Update on invasive aspergillosis: clinical and diagnostic aspects
Identificadores
URI: http://hdl.handle.net/20.500.12020/1233ISSN: 1198-743X
DOI: https://doi.org/10.1111/j.1469-0691.2006.01603.x
Fecha
2006-12-01Tipo de documento
articleÁrea/s de conocimiento
Ciencias BiomédicasMateria/s Unesco
3201.03 Microbiología ClínicaResumen
Apergillus is a ubiquitious mould that can cause a wide variety of clinical syndromes ranging from mere
colonisation to fulminant invasive disease. Invasive aspergillosis (IA) is the most severe presentation of
aspergillosis. The lung is usually the portal of entry, from which the pathogen may disseminate to
almost any organ, often the brain and skin. The diagnosis remains a significant challenge. It is usually
based on a combination of compatible clinical findings in a patient with risk-factors and isolation of the
microorganism, radiological data, serological detection of antibodies or antigens, or histopathological
evidence of invasion. Chest radiographic findings in patients with pulmonary Aspergillus may initially
be normal in up to 10% of cases. Computed tomography scanning is probably the most useful imaging
technique for the diagnosis of IA, since it may reveal lung lesions up to 5 days earlier than would
radiograph techniques simply. Currently available laboratory diagnostic methods include several
techniques: histopathological evidence of invasion; isolation of the microorganism and direct
microscopy from clinical samples and non-invasive procedures (serological detection of antigens or
nucleic material of Aspergillus; detection of antibodies). The histological diagnosis of IA requires the
presence of invasion by fungus of the Aspergillus species. The truth is that, if no other variables are
considered, the positive predictive value is very low, and most of the isolates of A. fumigatus do not
represent proven or probable infection. Several molecules could be used as markers of infection, but two
of them are of special interest: Aspergillus galactomannan (GM) and (1 fi 3)-b-glucan (BG). GM has a
high specificity (above 85%) and a reported sensitivity that varies widely (between 30% and 100%). BG,
a main cell wall polysaccharide component of Aspergillus, can be colourimetrically detected and is useful
in diagnosis, with a sensitivity ranging from 50% to 87.5%. A specific Aspergillus PCR assay has also
been used in the diagnosis of IA and has shown very good results, with a sensitivity and specificity of
100% and 89%, respectively.