Horse to human: Streptococcus equi septicemia presenting as endogenous endophthalmitis

Abstract

Purpose: To present a rarely reported systemic infection with streptococcus equi subspecies zooepidemicus (streptococcus equi), transmitted from a horse, and to describe successful treatment when complicated by endogenous endophthalmitis.

Observations: We diagnosed suspected streptococcus equi septicemia presenting as loss of vision in the right eye of an otherwise healthy polo player/horse trainer. He received immediate intravenous antibiotics and three vitrectomies with two intravitreal antibiotic injections during the first week, to cure infection and subsequent retinal detachment. Blood and initial vitreous cultures rapidly grew streptococcus equi. The septicemia was quickly controlled by systemic antibiotics without developing commonly seen and often fatal meningitis. The right eye recovered 20/30 visual acuity three months post infection.

Conclusions: Presentation of this rare septicemia as endogenous endophthalmitis illustrates the potentially lifesaving role of early diagnosis by the ophthalmologist. Immediate and recurrent vitrectomy in conjunction with intravitreal and systemic antibiotic therapy resulted in recovery of near normal vision, whereas less timely and interventional treatments have failed heretofore.

Keywords: Endogenous endophthalmitis; Septicemia; Streptococcus equi; Vitrectomy.

Fig. 1

Anterior segment at presentation, with purulence covering the entire posterior lens surface, obliterating all fundus view.

Fig. 2

Wide angle image of the retina three months postoperatively, showing the site of original choroidal infection superonasal. Reflection overlying the inferior macula is artifactual.

Fig. 3

Optical coherence tomography (OCT) image of right macula three years post treatment, with visual acuity of 20/30 and moderate retinal atrophy temporally (endophthalmitis retinopathy). Unaffected left macula included for comparison.