Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Gene expression and antibiotic resistance in Escherichia coli from Swedish inland waters
Örebro University, School of Science and Technology.
2013 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Extensive use of antibiotics both from human-medicine and veterinary sources are believed to provide selective pressure on bacteria that leads to an increase in antibiotic resistance in environmental waters. Contamination of antibiotic resistant microbes will raise human health risks. Escherichia coli are Gram negative bacilli that belong to the coliform group. E. coli are used as fecal indicators organism (FIO) to determine microbial contamination and water quality. We aimed to investigate the prevalence of antibiotic resistant bacteria in Swedish inland waters and determine the response of uropathogenic E. coli to the environmental waters. Samples were collected in different locations near Örebro Sweden at 4 different time points during 2010-2011. Waters were filtered and FIO were isolated using selective medium. The highest numbers of FIO were detected for both E. coli and enterococci in the river Svartån near the effluent from the wastewater treatment plant (WWTP). Over the two years, 42% and 24% of the antibiotic resistant strains were multi-drug resistant (MDR) E. coli and enterococci, respectively. In addition, 15% of MDR E. coli were extended spectrum beta-lactamase producing and AmpC overproducing strains. A vancomycin resistant E. faecium was also identified. Tetracycline resistance was the most common in FIO isolates. Our study suggests that WWTP distributed FIO and antibiotic resistant bacteria. In a second study we analyzed for the presence of various pharmaceutical residues from lake Mälaren in Västerås Sweden. Some pharmaceutical compounds were present at detectable levels but were removed by the drinking water treatment plant. Quantitative PCR was performed to investigate the effects on genes focused on antibiotic resistance, virulence factors and stress response. Forty one-gene array was developed and tested using tetracycline treatment or environmental water. No significant difference was found when compared to controls in the gene expression profile of bacteria grown in medium prepared with sub-MIC of tetracycline or environmental waters. We concluded that the pharmaceutical levels detected did not exert any significant effects on the E. coli strain tested. From this study, we conclude that MDR bacteria may actually persist in environmental waters in what is considered as a clean urban region. Pharmaceutical pollutants in the inland water did not exert a significant effect on the E. coli, suggesting that MDR strains are released in the effluent of the WWTP rather than induced through selective pressure by the pharmaceuticals contamination.

Place, publisher, year, edition, pages
Örebro: Örebro universitet , 2013. , 33 p.
National Category
Biological Sciences Ecology
Research subject
Biology
Identifiers
URN: urn:nbn:se:oru:diva-28741OAI: oai:DiVA.org:oru-28741DiVA: diva2:617077
Supervisors
Available from: 2013-04-22 Created: 2013-04-22 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. Gene expression in Escherichia coli CFT073 grown in sub-MIC tetracycline and environmental waters
Open this publication in new window or tab >>Gene expression in Escherichia coli CFT073 grown in sub-MIC tetracycline and environmental waters
(English)Manuscript (preprint) (Other academic)
Abstract [en]

We examined the prevalence of fecal indicator bacteria (coliform E. coli and enterococci) for water quality (World Health Organization, 2011, European Enviroment Agency, 2012) and antibiotic resistant E. coli in lake Mälaren from surface water in Björnö Island at Vinterviken bay and in untreated incoming water to Mälarenergi, drinking water treatment plant (DWTP) in Västerås, Sweden. Our studies have demonstrated that the water quality of environmental water was ‘excellent‘ in both surface water at Bjornö in Vinterviken bay and in the untreated incoming water to the DWTP. However, one multi-antibiotic resistant and one antibiotic resistant strain were isolated from the surface waters. Hence antibiotic resistant strains can persist even in low population of fecal bacterial contamination in the waters. Pharmaceutical compounds in the environment are believed to provide a selective pressure for the development of antibiotic resistance in bacteria (Tenover, 2006, Alekshun and Levy, 2007, Mazumdar et al., 2006). Our study demonstrated that pharmaceutical compounds persisted in lake waters with detectable concentrations as others have shown (Godfrey et al., 2007, Loos et al., 2009). Caffeine, naproxen, hydrochlorothiazide, metoprolol and tramadol were present at detectable levels. To study the effect of contaminants on microorganisms, qPCR method was chosen due to its rapid, sensitive and quantitative analyses of gene expression. Thus a qPCR array was designed, to determine the effect of environmental waters on E. coli isolates. Specific genes that were responsible for antibiotic resistance, virulence factors and stress responses were selected. E. coli CFT073 was treated with either sub-MIC levels (0.1 μg/ml) of tetracycline in LB medium or incoming untreated waters to DWTP in LB medium and compared to controls. Gene expression was determined using qPCR. No significant difference in gene response was observed after treatment with sub-MIC of tetracycline or environmental waters. Pharmaceutical compounds which contaminated the water did not appear to exert a significant gene response in the pathogenic E. coli. Pharmaceutical contamination in the water can promote human and animal health risks however the effect of long-term exposure is yet unknown (European Environment Agency, 2011, Wennmalm and Gunnarsson, 2005, Triebskorn et al., 2007). The antibiotic resistant strains likely originated from the WWTP rather than the selective pressure due to pharmaceutical pollutants in the water. 

National Category
Biological Sciences
Research subject
Biology
Identifiers
urn:nbn:se:oru:diva-28743 (URN)
Available from: 2013-04-22 Created: 2013-04-22 Last updated: 2017-10-17Bibliographically approved

Open Access in DiVA

webbfil(791 kB)768 downloads
File information
File name FULLTEXT01.pdfFile size 791 kBChecksum SHA-512
b873773b7190c4981c1fab730ea57d92fafc58b2136ca1272abf5454e181bc9bf9f3e275d52ed4551d15fc8e5aac8d54319c6a955fc324687d0eca51b67e0dc0
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Poonlapthawee, Sirirat
By organisation
School of Science and Technology
Biological SciencesEcology

Search outside of DiVA

GoogleGoogle Scholar
Total: 768 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 374 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf