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Objective: The aim of the study was to evaluate whether poor compliance can be considered as the main cause of the low Helicobacter pylori (H. pylori) eradication rate observed in an ambulatory population., Methods: Seventy-eight patients with non-ulcer dyspepsia or gastroduodenal ulcer in whom H. pylori infection was confirmed by urease Clo-test and histology or bacterial culture, received a 1-week triple therapy comprising lansoprazole 30 mg b.d., amoxicillin 1000 mg b.d. and clarithromycin 500 mg b.d. Compliance was assessed using MEMS(R) containers (Medication Event Monitoring System) which recorded time of medicines consumption., Results: The overall H. pylori eradication rate was 65.4% (95% CI: 54.8-76.0%) (intention to treat). Sixty-nine subjects (88.5%) consumed greater than 85% of doses and were considered as "good compliers". The major reason listed by the nine remaining patients for stopping treatment prematurely was side effects. In the population categorised as "good compliers", H. pylori eradication rate was 69.6% (95% CI: 58.7-80.5%) (per protocol) indicating that compliance could not be considered as the sole reason for treatment failure. Bacterial culture in a subset of 30 patients further showed a H. pylori eradication rate of 73.9% (95% CI: 55.7-92.1%) in "good compliers" with a clarithromycin-sensitive H. pylori strain. On multivariate analysis, H. pylori eradication was inversely associated with poor compliance (P=0.029). Presence of a gastroduodenal ulcer, age, gender and smoking habit did not differ significantly between the eradicated and noneradicated groups., Conclusion: Although poor compliance and bacterial resistance were important factors in determining treatment success in our population, they could only explain 40% of failures suggesting that other factors must be involved.

A total of 234 pools were prepared from 10,692 consecutive serum samples negative for antibodies to human immunodeficiency virus type 1 (HIV-1) and HIV-2 collected at five virological laboratories (average pool size, 45 serum samples). Pools were screened for the presence of HIV-1 RNA by a modified commercial assay (Amplicor HIV-1 Monitor test) which included an additional polyethylene glycol (PEG) precipitation step prior to purification of viral RNA (PEG Amplicor assay). The sensitivity of this assay for HIV-1 RNA detection in individual serum samples within pools matches that of standard commercial assays for individual serum samples, i.e., 500 HIV-1 RNA copies per ml. Five pools were identified as positive, and each one contained one antibody-negative, HIV-1 RNA-positive serum sample, corresponding to an average of 1 infected sample per 2,138 serum samples. Retrospective analysis revealed that the five HIV-1 RNA-positive specimens originated from individuals who had symptomatic primary HIV-1 infection at the time of sample collection and who were also positive for p24 antigenemia. We next assessed the possibility of performing the prepurification step by high-speed centrifugation (50,000 x g for 80 min) of 1.5-ml pools containing 25 microl of 60 individual serum samples, of which only 1 contained HIV-1 RNA (centrifugation Amplicor assay). The sensitivity of this assay also matches the sensitivities of standard commercial assays for HIV-1 RNA detection in individual serum samples. The results demonstrate that both assays with pooled sera can be applied to the screening of large numbers of serum samples in a time- and cost-efficient manner.