[Hurdles to HIV cure. Part 1 : the latent reservoirs]. / Obstacles à la guérison de l'infection par le VIH. Partie 1 : les réservoirs latents.

The human immunodeficiency virus (HIV), responsible for acquired immunodeficiency syndrome or AIDS, is a major public health problem. In Belgium, 2 to 3 new cases are diagnosed every day. Since the advent of combined antiretroviral treatments in 1996, the life expectancy and quality of life of infected patients have greatly improved. However, to date there is no cure for HIV. Individuals infected with HIV must remain on antiretroviral treatment for life. One of the reasons for the difficulty in finding a cure for HIV is that the virus can remain in a latent form, i.e. dormant, in some of the cells it infects. These latent reservoirs are not recognized by the immune system and can reactivate and thus restart the infection if the patient stops the treatment. These latent reservoirs are therefore a major obstacle to cure HIV and a great deal of research is being conducted by the scientific community to find an eradication strategy. In this article, we will present the different characteristics of these latent reservoirs and the different strategies put in place to identify and eliminate them.

Le virus de l'immunodéficience humaine (VIH), responsable du syndrome d'immunodéficience acquise ou SIDA, est un problème de santé publique majeur. En Belgique, 2 à 3 nouveaux cas sont diagnostiqués par jour. Depuis l'arrivée des traitements antirétroviraux combinés en 1996, l'espérance et la qualité de vie des patients infectés se sont grandement améliorées. Cependant, il n'existe, à ce jour, aucun traitement curatif de cette infection. Les individus atteints doivent rester sous traitement antirétroviral toute leur vie. Cette difficulté à trouver un traitement curatif du VIH provient, notamment, du fait que le virus peut rester sous une forme latente, c'est-à-dire endormie, dans certaines cellules qu'il infecte. Ces réservoirs latents ne sont pas reconnus par le système immunitaire et peuvent se réactiver lorsque le patient arrête son traitement et ainsi redémarrer l'infection. Ces réservoirs latents sont, donc, un obstacle majeur à la guérison et de nombreuses recherches sont menées par la communauté scientifique afin de trouver une stratégie d'éradication. Dans cet article, nous présentons les différentes caractéristiques de ces réservoirs latents et les différentes stratégies mises en place pour les identifier et tenter de les éliminer.

[Hurdles to HIV cure. Part 2 : ongoing HIV replication despite therapy]. / Obstacles à la guérison de l'infection par le VIH. Partie 2 : la réplication continue malgré le traitement.

The antiretroviral therapy (ART) has proven its effectiveness in improving the life expectancy of people infected with human immunodeficiency virus (HIV). Based on the inhibition of HIV replication, ART ensures the reduction of plasma viral load to undetectable levels on long-term. Unfortunately, once ART is interrupted, the viral load rises up. Consequently, the therapy remains not curative. The reasons for this failure lie in the presence of latent reservoirs of the virus and/or the presence of ongoing replication, responsible for the persistence of the virus. This ongoing replication despite ongoing therapy has been demonstrated in sanctuary sites where the penetration of antiretroviral drugs is suboptimal. Moreover, some treatment intensification studies, mostly through addition of an integrase inhibitor, transiently resulted in increases in HIV replication by-products, highlighting that such strategies could reduce ongoing replication. Although the debate is still open, confirming the presence of this ongoing replication and finding strategies to eliminate it would be part of the key to a cure for HIV.

Le traitement antirétroviral (ART) a prouvé son efficacité ces vingt-cinq dernières années en améliorant l'espérance de vie des personnes infectées par le virus de l'immunodéficience humaine (VIH), et en empêchant la transmission du virus. Basé sur l'inhibition de la réplication du VIH, ce traitement permet de diminuer la charge virale plasmatique du virus, à des niveaux indétectables, de façon durable. Malheureusement, le traitement n'est pas curatif et un arrêt de celui-ci résulte inévitablement en un rapide rebond de la virémie. Les raisons de cet échec sont, d'une part, la présence de réservoirs latents du virus et, d'autre part, la persistance d'une réplication du virus à bas bruit, malgré le traitement. Cette réplication se produirait dans les sites sanctuaires où la concentration des antirétroviraux serait sous-optimale. Des études d'intensification du traitement antirétroviral, par ajout d'une drogue supplémentaire (généralement, un inhibiteur de l'intégrase), ont produit des résultats en faveur de la persistance d'une réplication continue du virus, malgré le traitement préalable, chez certains patients. Comprendre ce phénomène et développer des stratégies visant à l'éliminer constituent des éléments clés dans la quête d'une guérison des patients infectés par le VIH.

[The COVID-19 breaker : PCR to the rescue !] / La déferlante COVID-19 : la PCR à la rescousse ! Chronique d'une gestion de crise au Laboratoire de Microbiologie clinique du CHU de Liège.

Chronicle of a crisis management at the Clinical Microbiology Laboratory of CHU Liège The SARS-CoV-2 outbreak in December 2019 in China and its expansion across the world and Europe have requested the participation of clinical laboratories as major players in the diagnosis of COVID-19, to perform PCR tests mainly on nasopharyngeal swabs. In Belgium, the first confirmed COVID-19 patient was diagnosed in early February, the first of many, especially travelers returning from winter sports. In order to meet the ever-increasing demands for testing, the Clinical Microbiology Laboratory of the CHU of Liege had to adapt to this situation: firstly, by developing manual PCR tests and then automated solutions, permitting to increase the number of analyzes by ensuring a short turnaround time of results. Then, a system for the communication of results on a large scale has been set up, and finally solutions to deal with the lack of sampling devices have been found. This first wave of the pandemic has also highlighted an unprecedented solidarity within the institution. In this article, we recount the chronology of the management of this unprecedented health crisis within the Clinical Microbiology Laboratory of the CHU of Liege.

L'émergence du virus SARS-CoV-2 en décembre 2019 en Chine et son expansion à travers le monde et l'Europe ont sollicité la participation des laboratoires de Biologie clinique en tant qu'acteurs majeurs dans le diagnostic de la COVID-19, via la réalisation de tests PCR principalement sur des prélèvements nasopharyngés. En Belgique, le premier patient confirmé COVID-19 a été diagnostiqué début février, avant d'être suivi par de nombreux cas d'infections, initialement chez des vacanciers revenant des sports d'hiver. Afin de répondre à l'augmentation du nombre de tests, le laboratoire de Microbiologie clinique du CHU de Liège a dû s'adapter en développant des tests PCR, d'abord manuels puis automatisés. Ceux-ci ont permis d'augmenter le nombre d'analyses, tout en garantissant un temps de rendu des résultats court, en mettant en place un système de communication des résultats à grande échelle et en trouvant des solutions pour faire face à la pénurie des dispositifs de prélèvement. Cette première vague de la pandémie a aussi révélé une solidarité sans précédent au sein de l'institution. Dans cet article, nous retraçons la chronologie de la gestion de cette crise sanitaire inédite au sein du laboratoire de Microbiologie clinique du CHU de Liège.

Late presentation to HIV testing is overestimated when based on the consensus definition.

OBJECTIVES: In 2011, a consensus was reached defining "late presenters" (LPs) as individuals presenting for care with a CD4 count < 350 cells/µL or with an AIDS-defining event, regardless of CD4 count. However, a transient low CD4 count is not uncommon in recent infections. The objective of this study was to investigate how measurements of late presentation change if the clinical stage at the time of diagnosis is taken into account. METHODS: Case surveillance data for newly diagnosed patients in Belgium in 1998-2012 were analysed, including CD4 count at diagnosis, the presence of AIDS-defining events, and recent infections (< 6 months) as reported by clinicians in the case of acute illness or a recent negative test. First, proportions of LPs were calculated according to the consensus definition. Secondly, LPs were reclassified as "nonlate" if infections were reported as recent. RESULTS: A total of 7949 HIV diagnoses were included in the study. Recent infections were increasingly reported over time, accounting for 8.2% of new infections in 1998 and 37.5% in 2012. The consideration of clinical stage significantly modified the proportion of LPs: 18.2% of men who have sex with men (MSM) diagnosed in 2012 would be classified as LPs instead of 30.9% using the consensus definition (P < 0.001). The proportion of patients misclassified as LPs increased significantly over time: 5% in MSM in 1998 vs. 41% in 2012. CONCLUSIONS: This study suggests that low CD4 counts in recent infections may lead to overestimation of late presentation when applying the consensus definition. The impact of transient CD4 count on late presentation estimates should be assessed and, if relevant, the introduction of clinical stage in the definition of late presentation should be considered.

First-line therapies for H. pylori infection in Italy: a pooled-data analysis.

Background: Curing H. pylori infection remains challenging, and the use of most effective first-line therapy represents a therapeutic cornerstone. To monitor the efficacy of first-line therapies in Italy, we designed a systematic review with pooled- data analysis of data published in the last 15 years. Methods: The search was focused on standard regimens and adult patients. Studies that included modified therapy regimens, pediatric patients, case series with less than 5 patients, and those in language other than English were excluded. Results: A total of 40 studies, with 74 therapeutic arms and 13,539 patients were evaluated. Among the 14-day triple therapies, the combination with proton pump inhibitor (PPI), clarithromycin and amoxicillin achieved the highest (77.9%) success rate, whilst the lowest success rate (62.7%) was observed following the 14-day PPI, clarithromycin and tinidazole regimen. The overall efficacy of triple therapies significantly decreased from 75.7% to 72.1% in the last decade. Sequential (88.3% on 3431 patients), concomitant (88.8% on 376 patients), and the bismuth-based quadruple therapy with three-in-one capsule, containing bismuth subcitrate potassium (140 mg), metronidazole (125 mg), tetracycline (125 mg) (90.4% on 999 patients) achieved similarly high eradication rates, but data on concomitant are still limited. The bismuth-based was associated with the higher (38.7%) incidence of side-effects. Conclusions: Data found that all triple therapies, irrespective of drug combination and therapy duration, should be abandoned in Italy due to their unacceptable low success rates. Monitoring the efficacy of standard first-line therapies in other countries could be clinically useful for both patients and clinicians.

Concordance between HIV-1 genotypic coreceptor tropism predictions based on plasma RNA and proviral DNA.

OBJECTIVE: The aim of the study was to evaluate the use of proviral DNA as a source of viral genetic material for genotypic coreceptor tropism testing (GTT). METHODS: GTT consisted of bulk V3 sequencing followed by geno2pheno interpretation with the interpretative cut-off [false positive rate (FPR)] set at 5 and 10%. GTT was performed for 165 patients with a viral load of >500 HIV-1 RNA copies/mL on simultaneously collected plasma RNA and proviral DNA, and for 126 patients with a viral load of <500 copies/mL on current proviral DNA and pretreatment plasma RNA. Phenotypic tropism testing (PTT) results were available for 142 samples. RESULTS: In the simultaneous RNA/DNA comparison, concordance in prediction was 95.2% (at FPR 10%) and 96.4% (at FPR 5%). Six RNA-R5/DNA-X4 and two RNA-X4/DNA-R5 discordances were observed at an FPR of 10%, and six RNA-R5/DNA-X4 discordances were observed at an FPR of 5%. In the longitudinal RNA/DNA comparison, concordance was 88.1% (at FPR 10%) and 90.5% (at FPR 5%). Eight RNA-X4/DNA-R5 and seven RNA-R5/DNA-X4 discordances were seen at an FPR of 10%, and 10 RNA-R5/DNA-X4 and two RNA-X4/DNA-R5 discordances at an FPR of 5%. The overall concordance of RNA GTT with PTT was 82% (at FPR 10%) and 83% (at FPR 5%). The overall concordance of DNA GTT with PTT was 85% (at both 10 and 5% FPRs). CONCLUSIONS: GTT produced highly concordant tropism predictions for proviral DNA and plasma RNA. GTT on proviral DNA offers a promising approach for tropism prediction in clinical practice, particularly for the assessment of treated patients with low or suppressed viraemia.

Antibiotic Resistance and Therapy Outcome in H. pylori Eradication Failure Patients.

Helicobacter pylori (H. pylori) eradication fails in a definite amount of patients despite one or more therapeutic attempts. Curing these patients is progressively more difficult, due to development of antibiotic resistance. Current guidelines suggest testing antibiotic susceptibility in H. pylori isolates following two therapeutic attempts. AIM: to evaluate the development of antibiotic resistance, MIC values trends and therapeutic outcomes in patients who failed at least one H. pylori eradication therapy. METHODS: consecutive patients, referred to perform upper gastrointestinal endoscopy (UGIE) to our Unit from January 2009 to January 2019 following at least one therapeutic attempt were considered. Bacterial resistance towards clarithromycin, metronidazole and levofloxacin was tested. Patients received either a susceptibility-guided therapy or Pylera®. RESULTS: a total of 1223 patients were H. pylori positive, and antibiotic susceptibility was available for 1037. The rate of antibiotic resistance and MIC values significantly increased paralleling the number of previous therapeutic attempts. Eradication rates of antibiogram-tailored therapies remained stable, except for the sequential therapy if used as a third line. As a rescue treatment, the Pylera® therapy achieved cure rates comparable to those of the other culture-guided therapies. CONCLUSIONS: A significant increase in the secondary resistance towards the three tested antibiotics was observed, both as rate and MIC values, in correlation with the number of therapy failures. These findings should be considered when administering an empirical second-line therapy. Pylera® therapy eradication rates are comparable to culture-tailored therapies.

[A fixed dose anti-HIV combination for the poor? Triomune]. / Triom une: la trithérapie du pauvre ?

Despite a relative global stabilization of its incidence, HIV infection remains a major threat for public health, principally in Africa where it concerns more than 22 million people and constitutes the first cause of death on the continent. To face the emergency of the HIV/AIDS epidemics on the African continent, the primary goal is to make available to all patients free and efficient antiretroviral medications. Such a goal cannot be dissociated from large scale prevention campaigns. In 2000, Triomune, one of the first fixed dose combinations of three antiretrovirals (stavudine, lamivudine & nevirapine) was launched by the Indian drug company Cipla, specialized in the production of low cost medications. Its convenient pill burden (one pill twice a day) and its very low cost (around 30 US $ per month) make Triomune an appealing solution for the treatment of HIV/AIDS in Africa. Unfortunately, Triomune presents several drawbacks (low genetic barrier, frequent side effects) and one of its constituents is not used in Europe anymore. Other first line treatments are urgently needed.

Impact of primary antibiotic resistance on the effectiveness of sequential therapy for Helicobacter pylori infection: lessons from a 5-year study on a large number of strains.

BACKGROUND: The increasing prevalence of strains resistant to antimicrobial agents is a critical issue in the management of Helicobacter pylori (H. pylori) infection. AIMS: (1) To evaluate the prevalence of primary resistance to clarithromycin, metronidazole and levofloxacin (2) to assess the effectiveness of sequential therapy on resistant strains (3) to identify the minimum number of subjects to enrol for evaluating the effectiveness of an eradication regimen in patients harbouring resistant strains. METHODS: Consecutive 1682 treatment naïve H. pylori-positive patients referred for upper GI endoscopy between 2010 and 2015 were studied and resistances assessed by E-test. Sequential therapy was offered, effectiveness evaluated and analysed. RESULTS: H. pylori-primary resistance to antimicrobials tested was high, and increased between 2010 and 2015. Eradication rates were (estimates and 95% CIs): 97.3% (95.6-98.4) in strains susceptible to clarithromycin and metronidazole; 96.1% (91.7-98.2) in strains resistant to metronidazole but susceptible to clarithromycin; 93.4% (88.2-96.4) in strains resistant to clarithromycin but susceptible to metronidazole; 83.1% (77.7-87.3) in strains resistant to clarithromycin and metronidazole. For any treatment with a 75%-85% eradication rate, some 98-144 patients with resistant strains need to be studied to get reliable information on effectiveness in these patients. CONCLUSIONS: H. pylori-primary resistance is increasing and represents the most critical factor affecting effectiveness. Sequential therapy eradicated 83% of strains resistant to clarithromycin and metronidazole. Reliable estimates of the effectiveness of a given regimen in patients harbouring resistant strains can be obtained only by assessing a large number of strains.

Cameron lesions: A still overlooked diagnosis. Case report and systematic review of literature.

Cameron lesions are erosive-ulcerative alterations of gastric mucosa occurring in patients with large hiatal hernia, potentially causing gastrointestinal bleeding and iron deficiency anaemia. Diagnosis may be challenging, and not infrequently erosions are overlooked at endoscopy, so that repeated and unnecessary diagnostic procedures are performed, particularly in those patients with chronic anaemia. We described two peculiar cases of patients with iron deficiency anaemia in whom Cameron lesions were either overlooked or misinterpreted. By reviewing data of 22publications reporting endoscopic and clinical data of 140patients, we noted a large prevalence of females (75%). The most frequent presenting symptoms were anaemia (62%) and overt gastrointestinal bleeding (36%). Noteworthy, as many as 69% of patients underwent one or more previous upper endoscopy before diagnosis of Cameron lesion was achieved. Patients were mainly treated with proton pump inhibitor (PPI) therapy and iron supplementation. Moreover, endoscopic haemostasis was performed in 10% of case, blood transfusion was required in one third of cases, and a similar quote of patients underwent a surgical approach for hiatal hernia repair. The observation that as many as 60% patients were already receiving standard PPI therapy when diagnosis was performed would suggest that either long-term treatment with adequate dose PPI or surgical approach for hiatal hernia repair is required. In conclusion, Cameron lesion is still an overlooked diagnosis in patients with iron deficiency anaemia in whom a 5-9.2% prevalence has been reported.

Meta-analysis: the efficacy of proton pump inhibitors for laryngeal symptoms attributed to gastro-oesophageal reflux disease.

BACKGROUND: Many investigators have proposed an association between gastro-oesophageal reflux disease and laryngo-pharyngeal symptoms, suggesting that medical or surgical therapy for reflux may be useful. AIM: To perform a meta-analysis assessing the effectiveness of medical or surgical therapy for reflux disease in adult patients with laryngeal or pharyngeal symptoms presumed to be due to gastro-oesophageal reflux disease. METHODS: Randomized controlled trials comparing medical or surgical treatments for gastro-oesophageal reflux disease against placebo were identified by searching MEDLINE (1966-September 2005), EMBASE (1974-September 2005), the CCRCT (until September 2005) and abstracts from gastroenterology and ENT meetings. The relative risks of reporting symptomatic improvement or resolution of symptoms was evaluated using a random-effects model. RESULTS: Five studies using high-dose proton pump inhibitor as intervention met the inclusion criteria and were included in the meta-analysis. No surgical studies met inclusion criteria. The pooled relative risk was 1.18 (95% confidence interval: 0.81-1.74). There was no heterogeneity between studies but evidence of significant publication bias. Sub-group analysis performed evaluating Jadad scores and symptom type, did not change the relative risk. CONCLUSIONS: Therapy with a high-dose proton pump inhibitor is no more effective than placebo in producing symptomatic improvement or resolution of laryngo-pharyngeal symptoms. Further studies are necessary to identify the characteristics of patients that may respond to proton pump inhibitor therapy.

Primary antibiotic resistance in Helicobacter pylori strains isolated in northern and central Italy.

BACKGROUND: Helicobacter pylori resistance to antibiotics is increasing worldwide, and it reduces the efficacy of therapy. AIM: To assess current primary antibiotic resistance in H. pylori strains isolated in Italy. METHODS: Between June 2004 and June 2006, H. pylori strains were isolated consecutively in the two participating centres (Bologna, northern Italy; Rome, central Italy) from patients never previously treated for the infection. Isolated strains were tested for primary clarithromycin, metronidazole and levofloxacin resistance using as break point the minimal inhibitory concentration >/=1, >/=8 and >/=1 mg/L for the three antibiotics, respectively. RESULTS: Overall, 255 H. pylori strains were evaluated. The resistance rate was 16.9% for clarithromycin, 29.4% for metronidazole and 19.1% for levofloxacin. Clarithromycin resistance was significantly higher in non-ulcer dyspepsia than in peptic ulcer patients (19.1% vs. 0%, P = 0.02), metronidazole resistance was higher in foreign than Italian patients (50% vs. 22.9%, P = 0.0004) and levofloxacin resistance was higher in old than younger patients (28.4% vs. 14.4%, P = 0.048). Levofloxacin resistance was also more frequent in those strains with either clarithromycin or metronidazole resistance. CONCLUSION: A very high rate of primary resistance towards the tested antibiotics was detected in our study.

Levofloxacin-based triple therapy for Helicobacter pylori re-treatment: role of bacterial resistance.

BACKGROUND: First-line Helicobacter pylori therapy fails in more than 20% of patients. Quadruple therapy is the suggested second-line therapy, but bismuth salts are not anymore available worldwide. This study aimed to assess the efficacy of a levofloxacin-amoxycillin triple therapy as a second-line treatment, and the role of primary levofloxacin resistance. METHODS: Forty patients, in whom first treatment with either standard 10-day triple or sequential therapy had failed, received 10-day triple therapy with rabeprazole (20mg b.d.), levofloxacin (250mg b.d.), and amoxycillin (1g b.d.). Cure rates were evaluated by the (13)C-urea breath test. Primary levofloxacin resistance was detected by culture. RESULTS: Bacterial culture was available in 33 (82.5%) out 40 patients, and primary levofloxacin resistance was detected in 10 (30.3%) patients. Overall, 33 of 40 patients accepted to participate in this study, and all returned for follow-up after therapy. Compliance to the therapy was safe except 1 patient only who stopped earlier the treatment due to side effects (oral candidiasis). H. pylori infection was eradicated in 24 patients, accounting for a 72.7% (95% CI: 57-88) eradication rate at both intention-to-treat and per protocol analyses. The eradication rate was higher in patients harbouring levofloxacin-susceptible than resistant strains (75% versus 33.3%; P=0.074). CONCLUSIONS: The eradication rate achieved by a levofloxacin-based re-treatment seems to be decreasing, and its efficacy is reduced in presence of levofloxacin resistance.

[New approaches to the treatment of the HIV-infected patient]. / Nouvelles approches dans la prise en charge de l'infection à VIH.

HIV infection remains a major problem of public health in Belgium as well as globally. The number of new diagnosies of HIV infection in Belgium remains between two and three daily. Given the dramatic effect of antiretroviral therapy on the mortality due to HIV infection, the number of patients is constantly increasing. The different problems related to HIV care are also changing. Aging of the patients and chronic exposure to antiretroviral medications have induced new complications. We will present in this brief article several new experimental and clinical approaches in which our centre has participated during the last two years.

High rate of Helicobacter pylori eradication with sequential therapy in elderly patients with peptic ulcer: a prospective controlled study.

BACKGROUND: Helicobacter pylori eradication rates with triple therapies are decreasing, and few data in elderly patients are available. A 10-day sequential regimen succeeded in curing such H. pylori infection in unselected patients. AIM: To compare this sequential regimen and the standard triple therapy for H. pylori eradication in geriatric patients with peptic ulcer. METHODS: Overall, 179 H. pylori-infected patients with peptic ulcer were enrolled (mean age: 69.5 years; range: 65-83). Patients were randomized to 10-day sequential therapy (rabeprazole 20 mg b.d. plus amoxicillin 1 g b.d. for the first 5 days, followed by rabeprazole 20 mg, clarithromycin 500 mg and tinidazole 500 mg, all b.d., for the remaining 5 days) or standard 7-day triple regimen (rabeprazole 20 mg, clarithromycin 500 mg and amoxicillin 1 g, all b.d.). Helicobacter pylori status was assessed by histology and rapid urease test at baseline and 4-6 weeks after completion of treatment. RESULTS: The sequential regimen achieved eradication rates significantly higher in comparison with the standard regimen at both intention-to-treat (94% vs. 80%; P = 0.008) and per-protocol (97% vs. 83%; P = 0.006) analyses. In both treatment groups, compliance to the therapy was high (> 95%), and the rate of mild side-effects was similarly low (< 12%). At repeated upper endoscopy, peptic ulcer lesions were healed in 97% patients, without a statistically significant difference between the sequential regimen and the standard triple therapy. CONCLUSIONS: In elderly patients with peptic ulcer disease, the 10-day sequential treatment regimen achieved significantly higher eradication rates in comparison with standard triple therapy.

A 10-day levofloxacin-based triple therapy in patients who have failed two eradication courses.

BACKGROUND: A standard third-line treatment is lacking, and European guidelines recommend performing culture in these patients. However, the use of this procedure as 'routine practice' is definitively not feasible. AIM: To evaluate the eradication rate of a 10-day levofloxacin-based triple therapy in patients who have failed two eradication courses for Helicobacter pylori. METHODS: A total of 151 patients with persistent Helicobacter pylori infection after two treatments were studied. Patients were considered positive if two of three endoscopic tests were positive. Susceptibility testing was also performed. Patients received a standard dose of proton-pump inhibitors twice daily, levofloxacin 250 mg twice daily and amoxicillin 1 g twice daily, for 10 days. Endoscopic follow-up was carried out 4-6 weeks after the end of eradication therapy. RESULTS: About 76% (95% CI: 68.8-82.3), and 85% (95% CI: 77.5-89.7) of patients were eradicated according to intention-to-treat and per-protocol analysis, respectively. Eradication rates of the strains showed as 92% (95% CI: 83.2-96.7) of those resistant to both metronidazole and clarithromycin but susceptible to levofloxacin. CONCLUSIONS: In patients who failed previous regimens, the 10-day levofloxacin-based triple therapy is safe and effective, allowing eradication in almost 80% of the patients.

Diagnostic accuracy of a new rapid urease test (Pronto Dry), before and after treatment of Helicobacter pylori infection.

AIM: The diagnosis of Helicobacter pylori infection can be made easily by the rapid urease test during endoscopy. The mainly commercial rapid urease test available in routine practice, is in liquid phase, need to be stored at 4 degrees C and generally they are not ready to use. Recently a new rapid urease test, the Pronto Dry, has been reported to be faster in the final reading, ready to use, and it can be stored at room temperature. Aim of the study was to evaluate the diagnostic accuracy and the reaction time of Pronto Dry vs liquid phase-rapid urease test, before and after treatment of Helicobacter pylori infections. METHODS: A total of 315 untreated dyspeptic patients and 323 post-treatment patients, were enrolled in this study. At endoscopy, 5 biopsy samples were obtained from the antrum and from the corpus for histology; culture and rapid urease tests (liquid phase and Dry test). Helicobacter pylori status was defined according to European guidelines. Sensitivity and specificity of both rapid urease test were assessed at 5, 15, 30 minutes, and 3 and 24 hours after the endoscopy. RESULTS: One hundred and eleven out of 315 untreated dyspeptic patients were found to be positive for Helicobacter pylori infection, and 56/323 patients were found still positive after treatment. Sensitivity at 5, 15, 30 minutes, and 3 and 24 hours in untreated patients were 45%, 71.2%, 81.1%, 90.1% and 91.9% respectively for the Pronto Dry vs 6.3%, 31.5%, 51.3%, 78.4% and 90.1% for liquid phase rapid urease test. Sensitivity at the same times in not eradicated patients were 33.9%, 66.1%, 85.7%, 92.8 and 92.8% respectively for the Pronto Dry vs 3.6%, 37.5%, 55.3%73.2%, 92.8% for liquid phase rapid urease test. CONCLUSIONS: Pronto Dry showed to have higher sensitivity in pre and post treatment setting compared to liquid phase-rapid urease test within 3 hours of incubation time.

Prevalence of genotypic resistance among antiretroviral drug-naive HIV-1-infected patients in Belgium.

OBJECTIVES: To estimate the prevalence and the evolution over time (1995-1998) of genotypic resistance to antiviral drugs in antiretroviral drug-naive HIV-1-infected patients in Belgium. DESIGN: Belgian Aids Reference Laboratories provided retrospective samples and clinical data from antiretroviral drug-naive HIV-1-infected patients who visited the hospital for the first time in 1995 (n=45), 1997 (n=75) and 1998 (n=111). Genotypic resistance to the three available classes of drugs was monitored using the Line Probe Assay (Innogenetics, Gent, Belgium). Additionally, ARMS-151 was performed for scoring multinucleoside resistance. RESULTS: The prevalence of genotypic resistance at baseline to nucleoside analogue reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) were each between 10% and 20% for 1995, 1997 and 1998 without an increasing trend over time. For NRTIs, resistance mutations were mainly related to zidovudine in 1995, whereas in 1997 and 1998 baseline resistance was scored for zidovudine, lamivudine or for both drugs simultaneously. No patients displayed the multi-nucleoside resistance Q151M mutation. Baseline resistance mutations to protease inhibitors (PIs) did not rise significantly: 4.4% in 1995, 8% in 1997 and 9.9% in 1998. When scoring any resistance-related mutation, 26.6% displayed genotypic baseline resistance in 1995, 26.6% in 1997 and 31.5% in 1998. DISCUSSION: The prevalence of genotypic baseline resistance to any drug, as scored with LiPA, in naive HIV-1 patients in Belgium is 29%, with baseline resistance mutations to one or several drugs from all available classes of antiviral drugs. The ability of LiPA to pick up minor variants could be an explanation for the higher overall prevalence we observe, when compared to recent estimates in other countries of 16.3% and 22%, which were based on sequencing methods. According to the European guidelines for resistance testing, resistance testing in Belgium before starting antiviral therapy should be considered.

Activation of human immunodeficiency virus type 1 by oxidative stress.

An important aspect of the infection by the human immunodeficiency virus (HIV-1) type 1 is its clinical latency, suggesting that the virus itself or the provirus may remain latent for extended periods of time after primary infection. Certain heterologous viral proteins or chemical and physical agents are able to reactivate latent virus. Since a common denominator shared by these agents is the ability to cause stress response in cells, we have examined the effects of oxidative stress mediated by hydrogen peroxide (H2O2) on HIV-1 latently infected promonocytic cell line termed U1. After exposure to H2O2 in concentrations ranging from 0.1 to 2 mM, the viability of the U1 cells decreased during 24 h before recovery. At 24 h post stress, the U1 cells began to express virus as assessed by elevated reverse transcriptase activities in culture supernatants. Immunofluorescence carried out on stressed U1 cells using anti-HIV-1 polyclonal antibodies showed that H2O2 leads to HIV-1 gene expression activation, but not to a release of viral particles from damaged cells. Additionally, using a HeLa cell line containing integrated the bacterial chloramphenicol acetyl transferase (CAT) gene under the control of the HIV-1 long terminal repeat (LTR), we have shown that oxidative stress mediated by H2O2 allows transactivation of the viral LTR revealed by intracellular CAT activity. A stimulation factor of around 4 of CAT activity can be reached when these cells are treated with 0.5 mM H2O2.(ABSTRACT TRUNCATED AT 250 WORDS)