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As with other nucleoside analogues, tenofovir (TDF) can be affected by several mutations in the reverse transcriptase gene. Most nucleoside analogue mutations (NAMs) are not induced specifically by TDF, although they can affect the activity of this drug. The impact of thymidine analogue mutations (TAMs) on tenofovir varies and, as with the remaining nucleoside analogue reverse transcriptase inhibitors, largely depends on the type and number present. Thus, the greater the number of TAMs, and the greater the number of type 1 TAMs, the more TDF activity will be affected. The 41L and 210W mutations have the greatest effect. The incidence of the 65R mutation was slight before the clinical introduction of TDF. This mutation was selected by treatments with zalcitabine monotherapy. However, after TDF came on to the market, the 65R mutation began to be more frequently reported and is currently the signature mutation of this drug. TDF has been shown to be safe and effective in patients with prior virological failure and resistance mutations in the reverse transcriptase gene. In these patients, the presence of the 41L and 210W mutations is associated with a worse response to rescue therapy containing TDF. In contrast, the presence of type 2 TAMs (67N, 70R and 219Q/E/N) has little effect on TDF activity in these patients. Importantly, in TDF therapy, the presence of the 184V mutation is associated with a more favorable virologic response than the absence of this mutation, with any of the distinct combinations of mutations present.

Currently, there are around 150,000 HIV-infected patients in Spain. This number, together with the fact that this disease is now a chronic condition since the introduction of antiretroviral therapy, has generated an increasing demand on the clinical microbiology laboratories in our hospitals. This increase has occurred not only in the diagnosis and treatment of opportunistic diseases, but also in tests related to the diagnosis and therapeutic management of HIV infection. To meet this demand, the Sociedad de Enfermedades Infecciosas y Microbiología Clinica (Spanish Society of Infectious Diseases and Clinical Microbiology) has updated its standard Procedure for the microbiological diagnosis of HIV infection. The main advances related to serological diagnosis, plasma viral load, and detection of resistance to antiretroviral drugs are reviewed in this version of the Procedure.

Resistance to medication, adverse effects in the medium-long term, and cost are important limitations to lifelong adherence to highly active antiretroviral therapy (HAART). The combination of HAART with immune therapy to restore and/or boost immune-specific responses to HIV has been proposed, with the ultimate aim of controlling viral replication in the absence of HAART over long periods. The functional defects of the cellular and humoral responses would explain the lack of control of the immune system over viral replication. Different types of immune-mediated therapy have been investigated to solve these problems, including passive immune therapy, cytokines, structured treatment interruptions, immunosuppressors and therapeutic vaccines. Our still limited knowledge of immune mechanisms which can control HIV viral replication and of the causes of the deterioration of cellular and humoral immunity have produced only modest benefits in immune-mediated therapy, and are therefore confined to research for the time being. The availability of an optimal therapeutic vaccine would be an important scientific advance which could be compared with the arrival of protease inhibitors in clinical practice. Therefore, priority should be given to research in this field.

Objective: To provide an update of guidelines from the Spanish AIDS Study Group (GESIDA) and the National AIDS Plan (PNS) committee on the prevention of opportunistic infections in adult and adolescent HIV-infected patients., Methods: These consensus recommendations have been produced by a group of experts from GESIDA and/or the PNS after reviewing the earlier document and the scientific advances in this field in the last years. The system used by the Infectious Diseases Society of America and the United States Public Health Service has been used to classify the strength and quality of the data., Results: This document provides a detailed review of the measures for the prevention of infections caused by viruses, bacteria, fungi and parasites in the context of HIV infection. Recommendations are given for preventing exposure and for primary and secondary prophylaxis for each group of pathogens. In addition, criteria are established for the withdrawal of prophylaxis in patients who respond well to highly active antiretroviral therapy (HAART)., Conclusions: HAART is the best strategy for the prevention of opportunistic infections in HIV-positive patients. Nevertheless, prophylaxis is still necessary in countries with limited economic resources, in highly immunodepressed patients until HAART achieves beneficial effects, in patients who refuse to take or who cannot take HAART, in those in whom HAART is not effective, and in the small group of infected patients with inadequate recovery of CD4+ T lymphocyte counts despite good inhibition of HIV replication.

We have evaluated the efficacy of fluconazole, 50 mg/day for 2 weeks, to treat oropharyngeal candidiasis in immunologically compromised patients. There were overall 27 patients, 25 of which were HIV+ and 2 had neutropenia. The rate of clinical response at the end of therapy, and one week and one month afterwards were 96%, 76% and 64%, respectively. The microbiological eradication was achieved in 36% of patients. The tolerance of the drug was satisfactory, although in 3 cases features of hepatic toxicity were detected. The convenience, good tolerance and clinical efficacy of fluconazole make it the therapy of choice for oropharyngeal candidiasis in immunologically compromised patients.