Endophthalmitis Due to Proteus vulgaris after Pars Plana Vitrectomy with Devastating Outcome.

Postoperative infectious endophthalmitis is rare, yet devastating loss of vision or loss of the eye can occur due to a highly purulent microorganism or uncontrolled endophthalmitis that may spread to all coats of the eye. We report, herewith, a case of rapidly progressive postoperative endophthalmitis after pars plana vitrectomy which ended up with enucleation. The isolated microorganism was Proteus vulgaris which has not been reported as causative bacteria of postoperative infections following pars plana vitrectomy.

Introduction

Infectious endophthalmitis can be a devastating complication after ophthalmic surgery due to the risk of complete loss of vision or loss of the eye. In some cases, endophthalmitis can progress to panophthalmitis. Most simply, panophthalmitis is defined as an inflammation of all coats of the eye. The incidence of postoperative endophthalmitis varies between 0.06% and 0.20%.[12] However, the incidence is even lower after pars plana vitrectomy as it varies from 0.02% to 0.05%.[3]

The microbial spectrum in infectious endophthalmitis may vary based on the geographic location.[4] In addition, immunocompromised patients have a greater susceptibility to develop postoperative endophthalmitis[5] that may further progress to panophthalmitis. Endophthalmitis due to Enterobacteriaceae such as Proteus species has been previously reported.[6] However, to the best of our knowledge, endophthalmitis after pars plana vitrectomy due to Proteus vulgaris has not been reported in the English peer reviewed literature. In this case report, we present a case of postoperative endophthalmitis due to P. vulgaris after pars plana vitrectomy.

Case Report

A 75-year-old female presented to the emergency room complaining of severe lid swelling and pain in the left eye for the previous 3 days. The patient had undergone left eye uneventful pars plana vitrectomy, membrane peeling, endolaser photocoagulation with silicone oil tamponade for chronic tractional retinal detachment at Ophthalmology Department, King Abdul Aziz University Hospital, King Saud University, Riyadh, KSA 1 week before presentation. Medical history included diabetes which was not well controlled for 13 years and hypertension that was being medically treated. Previous ophthalmic history included uncomplicated cataract surgery 6 months before presentation in the right eye and 8 months before presentation in the left eye.

On examination at presentation, visual acuity in the right eye was 20/100 and in the left eye was no light perception. Examination of the right eye showed pseudophakic globe with flat retina with a good panretinal photocoagulation. Examination of the left eye showed severe lid swelling with difficulty to open the eye [Figure 1a], the cornea was opaque with a hypopyon, conjunctival chemosis and hyperemia and the globe was frozen. The patient was diagnosed with endophthalmitis progressed into panophthalmitis, and computed tomography (CT) scan was done and showed proptosed left eye, increased density of orbital fat and preseptal edema [Figure 1b].

Figure 1

(a) Severe lid swelling with difficulty to open the left eye. (b) Computed tomography-scan shows proptosed left eye, increased density of orbital fat and preseptal edema

The patient received systemic intravenous antibiotics in the form of ceftriaxone and clindamycin. An oculoplastic consultation was performed on the same day, and left eye was enucleated that day. Interestingly, pale tissues with minimal bleeding were noticed throughout the procedure [Figure 2a–c]. Culture samples were positive for P. vulgaris and were negative for microbes at the margin where the optic nerve was cut during enucleation.

Figure 2

(a and b) Very minimal bleeding with pale tissues during lateral canthotomy to widen the palpebral fissure for better surgical field exposure. (c) Pale medial rectus muscle

Postoperatively, during hospitalization, the patient settled with a quiet socket. At last visit, 2-month postenucleation, the visual acuity was 20/200 in the right eye, and the left eye socket was quiet, and inflammation was well controlled.

Discussion

Postoperative infectious endophthalmitis can be caused by all groups of microbes. However, the most common causative organisms from recent studies in the Middle East are Gram-positive microorganisms followed by Gram-negative microorganisms and least frequently, fungi.[47] The most common Gram-negative isolates are generally Pseudomonas species and Haemophilus. Proteus related endophthalmitis is rare. In Saudi Arabia, systemic Proteus infections are most commonly due to P. mirabilis (89%), P. vulgaris (6%), and other Proteus species (5%).[8] Those typically associated with endophthalmitis are P. mirabilis in 90% of the cases.[6] P. vulgaris is an opportunistic human pathogen that is isolated in individuals with underlying disease or those who are immunocompromised.[91011] P. vulgaris is susceptible to fluoroquinolones, cephalosporins, beta-lactams, and aminoglycosides. Recently, some Proteus isolates in Saudi Arabia have exhibited resistance to expanded-spectrum beta-lactam antibiotics.[8]

Risk factors for postoperative endophthalmitis include the lack of subconjunctival antibiotics, leaking sclerotomies resulting in postoperative hypotony, vitreous wick after sclerotomy, wound construction, bacterial inoculum into the vitreous in immune-compromised patients such as diabetics and the elderly.[5] In our case, the patient was a diabetic which is also known risk factor for endophthalmitis.[78] However, the endophthalmitis vitrectomy study (EVS) has reported that postoperative infectious endophthalmitis is more likely due to Gram-positive bacteria in diabetics.[9] Notably, the EVS reported results after cataract surgery rather than pars plana vitrectomy. Wykoff et al. have reported that the incidence of endophthalmitis after pars plana vitrectomy is significantly lower compared to other intraocular procedures.[10] The aggressive nature of the isolated microorganism and the immune-comprised state of this patient combined with the multiple surgeries in the left eye may have allowed progression to panophthalmitis. P. vulgaris infections are highly purulent, which was consistent with the finding of hypopyon in this case. In addition, the presentation was consistent with previous literature that described more severe initial presentation in Gram-negative cases.[1] Visual acuity after endophthalmitis following pars plana vitrectomy is typically worse than following anterior segment surgery.[11] P. vulgaris infections can cause occlusive vasculitis and even symmetric peripheral gangrene which could explain the notably minimal bleeding and pale tissues during enucleation procedure.[12]

Our search engine could not find a case of postoperative panophthalmitis due to P. vulgaris in the PubMed literature, Google, and Google Scholar. This is a relatively rare entity, yet should be included in the differential diagnosis of any suspected cases of postoperative infections following pars plana vitrectomy.

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Conflicts of interest

There are no conflicts of interest.