Nile tilapia (Oreochromis niloticus) as an aquatic vector for Pseudomonas species of medical importance: Antibiotic Resistance Association with Biofilm Formation, Quorum Sensing and Virulence

Pseudomonas aeruginosa produces a suite of virulence factors that are coordinated by Quorum Sensing (QS) contributing to its disease-causing ability in aquaculture. However, the bacterial infections in aquaculture hatcheries and farms cause a huge loss in productivity and remain a major challenge for the growth of this vital industry and to the ill effects to the environment and public health. It has been well documented that the exhibition of virulence factors and formation of biofilms are the major factors for the establishment of disease in aquaculture animals by the bacterial pathogens. The present study is first of its kind to obtain information regarding the presence and distribution of QS, virulence and Extended-spectrum beta-lactamases genes of Pseudomonas species isolated from fish meat by direct PCR. In addition, quantification of their in vitro production of QS regulated phenotypes, including biofilm formation, virulence factor production and antibiotic susceptibility were executed. The influence of resistance genes in the prevalence of antibiotic resistance was evaluated by using correlation analyses. Only four correlations showed a significant level higher than 0.05. Besides, all correlations were related to extended spectrum beta-lactamase (SHV, TEM and PER). In order to verify which characteristics, represent the sample, we carried out a principal component analysis (PCA) using all phenotypic (antibiotic resistance profile) and genotypic (resistance, virulence and QS genes) data from the strains. Based on the results, the P. alkylphenolia seems to be the most different of the species identified, being well clustered. Moreover, only six (resistance to Chloramphenicol, Aztreonam, Cefepime and Ceftriaxone, VEB and CTX-M1 resistance genes) of the 23 characteristics represent almost 70% of the variation. The outcomes of this study have great significance for the strategic designation of QS quenching. By the use of Quorum quenching (QQ) may provide a novel approach for treating bacterial infections of aquacultures. QQ may act as a non-specific (or broad-spectrum) inhibitor of biofilm formation that will help control infectious diseases that adversely affect the aquaculture industry. Effective inhibitors of biofilm formation may prove to be important for protecting industrial aqua culture from the devastating effects of bacterial infections.