Accompanying a semi-nested PCR assay to support histopathology findings of fungal keratitis in formalin-fixed paraffin-embedded corneal samples

© 2022 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC..

BACKGROUND: Fungal species are responsible for 40%-50% of all microbial keratitis cases. Due to the low amount of extracted DNA in ocular Formalin-fixed Paraffin-embedded (FFPE) samples, selecting a reliable molecular method is a substantial issue in this field.

METHODS: Sixty-six samples were collected via the penetrating keratoplasty (PK) technique. Histopathology assays were performed using hematoxylin-eosin (H&E) and periodic acid Schiff (PAS) staining methods. The ITS1/ITS4 and ITS1/ITS2 primer pairs were used in a semi-nested polymerase chain reaction (PCR) to target the universal internal transcribed spacer (ITS) region. Some PCR results were validated through sequencing.

RESULTS: Fungal DNA was detected in 44 of 66 samples (66.7%), and histopathology was positive for 41 of 66 samples (62.1%). Of 41 histopathologically proven fungal-positive cases, 39 were PCR-positive (95%). Moreover, of 44 PCR-positive samples, 39 (88.6%) were histopathology-positive, and 5 (11.3%) were histopathology-negative. Totally in 39 cases (59%), both histopathology and PCR yielded positive results. The Kappa agreement rate between the two diagnostic methods, including histopathology and PCR, was 0.77. Sensitivity, specificity, positive predictive value, and false predictive value were reported as 88.64%, 90.9%, 95.12%, and 80%, respectively.

CONCLUSION: As we reached the acceptable Kappa agreement rate, we concluded that applying the semi-nested PCR assay is a promising method for supporting the evidence by histopathology. Finally, we suggest targeting more specific gene regions using primer pairs that amplify smaller amplicon sizes and surveying novel molecular methods such as NGS to achieve higher sensitivity and Kappa agreement rates.

Medienart:

E-Artikel

Erscheinungsjahr:

2022

Erschienen:

2022

Enthalten in:

Zur Gesamtaufnahme - volume:36

Enthalten in:

Journal of clinical laboratory analysis - 36(2022), 12 vom: 20. Dez., Seite e24764

Sprache:

Englisch

Beteiligte Personen:

Ashraf, Mohammad Javad [VerfasserIn]
Shamsizadeh, Foroogh [VerfasserIn]
Morovati, Hamid [VerfasserIn]
Hejazinia, Safoora [VerfasserIn]
Kord, Mohammad [VerfasserIn]
Ansari, Saham [VerfasserIn]
Pakshir, Keyvan [VerfasserIn]
Shekarkhar, Golsa [VerfasserIn]
Zomorodian, Kamiar [VerfasserIn]

Links:

Volltext

Themen:

1HG84L3525
DNA, Fungal
Formaldehyde
Formalin-fixed paraffin-embedded
Fungal keratitis
Histopathology
Journal Article
Ocular samples
Semi-nested PCR

Anmerkungen:

Date Completed 20.12.2022

Date Revised 21.12.2022

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1002/jcla.24764

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM34885286X