Recurrent post-operative endophthalmitis caused by Sphingomonas paucimobilis despite vitrectomy – a case and review of the literature

Over the past 20 years, scattered reports have emerged about a low virulence, gram negative bacillus, Sphingomonas paucimobilis, causing unpredictable clinical presentations of endophthalmitis. Previous reports have characterised the organism as being resistant to aggressive treatment and prone to recurrence up to several months later, with few warning signs of any residual infection. We report a case of a 75 year-old male who returned 10 days after a left eye cataract surgery with an atypical, indolent endophthalmitis. He was treated with broad-spectrum intravitreal antibiotics and vitrectomy, and despite initial improvement, the patient suffered a recurrence after 2 weeks, necessitating successive rounds of intravitreal antibiotics. While our patient was able to achieve an excellent final visual acuity of 6/9, there are several cases in the literature reporting similar cases with much worse visual outcomes. Further research is required to elucidate early warning signs that may indicate a recurrence of S. paucimobilis infection, and the underlying mechanism by which it is resistant to standard endophthalmitis therapy. Alongside this case, we review and summarise the literature on postoperative endophthalmitis involving this organism.