MEMS based electrochemical DNA sensor to detect methicillin resistant Staphylococcus aureus and vancomycin resistant Enterococcus species

Ceylan Koydemir, Hatice
Methicillin Resistant Staphylococcus aureus (MRSA) is one of the most important threats of nosocomial infections in many regions of the world and Vancomycin Resistant Enterococcus (VRE) is an emerging pathogen that develops full resistance against third-generation glycopeptide antibiotics. Conventional methods for identification of MRSA and VRE generally depend on culturing, which requires incubation of biological samples at least 24-72 hours to get accurate results. These methods are time consuming and necessitate optical devices and experts for evaluation of the results. On the other hand, early diagnosis and initiation of appropriate treatment are necessary to decrease morbidity and mortality rates. Thus, new diagnostic systems are essential for rapid and accurate detection of biological analytes at the point of care. This study presents design, fabrication, and implementation of MEMS based micro electrochemical sensor (µECS) to detect the methicillin resistance in Staphylococcus aureus and vancomycin resistance in Enterococcus species. To the best of our knowledge, the developed sensor is the first µECS which utilizes on-chip reference (Ag), working (Au), and counter (Pt) electrodes together with a microchannel to detect MRSA and VRE. The characterization of the designed sensor was achieved analyzing the interactions of the buffer solutions and solvents with the electrodes and Parylene C film layer by using optical and electrochemical methods. Specific parts of genes that are indicators of antimicrobial resistances were used in order to detect the resistances with high selectivity and sensitivity. Thus, synthetic DNA and bacterial PCR product were used as target probes in redox marker based detection and enzyme based detection, respectively. In order to enhance the hybridization, folding structures of the capture probe were investigated by using mfold Web Server. In redox marker based detection, the hybridization of DNA was indirectly detected by using Hoechst 33258 as redox marker with differential pulse voltammetry. The cross reactivity of the tests were performed by using different target probes of femA genes of S. aureus and S. epidermis, which are the major genes detected in methicillin detection assays. Consequently, amplification of signal by using horseradish peroxidase and TMB/H2O2 as substrate was achieved in order to enhance detection sensitivity. The sensor could detect 0.01 nM 23-mer specific part of mecA gene with redox marker based detection and 10 times diluted PCR product with enzyme-based detection in about six hours including the steps of sample preparation from whole blood. This sensor with its compatibility to MEMS fabrication processes and IC technology has a promising potential for a hand-held device for POC through the integration of micropotentiostat


MEMS biosensors for detection of methicillin resistant Staphylococcus aureus
Ceylan Koydemir, Hatice; Külah, Haluk; Özgen, Canan; ALP, ALPASLAN; Hascelik, Gulsen (2011-11-15)
This review presents the current state of the conventional methods, microfluidic based biosensors, and the commercial products used in the detection of methicillin resistant Staphylococcus aureus (MRSA), which is one of the most important threats of nosocomial infections in many parts of the world. The early detection of MRSA in the specimens of the patients is important to enable the appropriate treatment, to decrease morbidity and mortality rates, and to manage control actions in the healthcare units. Thu...
Characterization and genomic analysis of a novel bacteriophage against methicillin-resistant staphylococcus aureus
Çotak, Medine; Akkaya, Mahinur S.; Karahan, Zeynep Ceren; Department of Biotechnology (2019)
Methicillin resistant Staphylococcus aureus (MRSA) is one of the most frequent hospital and community acquired infectious agents causing severe diseases. Bacteriophages may offer a solution to treat the bacterial infections that are not responding to classical antibiotics. In this context, a new lytic phage, named as vB_SauM-MikSA913, was isolated from sewage treatment center in Samsun (Turkey). MRSA clinical strains obtained from a local hospital were used as propagating hosts while searching for the lytic...
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...
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...
Monitoring methicillin-resistant bacteria in river water by using MECA-specific DNA probe
Seyedmonir, Elnaz; İçgen, Bülent; Department of Biochemistry (2015)
Aquatic ecosystems represent important vehicles for the dissemination of not only antibiotic resistant bacteria but also antibiotic resistance genes. Of particular interest are methicillin-resistant staphylococci (MRS) harbouring mecA gene that confers their resistance to β-lactams. Therefore, in this study, water samples collected from different locations of a river impacted by surrounding facilities and domestic effluents were analysed to learn more about the occurrence of MRS and mecA gene. Out of 290, 1...
Citation Formats
H. Ceylan Koydemir, “MEMS based electrochemical DNA sensor to detect methicillin resistant Staphylococcus aureus and vancomycin resistant Enterococcus species,” Ph.D. - Doctoral Program, Middle East Technical University, 2013.