Phylogenetic analysis of bacterial community in the gut of American cockroach (Periplaneta americana).

OBJECTIVE: The present study was to fully evaluate the intestinal bacterial community of Periplaneta americana, an important model to study insects. METHODS: We investigated the bacterial community of P. americana gut by culture-independent methods, involving constructing the 16S rRNA gene library and microbial diversity analysis. RESULTS: The phylotypes were affiliated with Proteobacteria (66.4%), Bacteroidetes (17.8%), Firmicutes (14.5%), Fusobacteria (0.6%) and unclassified bacteria (0.6%). Phylogenetic analysis shows that 15% of the sequences clustered with that from a closely related omnivorous cockroach; and 59% clustered with that from more distantly related animals, including omnivorous, herbivorous, and carnivorous animals, which differ greatly in feeding habits. Moreover, 18% of the clones showed high sequence identity with potential pathogens closely related to human diseases, which also reinforces the concept of the cockroach as a carrier of pathogens. CONCLUSION: Due to their habits of feeding on a variety of foodstuffs, omnivorous cockroaches harbor a large and diverse microbial community in the gut. The host phylogeny and dietary habits might be critical for the intestinal bacterial community composition of cockroaches.