BackgroundDiet has a major influence on the composition of the gut microbiota, whose importance for gut health and overall well-being is increasingly recognized. Knowledge is limited regarding health implications, including effects on the faecal microbiota, of feeding a diet with high content of red meat to dogs, despite some owners’ apparent preference to do so. The aim of this study was to evaluate how a diet change from commercial dry food to one with a high content of boiled minced beef and vice versa influenced the faecal microbiota, and short chain fatty acid profile in healthy, adult, client-owned dogs.ResultsThe diet change influenced the faecal microbiota composition and diversity (Shannon diversity index). The most abundant OTUs in samples of dogs fed the dry food and high minced beef were affiliated with the species Faecalibacterium prausnitzii and Clostridia hiranonis respectively. The high minced beef diet apparently also influenced the short chain fatty acid profile, with increased isovaleric acid, as well as an increase in faecal pH. These effects were reversed when the commercial dry food was reintroduced in weeks 6 and 7.ConclusionsResults of this study can aid in the understanding of how diet changes influence the faecal microbiota and metabolite content on a short-term basis. Long-term studies are required to investigate potential implications for canine gut and general health.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-017-1073-9) contains supplementary material, which is available to authorized users.

Honey bees (Apis mellifera) are prominent crop pollinators and are, thus, important for effective food production. The honey bee gut microbiota is mainly host specific, with only a few species being shared with other insects. It currently remains unclear how environmental/dietary conditions affect the microbiota within a honey bee population over time. Therefore, the aim of the present study was to characterize the composition of the midgut/pyloric microbiota of a honey bee apiary throughout a season. The rationale for investigating the midgut/pyloric microbiota is its dynamic nature. Monthly sampling of a demographic homogenous population of bees was performed between May and October, with concordant recording of the honey bee diet. Mixed Sanger-and Illumina 16S rRNA gene sequencing in combination with a quantitative PCR analysis were used to determine the bacterial composition. A marked increase in α-diversity was detected between May and June. Furthermore, we found that four distinct phylotypes belonging to the Proteobacteria dominated the microbiota, and these displayed major shifts throughout the season. Gilliamella apicola dominated the composition early on, and Snodgrassella alvi began to dominate when the other bacteria declined to an absolute low in October. In vitro co-culturing revealed that G. apicola suppressed S. alvi. No shift was detected in the composition of the microbiota under stable environment/dietary conditions between November and February. Therefore, environmental/dietary changes may trigger the shifts observed in the honey bee midgut/pyloric microbiota throughout a season.

The human intestinal microbiota plays a major beneficial role in immune development and resistance to pathogens. The use of antibiotics, however, can cause the spread of antibiotic resistance genes within the resident intestinal microbiota. Important vectors for this are integrons. This review therefore focuses on the integrons in non-pathogenic bacteria as a potential source for the development and persistence of multidrug resistance. Integrons are a group of genetic elements which are assembly platforms that can capture specific gene cassettes and express them. Integrons in pathogenic bacteria have been extensively investigated, while integrons in the intestinal microbiota have not yet gained much attention. Knowledge of the integrons residing in the microbiota, however, can potentially aid in controlling the spread of antibiotic resistance genes to pathogens.

Use of antibiotics in medicine and farming contributes to increasing numbers of antibiotic-resistant bacteria in diverse environments. The ability of antibiotic resistance genes (ARG) to transfer between bacteria genera contributes to this spread. It is difficult to directly link antibiotic exposure to the spread of ARG in a natural environment where environmental settings and study populations cannot be fully controlled. We used managed honeybees in environments with contrasting streptomycin exposure (USA: high exposure, Norway: low exposure) and mapped the prevalence and spread of transferrable streptomycin resistance genes. We found a high prevalence of strA-strB genes in the USA compared to Norway with 17/90 and 1/90 positive samples, respectively (p < 0.00007). We identified strA-strB genes on a transferrable transposon Tn5393 in the honeybee gut symbiont Snodgrassella alvi. Such transfer of resistance genes increases the risk of the spread to new environments as honeybees are moved to new pollination sites.

The gut microbiota of honeybees (Apis) and bumblebees (Bombus) include the symbiotic bacterial genus Gilliamella. This genus shows a high degree of functional and genomic diversity and separates into distinct lineages. Gilliamella apicola wkB1, which was isolated from Apis, was the first species to be described. Recently four new species, isolated from Bombus, were identified. In this paper, we compare several genomes/strains from previous studies spanning this diversity, which gives insight into the phylogenetic relationship among different Gilliamella species. We show that one lineage, isolated only from Apis, is different from other gilliamellas described, based on average nucleotide identity calculation (about 80 %) and phenotypic characterizations. We propose the new species name for this lineage: Gilliamella apis sp. nov. We present the characterization of the type strain NO3 (=DSM 105629=LMG 30293), a strain isolated from the Western honeybee Apis mellifera, which clusters within this lineage. Cells of strain NO3 grow best in a microaerophilic atmosphere with enhanced CO2 levels at 36 °C and pH 7.0-7.5. Cells also grow well in anaerobic conditions, but not in aerobic conditions. Cells are approximately 1 µm in length and rod-shaped, and the genomic G+C content is 34.7 mol%. Differential characteristics between strain NO3 and the different type strains of Gilliamella were revealed based on API kit tests and genomic content comparisons. The main respiratory quinone of strain NO3 was ubiquinone-8, and the predominant fatty acids were C18 : 1ω7c/C18 : 1ω6c, C16 : 0, consistent with the genus Gilliamella.