Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2014

Isolation and identification of bacteria from the sub-gingival plaque of horses (#227)

Teerapol Dr. Chinkangsadarn 1 , Sean Corley 2 , Gary Dr. Wilson 1 , Lisa Dr. Kidd 1 , Philip Dr. Bird 1
  1. University of Queensland, Gatton, QLD, Australia
  2. Animal Genetic Laboratory, School of Veterinary Science, University of Queensland, Gatton, Queensland, Australia

Oral diseases in horses are a common problem1,2 . While there are numerous reports on the dental anatomy and clinical aspects of oral disease in horses, there are very few reports in the literature on the oral microbiology associated with health or disease3,4. Therefore the aim of this study was to isolate and identify cultivable bacteria from sub-gingival plaque of horses using culture and identification using 16S rRNA sequencing.

A dental examination was performed and the animals classified into either healthy or diseased groups.  Plaque samples were taken from the gingival sulcus of six horses, four with clinically healthy gingiva and two with periodontal disease. Plaque samples were plated onto Wilkins-Charlgen Agar (WCA) supplemented with 5% defibrinated blood, incubated at 37°C for up to 7 days in an anaerobic chamber (atmosphere of 90% N2/ 5% CO2/5% H2)  Up to 30 bacterial isolates from each plaque sample were identified by conventional phenotypic tests  and 16S rRNA gene sequencing5,6. Bacterial DNA was extracted using Prepman Ultra® amplified by PCR using the universal primers (27f and 1492r) and the sequence were compared with 16S rRNA gene sequences from Genbank sequence database; The National Centre for Biotechnology Information Website (http://www.ncbi.nlm.nih.gow/BLAST).

The results show that bacteria from 16 genera were isolated from the plaque of healthy horses and 11 genera of bacteria from the diseased. The most common isolates being Veillonella  (12%), Gram positive anaerobic cocci (12%), Streptococcus  (9%), Porphyromonas (6% include P. asaccharolytica 3%,  P. uenonis 1%), Fusobacterium (7% include F. equinum 1%, F. nucleatatum 1%), Actinobacillus (6%) and Prevotella ( 5% include P. intermedia 2%, P. dentasini 2%) and a number of “uncultured” species/clones. The preliminary results from the present study showed that equine oral microbiology in health and periodontitis is highly diverse with a higher diversity associated with health.  A number of isolates were identified as “uncultured” clones highlighting the high potential for isolation of novel species. 

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