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5 Publications visible to you, out of a total of 5
Cultivation-Free Raman Spectroscopic Investigations of Bacteria.

Abstract (Expand)

Raman spectroscopy is currently advertised as a hot and ambitious technology that has all of the features needed to characterize and identify bacteria. Raman spectroscopy is rapid, easy to use, … noninvasive, and it could complement established microbiological and biomolecular methods in the near future. To bring this vision closer to reality, ongoing research is being conducted on spectral fingerprinting. This can yield a wealth of information, from even single bacteria from various habitats which can be further improved by combining Raman spectroscopy with methods such as stable isotope probing to elucidate microbial interactions. In conjunction with extensive statistical analysis, Raman spectroscopy will allow identification of (non)pathogenic bacteria at different taxonomic levels.

Authors: B. Lorenz, C. Wichmann, S. Stockel, P. Rosch, J. Popp

Date Published: 12th Feb 2017

Publication Type: Not specified

Rapid Identification of Pseudomonas spp. via Raman Spectroscopy Using Pyoverdine as Capture Probe

Abstract (Expand)

Pyoverdine is a substance which is excreted by fluorescent pseudomonads in order to scavenge iron from their environment. Due to specific receptors of the bacterial cell wall, the iron loaded pyoverdine … molecules are recognized and transported into the cell. This process can be exploited for developing efficient isolation and enrichment strategies for members of the Pseudomonas genus, which are capable of colonizing various environments and also include human pathogens like P. aeruginosa and the less virulent P. fluorescens. A significant advantage over antibody based systems is the fact that siderophores like pyoverdine can be considered as "immutable ligands," since the probability for mutations within the siderophore uptake systems of bacteria is very low. While each species of Pseudomonas usually produces structurally unique pyoverdines, which can be utilized only by the producer strain, cross reactivity does occur. In order to achieve a reliable identification of the captured pathogens, further investigations of the isolated cells are necessary. In this proof of concept study, we combine the advantages of an isolation strategy relying on "immutable ligands" with the high specificity and speed of Raman microspectroscopy. In order to isolate the bacterial cells, pyoverdine was immobilized covalently on planar aluminum chip substrates. After capturing, single cell Raman spectra of the isolated species were acquired. Due to the specific spectroscopic fingerprint of each species, the bacteria can be identified. This approach allows a very rapid detection of potential pathogens, since time-consuming culturing steps are unnecessary. We could prove that pyoverdine based isolation of bacteria is fully Raman compatible and further investigated the capability of this approach by isolating and identifying P. aeruginosa and P. fluorescens from tap water samples, which are both opportunistic pathogens and can pose a threat for immunocompromised patients.

Authors: S. Pahlow, S. Stockel, S. Pollok, D. Cialla-May, , K. Weber,

Date Published: 8th Jan 2016

Publication Type: Not specified

The application of Raman spectroscopy for the detection and identification of microorganisms

Abstract (Expand)

A fast and reliable detection and identification of microorganisms is crucial in environmental science, for food quality as well as medical diagnosis. In these fields, all types of Raman spectroscopy … are gaining more and more importance during the last years. The review provides an extensive overview of recent research, technical expertise, and scientific findings based on Raman spectroscopic detection and identification of microorganisms within the years 2010 and 2015, demonstrating the diverse capability of Raman spectroscopy as a modern analytical tool. Raman spectroscopy distinguishes itself from other currently applied techniques by its easy application at low cost, its high speed of analysis, and its broad information content on both the chemical composition and the structure of biomolecules within the microorganisms. Slight chances in the chemical composition of microorganisms can be monitored by means of Raman spectroscopy and used to differentiate genera, species, or even strains. Detection of pathogens is possible from complex matrices, such as soil, food, and body fluids. Further, spectroscopic studies of host–pathogen interactions are addressed as well as the effect of antibiotics on bacteria.

Authors: Stephan Stöckel, Johanna Kirchhoff, Ute Neugebauer, Petra Rösch, Jürgen Popp

Date Published: 7th Dec 2015

Publication Type: Not specified

Raman spectroscopy towards clinical application: drug monitoring and pathogen identification

Abstract (Expand)

Raman spectroscopy is a label-free method that measures quickly and contactlessly, providing detailed information from the sample, and has proved to be an ideal tool for medical and life science research. … In this review, recent advances of the technique towards drug monitoring and pathogen identification by the Jena Research Groups are reviewed. Surface-enhanced Raman spectroscopy (SERS) and ultraviolet resonance Raman spectroscopy in hollow-core optical fibres enable the detection of drugs at low concentrations as shown for the metabolites of the immunosuppressive drug 6-mercaptopurine as well as antimalarial agents. Furthermore, Raman spectroscopy can be used to characterise pathogenic bacteria in infectious diseases directly from body fluids, making time-consuming cultivation processes dispensable. Using the example of urinary tract infection, it is shown how bacteria can be identified from patients' urine samples within <1h. The methods cover both single-cell analysis and dielectrophoretic capturing of bacteria in suspension. The latter method could also be used for fast (<3.5h) identification of antibiotic resistance as shown exemplarily for vancomycin-resistant enterococci.

Authors: U. Neugebauer, ,

Date Published: 6th Nov 2015

Publication Type: Not specified

Raman spectroscopic monitoring of the growth of pigmented and non-pigmented mycobacteria

Abstract (Expand)

Raman microspectroscopy has increased in popularity in the field of microbiology because it allows a spectral fingerprinting of bacterial pathogens at an unrivaled speed, which is important for the … early treatment of infectious diseases such as tuberculosis. An indispensable prerequisite for the success of this method is a profound knowledge, how the spectral profiles depend on the age of the bacteria. We therefore followed the growth of two rapidly growing Mycobacterium tuberculosis relatives, the pigmented Mycobacteriumaurum, and the non-pigmented Mycobacteriumsmegmatis, by means of Raman microspectroscopy. Both species showed remarkable temporal changes in the single-bacteria Raman spectra: In the signatures of M.aurum, pigment-associated Raman signals could be detected not until 72 h of growth and also remained highly variable thereafter. The Raman spectra of M.smegmatis exhibited lipid signals presumably arising from mycolic acids, which are a hallmark feature of mycobacteria, but only after the bacteria reached the late stationary growth phase (>48 h). A principal component analysis thus classified the Raman spectra according to the cultivation age. In summary, these findings have to be reckoned with in future studies dealing with the identification of mycobacteria via Raman microspectroscopy. Graphical abstract Changes in the chemical composition of bacterial cells over growth time may influence the results of Raman spectroscopic studies of bacteria.

Authors: S. Stockel, A. S. Stanca, J. Helbig, ,

Date Published: 21st Sep 2015

Publication Type: Not specified

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