Clinical implications of trichomonads detected in bronchoalveolar fluid by metagenomic next-generation sequencing: a multicenter retrospective study.

Background: Pulmonary trichomoniasis is considered a neglected disease due to failures in recognizing it, stemming from insensitive microbial methods and a lack of specific clinical features. This study aims to analyze the clinical implications of trichomonads detected in bronchoalveolar lavage fluid (BALF) by metagenomic next-generation sequencing (mNGS). Methods: This multicenter retrospective study included patients diagnosed with pneumonia, admitted to three tertiary hospitals in China from July 2018 to September 2022, with trichomonads detected in BALF through mNGS. The analysis covered demographics, comorbidities, symptoms, laboratory findings, mNGS results, clinical treatment, and outcomes of these patients. Results: A total of 17 patients were enrolled, comprising 14 males and 3 females. Trichomonas tenax and Trichomonas vaginalis were detected by mNGS in BALF samples of 15 and 2 patients, respectively. Patients were categorized into two groups based on the presence of risk factors for trichomonad infection, including immunocompromised conditions, uncontrolled diabetes mellitus, oral/periodontal diseases, and aspiration. Among 11 patients with risk factors (Case 1-11), 4 received nitromidazoles as part of comprehensive treatment, achieving a 100% treatment success rate. The remaining 7 patients, who did not receive nitromidazoles, had only one achieving relief after broad-spectrum antimicrobial therapy, resulting in a 14.3% treatment success rate. For the 6 patients without any risk factors for trichomonad infection (Case 12-17), none received nitromidazoles during hospitalization. However, 4 out of these 6 patients (66.7%) eventually recovered. Conclusion: mNGS proves to be an efficient tool for detecting trichomonads in BALF samples. Comprehensive analysis of clinical features and laboratory indicators is essential to distinguish between infection and colonization of trichomonads. Pulmonary trichomoniasis should not be overlooked when trichomonads are detected in BALF from patients with risk factors.

A Case of Pulmonary Trichomoniasis in a Young Healthy Male / 결핵및호흡기질환

Bronchopulmonary infections caused by trichomonads have been reported principally in patients with pre-existing pulmonary diseases, such as bronchial carcinoma, lung abscess, or bronchiectasis. Pulmonary trichomoniasis is most often caused by Trichomonas tenax, which is usually regarded as a harmless commensal organism of the human mouth. However, pulmonary infection may rarely be caused by other trichomonas species, including Trichomonas vaginalis from the genitourinary tract and Trichomonas hominis from the intestines. Because of the rarity of trichomonas pulmonary infection, and because of its close association with underlying lung and systemic disease, pulmonary trichomoniasis is considered an opportunistic infection. We recently treated a case of pulmonary trichomoniasis occurring in a young, healthy male without obvious underlying pulmonary or systemic illness. To our knowledge, there has been only one reported case of pulmonary trichomoniasis in Korea, and there have been only two reported cases of pulmonary trichomoniasis occurring in normal lung worldwide.

A Case of Pulmonary Trichomoniasis / 대한임상병리학회지

Man is host to three distinct trichomonad species such as Trichomonas vaginalis, T. hominis, and T. tenax. Although reports of trichomonads found outside their natural habitat are rare, sporadic case reports have appeared describing trichomonads in the respiratory tract. The route of infection is unknown, but possible mechanisms include invasion from mouth, oral sex, bronchopleural or pleuroenteral fistula. Pulmonary trichomoniasis is a kind of oppotunistic infection and is usually caused by aspirated T. tenax in male adult patientis with chronic purulent or necrotic pulmonary disease. A 63-year-old male patient with alcoholic liver cirrhosis and chronic bronchiectasis was admitted due to copious sputum, dyspnea, fever and severe weight loss. On the thoracentesis from his right pleural cavity, 1 L of foul-smelling, brownish-yellow exudate was withdrawn and showed a large number of neutrophil, bacteria and numerous flagellated, actively motile organisms with typical appearance of thrichomonads in wet preparation. This patient was expired due to sepsis and insufficiency of multiple organs inspite of chemotherapy with metronidazole, cefuroxime and gentamicin on day 35 of admission. So, we report the first case of pulmonary trichomoniasis diagnosed in wet preparation of pleural fluid in Korea.