A-308 Respiratory Fungal Infection Caused by Candida blankii in an Immunocompromised Patient - Clinical Presentation and Management Challenges in Fortaleza, Ceará, Brazil: a case report

Abstract Background The frequency of Candida blankii infections is increasing as an opportunistic pathogen causing fungal infections in some parts of the world in recent decades, with most cases reported in immunocompromised individuals, which has led to increased attention in medical literature. Methods We present a 58 years old woman case who had respiratory problems for approximately ten years. During this time, several tests were carried out, such as cultures for bacteria, fungi and mycobacteria from sputum and bronchoalveolar lavage material until Candida blankii was isolated from sputum. Results A 58-year-old woman experienced symptoms of recurrent respiratory infection since 2014. In 2015, she was diagnosed with pulmonary tuberculosis and treated with specific therapy for six months. She remained asymptomatic until 2016, when presented productive cough with purulent sputum and occasional hemoptysis. Multiple antibiotic regimens were prescribed with limited success. In 2017, she underwent resection of the upper and middle lobes of the right lung but continued with productive cough and mild weight loss. A chest CT scan revealed persistent bronchiectasis in the right upper and middle lobe, and lingula, along with multiple bilateral centrilobular nodules and a tree-in-bud pattern, suggestive of active disease. In 2018, she was diagnosed with cutaneous mycobacteriosis caused by Mycobacterium abscessus. A second-line treatment regimen was initiated for 12 months. A follow-up CT scan showed radiological improvement. In 2019, the patient reported a productive cough with yellowish sputum and dyspnea but denied chest pain, fever, or significant weight loss. Diagnostic investigations, including fibrobronchoscopy with bronchoalveolar lavagem (BAL) and histopathological examination, were inconclusive. Bacteriological, mycological, and Mycobacterium tuberculosis tests were negative. Cultures for mycobacteria from BAL and skin tissue were negative. From 2020 to 2024, multiple BAL and sputum cultures isolated various pathogens due to intermittent episodes of productive cough, sometimes hemoptoic, with fever, fatigue, and dyspnea. Sputum cultures revealed fungal elements on direct examination (10% KOH), showing hyaline yeast-like blastoconidia and hyphae. Cultures on Sabouraud dextrose agar at 25°C yielded white yeast colonies, while growth on Chromoagar Candida medium at 35°C showed blue-to-gray yeast colonies (Figure 1). Slide cultures revealed pseudohyphae formation. The isolate was identified as Candida ciferri by Vitek 2™. Confirmation via MALDI-TOF mass spectrometry (Vitek MS™) and ITS region sequencing identified the strain as Candida blankii. Antifungal susceptibility testing was done according to M27-A3 CLSI, and the patient was started on fluconazole, leading to progressive clinical improvement. Conclusion The reported case reinforces the emerging relevance of Candida blankii as an opportunistic pathogen in patients with complex clinical conditions and highlights the need for greater clinical and laboratory attention to identify atypical fungal infections. It also emphasizes the use of advanced technologies such as molecular and proteomic methods to identify rare pathogens. The findings also open new avenues for research into the association between C. blankii and complex clinical conditions such as cystic fibrosis and surgical interventions like lobectomy. Continued investigation into the epidemiology, virulence, and therapeutic strategies for C. blankii is essential to address the challenges posed by this rare but significant pathogen.