Microbiological diversity among patients with Lemierre syndrome and clinical implications: an individual patient-level analysis.

Purpose: Lemierre syndrome is a rare condition traditionally defined by bacterial infection of the head/neck region, local thrombophlebitis, and septic embolism. Although in most cases Fusobacterium necrophorum is isolated, it is questionable whether the presence of this microbe is mandatory for diagnosis. In this study, we investigated microorganisms isolated in cases of Lemierre syndrome and their association with demographical and clinical features.

Methods: We conducted an analysis of individual patient data from 712 patients diagnosed with Lemierre syndrome. Demographics, clinical presentation, treatment strategies, and outcomes according to different pathogens were evaluated.

Results: Among a total of 712 patients, in 574 cases bacterial growth was detected. In 415 patients Fusobacterium spp. was isolated, in 108 either Streptococcus spp. or Staphylococcus spp., and in 51 other bacteria. Patients with different bacteria differed markedly in age, site of preceding infections, clinical presentation, and treatment. Fusobacterium spp. was typically isolated in younger patients (69% of patients aged 16 to 30 years) while Streptococcus spp. and Staphylococcus spp. were more prevalent in older subjects (30% of patients aged over 45 years). Of all cases with Fusobacterium spp., 63% had a thrombosis of the internal jugular vein and 91% septic embolism, compared with 94% and 69%, respectively, in cases with Streptococcus spp. or Staphylococcus spp.

Conclusion: In contrast to the available literature, our study suggests that Lemierre syndrome may be caused by multiple bacterial species, and that the clinical presentation and course may vary according to the specific bacterial species involved.