A case of psittacosis chlamydia pneumonia in patients with anti-infection drugs analysis and pharmaceutical care.

RATIONALE: Psittacosis pneumonia, caused by Chlamydia psittaci, is an underdiagnosed zoonotic infection. This case aims to demonstrate the efficacy of azithromycin as an alternative therapy and highlight the value of clinical pharmacists in managing drug-resistant infections.

PATIENT CONCERNS: A 56-year-old female poultry farmer presented with persistent high fever (38.5-39.0°C), chills, body aches, and fatigue for 2 weeks. Initial outpatient treatment with unspecified oral medication provided no relief.

DIAGNOSES: Metagenomic next-generation sequencing of bronchoalveolar lavage fluid confirmed C psittaci and rhinovirus co-infection, explaining treatment failure with empirical piperacillin-tazobactam for presumed bacterial pneumonia.

INTERVENTIONS: After pathogen identification, intravenous azithromycin monotherapy (4.5 g total dose) was initiated. Clinical pharmacists collaborated on regimen design, monitored for QTc prolongation/electrolyte imbalances, and ensured safety during the 12-day course.

OUTCOMES: Fever resolved within 48 hours; all symptoms improved by day 6. Follow-up computed tomography showed significant resolution of lung consolidation. The patient was discharged on day 11 with oral azithromycin continuation.

LESSONS: Azithromycin is effective as second-line therapy for severe psittacosis when tetracyclines are inaccessible. Metagenomic next-generation sequencing enables rapid diagnosis of atypical pathogens, while pharmacist-led pharmaceutical care optimizes antimicrobial selection and safety monitoring, particularly for cardiotoxic drugs.