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171053

ITS2 REGION-BASED MOLECULAR IDENTIFICATION OF FUNGAL PATHOGENS IN EQUINE CORNEAL ULCERATION

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Last updated: 05 Jan 2025

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Abstract

This study aimed to assess the utility of polymerase chain reaction (PCR) and DNA sequencing in diagnosing fungal ulcerative keratitis in horses and compare their sensitivity with conventional microbiologic techniques used in laboratories. Conjunctival swabs from 12 horses with corneal ulcerations admitted to the Veterinary Teaching Hospital, College of Veterinary Medicine, PurdueUniversity were collected for examinations. 14 conjunctival swabs were analyzed by the conventional culture method and by generic PCR using universal fungal primers to amplify the internal transcribed spacer 2 (ITS2) genetic region followed by DNA sequencing. The conventional culture method revealed that two samples exhibited fungal growth that identified as Aspergillus sp. and Penicillium sp. while three conjunctival samples contained bacterial growth which was identified as Staphylococcus intermedius, Staphylococcus epidermidis and Streptococcus zooepidemicus. Interestingly, PCR followed by DNA sequencing of the biological specimens on the swabs identified fungal pathogens in 9/14 samples and Ascomycete species in 3/14 samples. In 2/14 samples, no fungal pathogen was identified using PCR. Fungal pathogens detected included Aspergillus sp. in six eyes, Penicillium sp. in one eye, Fusarium sp. in one eye and Cladosporium sp. in one eye. Our findings demonstrate a limitation of the conventional culture method as a diagnostic tool as a fungal pathogen was detected in only two samples by this method as compared to nine samples using PCR and DNA sequencing. Therefore, PCR followed by DNA sequencing is able to identify a greater spectrum of agents including fastidious organisms or organisms present in lower numbers within mixed infections than can be identified by culture. In conclusion, PCR combined by DNA sequencing not only proved to be an effective and rapid method for the diagnosis of fungal keratitis, but was also a more sensitive diagnostic tool compared to the conventional culture method. Our findings demonstrate that PCR, in particular semi-nested PCR, is a promising tool for faster diagnoses of fungal keratitis in affected horses.

DOI

10.21608/avmj.2014.171053

Keywords

Key words: ITS2 region, Fungal pathogens, equine, corneal ulcers

Authors

First Name

M.

Last Name

HAMED

MiddleName

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Affiliation

Division of Infectious Diseases

Email

mahohzero@gmail.com

City

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Orcid

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First Name

HAROON

Last Name

MOHAMMAD

MiddleName

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Affiliation

Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, USA

Email

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City

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Orcid

-

First Name

WENDY

Last Name

TOWNSEND

MiddleName

-

Affiliation

Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, USA

Email

-

City

-

Orcid

-

First Name

MOHAMED

Last Name

N. SELEEM

MiddleName

-

Affiliation

Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, USA

Email

-

City

-

Orcid

-

Volume

60

Article Issue

143

Related Issue

24325

Issue Date

2014-10-01

Receive Date

2021-09-10

Publish Date

2014-10-01

Page Start

61

Page End

69

Print ISSN

1012-5973

Online ISSN

2314-5226

Link

https://avmj.journals.ekb.eg/article_171053.html

Detail API

https://avmj.journals.ekb.eg/service?article_code=171053

Order

9

Type

Research article

Type Code

1,840

Publication Type

Journal

Publication Title

Assiut Veterinary Medical Journal

Publication Link

https://avmj.journals.ekb.eg/

MainTitle

ITS2 REGION-BASED MOLECULAR IDENTIFICATION OF FUNGAL PATHOGENS IN EQUINE CORNEAL ULCERATION

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Article

Created At

23 Jan 2023