65 simply means inflammation of the cornea of any cause, infection and otherwise.
66 Infectious keratitis is the most frequent cause of keratitis where bacterial infection
67 account for approximately ninety percent of microbial keratitis [1,2]. Predisposing
68 factors can be divided to four categories: extrinsic factors such as physical or chemical
69 trauma, ocular surface disease as tear-film deficiencies, corneal epithelial
70 abnormalities and systemic diseases as vitamin A deficiency [3,4].
71 Bacterial keratitis may be caused either by Gram positive or Gram negative organisms.
72 Eighty percent of bacterial corneal ulcers are caused by S. pneumonia, S. aureus and
73 …show more content…
77 Rapid and successful treatment of bacterial keratitis may depend on accurate
78 diagnosis as well as antibiotic selection. The primary treatment for bacterial ulcerative
79 keratitis is intensive administration of antibiotics [1,2]. Currently, no single antibiotic
80 agent is effective against all bacterial species causing microbial keratitis [1,4]. Initial
81 treatment is done with a broad-spectrum antibiotic to cover both Gram positive and
82 Gram negative pathogens until microorganism is identified by culture. Vancomycin
83 and bacitracin are examples of antibiotics used against Gram positive cocci whereas
84 fluoroquinolones or a combination of cefazolin with tobramycin or gentamycin are
85 used in infection with multiple types of organisms [1].
4
Due to the side effects of synthetic 86 antimicrobial agents and the emerging increase in
87 bacterial resistance to current antibiotic and other antimicrobial agents, many studies
88 have recently focused on characterization of novel potential antimicrobial