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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.


Related in: MedlinePlus

Distribution of the community members in raw sewage (RS) and activated sludge (AS).AVA group: Actinobacteria, Verrucomicrobia, Acidobacteria. Other phyla: BD1-5, Candidate_division_OD1, Candidate_division_OP11, Candidate_division_OP8, Candidate_division_TM7, Candidate_division_WS3, Candidate_division_WS6, Chlamydiae, Chlorobi, Cyanobacteria, Elusimicrobia, Fusobacteria, Gemmatimonadetes, Lentisphaerae, Nitrospirae, SHA-109, Spirochaetae, Tenericutes.
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pone.0131532.g002: Distribution of the community members in raw sewage (RS) and activated sludge (AS).AVA group: Actinobacteria, Verrucomicrobia, Acidobacteria. Other phyla: BD1-5, Candidate_division_OD1, Candidate_division_OP11, Candidate_division_OP8, Candidate_division_TM7, Candidate_division_WS3, Candidate_division_WS6, Chlamydiae, Chlorobi, Cyanobacteria, Elusimicrobia, Fusobacteria, Gemmatimonadetes, Lentisphaerae, Nitrospirae, SHA-109, Spirochaetae, Tenericutes.

Mentions: The taxonomic diversity profile by V6 tag sequencing is shown in Fig 2 and S3 Table. The 1,174,486 reads were affiliated with 25 bacterial phyla. Additionally, 1,025 OTUs were considered to be unclassified at the phylum level and thus might represent new bacterial taxa. Importantly, three phyla (Proteobacteria, Bacteroidetes and Firmicutes) accounted for 97% and 85% all of the reads in the RS and AS samples, respectively. Although the RS and AS samples revealed similar phylum-level representation, distinct distributions were observed. Previous studies of microbial sewage and activated sludge communities also revealed a predominance of these phyla [8, 11, 15]; however, they showed a lower proportion of Proteobacteria (36%-65%) than that observed in our study. In contrast to our observations, Firmicutes was previously found in low abundance in the RS [8] and in high abundance in the AS [28]. Moreover, the abundance of Bacteroidetes ranged from 2.7% to 15.6% in activated sludge samples from 14 sewage treatment plants [11]. This difference between our data and those of previous studies can be due to differences in sewage composition because of climatic, geographical and population conditions [12, 29] as well as because of organic loading, pH, temperature, dissolved oxygen and sludge retention time applied in the aeration tank [12, 30].


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)

Distribution of the community members in raw sewage (RS) and activated sludge (AS).AVA group: Actinobacteria, Verrucomicrobia, Acidobacteria. Other phyla: BD1-5, Candidate_division_OD1, Candidate_division_OP11, Candidate_division_OP8, Candidate_division_TM7, Candidate_division_WS3, Candidate_division_WS6, Chlamydiae, Chlorobi, Cyanobacteria, Elusimicrobia, Fusobacteria, Gemmatimonadetes, Lentisphaerae, Nitrospirae, SHA-109, Spirochaetae, Tenericutes.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0131532.g002: Distribution of the community members in raw sewage (RS) and activated sludge (AS).AVA group: Actinobacteria, Verrucomicrobia, Acidobacteria. Other phyla: BD1-5, Candidate_division_OD1, Candidate_division_OP11, Candidate_division_OP8, Candidate_division_TM7, Candidate_division_WS3, Candidate_division_WS6, Chlamydiae, Chlorobi, Cyanobacteria, Elusimicrobia, Fusobacteria, Gemmatimonadetes, Lentisphaerae, Nitrospirae, SHA-109, Spirochaetae, Tenericutes.
Mentions: The taxonomic diversity profile by V6 tag sequencing is shown in Fig 2 and S3 Table. The 1,174,486 reads were affiliated with 25 bacterial phyla. Additionally, 1,025 OTUs were considered to be unclassified at the phylum level and thus might represent new bacterial taxa. Importantly, three phyla (Proteobacteria, Bacteroidetes and Firmicutes) accounted for 97% and 85% all of the reads in the RS and AS samples, respectively. Although the RS and AS samples revealed similar phylum-level representation, distinct distributions were observed. Previous studies of microbial sewage and activated sludge communities also revealed a predominance of these phyla [8, 11, 15]; however, they showed a lower proportion of Proteobacteria (36%-65%) than that observed in our study. In contrast to our observations, Firmicutes was previously found in low abundance in the RS [8] and in high abundance in the AS [28]. Moreover, the abundance of Bacteroidetes ranged from 2.7% to 15.6% in activated sludge samples from 14 sewage treatment plants [11]. This difference between our data and those of previous studies can be due to differences in sewage composition because of climatic, geographical and population conditions [12, 29] as well as because of organic loading, pH, temperature, dissolved oxygen and sludge retention time applied in the aeration tank [12, 30].

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.


Related in: MedlinePlus