Screening of Molecular Virulence Markers in Staphylococcus aureus and Pseudomonas aeruginosa Strains Isolated from Clinical Infections

Staphylococcus (S.) aureus and Pseudomonas (Ps.) aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections

New complexes of Co(II), Ni(II), Cu(II) with Schiff base N,N’-bis-(3-methoxy-saliciliden)-3,3’-dimethylbenzidine

The new N,N’-bis-(3-methoxy-saliciliden)-3,3’-dimetilbenzidine (H2L) Schiff base and complexes with Co(II), Ni(II) and Cu(II) of type [M(HL)Cl(H2O)] (M=Co(II), Cu(II)) [M2L(H2O)4]X2 (M=Co(II), X=ClO4 and M=Cu(II), X=NO3) and [M2L(CH3COO)2] (M=Co(II), Ni(II), Cu(II)) were synthesised. The ligand and complexes were characterized by elemental analysis, conductibility measurements, magnetic moments at room temperature, IR, NMR, UV-VIS-NIR, EPR spectra and thermogravimetric analysis. A molar ratio of 1:1 or 1:2 between ligand and metal was determined from the elemental analysis. Except for perchlorate complex that behave as electrolyte, the rest of complexes are non-electrolytes. The spectral data suggest a tetrahedral, pseudo-tetrahedral or square-planar stereochemistry respectively, data confirmed by magnetic behaviour of complexes. The antimicrobial tests indicate a fungicide effect both for ligand and complexes

Drastic Attenuation of Pseudomonas aeruginosa Pathogenicity in a Holoxenic Mouse Experimental Model Induced by Subinhibitory Concentrations of Phenyllactic acid (PLA)

Abstract: The discovery of communication systems regulating bacterial virulence has afforded a novel opportunity to control infectious bacteria without interfering with growth. In this paper we describe the effect of subinhibitory concentrations of phenyllactic acid (PLA) on the pathogenicity of Pseudomonas aeruginosa in mice. The animals were inoculated by oral (p.o.), intranasal (i.n.), intravenous (i.v.) and intraperitoneal (i.p.) routes with P. aeruginoasa wild and PLA-treated cultures. The mice were followed up during 16 days after infection and the body weight, mortality and morbidity rate were measured every day. The microbial charge was studied by viable cell counts in lungs, spleen, intestinal mucosa and blood. The mice batches infected with wild P. aeruginosa bacterial cultures exhibited high mortality rates (100 % after i.v. and i.p. route) and very high cell counts in blood, lungs, intestine and spleen. In contrast, the animal batches infected with PLA treated bacterial cultures exhibited good survival rates (0 % mortality) Int. J. Mol. Sci. 2007, 8 584 and the viable cell counts in the internal organs revealed with one exception the complet

Drastic Attenuation of Pseudomonas aeruginosa Pathogenicity in a Holoxenic Mouse Experimental Model Induced by Subinhibitory Concentrations of Phenyllactic acid (PLA)

The discovery of communication systems regulating bacterial virulence hasafforded a novel opportunity to control infectious bacteria without interfering withgrowth. In this paper we describe the effect of subinhibitory concentrations of phenyl-lactic acid (PLA) on the pathogenicity of Pseudomonas aeruginosa in mice. The animalswere inoculated by oral (p.o.), intranasal (i.n.), intravenous (i.v.) and intraperitoneal (i.p.)routes with P. aeruginoasa wild and PLA-treated cultures. The mice were followed upduring 16 days after infection and the body weight, mortality and morbidity rate weremeasured every day. The microbial charge was studied by viable cell counts in lungs,spleen, intestinal mucosa and blood. The mice batches infected with wild P. aeruginosabacterial cultures exhibited high mortality rates (100 % after i.v. and i.p. route) and veryhigh cell counts in blood, lungs, intestine and spleen. In contrast, the animal batchesinfected with PLA treated bacterial cultures exhibited good survival rates (0 % mortality) and the viable cell counts in the internal organs revealed with one exception the complete abolition of the invasive capacity of the tested strains. In this study, using a mouse infection model we show that D-3-phenyllactic acid (PLA) can act as a potent antagonist of Pseudomonas (P.) aeruginosa pathogenicity, without interfering with the bacterial growth, as demonstrated by the improvement of the survival rates as well as the clearance of bacterial strains from the body