The collagen-binding protein of Streptococcus mutans is involved in haemorrhagic stroke.

Although several risk factors for stroke have been identified, one-third remain unexplained. Here we show that infection with Streptococcus mutans expressing collagen-binding protein (CBP) is a potential risk factor for haemorrhagic stroke. Infection with serotype k S. mutans, but not a standard strain, aggravates cerebral haemorrhage in mice. Serotype k S. mutans accumulates in the damaged, but not the contralateral hemisphere, indicating an interaction of bacteria with injured blood vessels. The most important factor for high-virulence is expression of CBP, which is a common property of most serotype k strains. The detection frequency of CBP-expressing S. mutans in haemorrhagic stroke patients is significantly higher than in control subjects. Strains isolated from haemorrhagic stroke patients aggravate haemorrhage in a mouse model, indicating that they are haemorrhagic stroke-associated. Administration of recombinant CBP causes aggravation of haemorrhage. Our data suggest that CBP of S. mutans is directly involved in haemorrhagic stroke.

Brain herniation into the middle ear following temporal bone fracture.

Otorrhea of leaked cerebrospinal fluid and meningitis in a 33-year-old male originated from an encephalic herniation into the middle ear following traumatic temporal bone fracture. CT demonstrated a mixed-type fracture consisting of a longitudinal fracture and a posterior oblique fracture of the left temporal bone. The left tegmen tympani was broken into a bellows-like shape and a bone splinter from it had stuck in the epitympanum at the level of the incus body. Surgery via a middle cranial fossa approach confirmed penetration of the brain tissue between the incus and lateral semicircular canal. The diagnosis and management of this condition are discussed in the context of a literature review.