OBJECTIVE To report a case of infection with Microcystis gracilis in the pleural cavity secondary to refactory pneumothorax after closed chest drainage, and to share diagnostic and therapeutic ideas in light of the literature to improve the understanding of deep infection with Microcystis gracilis.
METHODS Patient with severe Omicron variant associated pneumonia and pulmonary fibrosis had a history of long-term smoking, chronic cough and asthma, nephrotic syndrome, long-term oral hormone usage, and elevated blood glucose. Spontaneous pneumothorax developed during treatment and continuous closed chest drainage was given, after that the patient developed invasive pulmonary Aspergillus infection, bacterial pneumonia and pyothorax, which were improved with targeted treatment. On the 87th day of closed chest drainage, the pleural rupture was still not healed and the chest tube was dislodged, so the original chest tube was replaced. After that, the pyothorax developed again. Fluorescence staining of the pleural fluid showed a large number of fungal hyphae, and Microascus gracilis was cultured. Lung CT showed aggravating lung infection, blood gas analysis results suggested the presence of respiratory failure, and blood lymphocyte subpopulation results suggested a significant decrease in T-lymphocytes, B-lymphocytes, and natural killer (NK) cells. Continuous closed chest drainage was given, and other treatment options included posaconazole combined with caspofungin and topical terbinafine in the tube incision for antifungal treatment, and propecia combined with thymofaxine for immune enhancement, controong blood sugar with nutritional supportive therapy.
RESULTS After treatment, the patient′s lymphocytes gradually rose, fever subsided, cough symptoms gradually improved, respiratory failure was corrected, pleural fluid culture turned negative, pneumothorax was absorbed, and the patient was successfully extubated on the 21st day of combined antifungal treatment. Sequential oral antifungal posaconazole combined with terbinafine was stopped after 2 months. Another 2 months after discontinuation of the drug, the lung CT showed improvement of infection, and pneumothorax and pleural effusion did not recur.
CONCLUSIONS Deep fungal infections caused by Microascus gracilis are clinically rare. Compromised immunity and fungal colonization on retained foreign bodies after invasive procedures are high risk factors for infection. Once deep invasive infection happen, the mortality rate is extremely high. Recognition of Microascus gracilis is difficult, fungal culture time is long, thus fungal fluorescence staining is a rapid and effective supplemental test. Clinical treatments include surgical debridement of infected lesions, extraction of foreign bodies suspected of the organism colonizing, and combination antifungal therapy. Enhanced immunotherapy plays an important role in treatment.
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