Pseudomonas aeruginosa related to Nosocomial and Animal infections. New approaches in diagnosis and therapy

Pseudomonas aeruginosa is a small bacillus gram negative, aerobic, asporogenous, monoflagellate, non-fermenting. P. aeruginosa infections often have a very severe course and are difficult to treat because of its ability to form biofilms characterized by a thick capsule coated with alginate (an exopolysaccharide consisting of D-mannuronic acid and glucuronic acid monomers). Alginate represent the main component of the extracellular matrix of P. aeruginosa biofilm; as a consequence, the alginate lysis facilitates the spread of antimicrobial substances. In fact, this extracellular matrix makes these micro-organisms resistant to antimicrobial agents and leads to the emergence of multidrug resistant clinical isolates (MDR) during therapy. Mutations in the mucA gene encode a protein involved in the production of this exopolysaccharide. In fact, in vitro inactivation of mucA in Pseudomonas aeruginosa PAO1 (non-mucoid) produces Alg+ strains; this seems to indicate, therefore, that mucA acts as a negative regulator of the production of alginate because it can bind and sequester the factor σ22, through the N-terminal cytoplasmic domain. The risk of P. aeruginosa infection may be related to several factors such as: (i) inappropriate therapies or prophylaxis measures, (ii) failure in the environmental monitoring systems (iii) inadequate laboratory protocols for detecting MDR strains. For example, the inappropriate use of peroxides as disinfectants could be increase the mutation rate in mucA gene. In this context, the P. aeruginosa biofilm studies allow to characterize new antimicrobials and to ascertain what are the useful ranges of the disinfectant that do not induce the mucoid phenotype more virulent and more resistant respectively to the not mucoid phenotype. Mutations present in the promoter of the gene or along the amino terminal part of the protein modulate an alginate hyper-expression giving the biofilm a barrier almost impermeable to the antimicrobials, this aspect must be considered during the use of oxidizing microbicides such as hydrogen peroxides, in able to determine mutations in the mucA gene. This work aims to study P. aeruginosa infections and its environmental contaminations as a global health problem. In fact, this multi-task pathogen can contaminate different areas in human, veterinary and agricultural fields. For this reason, a comprehensive work must be performed by different strategies in these points: 1 Pathogen detection: in this work, we describe a fast-molecular approach to detect the initial pathogen biofilm samples contaminated with Pseudomonas spp. (P. aeruginosa, P. fluorescens and P. putida). This procedure is based on the particular bi-functional FRET oligonucleotide probes named DUAL-FRET. 2 mucA / alginate profile: in P. aeruginosa, mucA genotype resulted essential to reveal high drug-resistant strains due to alginate hyperproduction in the biofilm. 3 Evaluation of potential new antimicrobials: a critical point in anti - P. aeruginosa prophylaxis is represented by the absence of highly performant disinfectant. 4 New cultural systems: design/use of bioreactors able to reproduce, in standard controlled conditions, the initial parameters in the primary contamination area, for example the cold storage implants in the food production 5 Future strategies: following the recent new molecular procedures obtained in biological field could be possible to design new clinical/laboratory strategies against P. aeruginosa, for example the study of miRNAs.