Prevalence of antibiotic resistance of Helicobacter pylori isolates in Estonia during 1995-2000 in comparison to the consumption of antibiotics used in treatment regimens

Clinical significance of various diagnostic techniques and emerging antimicrobial resistance pattern of Helicobacter Pylori from Gastric Biopsy Samples

BACKGROUND

There is no single technique that can meet the criteria in identification of Helicobacter pylori. The diagnosis is important asantimicrobial resistance is frequently observed and associated with treatment failure. The present study was conducted to evaluate diagnostic tests for identification of H pylori and to assess their antimicrobial resistance pattern.

MATERIALS AND METHODS

Biopsies of gastric tissue from 200 patients with disorders of the upper gastrointestinal tract were studied for detection of H pylori by various methods like culture, H and E staining and urease test. Antimicrobial susceptibility testing was carried out by Kirby Bauer's disc diffusion method.

RESULTS

Out of 200 patients, H pylori was detected by rapid urease test, H and E staining and culture in 26.5%, 14.5% and 2.5% cases respectively. H and E was taken as the gold standard. Sensitivity of urease test was 76.6% and of culture 13.3%. Specificity of urease was 81.7% in comparison with culture which showed 99.4% specificity. Metronidazole (05) showed high level of resistance followed by amoxicillin (03) and norfloxacillin (03). Tetracycline, erythromycin, levofloxacin and cotrimoxazole showed one resistance each to H pylori.

CONCLUSION

H and E is taken as the gold standard according to CDC. Urease test is a better screening procedure than culture. H pylori resistance to metronidazole in our zone was highest. This is due to general and extensive use of metronidazole for other infectious diseases. Our study suggests need for a systematic approach to determine antibiogram of the strains before considering the drug regimens.

Emerging antimicrobial resistance pattern of Helicobacter pylori in central Gujarat

BACKGROUND

Antimicrobial resistance is a growing problem in H. pylori treatment. The study was intended to evaluate the prevalence of resistance amongst 80 H.pylori isolates cultured from biopsy taken during routine endoscopies in 2008-2011.

MATERIALS AND METHODS

855 gastro duodenal biopsies were collected and cultured on H.pylori selective medium (containing Brucella agar and Columbia agar (Hi media), with Skirrow's supplement (antibiotic supplement) and 7% human blood cells). H.pylori was isolated from 80 specimens. The antimicrobial susceptibility of H.pylori isolates was carried out by the Kirby Bauer technique against metronidazole (5 µg), clarithromycin (15 µg), ciprofloxacin (5 µg), amoxicillin (10 µg), tetracycline (30 µg), erythromycin (15 µg), levofloxacin (5 µg), and furazolidone (50 µg) (Sigma- Aldrich, MO).

RESULTS

83.8% isolates were resistant to metronidazole, 58.8% were resistant to Clarithromycin 72.5% were resistant to Amoxicillin, 50% to Ciprofloxacin and 53.8% to tetracycline. furazolidone, erythromycin and Levofloxacin showed only 13.8% resistance to H.pylori. Multi drug resistance with metronidazole+clarithromycin+tetracycline was 85%. For all the drugs Antimicrobial resistance rate was found higher in males compare to females. Metronidazole and amoxicillin resistance was found noteworthy in patients with duodenal ulcer (p=0.018), gastritis (P=0.00), and in reflux esophagitis (P=0.00). clarithromycin and tetracycline resistance was suggestively linked with duodenitis (P=0.018), while furazolidone, erythromycin and levofloxacin showed excellent sensitivity in patients with duodenitis (P value--0.018), gastritis (P=0.00) and reflux esophagitis (P=0.00). Resistance with metronidazole (P=0.481), clarithromycin (P=0.261), amoxicillin (P=0.276), tetracycline (P=0.356), ciprofloxacin (P=0.164) was not correlated well with Age-group and Gender of the patients.

CONCLUSION

A very high percentage of patients were infected with metronidazole and clarithromycin resistant strains. The use of antibiotics for other indications seems to be the major risk factor for the development of primary resistance. High incidence should alarm the gastroenterologist while prescribing the eradication regimen.

The Primary Resistance of Helicobacter pylori in Taiwan after the National Policy to Restrict Antibiotic Consumption and Its Relation to Virulence Factors-A Nationwide Study

Objective

The Taiwan Government issued a policy to restrict antimicrobial usage since 2001. We aimed to assess the changes in the antibiotic consumption and the primary resistance of H. pylori after this policy and the impact of virulence factors on resistance.

Methods

The defined daily dose (DDD) of antibiotics was analyzed using the Taiwan National Health Insurance (NHI) research database. H. pylori strains isolated from treatment naïve (N=1395) and failure from prior eradication therapies (N=360) from 9 hospitals between 2000 and 2012 were used for analysis. The minimum inhibitory concentration was determined by agar dilution test. Genotyping for CagA and VacA was determined by PCR method.

Results

The DDD per 1000 persons per day of macrolides reduced from 1.12 in 1997 to 0.19 in 2008, whereas that of fluoroquinolones increased from 0.12 in 1997 to 0.35 in 2008. The primary resistance of amoxicillin, clarithromycin, metronidazole, and tetracycline remained as low as 2.2%, 7.9%, 23.7%, and 1.9% respectively. However, the primary levofloxacin resistance rose from 4.9% in 2000–2007 to 8.3% in 2008–2010 and 13.4% in 2011–2012 (p=0.001). The primary resistance of metronidazole was higher in females than males (33.1% vs. 18.8%, p<0.001), which was probably attributed to the higher consumption of nitroimidazole. Neither CagA nor VacA was associated with antibiotic resistance.

Conclusions

The low primary clarithromycin and metronidazole resistance of H. pylori in Taiwan might be attributed to the reduced consumption of macrolides and nitroimidazole after the national policy to restrict antimicrobial usage. Yet, further strategies are needed to restrict the consumption of fluoroquinolones in the face of rising levofloxacin resistance.

Management of Helicobacter pylori-related diseases in the Baltic States

Helicobacter pylori infection has been recognized as the main trigger of stomach-related diseases. The huge variation in H. pylori infection patterns across the globe requires targeted research and close monitoring of this infection in different regions. The Baltic countries have witnessed enormous changes in socioeconomic conditions in the last years. Evolution of H. pylori infection and related diseases has been a key interest of gastroenterology centers in the Baltic States over the last two decades, translating into up-to-date scientific data that are valuable locally and on the European level. The East-West gradient in the prevalence of H. pylori infection is still evident in the Baltic countries, but the gap is becoming smaller, and similar trends are expected for the coming years. Clarithromycin-based triple therapy remains the first-line treatment of H. pylori in the region; however, careful monitoring of resistance rates in the future remains highly relevant, though routine resistance testing is not available in all the countries. A high prevalence of gastric cancer is still notable in the Baltic States; nevertheless, a steady decline in gastric cancer incidence in Lithuania, Latvia and Estonia is present and expected to be continuing during the coming decades. Currently, H. pylori-related diseases still constitute a substantial part of gastroenterologists' workload in the region. This paper reviews epidemiological, diagnostic, treatment as well as basic research trends on H. pylori infection and related diseases in the Baltic States during the last two decades.

Review article: the effectiveness of standard triple therapy for Helicobacter pylori has not changed over the last decade, but it is not good enough

BACKGROUND  A decrease in the Helicobacter pylori eradication rate after standard triple therapy has been suggested in recent years. AIM  To assess the efficacy of standard triple therapy in the eradication of H. pylori through an epidemiological analysis of all published Spanish trials. A secondary aim was to review the prevalence of clarithromycin resistance in Spain. METHODS  Articles on H. pylori eradication in Spain published in peer-reviewed journals were identified through MEDLINE searches. Studies that included a triple therapy consisting of any proton pump inhibitor with clarithromycin (500 mg b.d.) and amoxicillin (1 g b.d.) for up to 14 days were selected. Spanish studies evaluating the prevalence of clarithromycin resistance were also reviewed. Meta-analysis was performed using the generic inverse variance method. RESULTS The pooled eradication rates by year from Spanish studies evaluating the efficacy of the standard triple regimen revealed a relatively constant rate over the years. Overall, the analysis of the 32 studies (4727 patients) showed a mean H. pylori cure rate of 80% (95% CI = 77-82%) by intention-to-treat and 83% (81-86%) by per-protocol. When only peptic ulcer disease or 7-day regimens were considered, results were similar. Based on 13 studies (3293 patients), mean clarithromycin resistance rate was 8% (5-10%). CONCLUSION Although a decrease in the H. pylori eradication rate after triple therapy has been suggested in recent years, cure rates with this regimen did not change in Spain between 1997 and 2008. However, this by no means indicates that the efficacy of standard triple therapy in Spain is acceptable, as it has been calculated to be around only 80%. Therefore, it is evident that new strategies to improve first-line treatment are urgently needed.

High Helicobacter pylori resistance to metronidazole but zero or low resistance to clarithromycin, levofloxacin, and other antibiotics in Malaysia

OBJECTIVE

Bacterial resistance to antibiotics is the single most important determinant of treatment success. The objective of this study was to determine the prevalence of Helicobacter pylori resistance to clarithromycin, amoxicillin, metronidazole, tetracycline, levofloxacin, rifabutin, and furazolidone in our local bacterial strains.

METHODS

Samples from consecutive ninety patients were obtained for culture and sensitivity testing. Resistance to individual antibiotics were tested using the E-test and MIC(90) read from the strips. Resistance to rifampicin and nitrofurantoin were used as a surrogate for rifabutin and furazolidine.

RESULTS

There was a high prevalence of resistance to metronidazole 68/90 (75.5%). No male (34/45 (75.5%) versus female (35/45 (77.7%) difference in frequency of metronidazole resistance was noted (p = 1.000). There was zero resistance (0) to clarithromycin, levofloxacin, amoxicillin, and nitrofurantoin/furazolidone. Resistance to rifampicin/rifabutin was for breakpoints of 1 and 4 μg/mL of 14.4 and 2.2% respectively.

CONCLUSIONS

Although there was high bacterial resistance to metronidazole, the absence of resistance particularly to the key antibiotics used in H. pylori eradication therapy: clarithromycin and levofloxacin is reassuring to note. Continued monitoring of antibiotic resistance should be carried out.

Clarithromycin resistance and efficacy of clarithromycin-containing triple eradication therapy for Helicobacter pylori infection in type 2 diabetes mellitus patients

BACKGROUND

Antimicrobial resistance in Helicobacter pylori infection is an important factor leading to failure of therapy. The aim of this study was to determine the eradication rate of H pylori in type 2 diabetes mellitus and to assess the effect of clarithromycin resistance on H pylori eradication.

METHOD

Fifty-six consecutive patients with type 2 diabetes mellitus and 58 age- and sex-matched control patients were included in the study. H pylori infection was assessed by a rapid urease test and histopathological examination of biopsy specimens. Biopsies were also taken for antibiotic susceptibility testing. All enrolled patients were treated with triple therapy consisting of clarithromycin, amoxicillin, and pantoprazole for 14 days. C-13 urea breath test was performed 6 weeks after completing the triple therapy to assess eradication and associated point mutations using real-time polymerase chain reaction (PCR).

RESULTS

H pylori was eradicated in 42.9% of diabetic patients and 79.3% of control patients, (P < 0.05). In type 2 diabetes mellitus patients, clarithromycin resistance was 64.3% (36/56), while in the control group, clarithromycin resistance was 35.7% (20/58) (P < 0.05). H pylori was eradicated in 14 (70%) of the 20 clarithromycin-susceptible diabetic patients and in only 10 (27.8%) of the 36 clarithromycin-resistant diabetic patients.

CONCLUSION

The H pylori eradication rate was significantly lower and clarithromycin resistance was significantly higher in type 2 diabetics. Alternative and new treatment protocols and antibiotic susceptibility testing are needed to achieve successful eradication rates.

Helicobacter pylori eradication has the potential to prevent gastric cancer: a state-of-the-art critique

Helicobacter pylori infection continues to play a key role in gastric diseases. Colonization of the gastric mucosa with the bacterium invariably results in the development of chronic gastritis and subsets of patients have a progression of the chronic gastritis to either ulcer or cancer. Epidemiological evidence indicates that the proportion of all gastric cancers attributable to H. pylori infection, and hence potentially preventable upon elimination of this risk factor, is somewhere in the range of 60% to 90%. This portends significant benefit in terms of morbidity and mortality, not least in populations with high prevalence of H. pylori infection coupled with high incidence of gastric cancer. The effect of prophylactic H. pylori eradication on gastric cancer incidence in humans remains unknown, however. Results from randomized trials are eagerly awaited, but availability of strong conclusive results may take many years. A growing number of studies show considerable variation in risk for gastric cancer development, depending on H. pylori strain type and the genetic predisposition of the host. There is also a remote possibility that elimination of the infection may have adverse health implications (e.g., antibiotic resistance), and therefore "simple" risk stratification and targeted chemoprevention is required. Based on "in depth" evidence presented at this workshop, the majority of the scientific task force favored a search-and-treat strategy in first-degree relatives of gastric cancer patients and an overwhelming majority felt that a more general screen-and-treat strategy should be focused in the first instance on a population with a high incidence of H. pylori-associated diseases.

Tetracycline-resistant clinical Helicobacter pylori isolates with and without mutations in 16S rRNA-encoding genes

Tetracycline-resistant Helicobacter pylori strains have been increasingly reported worldwide. However, only a small number of tetracycline-resistant strains have been studied with regard to possible mechanisms of resistance and those studies have focused on mutations in the tetracycline binding sites of 16S rRNA-encoding genes. We here report studies of 41 tetracycline-resistant H. pylori strains (tetracycline MICs, 4 to 32 microg/ml) from North America (n = 12) and from East Asia (n = 29). DNA sequence analyses of 16S rRNA-encoding genes revealed that 22 (54%) of the resistant isolates carried one of five different single-nucleotide substitutions (CGA, GGA, TGA, AGC, or AGT) at the putative tetracycline binding site (AGA(965-967)). Single-nucleotide substitutions were associated with reduced ribosomal binding and with slightly increased tetracycline MICs (1 to 2 microg/ml). The 19 tetracycline-resistant isolates with no detectable mutations in the tetracycline binding site had normal tetracycline-ribosome binding. All tetracycline-resistant isolates, including those with and those without mutations in the tetracycline binding site, showed decreased accumulation of tetracycline. These results suggest that tetracycline resistance is multifactorial, involving alterations both in ribosomal binding and in membrane permeability.

The diagnostic value of endoscopy and Helicobacter pylori tests for peptic ulcer patients in late post-treatment setting

Background

Guidelines for management of peptic ulcer patients after the treatment are largely directed to detection of H. pylori infection using only non-invasive tests. We compared the diagnostic value of non-invasive and endoscopy based H. pylori tests in a late post-treatment setting.

Methods

Altogether 34 patients with dyspeptic complaints were referred for gastroscopy 5 years after the treatment of peptic ulcer using a one-week triple therapy scheme. The endoscopic and histologic findings were evaluated according to the Sydney classification. Bacteriological, PCR and cytological investigations and ¹³C-UBT tests were performed.

Results

Seventeen patients were defined H. pylori positive by ¹³C-UBT test, PCR and histological examination. On endoscopy, peptic ulcer persisted in 4 H. pylori positive cases. Among the 6 cases with erosions of the gastric mucosa, only two patients were H. pylori positive. Mucosal atrophy and intestinal metaplasia were revealed both in the H. pylori positive and H. pylori negative cases. Bacteriological examination revealed three clarithromycin resistant H. pylori strains. Cytology failed to prove validity for diagnosing H. pylori in a post-treatment setting.

Conclusions

In a late post-treatment setting, patients with dyspepsia should not be monitored only by non-invasive investigation methods; it is also justified to use the classical histological evaluation of H. pylori colonisation, PCR and bacteriology as they have shown good concordance with ¹³C-UBT. Moreover, endoscopy and histological investigation of a gastric biopsy have proved to be the methods with an additional diagnostic value, providing the physician with information about inflammatory, atrophic and metaplastic lesions of the stomach in dyspeptic H. pylori positive and negative patients. Bacteriological methods are suggested for detecting the putative antimicrobial resistance of H. pylori, aimed at successful eradication of infection in persistent peptic ulcer cases.

Infection à Helicobacter pylori et résistance aux antibiotiques

PURPOSE

Seven days triple therapies combining a proton pump inhibitor (PPI) and 2 antimicrobial agents (clarithromycin [C], amoxicillin [A], metronidazole [M]), are recommended for the treatment of Helicobacter pylori infection. The eradication failures have increased these last years, particularly in France (about 30%). They are essentially related to the development of antimicrobial agents resistance, mainly concerning macrolides and nitro-imidazoles.

CURRENT KNOWLEDGE AND KEY POINTS

Primary resistance to clarithromycin is variable, but reaching now about 10% throughout the world and about 20% in France. It reduces the eradication success rate at 25%. The secondary resistance is very high, contra-indicating the use of clarithromycin in second line regimens. Primary resistance to amoxicillin has recently appeared, but remains very low until now, less than 2%, as the tetracyclin (T) resistance. Primary resistance to metronidazole is 3 times higher than macrolides resistance, but its determination is less accurate. Metronidazole resistance reduces eradication rate of about 25%, leading to the use of metronidazole in second line therapy, in increasing the triple therapy duration at 14 days (PPI-A-M), or in combination with quadruple therapy (Bismuth-PPI-T-M). Other rescue-treatments are efficacious, based on ranitidine bismuth citrate combined regimens or on rifabutine (R) based regimens (PPI-A-R).

FUTURE PROSPECTS AND PROJECTS

The recent knowledge of the mutations mainly responsible for H. pylori resistance to antimicrobial agents now allows the development of detection methods based on the study of bacterial DNA. These methods have been validated for clarithromycin and should favour in the near future the determination of resistance by the use of biopsy culture or directly on the gastric biopsy.

Prevalence of Helicobacter pylori resistance to clarithromycin and metronidazole determined by 23S ribosomal RNA and rdxA gene analyses in Hiroshima, Japan

BACKGROUND AND AIMS

Resistance to antibiotics in Helicobacter pylori is increasing and becoming a serious problem in eradication treatment of H. pylori. The prevalence of H. pylori infections that are resistant to clarithromycin, metronidazole, or both were determined in H. pylori isolates in Hiroshima, Japan.

METHODS

Sixty Japanese patients with H. pylori infection were collected between 1999 and 2000. To detect the resistance to clarithromycin and metronidazole, mutations of the 23S ribosomal RNA (rRNA) and rdxA genes that are responsible for resistance in H. pylori, were examined by direct sequencing analysis.

RESULTS

Resistance to clarithromycin and metronidazole was detected in 12 (20.0%) and nine (15.0%) of the patients, respectively. Dual resistance to clarithromycin and metronidazole was detected in five (8.3%) patients.

CONCLUSION

These results indicate that the relatively high prevalence of the dual resistance in H. pylori isolates may need special attention and new therapeutic approaches in Japan.