Incidence and microbiological profile of infection in contact lenses induced corneal ulcer / Sara Seleem Mahmoud Seleem ; Supervised Ismail Mohamed Kamel Ismail , Neveen Mahmoud Mohamed Mohamed , Mohamed Gamil Metwally Aly

Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Botany - Microbiology

Corneal specimens (scraping and contact lens) were collected from fifteen patients infected with corneal ulcer induced by contact lenses and applied to microbiological survey to isolate the bacterial and fungal contaminants. Four hundred bacterial isolates constituting 13 species were screened. Biochemical identification following Bergey{u00B4}s manual protocol indicated that Alcaligenes faecalis was the most prevalent in the eye lenses. Meanwhile, 117 fungal isolates were identified from specimens constituting 13 species. The yeast isolate was the most dominant fungal species in the eye lenses. Molecular analysis confirmed that bacterial species is alcaligenes faecalis strain NBRC 13111 and the yeast species is cyberlindnera fabianii strain S89 (de novo species isolated for the first time in corneal ulcer in Egypt). Susceptibility tests using disc diffusion method, microscan walkaway 96 and vitek 2 compact instruments revealed that the most active antibacterial and antifungal agents with broad spectrum are tobramycin and Natamycin, respectively. Three contact lens care solutions (Re-NU, Opti-Free, Bio- true) were tested for their disinfecting activities and found that they have neither antibacterial nor antifungal activities. In vivo study using tobramycin against thehigh prevalent bacterial species A. faecalis and Natamycin against the high frequent yeast species C. fabianii using rabbit groups indicated that the two microorganisms are severe pathogens for corneal ulcer causing strong histopathological alterations

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