Virulence inhibition by quorum quenchers in Pseudomonas aeruginosa is usually tested in laboratory strains and studies of their effects in relevant clinical and environmental strains are scarce. This study is significant as the effects of ZnO nanoparticles in QS-dependent virulence factor production were tested in six clinical strains from cystic fibrosis patients, a C-30 resistant clinical strain from urine, two PA14 gallium resistant mutants, a PA14 C-30 resistant mutant, and four environmental isolates. ZnO nanoparticles decreased elastase, pyocyanin, and biofilms for most of the strains; indicating they have broad spectrum and may be an alternative to treat Ps. aeruginosa infections.

<p>An alternative to remove polycyclic aromatic hydrocarbons (PAHs) of the environment is using hydrocarbonoclastic bacteria. The aim of this work was to study the bacterial diversity of indigenous isolates with potential to degrade pyrene. We used MALDI-Biotyper (Bruker Daltonics) as a powerful analytical tool for identification. Bacteria were isolated from surface seawater and marine sediments samples of three sites from the coast of Rosarito Port, B.C., Mexico. Total concentration of PAHs in collected samples was quantified by GC-MS, showed values ranged 0.461-0.525 ng mL^-1 and of 74 -266 ng g^-1 in seawater and sediments samples, respectively. A total of 52 bacteria with capacity to grow in 25 mg L^-1 pyrene as sole carbon and energy source were taxonomically identified and classified by MALDI-Biotyper system by comparing the mass spectra with library and/or to use chemometric tools as Principal Components Analysis (PCA) and Composite Correlation Index (CCI) to evaluate possible differences to isolate level. The identified isolates were represented by three phylogenetic groups: <em>Firmicutes, Actinobacteria and Proteobacteria</em>. Of these isolates, <em>Kocuria</em> strains appear to be excellent candidates to continue PAHs degradation studies.</p>