ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Characterisation of electrochemical immunosensor for detection of viable not-culturable forms of Legionellla pneumophila in water samples

Dejla Sboui, Mina Souiri, Stephanie Reynaud, Sabine Palle, Manel Ben Ismail, Thibaut Epalle, Ridha Mzoughi, Françoise Girardot, Séverine Allegra, Serge Riffard, and Ali Othmane

Laboratory of Avanced Materials and Interfaces, Faculty of Medicine, University of Monastir, 5019 Monastir, Tunisia

E-mail: serge.riffard@univ-st-etienne.fr

Abstract: Legionella pneumophila may cause a fatal pneumonia in humans known as Legionnaires’ disease (LD). The strategies of L. pneumophila to adapt to and resist stressful environmental conditions include the ability to enter into a VBNC (viable but not culturable) state. The detection of L. pneumophila in environmental samples benefits from the use of standardised methods: for detection and enumeration following membrane filtration (AFNOR T90-431, ISO 11731) and detection and quantification by polymerase chain reaction PCR (AFNOR T90-471, ISO 12869). Culture is hampered by its inability to detect VBNC forms and PCR is unable to discriminate between live and dead bacteria. The present immunosensor was obtained by the immobilisation of a monoclonal anti-L. pneumophila antibody (MAb) on an indium-tin oxide (ITO) electrode by the self-assembled monolayers (SAMs) method using an aminosilane. The immunosensor was characterised by wettability (contact angle measurement), atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM), and electrochemical impedance spectroscopy (EIS). A limit of detection of 10 bacteria per mL was observed on artificial samples.

Keywords: immunosensor – antibody immobilisation – Legionella pneumophila – VBNC – detection – electrochemical impedance spectroscopy

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0170

Chemical Papers 69 (11) 1402–1410 (2015)