RESUMO
New techniques have emerged for the detection of bacteria in blood, because the blood culture as gold standard is slow and insufficiently sensitive when the patient has previously received antibiotics or in the presence of fastidious organisms. DNA-based techniques, hybridisation probes, and PCR-based detection or protein-based detection by mass spectroscopy are aimed at rapid identification of bacteria and provide results within 2 h after the first signal of growth in conventional blood cultures. Also, detection of microorganisms directly in blood by pathogen-specific or broad-range PCR assays (eubacterial or panfungal) shows promising results. Interpretation is complex, however, because of detection of DNA rather than living pathogens, the risk of interfering contamination, the presence of background DNA in blood, and the lack of a gold standard. As these techniques are emerging, clinical value and cost-effectiveness have to be assessed. Nevertheless, molecular assays are expected eventually to replace the current conventional microbiological techniques for detection of bloodstream infections.
Assuntos
Bacteriemia/diagnóstico , Bactérias/isolamento & purificação , Técnicas de Tipagem Bacteriana/métodos , Reação em Cadeia da Polimerase/métodos , Bacteriemia/economia , Bactérias/classificação , Bactérias/genética , Bactérias/imunologia , Contagem de Colônia Microbiana/métodos , Meios de Cultura , DNA Bacteriano/análise , Humanos , Reação em Cadeia da Polimerase/normas , Sensibilidade e Especificidade , Especificidade da Espécie , Fatores de TempoRESUMO
The mean risk of acquiring HIV after an occupational exposure, injecting drug use or sexual exposure varies from < 0.1 to 3%. A high plasma HIV-RNA of the source increases the risk of each of the exposures. Other factors, such as the volume of the inoculum involved to which the individual was exposed, other sexually transmitted diseases and ruptures of mucous membranes are associated with a higher risk of HIV transmission. Based on the calculated risk, post-exposure prophylaxis (PEP) should be recommended. In the Netherlands, prescription of PEP in the occupational setting is a standard procedure and has proved to be feasible. This was associated with a high percentage (62%) of mild and reversible toxicity and a small percentage (2%) of serious adverse events related to antiretroviral drugs, i.e. nephrolithiasis (due to indinavir) and toxic hepatitis (due to nevirapine). In The Netherlands so far no HIV-seroconversions have been recorded after an occupational accident.