1. Section of Ophthalmology, Department of Surgical, Microsurgical, and Medical Sciences, University of Sassari, Sassari, Italy.
2. Section of Clinical and Experimental Microbiology, Department of Biomedical Sciences, University of Sassari, Sassari, Italy.
3. Department of Microbiology, Institute of Ophthalmology, Joseph Eye Hospital, Tiruchirapalli, India.