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.

Investigation of the influence of different physico-chemical parameters upon the susceptibility of planktonic and adherent Escherichia coli cells to beta-lactams and quinolones.

The purpose of this study was to evaluate the influence of different physico-chemical parameters on Escherichia coli susceptibility to ceftriaxone (CRO), cefotaxime (CTX), imipenem (IMP), and nalidixic acid (as marker for resistance by impermeability). The influence of chemical composition of culture medium was evaluated by the comparative assessment of inhibition growth diameters on different solid media: Mueller Hinton Medium (MH), Plate Count Agar Medium (PCA), MacConkey Medium (MC) and Eosin Methylen Blue Medium (EMB). In order to evaluate the differences in antibiotic susceptibility between the biofilm embedded and planktonic cells, an original, simple experimental model was used, by including the bacterial cells in an agar layer, mimicking the biofilm matrix.

In vivo experimental model for the study of the influence of subinhibitory concentrations of phenyllactic acid on Staphylococcus aureus pathogenicity.

The discovery of communication systems regulating bacterial virulence has afforded a novel opportunity to control infectious bacteria without interfering with their growth. In this paper the authors describe the effect of subinhibitory concentrations of phenyl-lactic acid (PLA) on the pathogenicity of Staphylococcus aureus in holoxenic mice. The animals were inoculated by oral (p.

Subinhibitory concentrations of phenyl lactic acid interfere with the expression of virulence factors in Staphylococcus aureus and Pseudomonas aeruginosa clinical strains.

The discovery of intra- and intercellular communication systems (quorum sensing systems) regulating bacterial virulence has afforded a novel opportunity to control infectious bacteria, without interfering with their growth. In this study, we investigated the ability of subinhibitory concentrations (sIC) of phenyl lactic acid (PLA), known to be produced by Lactobacillus probiotic strains, to attenuate the virulence and pathogenicity of Pseudomonas aeruginosa (as experimental model of intercellular bacterial communication in Gram-negative bacteria) and Staphylococcus aureus (as experimental model of intercellular bacterial communication in Gram-positive bacteria) by interfering with the coordinated expression of different virulence factors implicated in the pathogenicity of these opportunistic strains. Our results showed that sIC of PLA decreased the ability of the tested strains to adhere both to the cellular and inert substrata and induced changes in the adherence patterns as well as in the cell morphology.

New thioureides of 2-(4-methylphenoxymethyl) benzoic acid with antimicrobial activity.

The purpose of this study was to evaluate in vitro, by means of qualitative and quantative methods, the antimicrobial activity of some new synthesized chemical compounds previously solubilized in DMF (Dimethyl formamide). The qualitative screening of the susceptibility spectra of different microbial strains versus these compounds was performed by three adaptated diffusion methods: paper filter disk impregnation with the tested substances solutions, the disposal of tested solutions in agar wells and the spotting of tested solutions on solid medium previously inoculated with microbial suspension. The quantitative assay of the antimicrobial activity was performed by broth microdilution method in 96-well microplates in order to establish the minimal inhibitory concentration (MIC).

The role of proteins expressed under the stress condition in virulence of some Vibrio strains.

In order to survive in changing environments, bacteria possess enormous adaptive capabilities that allow them to modulate their behavior and reprogram gene expression in response to environmental cues. Vibrios are inhabitants of estuarine and fresh waters and some species are pathogenic to humans, and marine vertebrates and invertebrates. Surface attachment is believed to be essential for colonization of all of these natural environments.

Virulence and resistance markers in clinical and environmental Aeromonas strains isolated in Romania.

The virulence and resistance (R) features of 37 Aeromonas strains from diarrheal cases and 150 from the aquatic environment (isolated during cold and warm season) were tested at different incubation temperatures (4 degrees C, 28 degrees C and 37 degrees C). When incubated at 4 degrees C temperature, the Aeromonasstrains isolated during the cold season expressed the highest number of virulence factors by comparison with the strains isolated during warm season and from diarrhoeal cases, the virulence spectrum increasing simultaneously with the incubation temperature (i.e.