Detection of Coccidioides posadasii in a patient with meningitis using metagenomic next-generation sequencing: a case report

Abstract

Background: Coccidioidomycosis is a systemic infection caused by dimorphic fungi Coccidioides spp. endemic to Southwestern United States and Central and South America. A history of residence and travel in these areas is essential for the diagnostic of coccidioidomycosis, which has highly variable symptoms ranging from asymptomatic to severe, disseminated infection, and even death. Immunocompromised patients of coccidioidomycosis experience a high risk of dissemination, chronic infection, and mortality. Meningitis is one of the most deleterious coccidioidomycosis and can cause various life-threatening complications.

Case presentation: Here we report a case of Coccidioides posadasii meningitis in a 49-year-old female who returned to China after one and a half years residence in Los Angeles, USA. The repeated routine cultures using CSF for bacteria or fungi were all negative. To hunt for an infectious etiology, the state-of-the-art technology metagenomic next-generation sequencing (mNGS) was then utilized, suggesting Coccidioides posadasii. Organizational pathological examination and polymerase-chain-reaction (PCR) results subsequently confirmed the mNGS detection.

Conclusion: To our knowledge, cases for coccidioidal meningitis have been rarely reported in China. While global travelling may spread this disease across continents and make the diagnosis more difficult. mNGS can detect almost all known pathogens with high sensitivity and specificity, especially for uncommon pathogen, such as Coccidioides posadasii in China.

Keywords: Coccidioidomycosis; Meningitis; Metagenomic next-generation sequencing (mNGS).

Fig. 1

CSF investigation and antimicrobial drugs. After the adjustment of the treatment, the CSF factors including glucose content, protein content, WBC, and opening pressure gradually returned to normal

Fig. 2

The mNGS result of C. posadasii. 2.32% of bacterial reads corresponded to C. posadasii with a coverage of 0.0779%

Fig. 3

PCR detection of C. posadasii. Lane 1: 195-bp polymerase chain reaction product of C. posadasii; Lane M: DNA ladder; Lane N: Negative control

Fig. 4

Biopsy of back rash subcutaneous tissue. A HE stain, and B PSA stain, coarse spheroids were covered by double-layer envelope, with endospores inside, and surrounded by neutrophils and eosinophils; C Hexamine silver stain, positive spheroids can be seen in the pathology