Mixed infection with multiple bacteria and microsporidia (Enterocytozoon bieneusi) in a post-renal transplant patient: a case report.

BACKGROUND

Microsporidia are genetically diverse, obligate intracellular pathogens that are challenging to diagnose due to their resistance to conventional culture methods. Enterocytozoon bieneusi is a primary cause of microsporidiosis, particularly in immunocompromised individuals. This report details a complex case of mixed bacterial and microsporidial infection in a renal transplant recipient, highlighting the utility of advanced molecular diagnostics.

CASE PRESENTATION: A 37-year-old male with a 16-year history of renal transplantation presented with recurrent high fever, chills, and hematochezia. Initial workup revealed severe anemia, thrombocytopenia, and acute kidney injury. Blood cultures grew ESBL-producing Escherichia coli and Klebsiella pneumoniae. CT imaging suggested a duodenobiliary fistula. Due to persistent fever despite broad-spectrum antibiotics, metagenomic next-generation sequencing (mNGS) was performed, identifying E. bieneusi (185 reads) alongside multiple bacteria and viruses. Treatment was adjusted to include meropenem, daptomycin, and albendazole, with careful modulation of immunosuppression. The patient subsequently tested positive for SARS-CoV-2 but showed significant clinical improvement with the adjusted regimen and was discharged after 24 days.

CONCLUSION

This case underscores the diagnostic value of mNGS in identifying rare, opportunistic pathogens in immunocompromised hosts. Successful management requires a multidisciplinary approach, combining targeted antimicrobial therapy, immunomodulation, and aggressive supportive care.

CLINICAL TRIAL NUMBER: Not applicable.