Faecal microbiota characterisation of horses using 16 rdna barcoded pyrosequencing, and carriage rate of clostridium difficile at hospital admission.

Cristina Rodriguez,Antoine Bruwier,Michel Delmée,Aurélia Leroux,Bastien Brévers,Marjorie Gallot,Véronique Avesani,Georges Daube,Bernard Taminiau,Johan Van Broeck,Hélene Amory

doi:10.1186/s12866-015-0514-5

Cristina Rodriguez, Antoine Bruwier + Show 9 more

Open Access

https://doi.org/10.1186/s12866-015-0514-5

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Abstract

BackgroundThe equine faecal microbiota is very complex and remains largely unknown, while interspecies interactions have an important contribution to animal health. Clostridium difficile has been identified as an important cause of diarrhoea in horses. This study provides further information on the nature of the bacterial communities present in horses developing an episode of diarrhoea. The prevalence of C. difficile in hospitalised horses at the time of admission is also reported.ResultsBacterial diversity of the gut microbiota in diarrhoea is lower than that in non-diarrhoeic horses in terms of species richness (p-value <0.002) and in population evenness (p-value: 0.02). Statistical differences for Actinobacillus, Porphyromonas, RC9 group, Roseburia and Ruminococcaceae were revealed. Fusobacteria was found in horses with diarrhoea but not in any of the horses with non-diarrheic faeces. In contrast, Akkermansia was among the three predominant taxa in all of the horses studied. The overall prevalence of C. difficile in the total samples of hospitalised horses at admission was 3.7 % (5/134), with five different PCR-ribotypes identified, including PCR-ribotype 014. Two colonised horses displayed a decreased bacterial species richness compared to the remaining subjects studied, which shared the same Bacteroides genus. However, none of the positive animals had diarrhoea at the moment of sampling.ConclusionsThe abundance of some taxa in the faecal microbiota of diarrhoeic horses can be a result of microbiome dysbiosis, and therefore a cause of intestinal disease, or some of these taxa may act as equine enteric pathogens. Clostridium difficile colonisation seems to be transient in all of the horses studied, without overgrowth to trigger infection. A large proportion of the sequences were unclassified, showing the complexity of horses’ faecal microbiota.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-015-0514-5) contains supplementary material, which is available to authorized users.

Highlights

The equine faecal microbiota is very complex and remains largely unknown, while interspecies interactions have an important contribution to animal health
Equine gut microbiota is poorly characterised and studies are currently underway to increase understanding of how defined microbial communities are able to interfere with different bacterial aetiologies of diarrhoea in horses
Diarrhoea and colitis have been associated with a number of different pathogenic agents, including Clostridium difficile, Clostridium perfringens, Salmonella spp and Escherichia coli [4,5,6,7]

Summary

Introduction

The equine faecal microbiota is very complex and remains largely unknown, while interspecies interactions have an important contribution to animal health. Clostridium difficile has been identified as an important cause of diarrhoea in horses. Equine gut microbiota is poorly characterised and studies are currently underway to increase understanding of how defined microbial communities are able to interfere with different bacterial aetiologies of diarrhoea in horses. Clostridium difficile is amongst the most important agents of diarrhoea and serious colitis in horses [8]. While both adult horses and foals can suffer C. difficile enteric disease, it seems that foals are more likely to be colonised by the bacterium [9]. Other possible causes of acute colitis must be ruled out [8]

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