Este volumen de la Revista Anti reune trabajos presentados en el XIII Coloquio Binacional Argentino – Peruano, llevado a cabo en la Ciudad Autonoma de Buenos Aires. El interes por los cambios educativos que programa esta jurisdiccion, los dilemas que plantea la calidad de la escuela y la incertidumbre sobre el futuro de las ciencias y la cultura estuvieron en el centro de los debates de este evento cientifico. No fue casual, dado que el mismo tuvo como sede el Instituto Superior del Profesorado Dr. Joaquin V. Gonzalez, institucion centenaria y vanguardista. Estas cualidades no son contradictorias. El volumen se completa con aportes epistemologicos, politicos e historicos. Los Editores
El Seminario “Los Andes antes de los Inka” ha sido declarado de “Interes de la Ciudad de Buenos Aires” por el Consejo Deliberante en su sesion del 19 de diciembre de 1996, con la sancion de la Ordenanza N° 51.426, segun expediente 2892-C-96, mediante despacho de la Comision de Cultura y Asuntos Intercomunales
Pseudomonas aeruginosa bacteremia are mainly nosocomial or health-related diseases. They occur, above all, in old patients who are immunocompromised, who care invasive devices or have been previously treated with antibiotics. It accounts for 3,8% of bacteremia in France. The main origins are urinary or pulmonary infections. It is a severe disease, with an average mortality of 30%. Factors associated with a poor prognosis are: a collapse, a pulmonary origin, a neutropenia or an inappropriate empirical antimicrobial therapy. Treatment is difficult, due to high resistance rates to antibiotics, which are increased by previous antibiotic therapies and invasive devices or procedures. Evaluation of the risk of P aeruginosa bacteremia and the risk of resistance to antibiotics is necessary in front of a patient with signs of bacteremia, in order to prescribe quickly an appropriate therapy. A combination therapy is justified until the receipt of antibiogramm. (C) 2010 Elsevier Masson SAS. All rights reserved.
Procalcitonin is considered to be a pro-hormone that behaves like a cytokin. It has been extensively assessed for more than 15 years as a help for diagnosis and prognosis of infectious diseases. There is a controversy concerning its usefulness but its limits are related to the use of insensitive tests and the absence of "gold standard" for good comparisons. The use of serial measurement of procalcitonin with the latest high sensitive test allowed researchers to carry out several interventional studies regarding respiratory tract infections and sepsis in critically ill-patients. These studies demonstrated a dramatic reduction on antibiotic consumption without modification of the outcome. Elderly population is more prone to infection, while definite diagnosis and prognosis are more difficult to provide because of atypical clinical presentation, and yields of CT scan, radiographic and microbiological diagnosis are decreasing. Yet, the usefulness of biomarkers such as procalcitonin is an evidence helping for diagnosis, prognosis and therapy as well. However, to date only four studies have been carried out specifically in elderly population. It shows some differences as compared to younger patients. Consequently, it seems urgent to perform interventional studies with the latest high sensitive test to determine whether procalcitonin may improve the management of infectious diseases in elderly population. (C) 2010 Elsevier Masson SAS. All rights reserved.
The role of the human immunodeficiency virus type 1 protease is to cleave Gag and Gag-Pot polyproteinic precursors at specific sites called cleavage sites to release the structural proteins (p7, p17 and p24) and enzymes (protease, reverse transcriptase and integrase) of the virus. Ribosomal -1 frameshifting mediated by a downstream signal is required for translating the messenger RNA in these precursors. At time of virological failure, mutations associated with resistance to PI in protease gene are selected. These substitutions are responsible for a decrease in viral replicative capacity. Mutations at group specific antigen (gag) cleavage sites can be selected in virus from patients failing PI containing regimen. Studies have shown that presence of gag cleavage sites substitutions in the absence of mutations in the protease gene might be associated with virological failure. (C) 2010 Elsevier Masson SAS. All rights reserved.
Microbiological resistance of Aspergillus spp. is increasing. The first step is a correct species identification since the taxonomy of Aspergillus sections has been recently revised. Inside a given section, resistant and susceptible species can coexist. For the azole resistance in Aspergillus fumigatus, mutations in cyp51A gene have been evidenced. For the other molecules and the other species, the responsible mutations are still being described. Knowledge of epidemiology of resistance is insufficient. Environmental pressure due to agriculture use of fungicides seems to be a major cause compared to medical use of antifungal drugs. Surveillance programs are needed for the next years for surveying these phenomena and to adapt our therapeutic guidelines. (C) 2010 Elsevier Masson SAS. All rights reserved.
The purpose of this paper was to detail the different steps of a nosocomial infection outbreak investigation. The first steps of an investigation are infection and outbreak confirmation, cases definition and exhaustive case identification. A descriptive study is useful to generate hypotheses on the source or on the routes of transmission that should be tested in an analytical study. At the same time, appropriate control measures based on investigation results should be established as soon as possible to control outbreak extension. Collaborative work between health professionals is required for an efficient outbreak investigation and is a determining factor of its control. (C) 2010 Elsevier Masson SAS. All rights reserved.
In recent years, marked progress has been made in the treatment of chronic hepatitis B. Several agents are currently approved: interferon alpha (IFN), pegylated interferon alpha 2a (PEG-IFN alpha 2a), lamivudine, adefovir, entecavir, tenofovir and telbivudine. Each agent has advantages and inherent limitations. IFN and PEG-IFN alpha 2a have the advantage to induce a sustained virologic response after a defined, self-limited course of treatment. However, these agents are effective in a minority of patients and have frequent side effects that limit its tolerability. Analogues have the advantages of oral administration and excellent safety profiles with very high antiviral effect. However, these drugs need to be indefinitely administered since withdrawal of therapy is generally associated with reactivation, and sustained response is uncommon except in HBe Ag positive patients who developed HBe seroconversion. In case of HBe seroconversion, it is generally recommended to prolonge therapy for at least 24 weeks before its withdrawal. The efficacy of lamivudine is limited by the emergence of lamivudine-resistant HBV. Adefovir is associated with moderate incidence of resistance but its antiviral effect is not optimal. Telbivudine may have enhanced potency and lower rates of resistance than lamivudine but its resistance rate is significantly superior to other approved therapies. Entecavir and tenofovir which have recently been approved, showed an increased effectiveness against HBV with favourable safety profile and low incidence of resistance. (C) 2010 Published by Elsevier Masson SAS.
HIV controllers (HIC) constitute a homogeneous subset of untreated HIV1 infected patients with prolonged undetectable viral load. They are defined according to a virological definition. Characteristics of these rare patients may help to understand how HIV1 replication can be controlled. This could lead to help vaccine development. These patients are infected by replication competent virus strains. Their CD4 T cells are fully susceptible to HIV infection, and till now, no intrinsic host resistance factor has been found. Control of the virus is related to an immune pathway. Humoral immune response (neutralizing antibodies) is heterogeneous but Antibody Dependant Cell Cytotoxicity (ADCC) seems to be higher in controllers. T cell immune response seems to be the most important. Specific anti-gag CD8+ T cell response is multifunctional and leads to elimination of infected CD4+ T cells by cytotoxic mechanisms. This response is HLA I restricted, and HLA B27 and B57 alleles are overrepresented in HIC. Specific CD4+ T cell response and central memory T cells are preserved. High avidity of HIV-specific CD4 T cells allows a rapid anti-HIV response. This anti-HIV1 control may be efficient early after the infection. Innate immunity combined with unknown genetic factors may be important. A better knowledge of the mechanisms underlying this spontaneous control of HIV infection should help to provide new clues for the design of therapeutic strategies or vaccine. To better understand the mechanisms explaining the rare HIV controller phenotype and to facilitate the long-term follow-up of these rare patients, a French cohort (Agence nationale de recherche pour le Sida [ANRS] CO18 HIC) was created. (C) 2010 Elsevier Masson SAS. All rights reserved.
In the recent recommendations regarding the therapeutic management of Helicobacter pylori infection, originating from European, North-American and Asia-Pacific consensus guidelines, novel indications for eradication appear: prior to non-steroidal anti-inflammatory drug therapy in high-risk patients; patients under long-term aspirin treatment and a history of bleeding; patients with uninvestigated dyspepsia under the age of 45 without alarm symptoms; patients receiving long-term proton pump inhibitor (PPI) treatment; unexplained iron defiency anemia, idiopathic thrombocytopenic purpura. Concerning the prevention of distal gastric cancer, eradication is recommended after gastric cancer resection, in the presence of atrophic gastritis, and for patients who are first degree relatives of patients with gastric cancer. The firstline treatment recommended in France is the amoxicillin-clarithromycin-PPI tritherapy, which has an efficacy of about 70%. In case of failure, due in most cases to clarithromycin resistance, this drug must be replaced by metronidazole. If this treatment also fails, antibiotic susceptibility testing has to be performed. However, given that the prevalence of primary resistance to clarithromycin already reaches almost 20% in France, testing the susceptibility to clarithromycin before any treatment could be a more judicious approach, which has to be evaluated. Two other drugs can be associated with amoxicillin and PPIs: a fluoroquinolone, levofioxacin, and a rifampin derivative, rifabutin. (C) 2010 Elsevier Masson SAS. All rights reserved.
The treatment of bone and joint infections can be difficult and quite challenging since it frequently involves prolonged administration of antibiotics as well as appropriate surgical procedures. First line drugs fail to cure the infection in some cases. We performed a systematic review of the available literature to further clarify the effectiveness and safety of daptomycin in the treatment of bone and joint infections. Daptomycin, which is a new intravenous lipopeptidic antibiotic, has potent in vitro bactericidal activity against Gram-positive bacteria, including most resistant pathogens to methicillin and vancomycin. Our review indicates that in vitro, animal and human data are promising regarding efficacy and safety profile of this new antibiotic for bone and joint infections that are not responsive to other traditionally used antimicrobial agents. However, the possible emergence of resistance associated with prolonged administration of daptomycin should be considered. Further randomised studies are warranted with analysis of bone penetration and activity in bone tissue in human. (C) 2010 Elsevier Masson SAS. All rights reserved.
Buruli ulcer is due to Mycobacterium ulcerans, described in 1948 in Australia. It is an important health problem in 30 countries, mostly in tropical areas in a humid and hot climate (West Africa, Asia, Papua New Guinea, Australia). There is an increasing prevalence due to the deforestation and the ecological alterations. Children under fifteen years of age have a higher risk. In 80% of cases, lesions are in the limbs. M. ulcerans was found in aquatic insects. The mode of transmission of infection remains uncertain (mild traumatic injuries). Lesions in the skin are nodules, cutaneous ulcers, oedema, which evoluate to extensive ulcers, with necrosis and severe deformity. Diagnosis must be done with cutaneous leishmaniasis, tropical phagedenic ulcer, noma or mycosis. Diagnosis is based on ulcer swabs or biopsies and a culture in Loewenstein medium at 30 degrees C. Antibiotic therapy (rifampicin streptomycin) and surgical excision are useful to the recovery. Regular use of soap for washing and treating injuries appeared protective against M. ulcerans. BCG vaccination has a mild protective effect. (C) 2009 Elsevier Masson SAS. All rights reserved.
Apart from a few new drugs, the last 10 years have not been characterized by any real progress in the field of antibiotics. The only significant advances have been done in the field of health care control and have included the reduction of unnecessary antibiotic consumptions. Experimental infections have contributed to the proper use of antibiotics by showing differences in activity in vivo between different treatment dosing regimens that have optimized the method of administration of antibiotics or antibiotic dosing required to overcome some resistance mechanisms. In the future, animal models may continue to contribute to the evaluation of new drugs. (C) 2010 Elsevier Masson SAS. All rights reserved.
Rift Valley fever is a tropical arboviral disease, described in 1931 in Kenya, due to a bunyavirus (genus Phlebovirus), which affects a wide range of domestic and savage animals and human beings. Human can be exposed to virus by handling infected animal tissues and by the vectors (Aedes and Culex). The disease is located mostly in Africa and also in Comoros, Arabian peninsula, Yemen and Egypt. Clinical incidence is high in ruminants, causing abortions in pregnant animals and high mortality rates in newborns. The human disease occurs during periods of intense epizooty, and patients complain of fever, arthralgia, gastrointestinal disturbances, then jaundice, abdominal pain, delirium and sometimes hemorrhagic manifestations. An effective vaccine of animals is the best approach to control the Rift valley disease. (C) 2010 Elsevier Masson SAS. All rights reserved.
M. xenopi pulmonary infections are responsible for more than 20% of non-tuberculous mycobacteria infections in France. Only few data are available on the optimal treatment regimen for M. xenopi pulmonary disease. The first step in the management of these patients is to check whether patients met infection criteria (clinical, radiological and microbiological criteria). An appropriate exclusion of other diagnoses should be done. Treatment decision is secondarily based on potential risks and benefit therapy for individual patients. The optimal treatment regimen is unknown. In vitro, clarithromycin and moxifloxacin have the lowest MIC. But no correlation between susceptibility in vitro and clinical efficacy has been found. Very few human studies are available (two randomized clinical trials with 42 and 34 patients, respectively, and some retrospective studies). A treatment with at least three active drugs against M. xenopi is required during 12 to 18 months. The American Thoracic Society has proposed a regimen with clarithromycin, rifampin and ethambutol. Moxifioxacin could be used instead of one of these three drugs. Among these four drugs, the choice of the regimen depends on patient's contra-indications, drugs interactions and adverse effects. Treatment should be adapted to the efficacy and tolerance. A control of sputum conversion is required. (C) 2010 Elsevier Masson SAS. All rights reserved.
Microbicides can be defined as topical compounds able to reduce significantly the risk of sexually-transmitted diseases. The aim of this review is to present an overview of the knowledge concerning the capacity of vaginal microbicides to protect women against the sexual transmission of human immunodeficiency virus type 1 (HIV-1). Anti-HIV-1 microbicides include non-specific compounds such as detergents, polyanions or entry inhibitors, and HIV-specific compounds that include mainly inhibitors of the initial steps of the virus cell cycle and reverse transcriptase inhibitors. Although the microbicide approach looks very attractive from the conceptual point of view, no controlled randomised clinical trial using first generation compounds has demonstrated any preventive protection against HIV-1 infection. Encouraging results were obtained recently in models using non human primates and several clinical trials are in progression in different countries that will give their verdict very soon. The present review displays a summary of these different data and discusses further the preclinical evaluation of the benefit-risk balance of microbicides, the usefulness of combining different microbicide compounds and the ability of topical microbicides to select resistant viral mutants. A better knowledge of the way(s) the virus penetrates through the sexual mucosa could contribute to develop more adapted microbicide strategies. In the absence of short-coming perspective relative to HIV-1 immunisation, microbicides must be evaluated as a valuable alternative to prevent women - and especially the most vulnerable of them- from being infected by HIV-1. (C) 2010 Elsevier Masson SAS. All rights reserved.
Candida spp. vertebral osteomyelitis is rare and remains poorly understood. Most patients have risk factors for candidemia or are intravenous drug addicts. Clinical presentation is unspecific: back pain, and sometimes fever. The microbiological diagnosis requires culture of a biopsy specimen. Radiological features are unspecific. Medical treatment is the first step of therapeutic management, based on prolonged courses of fluconazole or liposomal amphotericine B. Surgery is indicated in case of complication (instable location, spinal cord impingement), or to obtain biopsy specimens. The prognosis is good in the absence of significant comorbidity. (C) 2010 Elsevier Masson SAS. All rights reserved.
Colistin (polymyxin E) designates two different drugs, colistin sulfate, an oral digestive decontaminant, and colismethate sodium (CMS) intended for intravenous, intrathecal/intraventricular, or inhaled therapy. Colistin interferes with bacterial membranes creating cytoplasmic leaks lethal to bacteria through interactions with membrane proteins and phospholipids (including LPS). This mechanism of action confers bactericidal activity to colistin on frequently multiresistant pathogens such as Acinetobacter spp., P aeruginosa, and Klebsiella spp. It also leads to specific resistance mechanisms, which arise from modifications in bacterial membrane proteins. New methods applied to pharmacokinetic studies of colistin take into account the in-solution and plasmatic hydrolysis of CMS, the inactive prodrug, into active compounds among which colistin. These studies show that current therapeutic regimens may be optimized. Colistin being a concentration dependent bactericidal antibiotic, the area under the curve (AUC)/MIC was proven the best PK/PD parameter associated with in vivo efficacy, opening new perspectives in alternate dosing regimens. Nephrotoxicity occurs at a rate comparable to aminoglycosides and neurotoxicity is more often benign; both being reversible upon discontinuation of therapy. In multiresistant Gram negative, mostly A. baumanii or P aeruginosa, nosocomial infections as well as in chronic P aeruginosa infections and exacerbations in cystic fibrosis patients, the efficacy of colistin has been demonstrated within the limitations inherent to studies of an antibiotic which can only be used after determination of susceptibility in severe infections nonetheless requiring urgent adequate therapy. Further clarifications are required concerning the added benefit of combination with antibiotics considered as synergistic such as rifampicin and carbapenems. (C) 2010 Elsevier Masson SAS. All rights reserved.
