High rate of post-therapeutic resistance after failure of macrolide-nitroimidazole triple therapy to cure Helicobacter pylori infection: impact of two second-line therapies in a randomized study

BACKGROUND

The optimal second-line treatment after failed Helicobacter pylori therapy has not been established.

AIMS

To ascertain whether quadruple therapy or triple therapy with omeprazole, clarithromycin and amoxicillin is the superior re-treatment after triple therapy containing a macrolide and a nitroimidazole, and to determine the impact of microbial in vitro resistance.

METHODS

Patients after failed triple therapy were randomly allocated to one of two 1-week second-line treatments: omeprazole, 40 mg, clarithromycin, 500 mg, and amoxicillin, 1 g, all b.d.; or omeprazole, 20 mg b.d., bismuth subsalicylate, 600 mg q.d.s., metronidazole, 400 mg t.d.s., and tetracycline, 500 mg q.d.s. Post-therapeutic Helicobacter pylori status was assessed by 13C-urea breath test at least 4 weeks after treatment.

RESULTS

The study was terminated after including 84 patients. H. pylori cure rates differed significantly: omeprazole-clarithromycin-amoxicillin: intention-to-treat, 43%; per protocol, 50%; omeprazole-bismuth subsalicylate-metronidazole-tetracycline: intention-to-treat, 68%; per protocol, 69%. The frequencies of resistance after first-line therapy were: metronidazole, 90%; clarithromycin, 71%; both combined, 68%. For clarithromycin resistance, H. pylori cure with omeprazole-clarithromycin-amoxicillin was 30% vs. 83% for clarithromycin susceptibility.

CONCLUSIONS

Omeprazole-bismuth subsalicylate-metron- idazole-tetracycline was superior to omeprazole-clarithromycin-amoxicillin, but both therapies yielded unsatisfactory results. The high rate of post-therapeutic dual resistance has a negative impact on omepraz- ole-clarithromycin-amoxicillin, and probably also on omeprazole-bismuth subsalicylate-metronidazole-tetracycline, and limits the choice for second-line treatment.

Internally shortened menin protein as a consequence of alternative RNA splicing due to a germline deletion in the multiple endocrine neoplasia type 1 gene

Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominantly inherited cancer syndrome (OMIM 131100), with tumours in several endocrine glands. In 1997 the responsible tumour suppressor gene was identified and recently it was shown that menin, its encoded protein, represses JunD-activated gene expression. Although many MEN 1 patients have been investigated both clinically and genetically, no genotype-phenotype correlation has been found yet. The vast majority of MEN1 gene mutations involve point mutations. We describe a patient in whom a 26 base pair deletion in the MEN1 gene, comprising part of exon 3 and part of intron 3, causes activation of a cryptic donor splice site at the beginning of exon 3. This germline mutation results in an in frame deletion of 105 nucleotides in MEN1 gene mRNA, i.e. an internal deletion of 35 amino acids in the menin protein. Since the deleted region of menin has been implicated in binding to JunD, this may explain the tumourigenic effect of this mutation. The knowledge of this MEN1 gene germline defect, may be used for presymptomatic identification of MEN 1 disease gene-carriers among family-members of this proband. This enables early detection of tumour development, timely treatment and genetic counseling.

Citric acid or orange juice for the 13C-urea breath test: the impact of pH and gastric emptying

BACKGROUND

There is an ongoing debate about the optimal test drink to be used in the 13C-urea breath test (13C-UBT). We recently reported that a citric acid solution is the optimal test drink in the 13C-UBT, because it provides a high 13CO2 recovery and the excellent accuracy of the test appears optimal compared to other test meals. Orange juice, because of a better taste, is also propagated as a test drink in the 13C-UBT.

AIM

To compare the diagnostic accuracy of the 13C-UBT with either orange juice or citric acid solution as a test drink. Furthermore, the effect of these test drinks on the gastric emptying rate was determined.

METHODS

H. pylori status was assessed by histology, rapid urease test and culture in 50 consecutive dyspeptic patients. A 13C-UBT was performed on two consecutive days by giving 75 mg of 13C-urea randomly dissolved in 200 mL 0.1 M citric acid solution or 200 mL orange juice. The 13CO2/12CO2 ratio was measured in breath samples taken before and 15, 30, 45 and 60 min after administration of the test drink. The gastric emptying rate of orange juice and citric acid solution was compared to that of water in 10 healthy subjects on three consecutive days by means of a 13C-sodium acetate breath test; 50 mg of 13C-sodium acetate was dissolved in 200 mL of each solution and breath samples were collected before and every 10 min for 90 min after administration of the test drink.

RESULTS

Twenty-six out of 50 patients (52%) were infected with H. pylori. Significantly higher values over baseline (35.7+/-5.2 per thousand vs. 23.2+/-3.4 per thousand, P<0.001) and higher area under the curve (1507+/-198 vs. 927+/-128, P<0.001) were observed in H. pylori-positive patients when citric acid solution was administered compared with orange juice. Sensitivity of the 13C-UBT was 100% when citric acid was used as a test drink and 88% with orange juice. Specificity was 100% with both test drinks. Gastric emptying of citric acid solution (t1/2 = 60.9+/-3.5 min) was significantly slower than that of orange juice (t1/2 = 49.7+/-3.1 min, P<0.001).

CONCLUSION

13C-UBT loses diagnostic accuracy when orange juice instead of citric acid is used as a test drink. The faster gastric emptying of orange juice might be responsible for the lower diagnostic accuracy of the 13C-UBT.