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Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM Objectives Histopathology is the gold standard for distinguishing between colonization and fungal infection, but it does not provide a precise diagnosis of genera/species. However, if the culture is negative or if no specimen is sent to the Mycology laboratory, only the specimen sent to the Pathology department is available. Formalin fixation and paraffin embedding (FFPE) cause DNA damage, making it difficult to perform molecular techniques. The objective was to develop and evaluate the contribution of massive parallel sequencing (MPS) to FFPE tissues. Methods Histopathological review of all cases was performed. Then, DNA extraction from FFPE tissues was optimized by: (1) macrodissecting the fungal-rich area on the paraffin block; (2) comparing the efficiency of two DNA extraction kits (QIAamp DNAmicro-kit, QIAGEN; Maxwell 16 LEVRNA FFPE Purification kit, Promega, optimized for RNA and DNA extraction), by comparison of Aspergillus fumigatus and Mucorale specific PCR results for 30 cases. For 124 other cases, the sensitivity of two primer pairs (ITS3/4 and MITS2A/2B) was tested for identification by Sanger sequencing and then MPS. Finally, a histomolecular comparison was performed. This work was funded by the Société de Pathologie Infectieuse de Langue Française (SPILF). Results To optimize extraction, DNA was extracted by both kits from samples of 16 mucormycoses and 14 A. fumigatus infections. PCR sensitivity was better with the QIAGEN extraction kit [100% (30/30)] compared to the Promega kit [86.7% (26/30)]. PCR amplification of fungal DNA from an additional 124 FFPE samples was performed. The primer pairs ITS3/4 and MITS2A/2B, allowed: (1) identification by Sanger sequencing-histopathological analysis in 38.7% (48/124) of the cases in total, and more specifically 33% (41/124) of cases with the ITS3/4 primers and 32.3% (40/124) of cases with the MITS2A/B primers; and (2) identification by integrated SMP-histopathological analysis in 75% (93/124) of all cases (primers ITS3/4 and MITS2A/2B), and more specifically 66.1% (82/124) for ITS3/4 and 62.1% (77/124) for MITS2A/B (both primer pairs did not detect/amplify the same fungal genera/species). The combination of all results from Sanger sequencing and MPS led to fungal identification in 75.8% (94/124) of cases. In total, the addition of NGS to Sanger sequencing increased the diagnostic proportion by 36.3% (45/124; P Conclusion The development of the fungal MPS on FFPE tissues is innovative and unprecedented for the achievement of an integrated histomolecular diagnosis in fungal pathology. It increases significantly the diagnostic proportion by 36.3%. This strategy can be used in hospitals and could improve patient management, especially when no sample is sent to the Mycology laboratory or when the culture is negative.

Occurrence of putative invasive pulmonary aspergillosis was screened in 153 consecutive adult intensive care unit (ICU) patients with respiratory samples addressed for mycological diagnosis during a 6-week period at the emergence of coronavirus disease 2019 (COVID-19) pandemic. Positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) was observed for 106 patients (69.3%). Nineteen of them (17.9%) with positive Aspergillus results were considered as having putative invasive pulmonary aspergillosis. These observations underline the risk of pulmonary aspergillosis in COVID-19 patients, even in patients not previously known to be immunosuppressed, advocating active search for Aspergillus infection and prompt antifungal treatment. Standardized surveillance protocols and updated definitions for ICU putative invasive pulmonary aspergillosis are needed. Lay Abstract Adult ICU patients with respiratory samples addressed for mycological diagnosis were screened during the emergence of COVID-19 pandemic. Positive SARS-CoV-2 PCR was observed for 106 patients, nineteen of them (17.9%) having aspergillosis. This underlines the risk of aspergillosis in COVID-19 patients.