Diversity of Microbial Species Implicated in Keratitis: A Review

Elisabeth Karsten1, Stephanie Lousie Watson2, 3, Leslie John Ray Foster*, 1
1 Bio/Polymer Research Group, Centre for Advanced Macromolecular Design, School of Biotechnology and Biomolecular Sciences, Faculty of Science
2 School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney
3 Save Sight Institute, University of Sydney, Sydney, Australia

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© Karsten et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Bio/polymer Research Group, School of Biotechnology & Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Tel: +61-2-9385-2054; Fax: +61-2-9313-6710; E-mail:



Microbial keratitis is an infectious disease of the cornea characterised by inflammation and is considered an ophthalmic emergency requiring immediate attention. While a variety of pathogenic microbes associated with microbial keratitis have been identified, a comprehensive review identifying the diversity of species has not been completed.


A search of peer-reviewed publications including case reports and research articles reporting microorganims implicated in keratitis was conducted. Search engines including PubMed, Scopus and Web of Science with years ranging from 1950-2012 were used.


232 different species from 142 genera, representing 80 families were found to be implicated in microbial keratitis. Fungi exhibited the largest diversity with 144 species from 92 genera. In comparison, 77 species of bacteria from 42 genera, 12 species of protozoa from 4 genera and 4 types of virus were identified as the infectious agents. A comparison of their aetiologies shows reports of similarities between genera.


The diversity of microbial species implicated in keratitis has not previously been reported and is considerably greater than suggested by incidence studies. Effective treatment is heavily reliant upon correct identification of the responsible microorganisms. Species identification, the risk factors associated with, and pathogenesis of microbial keratitis will allow the development of improved therapies. This review provides a resource for clinicians and researchers to assist in identification and readily source treatment information.

Keywords: Microbial Keratitis, Staphylococcus, Amoebic Keratitis, Acanthamoeba, Mycotic keratitis, Fusarium, Candida, Herpetic keratitis, HSV-1.