Epidemiology and Clinical Features of Pulmonary Fungal Infections in Patients with Pneumonia: A Single-Center Study from Southwestern Iran

Background: Pulmonary fungal infections (PFIs) are opportunistic infections that pose a serious threat to immunocompromised patients. Early diagnosis is challenging, and region-specific epidemiological data from southwestern Iran remain limited . Methods : In this cross-sectional study (June 2022–June 2023), 139 hospitalized patients with suspected fungal pneumonia at Imam Khomeini Hospital, Ahvaz, were evaluated according to EORTC/MSG 2020 criteria. Clinical samples underwent direct microscopy, culture, serological testing (galactomannan, 1,3-β-D-glucan), and calmodulin gene sequencing for Aspergillus isolates. Demographics, comorbidities, clinical signs, and chest CT findings were recorded. Results: PFIs were diagnosed in 58 patients (41.7%). Among them, 7 were proven (5%) and 51 probable (36.6%). Aspergillus species predominated (72.4% of PFIs), mainly sections Flavi and Nigri , followed by Pneumocystis jirovecii (19.0%) and Mucorales (8.6%). Common comorbidities included diabetes (29.3%) and prior COVID-19 infection (24.1%). Fever (58.6%) and cough (53.4%) were the most frequent symptoms. Cavitation (39.6%) and consolidation (37.9%) were the leading CT findings. Mortality in the PFI group was 25.8%, higher than in the overall cohort (20.9%). Male sex and prior COVID-19 infection were significantly associated with PFIs. Conclusions : PFIs, predominantly aspergillosis, are highly prevalent among pneumonia patients in southwestern Iran. Early recognition through combined radiological, mycological, and serological evaluation, along with attention to predisposing factors such as COVID-19 and male sex, is essential. These findings provide critical region-specific epidemiological insights to guide targeted diagnostic and therapeutic strategies and improve patient outcomes.