Abstract
Raman spectroscopy was used to discriminate between Legionella strains and between E. coli and coliform
strains. The relationship between triplicate Raman spectra derived from Legionella bacteria was compared
with that derived from a blind set of samples and amplified fragment length polymorphism (AFLP) data
from the same strains. Triplicate Raman spectra of E. coli and coliform bacteria were compared with
their 16S phylogeny. In all cases Raman spectra were reproducible and could be distinguished from
spectra of other organisms down to the strain level. All samples in a blind fourth set were identified
correctly. Raman spectra of organisms of the same coliform species clustered according to 16S rRNA
gene phylogeny, except for Enterobacter spp. At higher taxonomic levels the relationship between
species was less comparable. For Legionella strains the Raman spectra grouped according to AFLP
groups, based on the dataset used in this study. Raman spectroscopy could correctly distinguish E. coli
from other coliform bacteria and L. pneumophila from non-pneumophila strains. Incubation of
Legionella strains in different types of drinking water at different temperatures over a period of one
week introduced so little variation in the Raman spectra that only very closely related L. pneumophila
strains could not be distinguished from each other. Temperature, ageing and water type did not
influence the identification potency of Raman spectroscopy in all cases. Given the accuracy, speed and
simplicity of the Raman spectroscopy technique this method seems a welcome addition to the current
tools for identification of waterborne bacteria.
strains. The relationship between triplicate Raman spectra derived from Legionella bacteria was compared
with that derived from a blind set of samples and amplified fragment length polymorphism (AFLP) data
from the same strains. Triplicate Raman spectra of E. coli and coliform bacteria were compared with
their 16S phylogeny. In all cases Raman spectra were reproducible and could be distinguished from
spectra of other organisms down to the strain level. All samples in a blind fourth set were identified
correctly. Raman spectra of organisms of the same coliform species clustered according to 16S rRNA
gene phylogeny, except for Enterobacter spp. At higher taxonomic levels the relationship between
species was less comparable. For Legionella strains the Raman spectra grouped according to AFLP
groups, based on the dataset used in this study. Raman spectroscopy could correctly distinguish E. coli
from other coliform bacteria and L. pneumophila from non-pneumophila strains. Incubation of
Legionella strains in different types of drinking water at different temperatures over a period of one
week introduced so little variation in the Raman spectra that only very closely related L. pneumophila
strains could not be distinguished from each other. Temperature, ageing and water type did not
influence the identification potency of Raman spectroscopy in all cases. Given the accuracy, speed and
simplicity of the Raman spectroscopy technique this method seems a welcome addition to the current
tools for identification of waterborne bacteria.
| Original language | English |
|---|---|
| Pages (from-to) | 2679-2687 |
| Number of pages | 9 |
| Journal | Analytical Methods |
| Volume | 5 |
| DOIs | |
| Publication status | Published - 2013 |