Abstract
Purpose :
Acanthamoeba polyphagia Mimivirus and other giant viruses are ubiquitous in nature. Free living amoebas serve as hosts and potential dissemination vectors. Although reported from a contact lens case of a patient with amoebic keratitis in 2011, they have also been recovered from other human samples since their discovery (respiratory secretions, feces, and blood). Their pathology, frequency, and diversity are still unknown.
Our purpose was to investigate the frequency, abundance, and diversity of giant viruses and associated virophages, in contact lens cases of patients presenting with microbial keratitis.
Methods :
Shotgun proteomics coupled with mass spectrometry was used to determine quantity and diversity of proteins associated with 4 giant virus families in contaminated contact lens cases (CTL) of 8 patients presenting with both cornea (K) positive (n=5) and negative (n=3) microbial keratitis. Contact case cases were separated into 3 groups according to culture results; Group 1, (CTL+, Acanthamoeba, N=3), Group 2 (CTL +, bacteria, N=2) and Group 3 (CTL-, n=3). The correlation between corneal and contact lens cultures was 62.5%. Viral identification was determined using a blast searches of NCBI giant viruses proteins. Chi-square statistics were used to compare differences between the groups.
Results :
A total 1545 proteins from 4 different viral families (Mimiviridae (56.2%, n=869), Pandoraviridae (30.2% n=467), Marseilleviridae (10.6%, n=164) and Pithioviruses (Phycodnaviridae) - (2.9%, n=45) were found among our samples.
Of these 687 (44.5%) were mapped to known viral proteins. The highest number of characterized viral proteins were found in group 2 (92.8%, average, n=635) followed by group 1 (86.6%, average, n= 593), and group 3 (82%, average=563).
The frequency of giant viruses found in all samples was Pandora (88.3%), Marseille (87%), Pithoviruses(86%) and Mimi (85%). The differences between group 1 and 2 were significant for Mimi(p<0.0001), Marseille (p=0.0023) and total proteins (p=0.0005), between group 1 and 3 was significant for total proteins only (p=0.0401) and between group 2 and 3 was significant for , Pandora (p=0.034), Mimi (p<0.0001), Marseille (p=0.0186) and total proteins (p<0.0001).
Conclusions :
We confirmed a high prevalence and diversity of giant viruses in contact lens cases of patients presenting with microbial keratitis. Pathogenicity and their role in microbial keratitis is unknown.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.