Susceptibility to Campylobacter Infection Is Associated with the Species Composition of the Human Fecal Microbiota
ABSTRACTThe gut microbiota is essential for human health, but very little is known about how the composition of this ecosystem can influence and respond to bacterial infections. Here we address this by prospectively studying the gut microbiota composition before, during, and after naturalCampylobacterinfection in exposed poultry abattoir workers. The gut microbiota composition was analyzed with 16S amplicon sequencing of fecal samples from poultry abattoir workers during the peak season ofCampylobacterinfection in Sweden. The gut microbiota compositions were compared between individuals who became culture positive forCampylobacterand those who remained negative. Individuals who becameCampylobacterpositive had a significantly higher abundance ofBacteroides(P= 0.007) andEscherichia(P= 0.002) species than those who remained culture negative. Furthermore, this group had a significantly higher abundance ofPhascolarctobacterium(P= 0.017) andStreptococcus(P= 0.034) sequences than theCampylobacter-negative group, which had an overrepresentation ofClostridiales(P= 0.017), unclassifiedLachnospiraceae(P= 0.008), andAnaerovorax(P= 0.015) sequences. Intraindividual comparisons of the fecal microbiota compositions yielded small differences over time inCampylobacter-negative participants, but significant long-term changes were found in theCampylobacter-positive group (P< 0.005). The results suggest that the abundance of specific genera in the microbiota reduces resistance toCampylobactercolonization in humans and thatCampylobacterinfection can have long-term effects on the composition of the human fecal microbiota.IMPORTANCEStudies using mouse models have made important contributions to our understanding of the role of the gut microbiota in resistance to bacterial enteropathogen colonization. The relative abundances ofEscherichia coliandBacteroidesspecies have been pointed out as important determinants of susceptibility to Gram-negative pathogens in general andCampylobacterinfection in particular. In this study, we assessed the role of the human gut microbiota in resistance toCampylobactercolonization by studying abattoir workers that are heavily exposed to these bacteria. Individuals with a certain composition of the gut microbiota became culture positive forCampylobacter. As their microbiotas were characterized by high abundances ofBacteroidesspp. andE. coli, well in line with the findings with mouse models, these bacterial species likely play an important role in colonization resistance also in humans.