SESSION TYPE: Asthma Posters
PRESENTED ON: Wednesday, October 24, 2012 at 01:30 PM - 02:30 PM
PURPOSE: Status asthmaticus (SA) is an acute exacerbation of asthma and similar to conventional asthma, SA is thought to be induced through inhalational exposure to allergens including molds. The purpose of this study is to explore if fungi play a role in SA through identification of lower respiratory tract pathogens of intubated patients and determine if a fungal isolate can elicit allergic lung disease in mice.
METHODS: Clinical information was retrospectively obtained on five SA patients admitted to the Ben Taub General Hospital medical intensive care unit. Lower airway secretions by bronchoalveolar lavage or tracheal aspiration were obtained. Lower airway samples were processed using standard culture techniques and in parallel underwent specialized processing to remove mucus and cells prior to culture. The ability of a clinical isolate of Candida albicans, a yeast, found in all patient airway cultures to induce allergic lung disease in C57BL/6 mice was assessed.
RESULTS: Fungi were cultured from lower respiratory specimens in 2 out of 5 patients by standard culture techniques. In contrast, after removal of respiratory mucus, filamentous fungi (molds) were identified from three patients and heavy growth of yeast (Candida spp.) was found from all sample cultures. All patients received intravenous corticosteroids and broad-spectrum antibiotics. Mice exposed to intranasal C. albicans developed significant increases in airway hyperreactivity, BAL fluid eosinophilia and a dose-dependent predominance of lung IL-4 and IL-17A compared to controls.
CONCLUSIONS: Tracheobronchial mycoses was observed in a cohort of SA patients. An improved method of culture technique involving the removal of mucus is superior to standard culture techniques in revealing fungi in respiratory samples. An isolate of C. albicans elicited profound allergic inflammation and airway hyperreactivity similar to asthma-like disease when given intranasally to mice.
CLINICAL IMPLICATIONS: Combined use of glucocorticoids and broad-spectrum antibiotics may contribute to tracheobronchial mycoses and may have potential to cause or exacerbate fungal overgrowth in asthma. Treatment with anti-fungal antibiotics and avoidance of therapies that promote fungal overgrowth should be considered in the management of SA.
DISCLOSURE: The following authors have nothing to disclose: Garbo Mak, Paul Porter, Venkata Bandi, Amber Luong, Farrah Kheradmand, David Corry
We removed mucus and cells from respiratory specimens prior to fungal culture on Sabourand plates by processing samples with dithiothreitol. This step helps remove fungicidal mucus that surrounds pathogens found in the airway, thereby optimizing fungal culture growth. This process is not performed in standard fungal cultures.Baylor College of Medicine, Houston, TX