Diversity of Microbial Species Implicated in Keratitis: A Review

Abstract

Background: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.Methods: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.Results: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.Conclusions: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.

Corneal ulcer: a retrospective study of a cases seen at the Hospital das Clínicas, Federal University of Espirito Santo

“…Around the world, infectious keratitis is a major cause of morbidity and low visual acuity due to corneal opacity, ocular perforation, and endophthalmitis [1][2][3]5,6 . The severity of the disease depends on the aggressiveness of the agent, as well as adherence…”

“…Although studies comparing the aetiology and incidence of ICUs are still limited, important variations are known to occur across continents, countries and regions [1][2][3] . The epidemiology of ICUs is not well determined because most data come from referral hospitals, therefore results may not be representative of the general population.…”

“…The epidemiology of ICUs is not well determined because most data come from referral hospitals, therefore results may not be representative of the general population. In developing countries, 1.5 to 2 million ulcers are estimated to occur every year 2 , resulting in a large number of corneal opacities, which in turn represent the second leading cause of preventable blindness in certain tropical countries 1 . The infectious agent is identified through microbiological analysis of a sample of the lesion 1 , which should always include a culture with antibiogram.…”

“…Prior knowledge of the epidemiological profile of infectious ulcers in the region can be very useful for choosing the type of empirical treatment. Around the world, 232 species of microorganisms that cause ICUs have been identified 2 . Therefore, microbiological analysis in referral hospitals is critical to identify the most prevalent aetiological agents in the region and to provide important information on their sensitivity to existing antibiotics 4 .…”

Fungal Keratitis: Update for 2014

“…These numbers are compared to the much fewer 42 different genera of bacteria, 4 genera of protozoa, and 4 types of viruses that were documented as causative agents of infectious keratitis. Still, the causative agent in the majority of FK cases comes from only a few genera; namely Fusarium, Aspergillus, and Candida [5]. In Bangkok Thailand, Shandong China, and South India, Fusarium has been reported to be the most prevalent [6][7][8].…”