Isolation matters—processing blood for Raman microspectroscopic identification of bacteria

Lorenz, Björn; Rösch, Petra; Popp, Jürgen

doi:10.1007/s00216-019-01918-8

Cited by 25 publications

(43 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, they did not adopt the sonication treatment, while we found that such treatment greatly facilitated the lysis process. Finally, we also note that Lorenz and coworkers used another cell-lysis agent (Triton X-100) for the bacterial analysis with normal Raman scattering 47 . They found that the use of additional Pronase E would remove the hemoglobin affixed to the bacteria, owing to its enzymatic hemoglobin digestion, to avoid the interference of hemoglobin in their Raman analysis.…”

Section: Discussionmentioning

confidence: 91%

Rapid antibiotic susceptibility testing of bacteria from patients’ blood via assaying bacterial metabolic response with surface-enhanced Raman spectroscopy

Han

Lin

Cheng

et al. 2020

Sci Rep

View full text Add to dashboard Cite

Blood stream infection is one of the major public health issues characterized with high cost and high mortality. Timely effective antibiotics usage to control infection is crucial for patients' survival. The standard microbiological diagnosis of infection however can last days. the delay in accurate antibiotic therapy would lead to not only poor clinical outcomes, but also to a rise in antibiotic resistance due to widespread use of empirical broad-spectrum antibiotics. An important measure to tackle this problem is fast determination of bacterial antibiotic susceptibility to optimize antibiotic treatment. We show that a protocol based on surface-enhanced Raman spectroscopy can obtain consistent antibiotic susceptibility test results from clinical blood-culture samples within four hours. the characteristic spectral signatures of the obtained spectra of Staphylococcus aureus and Escherichia coli-prototypic Gram-positive and Gram-negative bacteria-became prominent after an effective pretreatment procedure removed strong interferences from blood constituents. Using them as the biomarkers of bacterial metabolic responses to antibiotics, the protocol reported the susceptibility profiles of tested drugs against these two bacteria acquired from patients' blood with high specificity, sensitivity and speed. Blood stream infection (BSI)-defined as the presence of viable bacteria in blood (i.e., bacteremia) documented by a positive blood culture result 1-arouses morbidity and mortality worldwide 2. It is the primary cause of sepsis, which is a major public health concern with particular high medical cost 3,4. Although the number of BSI incidence bears demographic difference, it shows increasing trend over time 5,6 and therefore remains an urgent medical challenge. Timely administration of appropriate antibiotic therapy is critical to avoiding its progression. A retrospective analysis study based on a large dataset showed that there was a linear increase in the risk of mortality for each hour delay in antibiotic administration 7 , which was confirmed by a recent study 8. However, owing to lack of timely microbiological evidence, antibiotics are usually forced to start empirically, rather than precisely upon specific target(s) 9. Improper antibiotic selection was not uncommon and the mortality markedly increased 10. Moreover, the initial empirical use of broad-spectrum antibiotics 11 , although prudent, inevitably

show abstract

Section: Discussionmentioning

confidence: 91%

Rapid antibiotic susceptibility testing of bacteria from patients’ blood via assaying bacterial metabolic response with surface-enhanced Raman spectroscopy

Han

Lin

Cheng

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…For example, by employing a combination of a Raman spectrometer and a microscope, the investigation of single bacterial cells is easily possible [22][23][24]. Sample preparation techniques which aim at enriching the target cells or analytes are frequently employed as well to improve the overall sensitivity of the Raman spectroscopic assay [25,26]. Furthermore, enhanced varieties of Raman spectroscopy, such as surface-enhanced Raman spectroscopy (SERS) [27,28] or resonance Raman spectroscopy (RRS) [29], provide sensitivities several orders of magnitude higher than conventional Raman spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Rapid detection of the aspergillosis biomarker triacetylfusarinine C using interference-enhanced Raman spectroscopy

et al. 2020

View full text Add to dashboard Cite

Triacetylfusarinine C (TAFC) is a siderophore produced by certain fungal species and might serve as a highly useful biomarker for the fast diagnosis of invasive aspergillosis. Due to its renal elimination, the biomarker is found in urine samples of patients suffering from Aspergillus infections. Accordingly, non-invasive diagnosis from this easily obtainable body fluid is possible. Within our contribution, we demonstrate how Raman microspectroscopy enables a sensitive and specific detection of TAFC. We characterized the TAFC iron complex and its iron-free form using conventional and interference-enhanced Raman spectroscopy (IERS) and compared the spectra with the related compound ferrioxamine B, which is produced by bacterial species. Even though IERS only offers a moderate enhancement of the Raman signal, the employment of respective substrates allowed lowering the detection limit to reach the clinically relevant range. The achieved limit of detection using IERS was 0.5 ng of TAFC, which is already well within the clinically relevant range. By using an extraction protocol, we were able to detect 1.4 μg/mL TAFC via IERS from urine within less than 3 h including sample preparation and data analysis. We could further show that TAFC and ferrioxamine B can be clearly distinguished by means of their Raman spectra even in very low concentrations. Electronic supplementary material The online version of this article (10.1007/s00216-020-02571-2) contains supplementary material, which is available to authorized users.

show abstract

“…Lorenz et al isolated bacteria from blood and achieved a yield of about 70%. They explained that bacteria could possibly adhere to the surfaces of pipette tips and reaction vessels, which could explain the loss during isolation [ 6 ]. For the isolation of bacteria from milk, yields of between 8% and 53% were achieved with various isolation methods [ 29 ].…”

Section: Resultsmentioning

confidence: 99%

“…One important consideration is the choice of medium and cultivation method. Some media or media supplements cause their own Raman signal, which needs to be avoided [5][6][7]. Before starting cultivation, one must be aware of the differences between liquid and solid media [5].…”

Section: Introductionmentioning

confidence: 99%

“…In more complex matrices, it might be necessary to chemically digest the surrounding matrix until no residues are adhered to the bacteria which might interfere with the Raman spectrum. This approach was shown, for example, for the isolation of bacteria from blood or sputum, which in the end showed that there was no longer an influence of hemoglobin or mucus in the bacterial spectra [ 6 , 21 ]. Surface-modified nanoparticles can also be used, which bind to the bacteria [ 22 ], and this connection is then isolated from the matrix by, for example, a magnet [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Isolation of bacteria from artificial bronchoalveolar lavage fluid using density gradient centrifugation and their accessibility by Raman spectroscopy

2021

Self Cite

View full text Add to dashboard Cite

Raman spectroscopy is an analytical method to identify medical samples of bacteria. Because Raman spectroscopy detects the biochemical properties of a cell, there are many factors that can influence and modify the Raman spectra of bacteria. One possible influence is a proper method for isolation of the bacteria. Medical samples in particular never occur in purified form, so a Raman-compatible isolation method is needed which does not affect the bacteria and thus the resulting spectra. In this study, we present a Raman-compatible method for isolation of bacteria from bronchoalveolar lavage (BAL) fluid using density gradient centrifugation. In addition to measuring the bacteria from a patient sample, the yield and the spectral influence of the isolation on the bacteria were investigated. Bacteria isolated from BAL fluid show additional peaks in comparison to pure culture bacteria, which can be attributed to components in the BAL sample. The isolation gradient itself has no effect on the spectra, and with a yield of 63% and 78%, the method is suitable for isolation of low concentrations of bacteria from a complex matrix.

show abstract

Isolation matters—processing blood for Raman microspectroscopic identification of bacteria

Cited by 25 publications

References 39 publications

Rapid antibiotic susceptibility testing of bacteria from patients’ blood via assaying bacterial metabolic response with surface-enhanced Raman spectroscopy

Rapid antibiotic susceptibility testing of bacteria from patients’ blood via assaying bacterial metabolic response with surface-enhanced Raman spectroscopy

Rapid detection of the aspergillosis biomarker triacetylfusarinine C using interference-enhanced Raman spectroscopy

Isolation of bacteria from artificial bronchoalveolar lavage fluid using density gradient centrifugation and their accessibility by Raman spectroscopy

Contact Info

Product

Resources

About