dr.k.pragathi assistant professor department of ... · serious cause of ocular morbidity. early...
TRANSCRIPT
DR.K.PRAGATHI ASSISTANT PROFESSOR
DEPARTMENT OF MICROBIOLOGY KIMS,NARKETPALLY.
DEFINITION: Inflammation of cornea that results from infection by a fungal organism. Serious cause of ocular morbidity.
Early diagnosis and treatment is necessary to
prevent further complications.
More common in tropics and sub-tropics.
Local : Ocular trauma with vegetable matter. Surgical trauma - LASIK, - Photorefractive Keratectomy. Contact lens. Dry eye . Topical steroids
Diabetes mellitus. Malnutrition. Alcoholism. HIV.
World wide - Aspergillus species (MC ) .
India : - Aspergillus - Fusarium - Penicillium - Candida (rare)
FILAMENTOUS FUNGI YEAST LIKE ORGANISMS
HYALINE FUNGI PHAEOID FUNGI
(Pigmented )
A.Hyaline Fungi : - Aspergillus fumigatus,A.flavus Fusarium solani,F.oxysporum Acremonium species Paecilomyces species Penicillium species Pseudallescheria boydii.
Curvularia sp. Bipolaris sp. Alternaria sp. Exserohilum sp. Cladosporium. Aureobasidium pullulans.
Yeast-like Fungi : Candida albicans. Canida tropicalis. Candida krusei.
Specimen collection : Corneal scrapings - Slit lamp examination Margin and base of ulcer. Aseptic technique. Local anaesthetic (4% xylocaine drops ) . Surgical blade/Kimuras spatula. Corneal Biopsy . Calcium alginate swabs .
DIRECT EXAMINATION
Gram Stain
10% KOH
Calcofluor white
Giemsa stain
Grocott methenamine silver stain.
DIRECT EXAMINATION
2 SETS OF SDA WITH ANTIBIOTICS ( 25 and 37 degree C)
1 SET OF BHI AGAR ( 37 degrees C)
BLOOD AGAR ( 37 degrees C)
INOCULATION :
C or S shaped streaks . Ensures growth is from inoculum and not a contaminant.
Cultures are checked every day – 1st week. Twice a week thereafter. Most fungi grow in 24 hrs – 2 weeks. Cultures are declared negative only after 3 weeks.
Positive cultures from 2 or more sets is convincing.
Mycelial isolates identified by – Colony morphology. - LCB mount. - Slide cultures.
ASPERGILLUS
A.Niger
SDA
A.Nidulans
A.fumigatus
GROWTH ON SDA LCB MOUNT
GROWTH LCB MOUNT
GROWTH ON SDA
Identification tests - Germ tube. - Reduction of tetrazolium medium. - Chlamydospores production. - Urease test. - Sugar fermentation . - Sugar assimilation.
GROWTH ON SDA GRAM STAIN
Molecular techniques : PCR.
Confocal Microscopy - Non invasive. - Invivo technique. - Identifies both hyphal and yeast forms.
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