Although the overall taxonomic diversity in the V6 rRNA amplicon libraries was lower than that detected in the cDNA transcript libraries, the diversity within bacterial classes was higher. Newly identified genera comprised predominantly environmental soil, sediment and water inhabitants (e.g. Aeromicrobium and Bdellovibrio), and the potential pathogens Stenotrophomonas, Rhodococcus, Rothia, and Gardnerella [40] [41] [42] [43] . These findings indicate that the V6 rRNA amplicon sequencing technology is a valuable tool in complementing information about the bacterial community in host tissues.