vanA harboring enterococcal and non-enterococcal surface water isolates monitored by an oligonucleotide DNA probe /

Download

index.pdf

Date

2016

Author

Nakipoğlu, Mustafa

Metadata

Show full item record

Item Usage Stats

178
views

113
downloads

Untreated wastewaters and treated effluents even after final disinfection inhabitate antibiotic resistant bacteria and resistance genes before they are released into surface waters. A correlation between resistant bacteria with antibiotic resistance genes in surface waters has been found. Of particular interest are vancomycin-resistant enterococci (VRE) harboring vanA gene that confers their high-level resistance to glycopeptide antibiotics including teicoplanin. Therefore, in this study, river water samples were analyzed to investigate vancomycin- and teicoplanin-resistant bacterial isolates harboring vanA gene. Out of 290, 18 surface water isolates displayed resistance to both antibiotics. These glycopeptide resistant enterococcal and non-enterococcal isolates, identified by 16S rRNA sequencing, were found to harbor vanA gene with sequence similarities of 58 to 100%. The presence of D-alanine-D-lactate ligase encoded by vanA gene was also shown for all vancomycin- and teicoplanin-resistant isolates through western blotting. The fate of vanA gene in surface waters provides information on the exposure and potential threats of those bacteria for the environment and human health. For this purpose, a 25-mer-oligonucleotide DNA probe based on the 909 bp BamHI-ClaI fragment from Enterococcus faecium plasmids pVEF1 and pVEF2 was also prepared by using Vector NTI Express software. Under the hybridization stringency conditions of 46 °C, 55 % formamide and 0.020 M NaCl, designed vanA probe appeared to be highly specific to vanA-positive Enterococcus faecalis tested. In situ fluorescent hybridizations under the same stringency conditions were also used to monitor the river water samples by using fluorescent microscopy. The results indicated that newly designed vanA-targeted oligonucleotide DNA probe was highly specific and quantitative tool for monitoring vancomycin- and teicoplanin-resistant bacteria in surface waters. Due to reuse of treated wastewater, antibiotic resistant bacteria and resistance genes are being introduced into surface waters and possess human health risks. Therefore, surface waters are not only hot spots for vanA harboring enterococcal isolates but also non-enterococcal ones due to gene dissemination and require special scientific consideration.

Subject Keywords

Vancomycin., Glycopeptides., Oligonucleotides., Sewage

URI

http://etd.lib.metu.edu.tr/upload/12619768/index.pdf
https://hdl.handle.net/11511/25487

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

vanA Gene Harboring Enterococcal and Non-enterococcal Isolates Expressing High Level Vancomycin and Teicoplanin Resistance Reservoired in Surface Waters Nakipoğlu, Mustafa; İçgen, Bülent (2017-05-01) Untreated wastewaters and treated effluents even after final disinfection contain antibiotic resistant bacteria and resistance genes before they are released into surface waters. A correlation between resistant bacteria and antibiotics in surface waters has been found, as have antibiotic resistance genes. Of particular interest are vancomycin-resistant enterococci harboring vanA gene that confers high level of resistance to glycopeptide antibiotics including teicoplanin. Therefore, in this study, river wate...
vanA-targeted oligonucleotide DNA probe designed to monitor vancomycin- and teicoplanin-resistant bacteria in surface waters Nakipoğlu, Mustafa; İçgen, Bülent (2016-10-01) The glycopeptide antibiotics teicoplanin and vancomycin are common to treat severe Gram-positive bacterial infections. The gene vanA confers high-level resistance to these antibiotics, and these phenomena have been shown to be transferable. Release of vancomycin-and teicoplanin-resistant bacteria to surface waters is, therefore, of particular concern since they might proliferate and spread in different environments. Monitoring of the fate of vanA gene in these waters provides information on the exposure and...
Investigation of activated sludge bioflocculation : influence of magnesium ions Turtin, İpek; Sanin, Faika Dilek; Department of Environmental Engineering (2005) Activated sludge systems are the most widely used biological wastewater treatment processes all over the world. The main working principles of an activated sludge system are the oxidation of biologically degradable wastes by microorganisms and the subsequent separation of the newly formed biomass from the treated effluent. Separation by settling is the most troublesome stage of an activated sludge process. A decrease in the efficiency of the separation of microbial biomass from the treated effluent causes a...
VanA-Type MRSA (VRSA) Emerged in Surface Waters İçgen, Bülent (Springer Science and Business Media LLC, 2016-09-01) Due to the widespread occurrence of mecA-encoded methicillin resistance in Staphylococcus aureus (MRSA), treatment of staphylococcal infections is shifted to glycopeptide antibiotics like vancomycin and teicoplanin. The selective pressure of glycopeptides has eventually led to the emergence of staphylococci with increased resistance. Of great concern is vanA-encoded high level vancomycin and teicoplanin resistance in MRSA (VRSA). Therefore, this study aimed at investigating the occurrence of VRSA in surface...
mecA Gene Dissemination Among Staphylococcal and Non-staphylococcal Isolates Shed in Surface Waters Seyedmonir, Elnaz; Yılmaz, Fadime; İçgen, Bülent (2015-07-01) Aquatic ecosystems represent important vehicles for the dissemination of antibiotic resistant bacteria and antibiotic resistance genes. Of particular interest are methicillin-resistant staphylococci (MRS) harboring mecA gene that confers their resistance to beta-lactams. Therefore, in this study, water samples collected from different locations of a river impacted by surrounding facilities and domestic effluents were analyzed to learn more about the occurrence of MRS and mecA gene. Out of 290, 12 surface wa...

Citation Formats

M. Nakipoğlu, “vanA harboring enterococcal and non-enterococcal surface water isolates monitored by an oligonucleotide DNA probe /,” M.S. - Master of Science, Middle East Technical University, 2016.