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Comparative Genomic Analysis of Nontuberculous Mycobacteria (NTM) and Environmental Isolates Associated with a Simulated Chloraminated Drinking Water Distribution System Subjected to Episodes of Nitrification - poster #2168
Citation:
Gomez-Alvarez, V., S. Pfaller, AND R. Revetta. Comparative Genomic Analysis of Nontuberculous Mycobacteria (NTM) and Environmental Isolates Associated with a Simulated Chloraminated Drinking Water Distribution System Subjected to Episodes of Nitrification - poster #2168. American Society for Microbiology, New Orleans, LA, May 30 - June 02, 2015.
Impact/Purpose:
The current research examined the Bacterial populations in a simulated chloraminated drinking water distribution system. The research used next generation high-throughput technology and culture-dependent assays to:(1)determine the extent to which the community structure varies temporally and spatially within the distribution system,(2)isolate environmental representatives from bulk water and biofilm samples obtained from various operational schemes,(3)describe, characterize and compare genomes obtained from environmental isolates after disturbances caused by changes in the operational parameters of the distribution system.
Description:
Bacterial populations were examined in a simulated chloraminated drinking water distribution system. After six months of continuous operation, coupons were incubated in CDC reactors receiving water from the simulated system to study biofilm development. The distribution system was then subjected to episodes of nitrification, followed by a ‘chlorine burn’ by switching disinfectant from chloramine to chlorine. A total of 322 isolates were collected from bulk water andbiofilm samples. Analysis of 16S rRNA revealed 35 genera, with Mycobacterium (50%) and Sphingopyxis (17%) as the most abundant representatives. The functional potential inferred from phylogenetic information (i.e. 16S rRNA data) was explored by principal component analysis (PCA)using PICRUSt software. The functional profile based on KEGG module predictions was unable to distinguish isolates according to operational parameters or surface material. Manually curated genomes of 122 environmental isolates, including 41 nontuberculous Mycobacterium (NTM) and20 Sphingopyxis, were annotated using the RAST server. On average, the genomes were shown to encode 60 (range 41-91) predicted RNAs with 5 034 (2 287-8 691) genes identified,representing 406 (331-539) subsystems (RAST). The whole-genome comparison of the metabolic reconstruction within similar NTM species reveals a high similarity (>97.4%), while the similarity between members of the NTM group range between 82.6 to 95.5%. The similarity between members of the Sphingopyxis specie was between 89.6 and 99.8%. Genes associated with multiple disinfectant resistance mechanisms and virulence factors, such as antibiotic resistance mechanisms, were found to be a component of the core genome of these isolates. Overall, the results provide valuable insights into the pan and core genome of NTM and environmental isolateswith potential relevance to disease pathogenesis and their ecology in chloraminated-treated drinking water systems.
