RESUMEN
BACKGROUND: Invasive aspergillosis (IA) is an increasingly common and fatal opportunistic fungal infection in patients with haematological diseases. Early diagnosis is difficult as mycological culture techniques have low sensitivity and the radiological tools have low specificity. Galactomannan enzyme immunoassay (GEI) detects galactomannan in the human serum with a reported sensitivity and specificity between 30% and 100%. AIMS: The aim of this study was to analyse the role of GEI in diagnosis of IA in patients with febrile neutropenia and to evaluate the role of GEI in the diagnosis of IA as per the revised (2008) European Organization for Research and Treatment of Cancer-Mycoses Study Group (EORTC-MSG) criteria at two different optical density (OD) cut-offs of 0.5 and 1.0. SETTING: This prospective study was conducted in Safdarjung Hospital, New Delhi, India. METHODS: GEI testing was performed in adult patients of febrile neutropenia with evidence of IA. Results at two different OD indices (ODIs) of 0.5 and 1.0 were analysed. The evaluation of the diagnostic parameter, that is, GEI was measured in terms of sensitivity, specificity and positive and negative predictive value and was validated with the revised (2008) EORTC-MSG diagnostic criteria of IA. RESULTS: One hundred and eleven patients had evidence of IA, of which 79 patients were GEI positive when cut-off ODI was 0.5, whereas with cut-off ODI 1.0, 55 patients were GEI positive. CONCLUSION: ODI of 1.0 should be considered as positive while in patients with OD between 0.5 and 1.0, repeat sampling from the patient is recommended.
Asunto(s)
Neutropenia Febril/diagnóstico , Técnicas para Inmunoenzimas/métodos , Aspergilosis Pulmonar Invasiva/diagnóstico , Mananos/sangre , Suero/química , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Galactosa/análogos & derivados , Humanos , India , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Sensibilidad y Especificidad , Adulto JovenRESUMEN
BACKGROUND: Invasive fungal infection (IFI) is a fatal infection in haematology patients. There is an urgent need for reliable screening methods facilitating timely diagnosis and treatment. A real-time panfungal polymerase chain reaction (PCR) assay based on TaqMan technology targeting 18S ribosomal RNA gene was used to screen whole blood specimen obtained from series of Haematology malignancy patients for IFIs. MATERIALS AND METHODS: The panfungal (Pan-ACF) assay was employed to investigate specimen from 133 patients in duplicate with suspected IFI. In addition twenty healthy subjects and twenty patients with bacterial infections were taken as control. The patients with suspected IFI were also diagnosed by conventional methods including direct microscopy, culture techniques and antigen detection (galactomannan antigen ELISA and latex agglutination for cryptococcal antigen). The results of molecular testing were evaluated in relation to the criteria proposed by the European Organization for Research and Treatment of Cancer and patients were classified as having proven and probable IFD. RESULTS: Of 133 patients, 89 had proven, 18 had probable and 26 had possible IFI. One hundred four samples were reverse transcription-PCR positive. Of 89 proven cases, 84 were panfungal PCR positive. These 84 cases included 82 cases which revealed growth on fungal blood culture and two cases were negative on fungal blood culture. Of the 82 cases which revealed growth on culture: 74 grew Candida in culture, 3 grew Fusarium solani, 5 grew Aspergillus species on blood culture. The later five were also galactomannan antigen positive. The five specimen which were negative on panfungal PCR, two grew Trichosporon asahii, one grew Candida rugosa and two grew as Cryptococcus neoformans var. neoformans. Of the 18 probable cases, 18 were panfungal PCR positive. These were also galactomannan antigen positive. The sensitivity and specificity of panfungal PCR in proven cases were 94.3% and 95.2%, respectively. The positive and negative predictive values proven cases were 97.6% and 88.9%, respectively. CONCLUSIONS: The panfungal (Pan-ACF) real-time PCR assay can detect common fungal genera and it may be used as an adjunct to conventional methods for screening of IFI.