Posttreatment 13C-urea breath test is predictive of antimicrobial resistance to H. pylori after failed therapy

Diagnostic Methods of Helicobacter pylori Infection for Epidemiological Studies: Critical Importance of Indirect Test Validation

Among the methods developed to detect H. pylori infection, determining the gold standard remains debatable, especially for epidemiological studies. Due to the decreasing sensitivity of direct diagnostic tests (histopathology and/or immunohistochemistry [IHC], rapid urease test [RUT], and culture), several indirect tests, including antibody-based tests (serology and urine test), urea breath test (UBT), and stool antigen test (SAT) have been developed to diagnose H. pylori infection. Among the indirect tests, UBT and SAT became the best methods to determine active infection. While antibody-based tests, especially serology, are widely available and relatively sensitive, their specificity is low. Guidelines indicated that no single test can be considered as the gold standard for the diagnosis of H. pylori infection and that one should consider the method's advantages and disadvantages. Based on four epidemiological studies, culture and RUT present a sensitivity of 74.2–90.8% and 83.3–86.9% and a specificity of 97.7–98.8% and 95.1–97.2%, respectively, when using IHC as a gold standard. The sensitivity of serology is quite high, but that of the urine test was lower compared with that of the other methods. Thus, indirect test validation is important although some commercial kits propose universal cut-off values.

Probiotics improve efficacy and tolerability of triple therapy to eradicate Helicobacter pylori: a meta-analysis of randomized controlled trials

OBJECTIVE

Gastric colonization by Helicobacter pylori is linked to a host of diseases, but eradication rates have declined in recent years. Some experimental studies suggest that probiotics may inhibit growth of H. pylori. This investigation was conducted to assess the impact of probiotics on both efficacy and tolerability of triple therapy to eradicate H. pylori.

METHODS

PubMed, Web of Science, and the Cochrane Collaboration were searched for relevant articles published through August 31, 2014. All analytics relied on commercially available software (Stata 11).

RESULTS

Twenty-three studies (N = 3900) qualified for meta-analysis. Pooled H. pylori eradication rates for triple therapy used alone and with added probiotics were 1464/2026 (72.26%; 95% CI, 67.66%-74.13) and 1513/1874 (80.74%; 95% CI, 74.68%-82.76%), respectively (odds ratio [OR] = 0.58; 95% CI, 0.50-0.68). Loss of appetite was similar in both groups (OR = 0.94; 95% CI, 0.61-1.45), but most adverse events (nausea, diarrhea, epigastric pain, vomiting, taste distortion, and skin rash) were mitigated through addition of probiotics. Publication bias was not evident, as indicated by Begg's and Egger's tests.

CONCLUSIONS

Probiotics may improve the efficacy of triple therapy in eradicating gastric H. pylori and alleviate most treatment-related adverse events.

Taking your breath away: metabolomics breathes life in to personalized medicine

Breath-based metabolomics (breathomics) is an exciting developing area of biotechnology that centers on the capture, identification, and quantification of volatile organic compound (VOC) patterns in human breath and their utilization as tools in the diagnosis of a broad spectrum of medical problems. With the age of personalized medicines demanding rapid bespoke diagnosis and treatment, this area of molecular diagnostics is beginning to see an upsurge in biotechnological advancement. Here, we discuss recent improvements and directions in the development of breath VOC analysis and diagnosis platforms that offer the potential for disease biomarker discovery and disease prognosis.

A review of rescue regimens after clarithromycin-containing triple therapy failure (for Helicobacter pylori eradication)

INTRODUCTION

Helicobacter pylori infection is generally treated with therapies that include a proton pump inhibitor (PPI) and, at least, two antibiotics being clarithromycin one of the most used. Antibiotic resistance, mainly to clarithromycin, seems to be increasing in many geographical areas, and this factor is considered a main cause leading to a treatment failure when the later therapies contain this antibiotic again. As clarithromycin is a key antibiotic in the eradication of H. pylori, the election of the rescue treatment is a matter of debate.

AREAS COVERED

The aim of this study is to systematically review the efficacy of the second-line rescue therapies after the failure of a first-line clarithromycin-containing regimen, and to link this information with the previous first-line treatment. Also, authors performed meta-analyses and inverse variance analyses with studies that met the inclusion criteria: first-line treatment must specify type and dosage; diagnosis and eradication confirmation must be performed by generally accepted tests; and second-line treatment must not be assigned depending on the antibiotic susceptibility or resistance.

EXPERT OPINION

In a routine clinical practice setting, the most adequate second-line treatment consists in a 10-day regimen of levofloxacin- amoxicillin-PPI given twice daily, unless regional or new data show high quinolone resistance. Other good options are the bismuth quadruple regimen and a metronidazole-amoxicillin-PPI therapy.

Meta-analysis of the efficacy and safety of Lactobacillus-containing and Bifidobacterium-containing probiotic compound preparation in Helicobacter pylori eradication therapy

GOALS

To meta-analyze whether Lactobacillus-containing and Bifidobacterium-containing probiotic compound preparation could improve Helicobacter pylori (H. pylori) eradication rates and reduce side effects.

BACKGROUND

There have been several studies demonstrating that Lactobacillus and Bifidobacterium species have an inhibitory effect on H. pylori. The application of probiotics in clinical practice is more often in the form of Lactobacillus-containing and Bifidobacterium-containing probiotic compound preparation.

STUDY

We included all parallel controlled trials comparing Lactobacillus-containing and Bifidobacterium-containing probiotic compound preparation supplementation or not during H. pylori eradication therapy in meta-analysis. Statistical analysis was performed with the Stata version 11.0 software. Subgroup analysis and sensitivity analysis were also performed.

RESULTS

Ten clinical trials were included in our meta-analysis. Eradication odds ratio (OR) was available for 1469 patients (708 in the probiotics supplementation group and 761 in the control group). The pooled OR by intention-to-treat analysis and by per-protocol analysis in the probiotics supplementation versus without probiotics was 2.066 [95% confidence interval (CI), 1.398-3.055] and 2.321 (95% CI, 1.715-3.142), respectively. The pooled OR of incidence of total side effects was significantly decreased in the probiotics supplementation group (OR=0.305; 95% CI, 0.117-0.793) by the random model without significant publication bias.

CONCLUSIONS

Lactobacillus-containing and Bifidobacterium-containing probiotic compound preparation during initial H. pylori eradication therapy in the adult may have beneficial effects on eradication rate and incidence of total side effects.

Helicobacter pylori antibiotic resistance and [13C]urea breath test values

A correlation between delta over baseline (DOB) values of the [(13)C]urea breath test (UBT) and Helicobacter pylori clarithromycin resistance has been reported, suggesting a possible predictive role of UBT in therapeutic outcome. However, available data are limited and conflicting. This study aimed to clarify this issue, assessing the possible relationship between H. pylori resistance towards different antibiotics (clarithromycin, metronidazole and levofloxacin) and UBT values. The data showed similar DOB values between susceptible and resistant strains for clarithromycin (46.9+/-32.3 vs 45.7+/-30.6; P=0.8), metronidazole (46.4+/-29.6 vs 47.4+/-37.9; P=0.8), and levofloxacin (45.0+/-30.2 vs 54.2+/-38.4; P=0.08). Likewise, comparable DOB values were observed between susceptible and multidrug-resistant strains (45.4+/-29.6 vs 54.8+/-44.8; P=0.1). In conclusion, our data failed to find a significant correlation between UBT values and H. pylori antibiotic resistance.

Interpretation of the 13C-urea breath test in the choice of second- and third-line eradication of Helicobacter pylori infection

BACKGROUND

The urea breath test (UBT) is one of the most accurate methods of assessing Helicobacter pylori status. The predictive value of the test is, however, uncertain. This study was a serial, prospective analysis of the change over time of UBT values after first-, second- and third-line treatments of patients with failed eradication therapy.

METHODS

One hundred thirty-four duodenal ulcer patients with persisting H. pylori infection after first-line triple therapy were enrolled in a cross-over manner to receive either pantoprazole (40 mg twice daily), amoxicillin (1000 mg twice daily), and clarithromycin (500 mg) or ranitidine bismuth citrate (400 mg twice daily), metronidazole (250 mg twice daily), and clarithromycin (500 mg twice daily) for 7 days. Forty-one patients with failed second-line treatment were randomized to receive third-line quadruple therapies with pantoprazole + amoxicillin and tetracycline (500 mg four times daily) and either nitrofurantoin (100 mg three times daily) or bismuth subsalicylate (120 mg four times daily). Breath tests were performed 6 weeks after therapy. The delta(13)CO(2) values ( per thousand) after primary, secondary, and tertiary treatment were analyzed, and the correlation between pretreatment values and the rate of H. pylori eradication was assessed.

RESULTS

In patients with successful second-line treatment, UBT values decreased from 12.4 per thousand [confidence interval (CI), 9.7-15.7)] to 2.8 per thousand (CI, 0.9-2.5) (P=0.001), and in those with persistent infection, they increased from 13.2 per thousand (CI, 7.3-19.1) to 19.2 per thousand (CI, 13.4-25.0) (P=0.03). After a failed quadruple regimen, UBT values increased from 19.3 per thousand (CI, 16.2-22.4) to 25.8 per thousand (CI, 19.8-312.8) (P=0.03). The correlation between the pretreatment UBT values and the rate of eradication was negative for both second- and third-line therapies.

CONCLUSIONS

Serial assessment showed that UBT values after successive treatments showed a marked tendency to increase over time in failed cases. The significance of this phenomenon must be further studied. It might indicate increased colonization, ongoing resistance, or urease gene overexpression. Higher pretreatment UBT values were associated with lower (<60%) eradication rates. In these cases, alternative/rescue therapies should be chosen.

13C-urea breath test values and Helicobacter pylori eradication

Delta over baseline (DOB) values of 13C-urea breath test (UBT) have been shown to be predictive of H. pylori eradication following therapy. This was a post hoc analysis of a large, double-blind, randomized trial. Consecutive patients with a positive UBT underwent upper endoscopy. H. pylori strains were tested for clarithromycin resistance. All patients received an eradication therapy with either a standard 10-day triple therapy or a 10-day sequential regimen. The infection was considered cured when two consecutive UBTs were negative. Basal DOB values were categorized as low (<16), intermediate (16-35), or high (>35). A total of 282 patients were selected. Eradication rates did not differ between patients with high and low DOB values. No significant difference in DOB values emerged between patients infected with clarithromycin-susceptible and clarithromycin-resistant strains. Under multivariate analysis, DOB values did not influence the bacterial eradication, which was significantly affected only by the presence of clarithromycin resistance. This large analysis failed to demonstrate a role for DOB value in H. pylori eradication with either a 10-day triple or sequential therapy.

Levofloxacin-containing triple therapy to eradicate the persistent H. pylori after a failed conventional triple therapy

OBJECTIVE

To identify the optimal dosage of levofloxacin to eradicate persistent Helicobacter pylori when triple therapy with amoxicillin, clarithromycin, and omeprazole fails.

METHODS

We investigated 124 patients whose triple therapy including clarithromycin had failed. Clarithromycin resistance was indirectly assessed by the (13)C-urea breath test, with a post-treatment value cut-off point at 15. All patients were randomly divided into two groups, to receive 1-week amoxicillin 1 g and lansoprazole 30 mg twice daily, plus either levofloxacin 500 mg once (ALL-500 group) or twice daily (ALL-1000 group). Six weeks later, the (13)C-urea breath test was repeated to assess whether H. pylori was eradicated.

RESULTS

Intention-to-treat (ITT) and per-protocol (PP) analysis showed no difference in H. pylori eradication rates in both the ALL-500 and ALL-1000 groups (ITT: 79% vs. 80.6%, p > .05; PP: 86% vs. 87.5%, p > .05). For both groups, the per-protocol H. pylori eradication rates were also similarly high between patients with a post-treatment value of (13)C-urea breath test < or = 15 and those with a value > 15 (ALL-500: 85% vs. 86.5%, p > .05; ALL-1000: 88.9% vs. 86.8%, p > .05).

CONCLUSION

One-week levofloxacin 500 mg daily-based triple therapy is effective for eradicating the persistent H. pylori after a failed triple therapy with amoxicillin, clarithromycin, and omeprazole.

Pretreatment with Lactobacillus- and Bifidobacterium-containing yogurt can improve the efficacy of quadruple therapy in eradicating residual Helicobacter pylori infection after failed triple therapy

BACKGROUND

Lactobacillus- and Bifidobacterium-containing yogurt (AB-yogurt) can suppress Helicobacter pylori. Improvement of the eradication rate by quadruple therapy of residual H. pylori after failed triple therapy is needed.

OBJECTIVE

We tested whether prior treatment with AB-yogurt improved the efficacy of quadruple therapy in eradicating residual H. pylori after failed triple therapy.

DESIGN

One hundred thirty-eight patients in whom triple therapy failed were enrolled for a culture study of H. pylori to assess antimicrobial resistance. These patients were then randomly assigned in equal numbers to either a yogurt-plus-quadruple therapy group or a quadruple therapy-only group. The patients received 1 wk of quadruple therapy with or without a 4-wk pretreatment with AB-yogurt (400 mL/d). In the yogurt-plus-quadruple group, excessive delta(13)CO(2)/mL values of the (13)C-urea breath test were collected before and every 2 wk during the 4-wk ingestion of yogurt. For both groups, a (13)C-urea breath test was conducted > or =6 wk after the quadruple therapy to assess the outcome of residual H. pylori eradication.

RESULTS

For the patients in the yogurt-plus-quadruple therapy group infected with either antibiotic-sensitive or -resistant H. pylori, the excessive delta(13)CO(2)/mL values of the (13)C-urea breath test were significantly decreased after the 4-wk ingestion of AB-yogurt (P < 0.0001). The yogurt-plus-quadruple therapy group had a higher H. pylori eradication rate than did the quadruple therapy-only group (intention-to-treat analysis: 85% compared with 71.1%, P < 0.05; per-protocol analysis: 90.8% compared with 76.6%, P < 0.05).

CONCLUSION

A 4-wk pretreatment with AB-yogurt can decrease H. pylori loads despite antimicrobial resistance, thus improving the efficacy of quadruple therapy in eradicating residual H. pylori.

Is there any correlation between 13C-urea breath test values and response to first-line and rescue Helicobacter pylori eradication therapies?

AIM

To study if there is a correlation between 13C-urea breath test values prior to treatment and the response to first-line and rescue Helicobacter pylori eradication therapies.

METHODS

Six-hundred patients with peptic ulcer or functional dyspepsia infected by H. pylori were prospectively studied. Pre-treatment H. pylori infection was established by 13C-urea breath test. Three-hundred and twelve patients were treated with first-line eradication regimen, and 288 received a rescue regimen. H. pylori eradication was defined as a negative 13C-urea breath test, 8 weeks after completion of treatment.

RESULTS

H. pylori eradication was achieved in 444 patients. No statistically significant differences were demonstrated when mean delta 13C-urea breath test values were compared between patients with eradication success and failure (49.4+/-33 versus 49.2+/-31). Differences in mean pre-treatment delta 13CO2 between patients with eradication success/failure were not demonstrated either when first-line or rescue regimens were prescribed. With the cut-off point of pre-treatment delta 13CO2 set at 35 units, sensitivity and specificity for the prediction of H. pylori eradication success was 43 and 60%. The area under the receiver operating characteristic curve evaluating all the cut-off points of the pre-treatment delta 13CO2 for the diagnosis of H. pylori eradication was 0.5. Finally, delta 13CO2 values did not influence the eradication in the logistic regression model.

CONCLUSION

No correlation was observed between 13C-urea breath test values before treatment and the response to first-line and rescue H. pylori eradication therapies. Therefore, we conclude that the quantification of delta 13CO2 prior to treatment is not useful to predict the success or failure of eradicating therapy.

Diagnosis of Helicobacter pylori Infection

A large number of studies on diagnostic tests have been published this year. New tests were proposed for the detection of Helicobacter pylori antigens in stools and new molecular methods (real-time polymerase chain reaction) to look for antimicrobial susceptibility. The other standard tests have been applied in different situations to improve the diagnosis of the infection.