<s>[INST] <<SYS>> This is a medical question of type : causes <</SYS>> What causes Lemierre syndrome ? [/INST] What causes Lemierre syndrome? In about 90% of cases, Lemierre syndrome is caused by Fusobacterium necrophorum; however, the syndrome has also been reported with other bacteria, including Stapylococcus aureus, Bacteroides, Eikenella, Porphyromonas, Prevotella, Proteus, Peptostreptococcus and Streptococcus pyogenes. </s>