Streptococcus pluranimalium: Emerging Animal Streptococcal Species as Causative Agent of Human Brain Abscess

Background: Streptococcus pluranimalium is a new and emerging animal streptococcal species associated with primary infection in bovine and avian species. Data in the literature regarding its pathogenic significance in human beings are limited. We hereby report a case of brain abscess caused by S. pluranimalium in a healthy adult male. S. pluranimalium, a causative agent of brain abscess, was unanticipated, and to the best of our knowledge, this is one of the rare cases reported in the medical literature.

Case description: A 44-year-old male presented with headache and occasional episodes of vomiting for 2 weeks, weakness of the left upper and lower limbs for 1 week, and 1 episode of generalized tonic clonic seizure 2 days back. He was afebrile and had no history of loss of consciousness or head trauma. His physical and neurologic examination was unremarkable. Magnetic resonance imaging of the brain revealed a focal ring enhancing lesion in right posterior parietal lobe, suggestive of infective etiology. The patient underwent right parietooccipital craniotomy and excision of cerebral abscess, from which S. pluranimalium was isolated. The patient responded to treatment with intravenous ceftriaxone, vancomycin, and metronidazole without any residual neurologic sequelae.

Conclusion: Clinical data regarding epidemiology, pathogenic mechanisms, and zoonotic potential of S. pluranimalium in human beings are lacking. The number of cases of human infections with S. pluranimalium are steadily increasing. Hence further detailed study of the pathogenesis of S. pluranimalium in human beings is warranted, which may help to develop new strategies to prevent and treat infection with this bacterium.