Discrimination of Enterobacterial Repetitive Intergenic Consensus PCR Types of Campylobacter coli and Campylobacter jejuni by Fourier Transform Infrared Spectroscopy

Abstract

Fourier transform infrared spectroscopy (FT-IR) has been used together with pattern recognition methodology to study isolates belonging to the species Campylobacter coli and Campylobacter jejuni and to compare FT-IR typing schemes with established genomic profiles based on enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). Seventeen isolates were cultivated under standardized conditions for 2, 3, and 4 days to study variability and improve reproducibility. ERIC-PCR profiles and FT-IR spectra were obtained from strains belonging to the species Campylobacter coli and C. jejuni, normalized, and explored by hierarchical clustering and stepwise discriminant analysis. Strains could be differentiated by using mainly the firstderivative FT-IR spectral range, 1,200 to 900 cm ؊1 (described as the carbohydrate region). The reproducibility index varied depending on the ages of the cultures and on the spectral ranges investigated. Classification obtained by FT-IR spectroscopy provided valuable taxonomic information and was mostly in agreement with data from the genotypic method, ERIC-PCR. The classification functions obtained from the discriminant analysis allowed the identification of 98.72% of isolates from the validation set. FT-IR can serve as a valuable tool in the classification, identification, and typing of thermophilic Campylobacter isolates, and a number of types can be differentiated by means of FT-IR spectroscopy.

Comprehensive Detection and Discrimination of Campylobacter Species by Use of Confocal Micro-Raman Spectroscopy and Multilocus Sequence Typing

“…There are several factors (parameters) that may affect vibrational spectrum reproducibility, including cell culture age, nutrient availability, cultivation temperature, and spectral wavenumber selection (42). In addition, vibrational spectral variability was due mainly to biological features and to a lesser extent to instrumental sources (55). This statement was further validated in this study by using two different Raman instruments.…”

“…In the case of Raman spectroscopy, there are several factors that may affect spectral reproducibility, including bacterial cultivation time, growth temperature, medium use, and wavenumber selection (42,43,55). We calculated the D y1y2 values and demonstrated that use of the wavenumber region of 1,800 to 650 cm Ϫ1 provided the lowest D y1y2 value, indicating that the highest reproducibility of Raman spectra would be within this wavelength range (55). Fortunately, this spectral range includes important features for proteins, polysaccharides, nucleic acids, and lipids.…”

“…Since the two groundbreaking publications in Nature about the use of infrared spectroscopy (57) and Raman spectroscopy (61) to study microorganisms, these two techniques have been extensively employed to detect and discriminate different microorganisms and have been shown to be useful as real-time typing methods in bacterial epidemiology (3,7,33,34,36,37,48,49,59,60,65,77). Fourier-transformed infrared (FT-IR) spectroscopy, in combination with multivariate analyses, has been used to identify and discriminate C. jejuni and C. coli (54,55). Recently, complementary infrared and Raman spectral features of C. jejuni planktonic cells, sessile cells in biofilm, and biofilm extracellular polymeric substance were characterized by our lab (42,44).…”

Comparison of methods for the identification and sub-typing of O157 and non-O157 Escherichia coli serotypes and their integration into a polyphasic taxonomy approach

“…One strain (C-600) remained unclustered. FT-IR spectroscopy has high discriminatory power at the subspecies level (Mouwen et al, 2005;Mouwen et al, 2011), including for E. coli (Davis et al, 2012;Sousa et al, 2013;Dawson et al, 2014;Prieto-Calvo et al, 2014). The current study also showed a significant level of agreement between certain groupings (strains MF2494, MF2522 and MF3578; strains EDL933 and MF3582) when using FT-IR spectra and ribotyping or ITS rRNA gene sequencing (Figure 2).…”

Analysis of major band of Enterobacter sakazakii by ERIC-PCR and development of a species-specific PCR for detection of Ent. sakazakii in dry food samples

“…Recently, ERIC-PCR was used for the evaluation of genetic analysis and epidemiology investigation of some pathogens such as Vibrio parahaemolyticus, Campylobacter, Escherichia coli, Salmonella enterica and Aeromonas sp. strains (Versalovic et al, 1991;Wong and Lin, 2001;Da Silverra et al, 2002;Mclellan et al, 2003;Szczuka and Kaznowski, 2004;Houf et al, 2005;Mouwen et al, 2005). However, little attempt has been focused on the typing of Ent.…”