Severe strongyloidiasis and Gram-negative bacterial superinfections: epidemiology, clinical implications, and therapeutic strategies.

PURPOSE OF REVIEW: Strongyloidiasis is a neglected tropical disease affecting over 600 million people worldwide. Its severe forms carry a fatality rate exceeding 60%, yet death is rarely attributable to the parasite alone: the terminal event is often bacterial sepsis or meningitis of enteric origin. We review recent evidence on Gram-negative and other bacterial superinfections in severe strongyloidiasis, and their diagnostic and therapeutic implications.

RECENT FINDINGS: Cohort studies show that bacteraemia is the commonest complication of severe disease, affecting 38.3% of cases against 4.1% of uncomplicated infections, and is predominantly Gram-negative, with Klebsiella pneumoniae and Escherichia coli most often isolated; Gram-positive and polymicrobial infections also occur. Beyond corticosteroids, targeted immunosuppressants and transplantation are increasingly implicated. Recognition is difficult, as eosinophilia is frequently absent and serological tests, including recent rapid assays, perform poorly in immunocompromised patients. Diagnostic delay is associated with higher risk of sepsis and mortality. Emodepside and moxidectin show promise in chronic infection but remain untested in severe disease.

SUMMARY: Enteric Gram-negative bacteraemia or meningitis in an at-risk patient, particularly if recurrent or polymicrobial, should prompt parasitological investigation. As treatment of established disease is unproven, detecting and treating chronic infection before immunosuppression, including transplant donors and recipients, remains the intervention most likely to reduce mortality.