title: Impedimetric detection of single-stranded PCR products derived from methicillin resistant Staphylococcus aureus (MRSA) isolates.
abstract: Using electrochemical impedance spectroscopy (EIS) the sensitive and specific detection of the antibiotic resistance gene mecA has been demonstrated. The gene sequence was obtained from clinical Staphylococcus aureus isolates. Initially a mecA specific probe was selected from hybridisation tests with a 3' and 5' version of a previously published probe sequence. When immobilised on a gold electrode in PNA form it was possible to detect hybridisation of mecA PCR product electrochemically at concentrations as low as 10nM. By incorporating an undecane-thiol and 1.8 nm glycol spacer into the PNA probe it was possible to extend the limit of detection for mecA to 10 pM. Most published studies on EIS and nucleic acid detection report the use of short artificial DNA sequences or novel signal amplification schemes which improve sensitivity whereas this study reports the successful detection of long DNA fragments produced by PCR following extraction from clinical isolates. Finally, using screen printed electrodes the paper demonstrates hybridisation monitoring of mecA in an "on-line" assay format under ambient conditions which paves the way for rapid mecA detection in point of care scenarios.
authors.affiliation: Division of Pathway Medicine, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, Scotland, UK.
authors.forename: Damion K
authors.initials: DK
authors.lastname: Corrigan
authors.forename: Holger
authors.initials: H
authors.lastname: Schulze
authors.forename: Grace
authors.initials: G
authors.lastname: Henihan
authors.forename: Ilenia
authors.initials: I
authors.lastname: Ciani
authors.forename: Gerard
authors.initials: G
authors.lastname: Giraud
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Terry
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Walton
authors.forename: Ronald
authors.initials: R
authors.lastname: Pethig
authors.forename: Peter
authors.initials: P
authors.lastname: Ghazal
authors.forename: Jason
authors.initials: J
authors.lastname: Crain
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Campbell
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Mount
authors.forename: Till T
authors.initials: TT
authors.lastname: Bachmann
mesh_terms: D001426:Bacterial Proteins / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D058266:Dielectric Spectroscopy / Q000379:methods*; D057230:Limit of Detection; D016106:Methicillin Resistance / Q000235:genetics; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification*; D009693:Nucleic Acid Hybridization; D046915:Penicillin-Binding Proteins; D016133:Polymerase Chain Reaction
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus