Rapid and specific SPRi detection of L. pneumophila in complex environmental water samples.

Sebastien P Faucher,Maryam Tabrizian,Amir M Foudeh,Teodor Veres,Nilmini Mendis,Hana Trigui

doi:10.1007/s00216-015-8726-y

Sebastien P Faucher, Maryam Tabrizian + Show 4 more

Open Access

https://doi.org/10.1007/s00216-015-8726-y

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Abstract

Legionellosis is a very devastating disease worldwide mainly due to unpredictable outbreaks in man-made water systems. Developing a highly specific and sensitive rapid detection system that detects only metabolically active bacteria is a main priority for water quality assessment. We previously developed a versatile technique for sensitive and specific detection of synthetic RNA. In the present work, we further investigated the performance of the developed biosensor for detection of Legionella pneumophila in complex environmental samples, particularly those containing protozoa. The specificity and sensitivity of the detection system were verified using total RNA extracted from L. pneumophila in spiked water co-cultured with amoebae. We demonstrated that the expression level of ribosomal RNA (rRNA) is extremely dependent on the environmental conditions. The presence of amoebae with L. pneumophila, especially in nutrition-deprived samples, increased the amount of L. pneumophila 15-fold after 1week as measured through the expression of 16s rRNA. Using the developed surface plasmon resonance imaging (SPRi) detection method, we were also able to successfully detect L. pneumophila within 3h, both in the presence and absence of amoebae in the complex environmental samples obtained from a cooling water tower. These findings suggest that the developed biosensing system is a viable method for rapid, real-time and effective detection not only for L. pneumophila in environmental samples but also to assess the risk associated with the use of water contaminated with other pathogens.

Highlights

Legionella species are the causative agent of legionellosis, and among them, Legionella pneumophila is responsible for more than 90 % of legionellosis
To determine the sensitivity and limit of detection (LOD) for total RNA (totRNA), a dilution series of L. pneumophila in AYE medium ranging from 3× 104 to 3×108 CFU/mL was made, and 1 mL of each sample was used for RNA extraction
Monitoring metabolically active bacteria rapidly with high specificity and sensitivity is the main challenge in water quality assurance to prevent any potential outbreaks due to contaminated water systems

Summary

Introduction

Legionella species are the causative agent of legionellosis, and among them, Legionella pneumophila is responsible for more than 90 % of legionellosis. De Mortagne, Boucherville, QC J4B 6Y4, Canada successfully detect L. pneumophila within 3 h, both in the presence and absence of amoebae in the complex environmental samples obtained from a cooling water tower. These findings suggest that the developed biosensing system is a viable method for rapid, real-time and effective detection for L. pneumophila in environmental samples and to assess the risk associated with the use of water contaminated with other pathogens.

Results

Conclusion