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The Microbiota and Abundance of the Class 1 Integron-Integrase Gene in Tropical Sewage Treatment Plant Influent and Activated Sludge.

Paiva MC, Ávila MP, Reis MP, Costa PS, Nardi RM, Nascimento AM - PLoS ONE (2015)

Bottom Line: Among the 25 phyla, Proteobacteria, Bacteroidetes and Firmicutes represented 85% (AS) and 92% (RS) of all reads.Increased relative abundance of Micrococcales, Myxococcales, and Sphingobacteriales and reduced pathogen abundance were noted in AS.At the genus level, differences were observed for the dominant genera Simplicispira and Diaphorobacter (AS) as well as for Enhydrobacter (RS).

View Article: PubMed Central - PubMed

Affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; Campus Dona Lindu, Universidade Federal de São João del Rei, Divinópolis, Minas Gerais, Brazil.

ABSTRACT
Bacteria are assumed to efficiently remove organic pollutants from sewage in sewage treatment plants, where antibiotic-resistance genes can move between species via mobile genetic elements known as integrons. Nevertheless, few studies have addressed bacterial diversity and class 1 integron abundance in tropical sewage. Here, we describe the extant microbiota, using V6 tag sequencing, and quantify the class 1 integron-integrase gene (intI1) in raw sewage (RS) and activated sludge (AS). The analysis of 1,174,486 quality-filtered reads obtained from RS and AS samples revealed complex and distinct bacterial diversity in these samples. The RS sample, with 3,074 operational taxonomic units, exhibited the highest alpha-diversity indices. Among the 25 phyla, Proteobacteria, Bacteroidetes and Firmicutes represented 85% (AS) and 92% (RS) of all reads. Increased relative abundance of Micrococcales, Myxococcales, and Sphingobacteriales and reduced pathogen abundance were noted in AS. At the genus level, differences were observed for the dominant genera Simplicispira and Diaphorobacter (AS) as well as for Enhydrobacter (RS). The activated sludge process decreased (55%) the amount of bacteria harboring the intI1 gene in the RS sample. Altogether, our results emphasize the importance of biological treatment for diminishing pathogenic bacteria and those bearing the intI1 gene that arrive at a sewage treatment plant.

No MeSH data available.


Venn diagram showing the exclusive and shared OTUs from raw sewage (RS) and activated sludge (AS).* % of all OTUs, ** % of all the reads.
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pone.0131532.g003: Venn diagram showing the exclusive and shared OTUs from raw sewage (RS) and activated sludge (AS).* % of all OTUs, ** % of all the reads.

Mentions: The core microbiota was determined using a Venn diagram (Fig 3). A total of 849 OTUs were shared by the two communities, resulting in an overlap of 20.3% of all OTUs. Common OTUs with more than 100 reads were assigned to the Proteobacteria (37 OTUs), Firmicutes (5 OTUs), Bacteroidetes (2 OTUs), Actinobacteria, and Fusobacteria (one OTU each) phyla, comprising 75.6% (RS) and 26.1% (AS) of the reads of these OTUs. Among the core community, the Comamonadaceae, Neisseriaceae, Rhodocyclaceae, Moraxellaceae, Xanthomonadaceae and Aeromonadaceae families were shared by the samples. Moreover, the Acinetobacter, Neisseria, Enhydrobacter, Dechloromonas, Tolumonas and Candidatus Accumulibacter genera were overrepresented in RS. In contrast, most OTUs were only detected in a particular bacterial community. These unique OTUs were largely dominant (72.3%) in relation to the total OTUs in the RS sample but were less important in relation to the relative abundance (2.5%, only 14,638 reads), which is in contrast to the AS sample (43.1%, 253,406 reads). Thus, changes in the community composition between these samples originated from rare OTUs, whereas the core microbiota included strikingly more abundant OTUs.


The Microbiota and Abundance of the Class 1 Integron-Integrase Gene in Tropical Sewage Treatment Plant Influent and Activated Sludge.

Paiva MC, Ávila MP, Reis MP, Costa PS, Nardi RM, Nascimento AM - PLoS ONE (2015)

Venn diagram showing the exclusive and shared OTUs from raw sewage (RS) and activated sludge (AS).* % of all OTUs, ** % of all the reads.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482650&req=5

pone.0131532.g003: Venn diagram showing the exclusive and shared OTUs from raw sewage (RS) and activated sludge (AS).* % of all OTUs, ** % of all the reads.
Mentions: The core microbiota was determined using a Venn diagram (Fig 3). A total of 849 OTUs were shared by the two communities, resulting in an overlap of 20.3% of all OTUs. Common OTUs with more than 100 reads were assigned to the Proteobacteria (37 OTUs), Firmicutes (5 OTUs), Bacteroidetes (2 OTUs), Actinobacteria, and Fusobacteria (one OTU each) phyla, comprising 75.6% (RS) and 26.1% (AS) of the reads of these OTUs. Among the core community, the Comamonadaceae, Neisseriaceae, Rhodocyclaceae, Moraxellaceae, Xanthomonadaceae and Aeromonadaceae families were shared by the samples. Moreover, the Acinetobacter, Neisseria, Enhydrobacter, Dechloromonas, Tolumonas and Candidatus Accumulibacter genera were overrepresented in RS. In contrast, most OTUs were only detected in a particular bacterial community. These unique OTUs were largely dominant (72.3%) in relation to the total OTUs in the RS sample but were less important in relation to the relative abundance (2.5%, only 14,638 reads), which is in contrast to the AS sample (43.1%, 253,406 reads). Thus, changes in the community composition between these samples originated from rare OTUs, whereas the core microbiota included strikingly more abundant OTUs.

Bottom Line: Among the 25 phyla, Proteobacteria, Bacteroidetes and Firmicutes represented 85% (AS) and 92% (RS) of all reads.Increased relative abundance of Micrococcales, Myxococcales, and Sphingobacteriales and reduced pathogen abundance were noted in AS.At the genus level, differences were observed for the dominant genera Simplicispira and Diaphorobacter (AS) as well as for Enhydrobacter (RS).

View Article: PubMed Central - PubMed

Affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; Campus Dona Lindu, Universidade Federal de São João del Rei, Divinópolis, Minas Gerais, Brazil.

ABSTRACT
Bacteria are assumed to efficiently remove organic pollutants from sewage in sewage treatment plants, where antibiotic-resistance genes can move between species via mobile genetic elements known as integrons. Nevertheless, few studies have addressed bacterial diversity and class 1 integron abundance in tropical sewage. Here, we describe the extant microbiota, using V6 tag sequencing, and quantify the class 1 integron-integrase gene (intI1) in raw sewage (RS) and activated sludge (AS). The analysis of 1,174,486 quality-filtered reads obtained from RS and AS samples revealed complex and distinct bacterial diversity in these samples. The RS sample, with 3,074 operational taxonomic units, exhibited the highest alpha-diversity indices. Among the 25 phyla, Proteobacteria, Bacteroidetes and Firmicutes represented 85% (AS) and 92% (RS) of all reads. Increased relative abundance of Micrococcales, Myxococcales, and Sphingobacteriales and reduced pathogen abundance were noted in AS. At the genus level, differences were observed for the dominant genera Simplicispira and Diaphorobacter (AS) as well as for Enhydrobacter (RS). The activated sludge process decreased (55%) the amount of bacteria harboring the intI1 gene in the RS sample. Altogether, our results emphasize the importance of biological treatment for diminishing pathogenic bacteria and those bearing the intI1 gene that arrive at a sewage treatment plant.

No MeSH data available.