04). This increase on day 14 was observed in 4 out of 5 dogs (Figure 2). Moraxallaceae decreased in 4 of 5 dogs on day 14, but increased in the remaining
dog (Table 2, Figure 6). A significant change was observed for ε-Proteobacteria (Figure 8; p = 0.039). Sequences belonging to this class were observed in 5 dogs on day 0, but only in 1 dog each on days 14 and 28 (p = 0.013). Decreases in Helicobacteariaceae and Campylobacteriaceae were both contributing to this change in ε-Proteobacteria (Table 2). Actinobacteria Sequences belonging to the phylum Actinobacteria were identified in all dogs at all time points. No consistent changes in response #FRAX597 price randurls[1|1|,|CHEM1|]# to tylosin were observed on the phylum level. However, significant changes were observed for some bacterial taxa within this phylum. Dietziaceae increased significantly by day 14 (Figure 6; p = 0.03). Selleckchem AZD1480 This group increased
in 3 dogs, remained stable in 1 dog, and was not detected in the remaining dog. Interestingly, no sequences belonging to Dietziaceae were detectable on day 28. Streptomycetaceae were detected in 3 dogs on day 0, but in none of the dogs on days 14 or 28 (Table 2; p = 0.039). Actinomycetaceae decreased in 4 of 5 dogs, but increased in the remaining dog on day 14. No Bifidobacterium spp. were detected in any of the samples. Discussion Assessment of microbial diversity in the small intestine of dogs remains challenging, because anesthesia is required to obtain a sample, followed by either endoscopic or surgical collection of intestinal samples. Anesthesia may alter intestinal motility, and also repeated endoscopy may lead to perturbations of the intestinal microbiota. Therefore, the response of the jejunal microbiota to tylosin was evaluated in healthy Beagle Dogs each with a pre-existing jejunal fistula . All dogs were accustomed to their fistula for several years and it is, therefore, unlikely that the presence of this fistula has impacted the intestinal microbiota. We collected samples using a sterile cytology Florfenicol brush that was advanced through the fistula. This approach is easier, faster,
and more reproducible compared to the aspiration of jejunal content. Furthermore, because an endoscope is too large to advance through the small lumen of the fistula, intestinal biopsies would have to be collected in a blinded fashion, which might have increased the variation in the sampling procedure. In contrast, mucosal brushings are technically easier to obtain and have been shown to be highly reproducible . We speculate that mucosal brushings represent a mixture of luminal content and the mucosa-adherent microbiota . In this study, massive parallel 16S rRNA gene pyrosequencing proved to be a powerful and sensitive method for the further characterization of canine small intestinal microbiota.