Work

Targeted Metagenomic Sequencing for the Rapid Diagnosis of Chlamydia Caviae Pneumonia in an Elderly Patient without Known Immunosuppression or Animal Exposure: A Case Report and Literature Review

Year: 2026

Type: article

Abstract: Background: Chlamydia caviae , a pathogen primarily causing conjunctivitis and respiratory diseases in guinea pigs, rarely infects humans. Previous human cases were mostly associated with direct contact with sick guinea pigs or occurred in immunocompromised individuals. Case Presentation: We report a case of a 79-year-old female from Sichuan, China, without known immunosuppressive disease or therapy who presented with fever, fatigue, and left upper lobe consolidation, and was diagnosed with community-acquired pneumonia (CAP). She had no documented history of contact with guinea pigs or other pets. Empirical antibiotic therapy proved ineffective. Subsequently, probe capture-based targeted next-generation sequencing (tNGS, specifically the MetaCAP™ panel) of bronchoalveolar lavage fluid (BALF) rapidly identified C. caviae (sequence count: 1107, relative abundance: 54.50%) as the highly probable causative pathogen. Following targeted therapy with a doxycycline-moxifloxacin combination regimen, the patient’s temperature rapidly normalized, achieving significant clinical and radiological improvement before discharge. Conclusion: This case demonstrates that pulmonary infection caused by C. caviae can occur in individuals without known immunosuppressive conditions and without direct animal contact, raising questions about potential alternative transmission routes and zoonotic reservoirs. The early application of targeted next-generation sequencing is of critical clinical value for the precise diagnosis and prompt management of rare and elusive respiratory pathogens. Keywords: Chlamydia caviae , community-acquired pneumonia, targeted metagenomic sequencing, zoonosis, doxycycline, MetaCAP

Source: Infection and Drug Resistance

DOI: 10.2147/idr.s648250