e. enrichment) analysis is consistent with the idea that sewage systems harbor favorable conditions for the establishment and propagation of antibiotic resistant bacteria [65]. Metagenomic data generated in this study enabled us to detect, identify and check details reconstruct metabolic pathways involved in MICC. The information generated from these sequencing

libraries will help us better understand the genetic Acadesine network and microbial members involved in wastewater biofilms. This information is also relevant to track microbial populations associated with concrete biofilms and to evaluate molecular assays used to detect key functional genes. In a recent study, Santo Domingo and colleagues [11] failed to detect the presence of ammonia oxidizing bacteria (AOB) on wastewater concrete biofilms using amoA-based PCR assays. These bacteria are expected to be associated with

wastewater systems. In this study we were able to detect the presence of putative membrane-associated ammonia monooxygenase in the BP biofilm. The metagenomic sequences were highly homologous to SNS-032 molecular weight sequences from heterotrophic representatives of the species Acidovorax delafieldii Thauera sp MZ1T and species of Rhizobiales (Additional file 1, Figure S 8). Heterotrophic ammonia oxidizing bacteria are commonly found in wastewater systems [66]. Ammonia oxidation by heterotrophic bacteria usually does not involve the generation of energy and is probably used as a sink for excess reducing power generated by oxidative metabolism [67]. Thus, the lack of previous detection of amoA genes by Santo Domingo et al.[11] can be explained by the fact that the assay cannot detect the amoA in heterotrophic ammonia oxidizing bacteria as they were designed to amplify representatives of the autotrophic ammonia monooxygenase, for example, Nitrosomonas species [68]. On the other

hand, this study confirmed the validity of the soxB PCR-based assay to detect the presence of thiosulfate-oxidizing Sox enzyme complex in wastewater concrete [11]. A high percentage (>90%) of our metagenome sequences belong to species that contain the region for the Sox primers designed by Petri and colleagues [69], suggesting that they can be used to ascertain the presence of SOB in this environment. In wastewater collection systems the sulfur and nitrogen Roflumilast pathways play an important role in MICC, and the populations engaged in these pathways are part of a complex and highly diverse microbial community [39]. The reconstruction of the sulfur metabolism network showed several pathways used to oxidize the end products of sulfate reduction leading to the production of H2SO4, e.g. Sox complex, sulfide quinone oxidoreductase (sqr) and the flavocytochrome c (fccAB) in the corroded section of the pipe (Figure 2). We detected similar levels of enrichment in both biofilms of the dsrB enzyme (Table 3).