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@PHDTHESIS{Hnings:673967,
author = {Hönings, Robert},
othercontributors = {Peltroche-Llacsahuanga, Heidrun and Blank, Lars Mathias and
Dott, Wolfgang},
title = {{M}ikrobiologische und molekulargenetische {U}ntersuchungen
zu bakteriellen {R}esistenzen in {A}bwasserproben
verschiedener {H}erkunft},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Aachen},
reportid = {RWTH-2016-08977},
pages = {1 Online-Ressource (vi, 342 Seiten) : Illustrationen,
Diagramme},
year = {2016},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, RWTH Aachen University, 2016},
abstract = {Antibiotic-resistant bacteria (ARB) are a serious problem
for the health of humans and animals. Antibiotic resistance
genes (ARG) and ARB, which are emitted from anthropogenic
sources such as clinical wastewaters and wastewater
treatment plants (WWTP), as well as the high consumption of
antibiotics in human and veterinary medicine, are now
regarded as a serious threat to the (aquatic) environment.
However, current investigations are not sufficient for a
meaningful risk assessment and there is a lack of uniform
methods. Therefore, different wastewaters were compared over
a period of more than three years by modified
microbiological and molecular genetic methods, which were
originally derived from clinical diagnostics, and a
comprehensive risk assessment was attempted. The
concentrations of different resistant pathogens with high
clinical relevance were determined and the resistance
patterns of more than 4000 identified isolates were analyzed
phenotypically and genotypically. The investigated
wastewaters came from two municipal WWTPs, only one of which
received clinical effluents, as well as the central sewer of
the Aachen University Hospital and the residential area of
Aachen-Kullen.The concentrations of the total number of
cultivable bacteria and overall enterobacteria were nearly
constant over the entire period; highest concentrations were
found in the inflows of both WWTPs. Enterobacteriaceae
exhibited a 10-fold lower concentration at all times. The
treatment process of both WWTPs resulted in a significant
reduction in the quantity of bacteria. ESBL-producing
enterobacteria were also detected at all times, with the
exception of the WWTP effluents, and were present in lower
concentrations than the counts of overall
Enterobacteriaceae. Almost all isolates were detected as
CTX-M1 producers. Carbapenem-resistant bacteria (CRB) were
only isolated after previous selective enrichment, whereas
no CRB were detected in the effluents of both WWTPs even
after enrichment. Different genotypes were detected in the
examined isolates (blaOXA-48, blaNDM-1, blaKPC). VRE could
be detected exclusively in the inflows of both WWTPs and the
sewage of the hospital in comparable concentrations.
Corresponding isolates were all identified as E. faecium
with vanA genotype and phenotype. In contrast, the
concentrations of S. aureus and MRSA were below the cultural
detection limit at all times.The new methodology provides
representative, reproducible and detailed results as well as
more detailed insights into the resistance situation and
potential hazards of different wastewaters so that primarily
wastewaters from WWTPs and the clinical setting are actually
hotspots for ARB and ARG, while the prevalence of the
investigated resistant bacteria is significantly lower in
domestic effluents. Furthermore, the quantities and the
sources of the incoming sewage in WWTPs do not seem to have
any influence on the resistance situation and
risk-assessment of the inflows, since no significant
differences could be observed when comparing both WWTPs. Due
to the high correlation with published data from clinical
iso-lates, an indirect derivation of the local resistance
situation also appears to be possible via wastewaters. The
three-stage clarification mechanism is also unspecific and
effective for both WWTPs so that the concentrations of the
investigated groups of resistant bacteria are always below
the microbiological detection limit, and thus a threat to
the connected aquatic environment by both WWTPs in Aachen
can be regarded as very low or unlikely.},
cin = {521000-2 / 161710 / 160000},
ddc = {570},
cid = {$I:(DE-82)521000-2_20140620$ / $I:(DE-82)161710_20140620$ /
$I:(DE-82)160000_20140620$},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:hbz:82-rwth-2016-089778},
url = {https://publications.rwth-aachen.de/record/673967},
}
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