Journal: Artificial DNA, PNA & XNA

Article Title: PNA-based microbial pathogen identification and resistance marker detection

doi: 10.4161/adna.1.2.13256

Figure Lengend Snippet: Detection discrimination of methicillin-sensitive (MSSA) versus methicillin-resistant (MRSA) strains. Images of S. aureus bacterial cells observed by fluorescent microscopy in experiments performed with simulated matrix (packed red cells and blood culture media) spiked with S. aureus bacterial cells. A combination of two probes (SA-3 and MR-1) was applied to simulated matrix specimens spiked with: the regular MSS A strain (A1 and B1); the Mu3 MRSA strain (A2 and B2) and their mixture (A3–C3). The fluorescent signals were acquired separately using three filter sets: A1–A3 present a superposition of two separate images, with DAPI and CY3; B1–B3 present a superposition of two separate images, with DAPI and FITC; C3 presents a superposition of three separate images, with DAPI, CY3 and FITC.

Article Snippet: All primers and labeled probes with a phosphate group ( p ), Cy3 or FITC were supplied by MWG biotech.

Techniques: Microscopy

Journal: Artificial DNA, PNA & XNA

Article Title: PNA-based microbial pathogen identification and resistance marker detection

doi: 10.4161/adna.1.2.13256

Figure Lengend Snippet: Experimenter-blinded tests with de-identified, codified bacteria contained S. aureus (both MSSA and MRSA) and coagulase-negative staphylococcal species (CNS). Images of methicillin-sensitive S. aureus (MSSA), coagulase-negative staphylococcus (CNS) and methicillin-resistant S. aureus (MRSA) cells observed by fluorescent microscopy when probes specific to SA (MSSA/MRSA) or the MR (to mec cassette—MRSA only) were applied. The fluorescent signals were acquired separately using three filter sets (DAPI for DNA and Cy3 or FITC for the RCA product). Images are superposition of two images: (SA-probe) DAPI and CY3; (MR-probe) DAPI and FITC. Signals were pseudocolored in blue for DAPI, red for CY3 and green for FITC. SA-probes (PNA binding sites are underlined): SA-1: AAA GAA AAA GCA ACA AGA GGA A, SA-2: AGA GGA AGC AGA GCG CAA GGG AAA, SA-3: AAA AGA AGA AAG ATT CAG AGG AAG; MR-probes (within mecA gene for penicillin-binding protein): MR-1: AAG GAG GAT ATT GAT GAA AAA GA, MR-2: GGA AGA AAA ATA TTA TTT CCA AAG AAA A.

Article Snippet: All primers and labeled probes with a phosphate group ( p ), Cy3 or FITC were supplied by MWG biotech.

Techniques: Microscopy, Binding Assay