders and compared with traditional culture methods, microscopy and an H. pylori-specific TaqMan real-time polymerase chain reaction (PCR). The most reliable and rapid growth of H. pylori, even at a small inoculum size, was obtained in Ham's F-12 medium with 5% horse serum. The developed system allowed the primary isolation of H. pylori in clinical samples and provided 87% sensitivity and 100% specificity.