Anncaliia algerae Microsporidiosis Diagnosed by Metagenomic Next-Generation Sequencing, China

Identification of Anncaliia algerae in Ascites in an Immunosuppressed Patient, China

Anncaliia algerae, a microsporidium, has risen to prominence as an opportunistic pathogen, particularly afflicting individuals who are immunocompromised with conditions such as rheumatoid arthritis, organ transplantation, and hematologic malignancy. Surprisingly, despite its recognized impact, the identification of A algerae in ascitic fluid has not been documented. As such, we pinpointed A algerae as the probable instigator of ascitic accumulation in a patient with a history of acute myeloid leukemia and extended periods of immunosuppressive therapy. For this patient, there were no signs of A algerae-related infections (eg, myositis), vocal cord involvement, or disseminated infection. The presence of A algerae was finally identified by next-generation metagenomic sequencing analysis of the ascitic fluid. Clinical presentation was characterized by elevated C-reactive protein levels (110.7 mg/L), diminished platelet count (48 × 109/L), abdominal distension secondary to ascitic fluid accumulation, and lower limb pain, and it showed marked improvement following a 4-day regimen of sulfamethoxazole/trimethoprim and albendazole. Despite this promising response, the patient succumbed to aspiration of vomitus. This case underscores the importance of considering rarer organisms, such as A algerae infection, in patients who are immunocompromised and present with unexplained ascites accumulation. It highlights the potential effectiveness of sulfamethoxazole/trimethoprim and albendazole in managing such cases. Further research is warranted to elucidate optimal management strategies and improve outcomes in similar clinical scenarios.

Metagenomic sequencing for investigation of a national keratoconjunctivitis outbreak, Israel, 2022

BackgroundEpidemics of keratoconjunctivitis may involve various aetiological agents. Microsporidia are an uncommon difficult-to-diagnose cause of such outbreaks.AimDuring the third quarter of 2022, a keratoconjunctivitis outbreak was reported across Israel, related to common water exposure to the Sea of Galilee. We report a comprehensive diagnostic approach that identified Vittaforma corneae as the aetiology, serving as proof of concept for using real-time metagenomics for outbreak investigation.MethodsCorneal scraping samples from a clinical case were subjected to standard microbiological testing. Samples were tested by calcofluor white staining and metagenomic short-read sequencing. We analysed the metagenome for taxonomical assignment and isolation of metagenome-assembled genome (MAG). Targets for a novel PCR were identified, and the assay was applied to clinical and environmental samples and confirmed by long-read metagenomic sequencing.ResultsFluorescent microscopy was suggestive of microsporidiosis. The most abundant species (96.5%) on metagenomics analysis was V. corneae. Annotation of the MAG confirmed the species assignment. A unique PCR target in the microsporidian rRNA gene was identified and validated against the clinical sample. The assay and metagenomic sequencing confirmed V. corneae in an environmental sludge sample collected at the exposure site.ConclusionsThe real-time utilisation of metagenomics allowed species detection and development of diagnostic tools, which aided in outbreak source tracking and can be applied for future cases. Metagenomics allows a fully culture-independent investigation and is an important modality for public health microbiology.

Encephalitis and myositis caused by Trachipleistophora hominis diagnosed by metagenomic next-generation sequencing-a case report

Background

Myositis is the main manifestation of Trachipleistophora hominis (T. hominis) infection and other microsporidians infection in immunocompromised patients. Clinical differential diagnosis of different microsporidians can be challenging, as the standard technique to distinguish various microsporidia species, transmission electron microscopy (TEM), is time-consuming and relies on equipment and experienced staffs who can perform the test and interpret the results.

Case presentation

We report a 37-year-old Chinese man with acquired immune deficiency syndrome (AIDS) developed headache and muscle pain in the extremities. Tramadol was used to relieve his pain. Infectious lesions in his brain were detected by cerebral magnetic resonance imaging (MRI). Oval-shaped pathogens was observed by biopsy of right gastrocnemius. Finally, T. hominis was identified by metagenomic next-generation sequencing (mNGS) in the gastrocnemius tissue and cerebrospinal fluid. After a 12-week course of antifungal treatment and antiretroviral therapy, the patient recovered from the encephalitis and myositis caused by T. hominis.

Conclusion

This report described the diagnosis and treatment of the first case of encephalitis caused by T. hominis. And mNGS is recommended for the rapid diagnosis of uncommon pathogens.