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Enterococcal distribution and responses toenvironmental waters
Örebro University, School of Science and Technology.
2013 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The release of antibiotics and pharmaceuticals into environmental waters contribute to the increasing risk of antibiotic resistant bacteria. The spread of antibiotic resistant bacteria in the environment increases the health risks to the community. Enterococci are fecal indicator bacteria (FIB) in aquatic environments for determining water quality. In order to study enterococcal distribution and their response to environmental waters, we first screened for fecal indicator bacteria and their antibiotic resistance. Samples were collected from different locations of inland waters near Örebro city, Sweden at 4 time points during 2010 and 2011. Waters were filtered and the bacteria were cultured on selective media. We observed that the distribution of fecal indicator bacteria was higher at Svartån at Naturens Hus (≤705 CFU/100 ml for enterococci and ≤5867 CFU/100 for E. coli) near the effluent of the wastewater treatment plant (WWTP) than other locations tested. The eastern side of Hjälmaren lake, Storhjälmaren, had the lowest number of FIB (0 CFU/100 ml for enterococci and ≤2 CFU/100 ml for E.coli). Isolated E. coli, E. faecalis and E. faecium were evaluated for antibiotic resistance. We observed that ≤18% of E. coli environmental isolates and 12% of E. faecium and E. feacalis isolates were resistant to antibiotics during 2010 and 2011. Fifteen percent of these were multi antibiotic resistant (MAR) enterococci in 2010 and 31% in 2011. Tetracycline resistance was the most widespread antibiotic resistance found in FIB insolates. Extended spectrum β-lactamase expressing E. coli strains were found to also be MAR. Vancomycin and imipenem resistance was found in E. faecium isolate. Our results suggest that WWTP contributes to the distribution of FIB and antibiotic resistance. Secondly we aimed to evaluate the cellular responses of human and bacterial cells in environmental waters. We found that the pro-inflammatory response (IL-1β and TNF-α) of THP-1 cell was significantly higher in Svartån at Naturens Hus downstream of WWTP than the other locations. Based on this we evaluated E. feacalis responses to the same water. There were no statistical significant changes in gene response found in E. feacalis isolates, suggesting that environmental waters contain unidentified substances can effect on human cells responses but not bacteria. In this report we conclude that transferring of MAR strains in the environmental waters were increased annually in enterococci and E. feacalis did not initiate a response to the unknown substances that are present in river. 

Place, publisher, year, edition, pages
Örebro: Örebro universitet , 2013. , p. 29
National Category
Ecology Microbiology
Research subject
Enviromental Science; Microbiology
Identifiers
URN: urn:nbn:se:oru:diva-28790OAI: oai:DiVA.org:oru-28790DiVA, id: diva2:617717
Supervisors
Available from: 2013-04-24 Created: 2013-04-24 Last updated: 2017-10-17Bibliographically approved
List of papers
1. Antibiotic resistance in fecal indicator bacteria in Hjälmaren lake system
Open this publication in new window or tab >>Antibiotic resistance in fecal indicator bacteria in Hjälmaren lake system
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Background: Increasing levels of multi-antibiotic resistant bacteria are ound in the environment, causing serious concerns for treatment of infectious diseases. his increase is believed to be due to release of antibiotic resistant bacteria and election pressure resulting from pharmaceuticals in the environment.

Objectives: We evaluated the presence of multi-antibiotic resistant fecal ndicator bacteria from the surface waters of a recipient river and lake downstream of he wastewater treatment plant (WWTP) in Sweden.

Methods: Surface waters from Svartån river and Hjälmaren lake in Sweden were ampled in 2010 and 2011. The waters were analyzed for fecal indicator bacteria Escherichia coli, enterococci) by membrane filtration and selective agar plating. E. coli nd enterococci were evaluated by Etest for resistance to tetracycline, chloramphenicol, alidixic acid, trimethoprim-sulfamethoxazole, ciprofloxacin, cefotaxime, ceftazidime, eropenem, imipenem, ampicillin, vancomycin, gentamycin and streptomycin.

Results: The highest concentration of E. coli and enterococci were found in vartån river at Naturens Hus closest site downstream of the WWTP. Tetracycline resistance as the most prominent in both fecal indicator bacteria. Over the two years, there was 42% (13/31) and 24% (7/29) multi-antibiotic resistant (≥2 antibiotics) E. coli and nterococci, respectively. Furthermore, we identified one ESBL and one AmpC hyperproducing . coli in 2010 and vancomycin (vanA) resistant E. faecium in 2011.

Conclusions: The presence, of multi-antibiotic resistant strains of fecal ndicator organisms in regions considered predominantly clean, is of great concern. While t currently may not be a major threat in the region, it is demonstrating the accelerating incidence and spread of antibiotic resistance worldwide.

National Category
Ecology Microbiology
Research subject
Microbiology; Enviromental Science
Identifiers
urn:nbn:se:oru:diva-28742 (URN)
Available from: 2013-04-22 Created: 2013-04-22 Last updated: 2017-10-17Bibliographically approved
2. The impact of environmental waters on cellular response in human and bacterial cells
Open this publication in new window or tab >>The impact of environmental waters on cellular response in human and bacterial cells
(English)Manuscript (preprint) (Other academic)
Abstract [en]

The escalating frequency of pharmaceutical and antibiotic use contributes to the increasing amounts of these substances being released into the environment. While wastewater treatment plants (WWTP) effectively remove substantial amounts of contaminating substances, some are persistent and are released into the environment. It is not possible to identify all of the potentially bioactive substances released into the environment, therefore it is more rational to explore the biological effects of the waters to determine prospective health hazards. The present study evaluates the cellular response of human and bacterial cells (Enterococcus faecalis) to environmental waters upstream anddownstream of the WWTP near the  city of Örebro, Sweden. Water samples werecollected from 4 sites during May 2011. These included a site upstream in Svartån at Tekniska Kvarn, downstream at Naturens Hus near the WWTP, in the recipient Hjälmaren lake and in Ånnaboda lake (control site). THP-1 monocytes exhibited a significant increase in secretion of pro-inflammatory cytokines TNF-α and IL-β when treated with waters from Svartån at Naturens Hus, justdownstream of the WWTP outlet. Water from this site was thereafter tested using an environmental E. faecalis isolate and the stress response, virulence and antibiotic gene expression was evaluated by qPCR. There was no statistically significant effect observed on the selected genes in E. faecalis when treated with the environmental waters compared to MQ water. Thus the waters contained substances that influence inflammatory response in human cells in vitro but did not affect fecal indicator enterococci.

National Category
Ecology Microbiology
Research subject
Enviromental Science; Microbiology
Identifiers
urn:nbn:se:oru:diva-28789 (URN)
Available from: 2013-04-24 Created: 2013-04-24 Last updated: 2017-10-17Bibliographically approved

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Elmarghani, Ebraheem M.

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