الفهرس 
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Abstract
There are many methods for identification of yeasts including phenotypic, biochemical commercial and molecular methods. RFLP-PCR method is simple, cost-effective and rapid method for differentiation between species that is applicable in clinical laboratories.
This study aimed to identify yeasts isolated from human, animals and poultry by different manual and commercial phenotypic methods, commercial biochemical methods ( API Candida and API 20C AUX) and RFLP-PCR. To that end, yeast isolates is examined phenotypically on RAT 80% media, chrOM candida agar and examined biochemically by API Candida, API 20C AUX and tweens assimilation test and the results confirmed and compared with RFLP-PCR.
Yeast isolates that didn’t identified by Commercial kits and RFLP PCR were subjected for sequencing of the PCR products.
One hundred and sixty six yeast isolates were obtained from human, animals and poultry samples from 227 samples represented in: 90 samples from human yeast infections cases (21 VVC, 22 PV, 20 urine, 15 sputum and 12 oral candidiasis), chronic diseased cows , 90 samples including 24 vaginitis, 17 diarrhea , 49 mastitis, 19 poultry crop mycosis and 28 dog otitis externa.
The present work revealed that biochemical identification of yeast isolates by commercial kits as API Candida and API 20C AUX method and RFLP-PCR genotypic method could identify yeast into level of genera and spp. And even to varities, while phenotypic methods not enough to identify most yeast species.
Phenotypically, sixteen yeast isolates that revealed from VVC were identified as 9 C.albicans, 2 c.parapsillosis, 4 C.glabrata and 1 C.krusei. Twelve samples were collected from oral candidiasis and 8 isolates were obtained that were 4 C.albicans. 1 C.tropicalis and 3 C.parapsillosis. Fifteen sputum samples were collected from patients with respiratory manifestations that all were identified phenotypically as C.albicans. Twenty urine samples were collected and they revealed 20 isolates that were 19 C.albicans and 1 C.glabrata. Twenty two skin scrapings from PV samples collected from cases that clinically diagnosed as PV phenotypically were revealed 11 M.furfur.
Concerning cow samples, 53 yeast isolates were obtained . the predominant Candida species isolated is C.krusei .
Twenty four samples were collected from animal vaginitis that give 23 positive yeast cultures which revealed 25 isolates that were identified phenotypically as 10 Trichosporon spp., 2 C.albicans, 5 C.krusei, 2 C.parapsillosis, 1 C.tropicalis, 1 C.glabrata and 4 Candida species (2 C.kefyr, 1 C.pelliculosa and 1 P.mandshurica).
Twelve isolates were revealed from 49 tested mastitic milk samples that were identified as 2 C.krusei, 1 C.glabrata, 1 C.parapsillosis, 5 Rhodotorula spp. and 3 Candida spp. (C.inconspicua, C.rugosa and C.norvogenesis)
Seventeen rectal swabs were collected from diahrreic calves that revealed 16 isolates from 14 positive yeast cultures. The predominant isolate is C.glabrata (31.25%) followed by C.krusei (18.75%) then C.albicans (12.5%) and 5 Candida species (3 C.kefyr, 1 C.inconspicua, 1 C.ethanolica) and single isolate of Saccharomyces species.
Ten isolates were identified by API Candida and identified by RFLP PCR and the misidentified species by API Candida were 50%.
Twenty two yeast isolates were examined by Api 20 C AUX kits that were firstly identified phenotypically.The API 20 C AUX test was able to distinguish between all species of Candida that present in its database. These isolates were identified by RFLP PCR. API 20C AUX is a more time-consuming but higher cost alternative method to RFLP PCR identification. Our study confirmed that the API 20C AUX is a reliable system; all yeast isolates that present in its database were successfully identified in a similar manner to the PCR-RFLP test.
API 20 C AUX differentiate between phenotypically related species C.rugosa and C.krusei (primitive pseudohyphae) have the same phenotypic appearance but they well differentiated by API 20C AUX and the result were confirmed by RFLP PCR.
In the present study, we applied PCR-RFLP method in order to differentiate 30 species belonging to the genus Candida and Genus Malassezia which have been isolated from human and animal yeast-associated infections. This method has been proved to be fast and simple for species recognition and differentiation.
Despite that the incidence of Candida-associated infections caused by non-albicans species is significantly increased, our result indicated C. albicans as the most common causing agent in the human but C.krusei and C.glabrata isolated with high percentage than C.albicans from animal yeast infection.
The unknown 7 yeast isolates that were isolated from cow diarrhea, mastitis and vaginitis and couldn’t be confirmed by API 20C AUX, RFLP PCR were subjected to sequencing of PCR products and results
were C.ethanolica, , C.pelliculosa, C.kefyr (3), C.krusei and P.manshurica.
Antifungal sensitivity test using disc diffusion methods for yeast isolates recorded that most of isolates were sensitive to Amphotricin B and Clotrimazol.