Isolation rooms for highly infectious diseases: an inventory of capabilities in European countries.

Isolation of patients with highly infectious diseases (HIDs) in hospital rooms with adequate technical facilities is essential to reduce the risk of spreading disease. The European Network for Infectious Diseases (EUNID), a project co-funded by European Commission and involving 16 European Union member states, performed an inventory of high level isolation rooms (HIRs, hospital rooms with negative pressure and anteroom). In participating countries, HIRs are available in at least 211 hospitals, with at least 1789 hospital beds. The adequacy of this number is not known and will depend on prevailing circumstances. Sporadic HID cases can be managed in the available HIRs. HIRs could also have a role in the initial phases of an influenza pandemic. However, large outbreaks due to natural or to bioterrorist events will need management strategies involving healthcare facilities other than HIRs.

Antiviral efficacy and resistance in patients on antiretroviral therapy in Kigali, Rwanda: the real-life situation in 2002.

Our study aimed to complete the published data on ARV therapy in Africa by describing the baseline situation in Rwanda before the launch of a large ARV programme (ESTHER). Prescription habits, frequency and reasons for treatment interruptions but also antiviral efficay, resistance to ARVs and genotypic variability of the viruses present in Rwanda were analysed. Among the 233 patients included in the study, it appeared that a vast majority (91%) were under triple therapy and that half of them had experienced at least one treatment interruption caused mainly by drug shortage or financial difficulties. Among 60 blood samples analysed, 26 were in virological failure with a viral load above 1000 RNA copies/ml and 11 presented major drug resistance mutations. Finally, virological failure could mainly be explained by the high frequency of treatment interruptions but also by the emergence of drug resistance mutations. Consequently the major objective for the ESTHER programme to improve the situation in Rwanda will be to reduce the drug shortage and facilitate the financial accessibility of the treatments.

Simple DNA extraction method for dried blood spots and comparison of two PCR assays for diagnosis of vertical human immunodeficiency virus type 1 transmission in Rwanda.

Dried blood spots (DBS) on filter paper facilitate the collection, transport, and storage of blood samples for laboratory use. A rapid and simple DNA extraction procedure from DBS was developed and evaluated for the diagnosis of human immunodeficiency virus type 1 (HIV-1) infection in children by an in-house nested-PCR assay on three genome regions and by the Amplicor HIV-1 DNA prototype assay version 1.5 (Roche Molecular Systems). A total of 150 samples from children born to HIV-1-infected mothers were collected in Kigali, Rwanda, in parallel as DBS and as peripheral blood mononuclear cell (PBMC) pellets. The results obtained on DBS by the two PCR assays were compared to the results of nested PCR on PBMCs. Of 150 PBMC samples, 10 were positive, 117 were negative, and 23 were indeterminate for HIV-1 infection. In DNA extracted from filter papers and amplified by using the in-house nested PCR, 9 of these 10 positive samples (90%) were found to be positive, and 1 was found to be indeterminate (only the pol region could be amplified). All of the negative samples and all of the 23 indeterminate samples tested negative for HIV-1 infection. When we used the Amplicor DNA test on DBS, all of the 10 PBMC-positive samples were found to be positive and all of the 23 indeterminate samples were found to be negative. Of the PBMC-negative samples, 115 were found to be negative and 2 were found to be indeterminate. We conclude that this simple rapid DNA extraction method on DBS in combination with both detection methods gave a reliable molecular diagnosis of HIV-1 infection in children born to HIV-infected mothers.

Financial situation of people living with HIV in Europe.

The objective was to investigate the financial situation of people living with HIV in Europe. Two surveys using an anonymous questionnaire were organized in Europe among people living with HIV, the first in 1996-97 and the second in 1998-99. One thousand one hundred and sixty-one people from the 1996-97 survey and 899 from the 1998-99 survey were included. Four hundred and fifty-seven (42%) of the 1996-97 participants reported that their income had decreased since HIV diagnosis. The latter participants reported significantly more often difficulties in paying for housing (27% vs 20%), food (18% vs 12%) and transport (17% vs 12%) compared to 1998-99 participants. In multiple regression analysis, severity of HIV disease, not being on highly active antiretroviral therapy (HAART), younger age, lower education level and living in the South of Europe were associated with having financial difficulties. We concluded that since the introduction of HAART, the financial situation of persons living with HIV in Europe has improved, but a relatively large percentage of them still have financial difficulties.

HIV-associated hematologic disorders are correlated with plasma viral load and improve under highly active antiretroviral therapy.

The relationship between HIV-1 replication and hematologic parameters was examined in two separate studies. The first study was a cross-sectional evaluation of 207 untreated patients. In this study, the proportion of patients with hematologic disorders increased with disease progression. There was a significant inverse correlation between HIV-1 plasma viral load and all hematologic values (r = -0.266 to -0.331). The second study was a longitudinal evaluation of patients on combination antiretroviral therapy (HAART) with hematologic alterations before treatment ( N = 27 with platelets <150,000/microl, 24 with hemoglobin <12 g/dl, 36 with neutrophils <2000/microl and 29 with leukocytes <3000/microl). Samples were analyzed every 3 months for 2 years. At 2 years, >50% of patients experienced a sustained virologic response, with viral loads <500 RNA copies/ml. Hematologic reconstitution occurred progressively for all blood cell lineages and became statistically significant after the sixth month of therapy ( p <.001). Mean values increased from 110 to 180 x 10(3)/microl for platelets, from 10.7 to 12.3 g/dl for hemoglobin (stabilizing finally at 11.4 g/dl), from 1,260 to 2,240/microl for neutrophils, and from 2,260 to 3,600/microl for leukocytes. In conclusion, hematologic disorders are corrected by combination antiretroviral therapy. This suggests a causative role of HIV-1 in hematologic disorders.

Role of p14(ARF) in replicative and induced senescence of human fibroblasts.

Following a proliferative phase of variable duration, most normal somatic cells enter a growth arrest state known as replicative senescence. In addition to telomere shortening, a variety of environmental insults and signaling imbalances can elicit phenotypes closely resembling senescence. We used p53(-/-) and p21(-/-) human fibroblast cell strains constructed by gene targeting to investigate the involvement of the Arf-Mdm2-p53-p21 pathway in natural as well as premature senescence states. We propose that in cell types that upregulate p21 during replicative exhaustion, such as normal human fibroblasts, p53, p21, and Rb act sequentially and constitute the major pathway for establishing growth arrest and that the telomere-initiated signal enters this pathway at the level of p53. Our results also revealed a number of significant differences between human and rodent fibroblasts in the regulation of senescence pathways.

Clinical outcome among HIV-infected patients starting saquinavir hard gel compared to ritonavir or indinavir.

OBJECTIVE: To compare the clinical response among patients who initiate protease inhibitor therapies with different virological potency. DESIGN: We analysed patients who started indinavir, ritonavir or saquinavir hard gel capsule (hgc) as part of at least triple therapy during prospective follow-up within the EuroSIDA study. METHODS: Changes in plasma viral load (pVL) and CD4 cell count from baseline were compared between treatment groups. Time to new AIDS-defining events and death were compared in Kaplan--Meier models, and Cox models were established to further assess differences in clinical progression (new AIDS/death). Adjustment was made for differences in baseline parameters, in particular pVL, CD4 cell count, and region of Europe. RESULTS: A total of 2708 patients (median follow-up: 30 months) were included, of which 556 started ritonavir (21%), 1342 indinavir (50%), and 810 saquinavir hgc (30%). The three groups were fairly evenly balanced at baseline regarding CD4 count, previous diagnosis of AIDS and pVL, After 12 months, the median changes in CD4 cell count were 90, 96 and 74 x 10(6) cells/l, respectively;P < 0.001, the proportions of patients with pVL < 500 copies/ml were 47, 54 and 41%; P < 0.001, and the proportions with clinical progression were 11.9, 9.2 and 11.9%, respectively; P = 0.20 (log-rank test). In multivariate models the relative risk of clinical progression for indinavir compared with saquinavir hgc was: 0.77 (0.60--0.99); P = 0.043, and for ritonavir 0.83 (0.62--1.11); P = 0.20. CONCLUSIONS: Saquinavir hgc was associated with an inferior long-term clinical response relative to indinavir, which was consistent with the observed differences in virological and immunological responses.

Antiretroviral treatments used among adults with HIV infection in Europe.

International guidelines for the treatment of human immunodeficiency virus (HIV) infection change rapidly. They are mainly based on results from large-scale randomized clinical trials, but also on hypotheses. The objective of the study was to look at the use of antiretrovirals (ARVs) in different HIV treatment centres in Europe. Between August 1996 and September 1997 self-administered anonymous questionnaires were distributed to persons with HIV infection at inpatient and outpatient departments in 11 European countries; 1,366 people completed the questionnaire. Important differences in use of ARVs were noted between different centres. Zidovudine was the drug that was used predominantly in all countries and by 77% of all patients; the use of didanosine, zalcitabine and stavudine differed widely. Use of ARVs was found to be lower for people who reported intravenous drug use (compared to homosexual transmission), people with a low education level, and those with a monthly income lower than 992 Euro. The use of a protease inhibitor containing ARV treatment regimen was significantly lower in the centres in the south of Europe. Between 1996 and 1997, many persons with HIV infection in Europe received a suboptimal ARV treatment regimen. Use of ARVs should be improved for intravenous drug users, persons with lower educational level and lower income.

Phase I/II dose escalation and randomized withdrawal study with add-on azodicarbonamide in patients failing on current antiretroviral therapy.

BACKGROUND: Azodicarbonamide (ADA), a HIV-1 zinc finger inhibitor, targets a new step in viral replication and cell infectivity. OBJECTIVE: A first phase I/II clinical study of ADA. METHODS: ADA was administered at escalating doses concomitantly with current antiviral therapy during a 3-month open-label period in patients with advanced AIDS and documented virological failure. After 3 months, patients were randomized in a double-blind placebo-controlled withdrawal, ADA being given at the highest tolerated dosage. RESULTS: Fifteen patients with advanced disease failing on combined antiretroviral therapy, 75% of them with proven phenotypic resistance, had a median baseline CD4 cell count of 85 x 10(6) cells/l, CD4/CD8 cell ratio of 0.09 and median plasma RNA viral load of 4.2 log10 copies/ml. Tolerance to ADA was dose dependent and some patients developed nephrolithiasis, glucose intolerance or showed an ADA-related cytotoxicity towards CD4 cells at higher dosages. No patient died during the study period. ADA increased CD4 cell percentage, increased the CD4/CD8 cell ratio and decreased plasma RNA viral load from baseline. At the end of the double-blind period, the ADA group, but not the placebo group, showed a significant response (P < 0.05). No phenotypic resistance to ADA was observed. Overall, 3/11 patients (27%) had consistent viral load reductions > 0.5 log10 copies/ml compared with baseline and 5/ 11 (45%) showed a CD4 cell recovery from baseline > 33%. In responders, ADA induced a median peak increase in CD4 cell percentage change from baseline of 65% (range 47-243%), and viral load decrease of 1.04 log10 copies/ml (range 0.52-1.23). CONCLUSIONS: The maximal tolerated dosage of ADA appears to be 2 g (three times daily). This study provides safety results that will allow larger clinical trials to confirm the preliminary efficacy data.

Comparison of DNA sequencing and a line probe assay for detection of human immunodeficiency virus type 1 drug resistance mutations in patients failing highly active antiretroviral therapy.

The resistance of human immunodeficiency virus type 1 (HIV-1) to drugs is a major cause of antiretroviral treatment failure. We have compared direct sequencing to a line probe assay (LiPA) for the detection of drug resistance-related mutations in 197 clinical samples, and we have investigated the sequential appearance of mutations under drug pressure. For 26 patients with virological failure despite the use of two nucleoside analogues and one protease inhibitor (indinavir [n = 6], ritonavir [n = 10], and saquinavir [n = 10]), genotypic resistance assays were carried out retrospectively every 3 months for up to 2 years by using direct sequencing (TruGene; Visible Genetics) and a LiPA for detection of mutations in the reverse transcriptase (INNO-LiPA HIV-1 RT; Innogenetics) and the protease (INNO-LiPA HIV Protease, prototype version; Innogenetics) genes. Comparison of the results from both assays found rare major discrepancies (<1% of codons analyzed). INNO-LiPA detected more wild-type-mutant mixtures than sequencing but suffered from a high rate of codon hybridization failures for the reverse transcriptase. LiPA detected earlier and more frequently than sequencing the transient mixed virus population that contained I84V, which appears before V82A in the protease sequence. Mutations M461, G48V, and L90M were often transient and drug pressure related. In conclusion, direct sequencing and LiPAs give concordant results for most clinical isolates. LiPAs are more sensitive for the detection of mixed virus populations. Mutation I84V appears in minor populations in the early steps of the pathways of resistance to indinavir and ritonavir. The fact that some mutations can be found only transiently and in minor virus populations highlights the importance of a low detection limit for resistance assays.

Variant human immunodeficiency virus type 1 proteases and response to combination therapy including a protease inhibitor.

The objective of this observational study was to assess the genetic variability in the human immunodeficiency virus (HIV) protease gene from HIV type 1 (HIV-1)-positive (clade B), protease inhibitor-naïve patients and to evaluate its association with the subsequent effectiveness of a protease inhibitor-containing triple-drug regimen. The protease gene was sequenced from plasma-derived virus from 116 protease inhibitor-naïve patients. The virological response to a triple-drug regimen containing indinavir, ritonavir, or saquinavir was evaluated every 3 months for as long as 2 years (n = 40). A total of 36 different amino acid substitutions compared to the reference sequence (HIV-1 HXB2) were detected. No substitutions at the active site similar to the primary resistance mutations were found. The most frequent substitutions (prevalence, >10%) at baseline were located at codons 15, 13, 12, 62, 36, 64, 41, 35, 3, 93, 77, 63, and 37 (in ascending order of frequency). The mean number of polymorphisms was 4.2. A relatively poorer response to therapy was associated with a high number of baseline polymorphisms and, to a lesser extent, with the presence of I93L at baseline in comparison with the wild-type virus. A71V/T was slightly associated with a poorer response to first-line ritonavir-based therapy. In summary, within clade B viruses, protease gene natural polymorphisms are common. There is evidence suggesting that treatment response is associated with this genetic background, but most of the specific contributors could not be firmly identified. I93L, occurring in about 30% of untreated patients, may play a role, as A71V/T possibly does in ritonavir-treated patients.

Role of T cells and cytokines in fatal and resolving experimental babesiosis: protection in TNFRp55-/- mice infected with the human Babesia WA1 parasite.

We characterized the cytokine response and T-cell requirements of mice infected with the intraerythrocytic parasites Babesia microti and WA1. WA1 infections were fatal, whereas B. microti infections were resolved. We measured production of tumor necrosis factor (TNF)-alpha, interferon-gamma, interleukin (IL)-10, and IL-4 by splenic CD4+, CD8+, and gammadelta+ T cells using flow cytometry. WA1 inoculation stimulated TNF-alpha production, whereas resolving B. microti infections were characterized by increased IL-10 and IL-4. The role of TNF-alpha in WA1 infections was further investigated by inoculating TNFRp55-/- mice with a lethal dose of WA1. A survival rate of 90% in the TNFRp55-/- mice indicated that a disruption in the TNF-alpha pathway abrogated the pathologic mechanism of WA1. Inoculation of WA1 into CD4-/- and CD8-/- mice resulted in survival rates of 60% and 78%, respectively, whereas WA1 infection in gammadelta-/- and control mice was fatal. These results suggest that CD8+ T cells may contribute to the WA1-associated disease. Babesia-infected CD4-/- mice experienced a longer duration of parasitemia, indicating that CD4+ T cells participate in parasite elimination. These studies demonstrate differences in immune responses during fatal or resolving Babesia infections, and they identify TNF-alpha as an important mediator of the WA1-associated pathogenesis.

Comparative estrogenicity of estradiol, ethynyl estradiol and diethylstilbestrol in an in vivo, male sheepshead minnow (Cyprinodon variegatus), vitellogenin bioassay.

An in vivo bioasssay for vitellogenin (VTG) synthesis was developed to screen individual chemicals or mixtures of chemicals for potentially estrogenic effects in a marine teleost model. An enzyme-linked immunosorbent assay (ELISA) was used to quantitate VTG synthesis in male sheepshead minnows (Cyprinodon variegatus) exposed to five concentrations of the natural estrogen (17beta-estradiol), a synthetic, steroidal pharmaceutical estrogen (17alpha-ethynyl estradiol), or a synthetic, non-steroidal, pharmaceutical estrogen (diethystilbestrol) for 16 days. At an exposure concentration of 20 ng/l, only diethystilbestrol elicited a vitellogenic response. At all test concentrations greater than 100 ng/l, VTG appeared in the plasma in a dose-dependent manner for the three estrogen treatments. Liver VTG mRNA measurements were also made, exhibiting no clear correlations between quantities, nor temporal appearance of the message and mature protein were apparent. This assay is short-term, relatively inexpensive, shows a direct response, and easily quantitated.

Up-regulation of tumor necrosis factor-alpha and interferon-gamma expression in the spleen and lungs of mice infected with the human Babesia isolate WA1.

We analyzed cytokine expression in mice infected with the intraerythrocytic parasites Babesia microti and WA1. In C3H/HeN mice, WA1 infections were fatal, whereas B. microti infections were resolved. We propose that the proinflammatory cytokines tumor necrosis factor-alpha (TNFalpha) and interferon-gamma (IFNgamma) contribute to the WA1-associated disease. WA1 infection was characterized by up-regulation of TNFalpha and IFNgamma mRNA in the spleen. Previous studies in WA1-infected mice showed that pathologic lesions occurred primarily in the lungs, including pulmonary edema and intravascular margination of leukocytes. Analysis of cytokine expression in the lungs is important for an understanding of the disease process in WA1-infected mice. Expression of both TNFalpha and IFNgamma mRNA was increased in the lungs of WA1-infected mice. Immunohistochemical staining confirmed the upregulation of these proinflammatory cytokines in the lungs. Expression of TNFalpha and IFNgamma was not up-regulated in the lungs of B. microti-infected mice. The results implicate TNFalpha and IFNgamma in the pathogenesis of WA1-associated disease.

Three-year effectiveness of highly active antiretroviral treatment in the Luxembourg HIV cohort.

UNLABELLED: Clinical trials have shown that highly active antiretroviral treatment (HAART) is able to reduce HIV plasma viral loads to undetectable in 70% to 90% of patients and to increase CD4 cell counts. HAART in community settings (i.e., nonclinical trial situations) is reported to be much less effective. STUDY DESIGN: Observational study. PURPOSE: The aim of our study was to evaluate the effectiveness of protease inhibitor (PI)-based HAART in the Luxembourg HIV cohort after 36 months of treatment in previously treated and untreated patients. The secondary aim was to identify surrogate markers associated with long-term virologic and immunologic outcomes. PATIENTS AND METHOD: Seventy-three PI-naive patients, who started on HAART, combining one PI and two nucleoside reverse transcriptase inhibitors (NRTIs),with a follow-up of 3 years, were evaluated with plasma viral load and CD4 cell counts every 3 months and were analyzed retrospectively. Patients who had been treated previously with NRTI (n = 48) were at a more advanced stage of disease. RESULTS: Overall, there was a mean decrease in viral load compared to baseline of -1.89 log RNA copies/mL (SD = 1.40) that persisted at month 36. Sixty-two percent (62%) of patients reached an undetectable viral load (i.e., below 500 copies/mL): 82% and 53% of NRTI-naive and NRTI-experienced patients, respectively (p =.013). CD4 cell counts increased progressively in both groups with a sustained effect (mean increase of 146 cells/mL +/- 241) at month 36. NRTI-naive patients had a mean increase of 257 cells/mL (SD = 305), in contrast to experienced patients who had an increase of 108 cells/mL (SD = 206) at 3 years. Proportions of patients with a CD4 count under 200 cells/mL fell after 3 years for NRTI-naive (from 66% to 43%) and for experienced patients (from 32% to 13%). Predictors of short duration of viral load response were in decreasing order of importance: clinical AIDS, the use of saquinavir hard gel formulation as initial PI, and the number of NRTIs previously used. Viral load response was the only significant predictor of CD4 changes. CONCLUSION: In a community setting, effectiveness of PI-based HAART at 3 years is still achieved for most patients. NRTI-experienced patients have a good long-term response rate even if it is lower than NRTI-naive patients. A poor treatment response is associated with a more advanced stage of disease before HAART is introduced.

Endothelial cell changes are associated with pulmonary edema and respiratory distress in mice infected with the WA1 human Babesia parasite.

A C3H/HeN mouse model was established to study the pathogenesis of the human babesial parasites, WA1 and Babesia microti. To evaluate the course of parasitemia and the associated lesions, mice were inoculated intraperitoneally with either WA1-infected, B. microti-infected, or uninfected hamster red blood cells. WA1-infected mice developed dyspnea and moderate parasitemias, after which death occurred. Babesia microti-infected mice experienced low parasitemias with no apparent morbidity or mortality. WA1-infected mice were thrombocytopenic but not anemic. Hemograms for B. microti-infected mice were similar to controls. Postmortem examination of WA1-infected mice revealed prominent lesions in the lungs, including pulmonary edema and intravascular margination of leukocytes. No pulmonary changes were detected in B. microti-infected mice. Blood gas measurements of WA1-infected mice showed reduced oxygen saturation and pH, and increased carbonic acid compared to controls, indicating hypoxia and respiratory acidosis. Ultrastructure studies of WA1-infected lungs showed hypertrophied endothelial cells containing transcellular channels associated with protein-rich intra-alveolar fluid. Endothelial cell activation was demonstrated by an upregulation of intercellular adhesion molecule-1 in the lungs of WA1-infected mice. The results suggest that recruitment of inflammatory cells to the lungs in WA1-infected mice induces endothelial cell alterations, leading to pulmonary edema and acute respiratory failure.

Haptoglobin polymorphism, iron metabolism and mortality in HIV infection.

BACKGROUND: Three phenotypes of the antioxidant protein haptoglobin are known: Hp 1-1, Hp 2-1 and Hp 2-2. OBJECTIVES: To investigate the outcome of HIV infection according to haptoglobin type. DESIGN AND METHODS: Haptoglobin phenotypes were determined using starch gel electrophoresis in serum obtained from 653 HIV-infected Caucasians in the AIDS reference centers of Gent (n = 184), Antwerp (n = 309), and Luxembourg (n = 160). Survival was compared between haptoglobin types using Kaplan-Meier curves. Plasma HIV-1 RNA was quantified by reverse transcriptase PCR. Serum iron, transferrin saturation, ferritin, and vitamin C were assayed to evaluate iron-driven oxidative stress in 184 HIV-infected patients and 204 controls. RESULTS: The haptoglobin type distribution amongst the patients (17.6% Hp 1-1, 49.9% Hp 2-1, 32.5% Hp 2-2) corresponded to that of the controls. Kaplan-Meier curves showed a higher mortality for the Hp 2-2 group (P = 0.0001; adjusted mortality risk ratio, 1.78; 95% confidence interval, 1.25-2.54). Median survival time was 11.0 years (Hp 1-1 and Hp 2-1) versus 7.33 years (Hp 2-2). Plasma HIV-1 RNA levels prior to antiviral therapy and their increase over 1 year were highest in Hp 2-2 patients (P = 0.03 and 0.003, respectively). The Hp 2-2 type was associated with higher serum iron, transferrin saturation, and ferritin levels and with low vitamin C concentrations. Furthermore, ferritin concentrations were higher in HIV-infected patients than in controls (P < 0.0001). CONCLUSION: HIV-infected patients carrying the Hp 2-2 phenotype show a worse prognosis, which is reflected by a more rapid rate of viral replication (in the absence of antiviral treatment). They also accumulate more iron and oxidize more vitamin C, suggesting that less efficient protection against haemoglobin/iron-driven oxidative stress may be a direct mechanism for stimulating viral replication.

Fast genotypic detection of drug resistance mutations in the HIV-1 reverse transcriptase gene of treatment-naive patients.

OBJECTIVES: This study was performed to assess the frequency of drug resistance mutations in treatment-naive HIV-1-infected patients. STUDY DESIGN/METHODS: Frozen plasma samples from 135 treatment-naive HIV-infected adults were available from the first time the patients were seen for their infection in our center between 1992 and 1997. A rapid genotypic assay based on reverse DNA hybridization (LiPA HIV-1 RT, Murex, London, U.K.) was used to study substitutions at reverse transcriptase (RT) codons 41, 69, 70, 74, 184, and 215. Additionally, a selective polymerase chain reaction (PCR) for the multiple dideoxynucleoside resistance (MddNR) mutation Q151M was performed. RESULTS: 16 patients (12%) harbored virus with one or more drug resistance mutations. The prevalence of patients with drug-resistant virus was 0% in 1992, 17% in 1993, 0% in 1994 (only 6 samples tested), 18% in 1995, 14% in 1996, and 9% in 1997. Mutation K70R (resistance to zidovudine) was found in 8 patients, M41L (resistance to zidovudine) in 5 patients, M184V/I (resistance to ddI/ddC/3TC) in 2 patients, and T215Y/F (resistance to zidovudine) in 4 patients. All samples were wild type at codons 69 (ddC), 74 (ddI), and 151 (MddNR). CONCLUSIONS: Virus strains containing drug resistance mutations are now found in about 1 of 10 treatment-naive HIV-1-seropositive patients in Luxembourg. We believe that testing for drug-resistant virus before starting treatment should be recommended and will help to improve the selection of the most effective antiretroviral treatment. We also suggest the need for an international surveillance program on HIV drug resistance in treatment-naive patients.