The Clinical Value Of Fish In The Detection Of Aspergillus Infection For Rapid Diagnosis

Objective The object of this study is to evaluate the application of fluorescence in situ hybridization (FISH) technology in the diagnosis of pediatric invasive fungal infections. As widespread existence in nature, Aspergillus is the major pathogenicbacteria of invasive fungal infections (IFI). Not only is IFI more common in immunocompromised people and higher mortality rate, but also it lacks rapid diagnostic methods in clinical.Methods 27 formalin-fixed and paraffin-embedded specimens from patients with fungal infection were included in this research. Aspergillus was detected by FISH as a positive control. 12 specimens without fungal infection were used as a negative control. 23-base pair oligonucleotide, which complement to 18S (18S-1 probes) rRNA of Aspergillus and labeled with digoxigenin (DIG) was used as probe. Simultaneously these tissue specimens were stained by HE and PAS.Results The results shown that, 14 cases FISH detection of Aspergillus rDNA were positive by using the 18S-1 probe. Positive control also showed specific hybridization. The green granular hybridization signals focused or scattered on slides. No signals were detected in negative controls and blank samples. The result of FISH was corresponded with that of HE and PAS staining. HE and PAS staining were suspected fungal infection in 23 cases and 27 cases. Some tissue showed fungal mycelium. HE staining showed red mycelium and PAS staining showed magenta. But they couldn't identify fungal genus.Conclusion FISH can detect Aspergillus hyphal elements in the formalin-fixed and paraffin-embedded tissue specimens. It can identify different fungus according to species-specific probes. While HE and PAS staining can only observe fungus morphologically but not identify different fungus. So FISH is a useful method for rapid and accurate identification of Aspergillus in tissues.