Clinical and Radiological Characteristics of Patients with Lophomonas blattarum Detected in Bronchial Lavage: A Single-Center Experience

Abstract Introduction Lophomonas blattarum (L. blattarum) is an emerging protozoan increasingly reported in respiratory specimens. This study aimed to characterize the clinical and radiological features of adult patients with L. blattarum detected in bronchial lavage samples. Methods This retrospective observational study included adult patients diagnosed at a tertiary care center between January 1, 2024 and January 1, 2026. Demographic data, comorbidities, clinical presentation, laboratory findings, radiological features, treatment approaches, and outcomes were analyzed descriptively. Results Fifty-one patients were included (mean age 59.0 ± 14.8 years; 51.0% male). Symptoms were predominantly chronic, with 73.3% reporting duration > 8 weeks. The most common symptoms were cough (73.3%), sputum (46.7%), and dyspnea (45.7%); fever was uncommon (6.5%). Frequent comorbidities included diabetes mellitus (31.9%), hypertension (29.8%), cardiovascular disease (23.4%), prior tuberculosis (25.0%), malignancy (26.0%), and immunosuppression (21.3%). More than half were never-smokers (52.2%). The mean leukocyte count was 9.02 ± 3.39 × 10⁹/L, and the median C-reactive protein level was 12.70 mg/L (IQR: 3.38–42.88). Chest CT findings were heterogeneous. Nodules were most frequent (38.3%), followed by ground-glass opacities (29.8%) and small airway signs (27.7%). Consolidation was observed in 16.3% and mediastinal or hilar lymphadenopathy was present in 48.9%. Metronidazole was administered to 54.9% of patients; radiological improvement was observed in 21.7%. Conclusion Microscopy-based detection of L. blattarum -like organisms in bronchial lavage was mainly observed in patients with chronic respiratory symptoms, heterogeneous and non-specific CT findings, and substantial comorbidity burden. Further prospective controlled studies with molecular confirmation are needed to clarify its clinical significance.