TY - JOUR
T1 - Experimental evaluation of host adaptation of Lactobacillus reuteri to different vertebrate species
AU - Duar, Rebbeca M.
AU - Frese, Steven A.
AU - Lin, Xiaoxi B.
AU - Fernando, Samodha C.
AU - Burkey, Thomas E.
AU - Tasseva, Guergana
AU - Peterson, Daniel A.
AU - Blom, Jochen
AU - Wenzel, Cory Q.
AU - Szymanski, Christine M.
AU - Walter, Jens
N1 - Funding Information:
We thank all the volunteers who participated in this study. We are also grateful to Huyen Tran and Vicky Samek for assistance with the pig experiment and to Janis Cole for assistance with the human trial. This study was funded in part by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery grant awarded to J.W. In addition, J.B. acknowledges the BMBF grant FKZ 031A533 from the de.NBI network. C.M.S. is an Alberta Innovates Technology Futures iCORE Strategic Chair in Bacterial Glycomics, and J.W. acknowledges support from BIoGiaa AB and the Campus Alberta Innovates Program. We declare no conflicts of interest. The funding sponsors had no role in the design of the study, in the collection, analyses, or interpretation of data, in the writing of the manuscript, or in the decision to publish the results.
PY - 2017/6/1
Y1 - 2017/6/1
N2 - The species Lactobacillus reuteri has diversified into host-specific lineages, implying a long-term association with different vertebrates. Strains from rodent lineages show specific adaptations to mice, but the processes underlying the evolution of L. reuteri in other hosts remain unknown. We administered three standardized inocula composed of strains from different host-confined lineages to mice, pigs, chickens, and humans. The ecological performance of each strain in the gastrointestinal tract of each host was determined by typing random colonies recovered from fecal samples collected over five consecutive days postadministration. Results revealed that rodent strains were predominant in mice, confirming previous findings of host adaptation. In chickens, poultry strains of the lineage VI (poultry VI) and human isolates from the same lineage (human VI) were recovered at the highest and second highest rates, respectively. Interestingly, human VI strains were virtually undetected in human feces. These findings, together with ancestral state reconstructions, indicate poultry VI and human VI strains share an evolutionary history with chickens. Genomic analysis revealed that poultry VI strains possess a large and variable accessory genome, whereas human VI strains display low genetic diversity and possess genes encoding antibiotic resistance and capsular polysaccharide synthesis, which might have allowed temporal colonization of humans. Experiments in pigs and humans did not provide evidence of host adaptation of L. reuteri to these hosts. Overall, our findings demonstrate host adaptation of L. reuteri to rodents and chickens, supporting a joint evolution of this bacterial species with several vertebrate hosts, although questions remain about its natural history in humans and pigs.
AB - The species Lactobacillus reuteri has diversified into host-specific lineages, implying a long-term association with different vertebrates. Strains from rodent lineages show specific adaptations to mice, but the processes underlying the evolution of L. reuteri in other hosts remain unknown. We administered three standardized inocula composed of strains from different host-confined lineages to mice, pigs, chickens, and humans. The ecological performance of each strain in the gastrointestinal tract of each host was determined by typing random colonies recovered from fecal samples collected over five consecutive days postadministration. Results revealed that rodent strains were predominant in mice, confirming previous findings of host adaptation. In chickens, poultry strains of the lineage VI (poultry VI) and human isolates from the same lineage (human VI) were recovered at the highest and second highest rates, respectively. Interestingly, human VI strains were virtually undetected in human feces. These findings, together with ancestral state reconstructions, indicate poultry VI and human VI strains share an evolutionary history with chickens. Genomic analysis revealed that poultry VI strains possess a large and variable accessory genome, whereas human VI strains display low genetic diversity and possess genes encoding antibiotic resistance and capsular polysaccharide synthesis, which might have allowed temporal colonization of humans. Experiments in pigs and humans did not provide evidence of host adaptation of L. reuteri to these hosts. Overall, our findings demonstrate host adaptation of L. reuteri to rodents and chickens, supporting a joint evolution of this bacterial species with several vertebrate hosts, although questions remain about its natural history in humans and pigs.
KW - Host adaptation
KW - Lactobacillus reuteri
KW - Probiotics
KW - Symbiosis
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U2 - 10.1128/AEM.00132-17
DO - 10.1128/AEM.00132-17
M3 - Article
C2 - 28389535
AN - SCOPUS:85019987878
VL - 83
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
SN - 0099-2240
IS - 12
M1 - e00132-17
ER -