Fundus lesions after carotid injection of Streptococcus mutans in monkeys

Area of Science:

• Ophthalmology
• Infectious Diseases
• Microbiology

Background:

• Bacteremia, a bloodstream infection, can lead to serious complications in various organs.
• Ocular involvement in bacteremia can manifest as vision-threatening lesions.
• Streptococcus mutans is a known oral bacterium, but its potential for causing systemic and ocular infections is less understood.

Purpose of the Study:

• To investigate the ocular effects of Streptococcus mutans bacteremia in a non-human primate model.
• To determine if S. mutans can cause pathological changes in the eye consistent with human bacteremic infections.

Main Methods:

• Pigtail monkeys underwent carotid artery injection with Streptococcus mutans.
• Fundus examinations were performed to assess ocular changes.
• Histopathological analysis of ocular tissues (retina, choroid, optic nerve) was conducted.
• Bacterial cultures were obtained from ocular tissues.

Main Results:

• Carotid injection of S. mutans induced fundus lesions in monkeys, clinically mimicking human bacteremic eye conditions.
• Histopathology revealed microabscesses in the retina, choroid, and optic nerve.
• S. mutans bacteria were identified within the microabscesses on histopathological examination.
• S. mutans was successfully cultured from the retina and choroid.

Conclusions:

• Streptococcus mutans bacteremia can lead to significant ocular pathology, including microabscess formation in the retina, choroid, and optic nerve.
• This animal model demonstrates that S. mutans can invade ocular tissues and cause lesions similar to those observed in humans with bacteremia.
• The findings highlight the potential for S. mutans to cause serious eye infections beyond the oral cavity.