In the presented case, early recognition along with prompt and effective treatment of the intraocular Capnocytophaga infection were crucial to preserve visual outcome. Even though no signs of ocular penetration were visible in the first place, clinical aspects, e.g. massive intravitreal inflammation despite intensive local antibiotic treatment and the rapid development of a secondary cataract after the trauma with a capsular defect diagnosed later, strongly suggested an eye penetration during cat bite injury. Initial daily follow-up examinations allowed us to respond quickly to the developing endophthalmitis, which otherwise would have potentially led to irreversible visual loss. Therefore, we recommend a strict control regimen after bite injuries, even if no obvious signs of ocular penetration can be detected.

Due to its rapid and aggressive progression, infectious endophthalmitis is a severe vision threatening disease [13]. In order to avoid retinal toxicity, an initial empiric treatment with local broad-spectrum antibiotic, like moxifloxacin, as well as intravitreal and intravenous treatments with broad-spectrum antibiotics can be necessary. Due to a progressive intraocular inflammation, we treated the patient with intravenous ceftazidime and imipenem/cilastatin. This combination has high potency especially in gram-negative endophthalmitis, including Capnocytophaga related endophthalmitis [7, 14, 15]. The combination of intravitreally applied vancomycin and ceftazidime covers a broad gram-positive and gram-negative spectrum and is known to be an ideal empiric treatment of endophthalmitis [15], under which the patient was already recovering well. As comprehensive culture analysis of vitreous punctate for aerobic, anaerobic and fungal pathogens did not show any growth, sequencing-based diagnostic was crucial in this case to detect Capnocytophaga felis, a recently newly described species isolated from the oral cavity of cats [16], as the cause of endophthalmitis. This was especially important to optimize antibiotic regimen to oral treatment with clindamycin, as recommended for the treatment of Capnocytophaga related ocular infections [9, 17] in order to prevent severe systemic infections, e.g. Capnocytophaga associated lethal sepsis [6]. Taken together, early recognition as well as prompt and effective diagnosis and treatment of the developing endophthalmitis were key to achieve best therapeutic outcome.