3 research outputs found
Toward Culture-Free Raman Spectroscopic Identification of Pathogens in Ascitic Fluid
The identification of pathogens in
ascitic fluid is standardly
performed by ascitic fluid culture, but this standard procedure often
needs several days. Additionally, more than half of the ascitic fluid
cultures are negative in case of suspected spontaneous bacterial peritonitis
(SBP). It is therefore important to identify and characterize the
causing pathogens since not all of them are covered by the empirical
antimicrobial therapy. The aim of this study is to show that pathogen
identification in ascitic fluid is possible by means of Raman microspectroscopy
and chemometrical evaluation with the advantage of strongly increased
speed. Therefore, a Raman database containing more than 10000 single-cell
Raman spectra of 34 bacterial strains out of 13 different species
was built up. The performance of the used statistical model was validated
with independent bacterial strains, which were grown in ascitic fluid
Culture Independent Raman Spectroscopic Identification of Urinary Tract Infection Pathogens: A Proof of Principle Study
Urinary tract infection (UTI) is
a very common infection. Up to
every second woman will experience at least one UTI episode during
her lifetime. The gold standard for identifying the infectious microorganisms
is the urine culture. However, culture methods are time-consuming
and need at least 24 h until the results are available. Here, we report
about a culture independent identification procedure by using Raman
microspectroscopy in combination with innovative chemometrics. We
investigated, for the first time directly, urine samples by Raman
microspectroscopy on a single-cell level. In a first step, a database
of eleven important UTI bacterial species, which were grown in sterile
filtered urine, was built up. A support vector machine (SVM) was used
to generate a statistical model, which allows a classification of
this data set with an accuracy of 92% on a species level. This model
was afterward used to identify infected urine samples of ten patients
directly without a preceding culture step. Thereby, we were able to
determine the predominant bacterial species (seven Escherichia coli and three Enterococcus
faecalis) for all ten patient samples. These results
demonstrate that Raman microspectroscopy in combination with support
vector machines allow an identification of important UTI bacteria
within two hours without the need of a culture step