Comparing Traditional Gram Stain to Cytospin-Enhanced Cytology of Vitreous Samples in Patients with Endophthalmitis

Abstract

Purpose : Endophthalmitis is a devastating infection of the eye. Gram stains provide immediate results and play a vital role in the management of endophthalmitis. A proportion of gram stains are negative using the standard smear technique. Cytospin is a cytology technique that optimizes collection of cells when small samples are available. Cytology-enhanced by cytospin has been used to analyze specimens from the anterior chamber and from other limited sources of body fluid to help diagnose malignancies. The purpose of this study was to investigate the potential value of the cytospin technique in analyzing cytology results from vitreous specimens in endophthalmitis.

Methods : 61 eyes of 61 patients with endophthalmitis of various etiologies were treated at the New York Eye & Ear Infirmary of Mount Sinai (NYEE) from February 2014 to February 2015 with tap and injection. Vitreous specimens were sent for gram stain and culture. Gram stains of 26 eyes were analyzed using the standard smear technique, while 35 eyes were analyzed using the cytospin technique. For the cytospin technique, the slide with the specimen is placed into a cytofunnel and centrifuged at low speed for 10 minutes. The sample is then examined and interpreted by a pathologist. A retrospective chart review was performed of the cases involved and gram stain results obtained from traditional smear method were compared to those processed using the cytospin method.

Results : 26 samples analyzed using standard smear technique showed positive stains in 4 cases (15.4%). 35 eyes analyzed using the cytospin technique revealed positive stains in 11 cases (31.4%). Preliminary results are not statistically significant, but we are still collecting samples and as the sample size increases we may be able to demonstrate statistical significance.

Conclusions : Performing gram stains using the cytospin technique enhances the yield of positive results in the setting of limited sample sizes by better utilization of the specimen available. In the emergent setting of endophthalmitis, this enhancement may make the difference in accurate diagnosis which is critical for successful management of the patient. Further investigation should reveal whether the methodology delivers a statistically robust difference in outcome between the two methods.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.