Dermatophilus congolensis infection in sheep and goats in Delta region of Tamil Nadu

Vet World Vol.10 November-2017 Article-5

Research Article

Veterinary World, 10(11): 1314-1318

https://doi.org/10.14202/vetworld.2017.1314-1318

M. Ananda Chitra¹, K. Jayalakshmi², P. Ponnusamy¹, R. Manickam¹, and B. S. M. Ronald¹

1. Department of Veterinary Microbiology, Veterinary College and Research Institute, Tamil Nadu Veterinary and Animal Sciences University, Orathanadu - 614 625, Thanjavur, Tamil Nadu, India.
2. Department of Veterinary Medicine, Veterinary College and Research Institute, Tamil Nadu Veterinary and Animal Sciences University, Orathanadu - 614 625, Thanjavur, Tamil Nadu, India.

Background and Aim: The study was conducted to isolate and identify Dermatophilus congolensis (DC) using conventional and molecular diagnostic techniques in scab materials collected from skin infections of sheep and goats in the Delta region of Tamil Nadu.

Materials and Methods: A total of 20 scab samples collected from 18 goats and 2 sheep from Nagapattinam, Thanjavur, and Tiruvarur districts of Tamil Nadu. Smears were made from softened scab materials and stained by either Gram's or Giemsa staining. Isolation was attempted on blood agar plates, and colonies were stained by Gram's staining for morphological identification. Identification was also done by biochemical tests and confirmed by 16S rRNA polymerase chain reaction (PCR), followed by sequencing and phylogenetic analysis of the amplified product.

Results: The peculiar laddering arrangement of coccoid forms in stained smears prepared from scab materials revealed the presence of DC. Isolated colonies from scab materials of sheep and goats on bovine blood agar plate were small, hemolytic, rough, adherent, and bright orange-yellow in color, but some colonies were white to cream color. Gram-staining of cultured organisms revealed Gram-positive branching filaments with various disintegration stages of organisms. 16S rRNA PCR yielded 500 bp amplicon specific for DC. Sequence analysis of a sheep DC isolate showed 99-100% sequence homology with other DC isolates available in NCBI database, and phylogenetic tree showed a close cluster with DC isolates of Congo, Nigeria, and Angola of Africa. Genes for virulence factors such as serine protease and alkaline ceramidase could not be detected by PCR in any of the DC strains isolated of this study.

Conclusion: The presence of dermatophilosis in Tamil Nadu was established from this study. Keywords: 16S rRNA sequence analysis, Dermatophilus congolensis, sheep and goats, Tamil Nadu.

Keywords: 16S rRNA sequence analysis, Dermatophilus congolensis, sheep and goats, Tamil Nadu.

How to cite this article: Ananda Chitra M, Jayalakshmi K, Ponnusamy P, Manickam R, Ronald BSM (2017) Dermatophilus congolensis infection in sheep and goats in Delta region of Tamil Nadu, Veterinary World, 10(11): 1314-1318.

Received: 04-07-2017 Accepted: 11-10-2017 Published online: 09-11-2017

Corresponding author: M. Ananda Chitra E-mail: anandachitra.m@tanuvas.ac.in

DOI: 10.14202/vetworld.2017.1314-1318

Copyright: Ananda Chitra, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.