Fate and persistence of a pathogenic NDM-1-positive Escherichia coli strain in anaerobic and aerobic sludge microcosms

Handle URI:
http://hdl.handle.net/10754/623263
Title:
Fate and persistence of a pathogenic NDM-1-positive Escherichia coli strain in anaerobic and aerobic sludge microcosms
Authors:
Mantilla-Calderon, David; Hong, Pei-Ying ( 0000-0002-4474-6600 )
Abstract:
The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly slower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable but no further decay was observed. Instead, 1 in every 10000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 were detected to have transferred to other native microorganisms in the sludge, or are released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24 h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater.IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study points at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic resistance gene were detected in the aerobic sludge by cultivation method. Detection of a subpopulation of persister E. coli were also detected in the aerobic sludge. The findings of this study suggest potential areas of concern arising from pathogenic and antibiotic-resistant E. coli during both anaerobic and aerobic sludge treatment processes.
KAUST Department:
Biological and Environmental Sciences and Engineering (BESE) Division; Water Desalination and Reuse Research Center (WDRC)
Citation:
Mantilla-Calderon D, Hong P-Y (2017) Fate and persistence of a pathogenic NDM-1-positive Escherichia coli strain in anaerobic and aerobic sludge microcosms. Applied and Environmental Microbiology: AEM.00640–17. Available: http://dx.doi.org/10.1128/aem.00640-17.
Publisher:
American Society for Microbiology
Journal:
Applied and Environmental Microbiology
KAUST Grant Number:
BAS/1/1033-01-01; FCC/1/1971-15-01
Issue Date:
15-Apr-2017
DOI:
10.1128/aem.00640-17
Type:
Article
ISSN:
0099-2240; 1098-5336
Sponsors:
The research reported in this publication was supported by funding BAS/1/1033-01-01 and FCC/1/1971-15-01 from King Abdullah University of Science and Technology (KAUST) awarded to P.-Y Hong.
Additional Links:
http://aem.asm.org/content/early/2017/04/10/AEM.00640-17
Appears in Collections:
Articles; Water Desalination and Reuse Research Center (WDRC); Biological and Environmental Sciences and Engineering (BESE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorMantilla-Calderon, Daviden
dc.contributor.authorHong, Pei-Yingen
dc.date.accessioned2017-04-20T08:08:16Z-
dc.date.available2017-04-20T08:08:16Z-
dc.date.issued2017-04-15en
dc.identifier.citationMantilla-Calderon D, Hong P-Y (2017) Fate and persistence of a pathogenic NDM-1-positive Escherichia coli strain in anaerobic and aerobic sludge microcosms. Applied and Environmental Microbiology: AEM.00640–17. Available: http://dx.doi.org/10.1128/aem.00640-17.en
dc.identifier.issn0099-2240en
dc.identifier.issn1098-5336en
dc.identifier.doi10.1128/aem.00640-17en
dc.identifier.urihttp://hdl.handle.net/10754/623263-
dc.description.abstractThe presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly slower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable but no further decay was observed. Instead, 1 in every 10000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 were detected to have transferred to other native microorganisms in the sludge, or are released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24 h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater.IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study points at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic resistance gene were detected in the aerobic sludge by cultivation method. Detection of a subpopulation of persister E. coli were also detected in the aerobic sludge. The findings of this study suggest potential areas of concern arising from pathogenic and antibiotic-resistant E. coli during both anaerobic and aerobic sludge treatment processes.en
dc.description.sponsorshipThe research reported in this publication was supported by funding BAS/1/1033-01-01 and FCC/1/1971-15-01 from King Abdullah University of Science and Technology (KAUST) awarded to P.-Y Hong.en
dc.publisherAmerican Society for Microbiologyen
dc.relation.urlhttp://aem.asm.org/content/early/2017/04/10/AEM.00640-17en
dc.rightsThis is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.en
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.subjectPersister cellsen
dc.subjectbacterial decayen
dc.subjectextracellular DNA decayen
dc.subjectantibiotic resistance genesen
dc.subjecthorizontal gene transferen
dc.subjectwastewater treatmenten
dc.titleFate and persistence of a pathogenic NDM-1-positive Escherichia coli strain in anaerobic and aerobic sludge microcosmsen
dc.typeArticleen
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.identifier.journalApplied and Environmental Microbiologyen
dc.eprint.versionPublisher's Version/PDFen
kaust.authorMantilla-Calderon, Daviden
kaust.authorHong, Pei-Yingen
kaust.grant.numberBAS/1/1033-01-01en
kaust.grant.numberFCC/1/1971-15-01en
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