A case of chlamydia psittaci caused severe pneumonia and meningitis diagnosed by metagenome next-generation sequencing and clinical analysis: a case report and literature review

Abstract

Background: Psittacosis, which is also known as parrot fever, is Chlamydia psittaci (C. psittaci) caused infectious disease. The clinical manifestations vary from asymptomatic infection to severe atypical pneumonia or even fatal meningitis. Early recognition of psittacosis is difficult because of its nonspecific clinical manifestations. Culture and gene probe techniques for C. psittaci are not available for routine clinical use, which makes the diagnosis difficult too. Although psittacosis has increasingly been recognized and reported in recent years, cure of severe pneumonia complicated with meningitis, with etiologic diagnosis aided by the use of metagenomic next-generation sequencing (mNGS), is still uncommon. So, it is necessary to report and review such potentially fatal case.

Case presentation: This report describes a 54-year-old woman with C. psittaci caused severe atypical pneumonia and meningitis. She presented with symptoms of fever, dry cough and dyspnea, accompanied by prominent headache. Her condition deteriorated rapidly to respiratory failure and lethargy under the treatment of empirical antibacterial agents, and was treated with invasive mechanical ventilation soon. She denied contact with birds, poultry or horses, but unbiased mNGS of both the bronchoalveolar lavage fluid (BALF) and the cerebrospinal fluid (CSF) identified sequence reads corresponding to C. psittaci infection, and there was no sequence read corresponding to other probable pathogens. Combined use of targeted antimicrobial agents of tetracyclines, macrolides and fluoroquinolones was carried out, and the patient's condition improved and she was discharged home 28 days later. Her status returned close to premorbid condition on day 60 of follow-up.

Conclusions: When clinicians come across a patient with atypical pneumonia accompanied by symptoms of meningitis, psittacosis should be taken into consideration. mNGS is a promising detection method in such condition and is recommended.

Keywords: Case report; Chlamydia psittaci; Meningitis; Metagenome next-generation sequencing; Psittacosis; Severe pneumonia.

Fig. 1

Chest computed tomography scan at admission (A), 14d later (B), 22d later (C) and 47d later (D)

Fig. 2

The cover charts (A1, A2) and Sequencing coverage and depth (B1, B2) of Chlamydia psittaci in bronchoalveolar lavage fluid (A1, B1) and cerebrospinal fluid (A2, B2)

Fig. 3

Body temperature and antimicrobial treatment during hospitalization Moxifloxacin 0.4 g qd (days 1–12), ceftriaxone 2.0 g qd (days 1–3), ganciclovir 0.25 g q12h (days 2–4), ribavirin 0.5 g q8h (days 2–4), meropenem 1.0 g q8h (days 4–7), oseltamivir 50 mg bid (days 5–7), doxycycline 0.2 g (day 8) and 0.1 g bid (days 8–28), azithromycin 0.5 g qd (days 15–21)

Fig. 4

Change in white blood cell count and neutrophil predominance during hospitalization

Fig. 5

Change in C-reactive protein and procalcitonin during hospitalization

Fig. 6

Change in oxygenation index and respiratory index during hospitalization