EMC - Maladies Infectieuses最新文献

Anaerobic bacteria can cause a variety of endogenous infections. Because of their fastidious nature, they are difficult to isolate from infectious sites, and are often overlooked. Anaerobic infections can occur in all body sites, including the central nervous system, the oral cavity, head and neck, chest, abdomen, pelvis, bone, and soft tissues. Their direct pathogenicity is well established in many infectious sites. The lack of adequate therapy may result in clinical failures. Their isolation requires appropriate methods of collection, transportation and specimen cultivation. Treatment is complicated by their slow growth, their polymicrobial nature and their growing resistance to antimicrobials. Antimicrobial therapy is often the only type of therapy required, whereas in a surgical approach it is used as an important adjunctive treatment. Because anaerobes are generally associated with aerobic organisms, the choice of antimicrobial agents should provide coverage of both types of pathogens.

Babesioses are emerging and ubiquitary diseases caused by a tick born protozoa. They affect primarily the cattles but also wild mammalians, particularly bovines. Human cases have been recently described; their frequency increase since new diagnostic tests are available, with higher sensibility, and new species have been characterized. The American type due to Babesia microti is often asymptomatic, whereas the European form, due to Babesia divergens, is more severe, above all in patients with splenectomy. Early emergency parasitologic diagnosis is necessary, so early treatment can be prescribed, associating clindamycin and quinin or atovaquone and azithromycin.

The therapeutic management of unusual mycosis which occur essentially in tropical areas has considerably improved the prognosis of this disease. Some new antifungal agents are under evaluation. There is no treatment of choice for rare mycosis, but recent trials on series of therapeutic options have generated recommendations. The selection of a treatment should consider several conditions, such as their cost, their secondary effects, but also the diagnosis possibility, and the health status of the patient.

Human papillomaviruses (HPVs) are responsible for frequent cutaneous and mucosal infections. The best known lesions are warts and genital condyloma. In the anogenital area, HPV are a true venereal disease. It is now well demonstrated that some HPVs are involved in the development of intraepithelial neoplasia and are considered as a necessary but not sufficient step for invasive cervical cancer. Organotypic cultures have allowed a better understanding of the viral cycle and carcinogenesis process. The in vitro production of virus-like particles has made possible a vaccinal approach.

HTLV-1 (Human T cell leukemia /Lymphoma virus type 1), the first oncogenic retrovirus discovered in Human in 1980, possesses the classical gag, pol, and env genes coding the structural and enzymatic proteins as well as a unique region (named pX) coding the regulatory proteins Tax and Rex. Tax stimulates the viral transcription and also plays a fundamental role in leukemogenesis by modifying the expression of several genes crucial for the survival as well as the proliferation of the cell. HTLV-1 is principally an etiological agent of two diseases associated to a very bad prognosis: malignant T cell lymphoproliferation; the adult T cell leukemia/lymphoma (ATLL) and a chronic neuromyelopathy, the tropical spastic parapareris/HTLV-1 associated myelopathy. HTLV-1 is not ubiquitous. Fifteen to 20 millions of individuals are infected worldwide, mainly in high endemic areas such as Southern Japan, intertropical Africa, the Caribbean region and the surrounding areas including parts of South America. In these areas, 0.5 % to 50 % of the people, depending on age and sex, are infected by the virus and are therefore HTLV-1 seropositive. HTLV-1 is transmitted from mother to child through prolonged breast-feeding, by sexual contacts mainly from male to female and by blood transfusion through passage of infected lymphocytes. The distribution of the different molecular subtypes (genotypes) is linked to the geographical origin of the infected populations rather than to the pathology (leukemia vs. neuromyelopathy). The great genetic stability of HTLV-1 can be used as a molecular mean to gain new insights into the origin, evolution and dissemination of this virus and of its host. HTLV-2, which is genetically related to HTLV-1, differs however from the latter by some specific epidemiological features. Indeed, HTLV-2 is mainly endemic in several Amerindians tribes and in some groups of intravenous drug users living mainly in the United States and in some European countries. Few cases of chronic neuromyelopathy have been associated with HTLV-2 and there is still no strong evidence that this retrovirus is linked to any malignant lymphoproliferation.