Highly specific fiber optic immunosensor coupled with immunomagnetic separation for detection of low levels of Listeria monocytogenes and L. ivanovii

Mendonça, Marcelo; Conrad, Neida Lucia; Conceição, Fabrı́cio R.; Moreira, Ângela Nunes; Silva, Wladimir Padilha da; Aleixo, José Antônio Guimarães; Bhunia, Arun K.

doi:10.1186/1471-2180-12-275

Cited by 55 publications

(39 citation statements)

References 65 publications

(105 reference statements)

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“…The growth of Listeria at different temperatures, for example 4, 25 or 37 °C, produces bacteria with different amount of flagella and a different level of virulence. 30 The presence of non-pathogenic listeria such as Listeria innocua may, however, indicate also contamination with L. monocytogenes. 18,25 In previous research, it has been shown that it is possible to differentiate bacteria through SERS analysis.…”

Section: Introductionmentioning

confidence: 99%

“…This affects the spectral fingerprint of the bacteria; in order to obtain reproducible spectra for bacteria, the same growing conditions in addition to detection processes are required. 30 Furthermore, as the morphologic structure of L. innocua is similar to L. monocytogenes a n d th eir Ra m a n/S ER Sspectra are quite similar, L. innocua can be used as a model for Listeria detection. [25][26][27][28] Preliminary results also indicate that SERS can be used for identifying bacteria and spores even at a strain level.…”

Section: Introductionmentioning

confidence: 99%

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Detection of Listeria innocua on roll-to-roll produced SERS substrates with gold nanoparticles

et al. 2016

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The rapid and accurate detection of food pathogens plays a critical role in the early prevention of foodborne epidemics.Current bacteria identification practises, including colony counting, polymerase chain reaction (PCR) and immunological methods, are time consuming and labour intensive; they are not ideal for achieving the required immediate diagnosis. Different SERS substrates have been studied for the detection of foodborne microbes. The majority of the approaches are either based on costly patterning techniques on silicon or glass wafers or on methods which have not been tested in large scale fabrication. We demonstrate the feasibility of analyte specific sensing using mass-produced, polymer-based low-cost SERS substrate in analysing the chosen model microbe with biological recognition. The use of this novel roll-to-roll fabricated SERS substrate was combined with optimised gold nanoparticles to increase the detection sensitivity.Distinctive SERS spectral bands were recorded for Listeria innocua ATCC 33090 using an in-house build (785 nm) near infra red (NIR) Raman system. Results were compared to both those found in the literature and the results obtained from a commercial time-gated Raman system with a 532 nm wavelength laser excitation. The effect of the SERS enhancer metal and the excitation wavelength on the detected spectra was found to be negligible. The hypothesis that disagreements within the literature regarding bacterial spectral results from conditions present during the detection process has not been supported. The sensitivity of our SERS detection was improved through optimization of the concentration of the sample inside the hydrophobic polydimethylsiloxane (PDMS) wells. Immuno-magnetic separation (IMS) beads were used to assist the accumulation of bacteria into the path of the beam of the excitation laser. With this combination we have detected L i s t e r i a w i t h g o l d e n h a n c e d S E R S i n a l a b e l f r e e m a n n e r f r o m s u c h l o w s a m p l e c o n c e n t r a t i o n s a s 1 0 4 CFU/ml.Figure 10. a) A normalised concentration series for LOD estimation. b) An exponential fit for the normalised concentration series in logarithmic scale for the entire series and a linear fit for the small concentrations. c) Comparison of the 737 cm -1 peak intensity for different concentration series with 5 -10 µl dried IMS bound L. innocua ATCC 33090 samples placed with AuNPs into a 1 -1.5 mm PDMS well on top of SERS substrate. d) Comparison of baseline corrected Raman intensities for three of the concentration series. All figures are a mean of 9 measurement points with mean absolute deviations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Detection of Listeria innocua on roll-to-roll produced SERS substrates with gold nanoparticles

et al. 2016

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“…Ideally, antibody specificity that distinguishes L. monocytogenes from L. ivanovii as well as pathogenic Listeria from non-pathogenic Listeria would be desired since L. monocytogenes is a more common human pathogen compared to L. ivanovii and other Listeria species. Antibodies that distinguish pathogenic from nonpathogenic Listeria were recently developed but do not discriminate between L. monocytogenes and L. ivanovii (Mendonça et al, 2012). Indeed, the pathogenic Listeria species possess similar virulence factors with considerable homology that make it difficult to produce non cross-reactive antibodies.…”

Section: Discussionmentioning

confidence: 98%

Magnetic bead based immuno-detection of Listeria monocytogenes and Listeria ivanovii from infant formula and leafy green vegetables using the Bio-Plex suspension array system

Day

Basavanna

2015

Food Microbiology

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“…Nevertheless, the detection limits achieved with Matrix-Lysis and qPCR are as good as the quantification limits associated with high-technology methods, such as fiber optic immunosensors coupled with immunomagnetic separation or antibody-based immunosensors [29,30]. To our knowledge, Matrix-Lysis is the only economical and easy-to-use tissue preparation method that can compete with these novel high-technology methods, considering the LOD and coefficients of determination in whole dilution series.…”

Section: Discussionmentioning

confidence: 99%

Quantification of Gram-positive bacteria: adaptation and evaluation of a preparation strategy using high amounts of clinical tissue

et al. 2014

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BackgroundA preparation method for quantification of bacteria in tissues is obligatory to reduce tissue mass, concentrate the target, purify, remove inhibitory substances and to achieve constant target recovery rates. No preparation method has been available until now for a high mass of tissue applicable for routine use and analytical veterinary diagnostics.ResultsThis study describes an easy-to-use tissue preparation protocol to quantify Gram-positive bacteria from a large volume of tissue matrix. A previously published sample preparation method (Matrix-Lysis) from food science was successfully adapted for clinical use on tissues from pigs, including cerebrum, spinal cord, lung, liver, ileum, colon, caecum, kidney and muscle tissue. This tissue preparation method now permits quantification of pathogens from 5 g of organic matrix, which is a 20–200 fold increase by weight compared to other methods. It is based on solubilization of the sample matrix with either a chaotrope plus detergent or divalent salts as solubilization agents. The method was designed as a modular system, offering the possibility to change lysis buffers, according to tissue solubilization characteristics and the intended detection method (molecular or culture). Using Listeria monocytogenes as model organism, viable cell quantification or DNA extraction and quantitative real-time PCR were performed after Matrix-Lysis to determine recovery rates and detection limit (LOD). The adapted Matrix-Lysis protocol resulted in high recovery rates (mean value: 76% ± 39%) for all tested organs, except kidney, and recovery was constant over 5 log scales for all tested buffer systems. The LOD for Matrix-Lysis with subsequent plate count method (PCM) was as low as 1 CFU/5 g, while for qPCR based detection the LOD was 102 bacterial cell equivalents (BCE)/5 g for two buffer systems.ConclusionsThis tissue preparation is inexpensive and can be easily used for routine and analytical veterinary diagnostics. Inoculation studies or hazard assessments can profit from this tissue preparation method and it is anticipated that this study will be a valuable source for further research on tissue preparation strategies.

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Highly specific fiber optic immunosensor coupled with immunomagnetic separation for detection of low levels of Listeria monocytogenes and L. ivanovii

Cited by 55 publications

References 65 publications

Detection of Listeria innocua on roll-to-roll produced SERS substrates with gold nanoparticles

Detection of Listeria innocua on roll-to-roll produced SERS substrates with gold nanoparticles

Magnetic bead based immuno-detection of Listeria monocytogenes and Listeria ivanovii from infant formula and leafy green vegetables using the Bio-Plex suspension array system

Quantification of Gram-positive bacteria: adaptation and evaluation of a preparation strategy using high amounts of clinical tissue

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