Pseudomonas aeruginosa in Peniche coastal waters

Abstract

Event Abstract Back to Event Pseudomonas aeruginosa in Peniche coastal waters Adriana P. Januário1*, Clélia N. Afonso1, Susana L. Mendes1 and Maria J. Rodrigues1 1 Polytechnic Institute of Leiria, MARE - Marine and Environmental Sciences Centre, Portugal P. aeruginosa is a ubiquitous organism with minimal requirements for survival and a remarkable ability to adapt to a variety of environmental conditions [1-2]. Members of this species can even survive for months in deionized or distilled water [3]. In the last decades, P. aeruginosa has become one of the most studied bacteria in the public health area due to the fact that a small percentage of strains, demonstrated to be a significant human threat [1]. It is primarily associated with ear, eye and skin infections, causing serious nosocomial infections in cystic fibrosis and burn patients [4-7]. Since the 60’s, that traditional microbiological techniques have been used for the detection and enumeration of P. aeruginosa, mostly the membrane filtration (MF) method, included in the ISO 16266:2006 [8]. Having several limitations, especially the fact that is time consuming, there is an urgent need for the development of alternative methods that overcome the limitations found in conventional methodologies. Pseudalert®/Quanti-Tray® MPN test is a new method, developed by IDEXX Laboratories Inc., which signals the presence of P. aeruginosa in just 24 hours, clearly reducing the time needed to obtain the results. But this methodology is only indicated for tap, pool and drinking water [9-10]. Results showed no significant differences (p-value>0.05) when comparing the new method with the traditional microbiological method, suggesting that Pseudalert®/Quanti-Tray® MPN test can be considered a faster, easier to perform, and safer alternative methodology to assess P. aeruginosa contamination in coastal waters. The major drawback of microbiological methods is the inability to detect viable but non-culturable (VNBC) forms [8]. PCR-based assays have become more attractive, but most authors still use a culture-enrichment step or a short grow step in the culture medium [11-12]. So, we developed a preliminary RT-PCR assay to detect P. aeruginosa without any of these previous steps. The estimated time of the assay was 6 hours, allowing the detection of P. aeruginosa through the amplification of the ecfX gene and using a TZ lysing solution to extract the bacterial genomic DNA of the membrane filters. This assay constitutes a viable alternative to the conventional methodologies, when applied to the detection of P. aeruginosa in seawater samples. Acknowledgements This study had financial support of Fundação para a Ciência e Tecnologia (FCT) through the strategic project UID/MAR/04292/2013 granted to MARE.