Characterization and phylogenetic diversity of Allorhizobium vitis isolated from grapevine in Morocco.

AIMS: Crown gall, a phytobacteriosis characterized by the formation of tumours on plant roots was observed in recently planted vineyards of the Meknes region (Morocco). The objective of this research was to analyse the diversity of pathogenic agrobacteria isolated from grapevine in Morocco. METHODS AND RESULTS: Eighty-two isolates from 11 affected vineyards were characterized by recA sequencing and were found to belong to Agrobacterium tumefaciens genomospecies G1, G4 or G7, Rhizobium rhizogenes, and to Allorhizobium vitis. Only the All. vitis isolates appeared to be pathogenic on tomato and multilocus sequence analysis phylogenetic analyses revealed a weak genetic diversity, with the definition of only four genomic groups. Definition of the All. vitis genomic groups correlated with specific pathogenic traits: indeed, genomic groups differed with respect to the severity of hypersensitive response symptoms on tobacco leaves, the intensity of necrotic response on grapevine explants and opine profiles. Both vitopine and octopine were detected by UHPLC in tumours induced by isolates of three genomic groups, an opine signature scarcely ever reported. CONCLUSIONS: Allorhizobium vitis is the only causative agent of crown gall on grape in Morocco, pathogenic isolates can be separated into four genomic groups. SIGNIFICANCE AND IMPACT OF THE STUDY: This study of recently crown-gall-infested vineyards demonstrated that All. vitis is the only causative agent and revealed the presence of nonpathogenic Agrobacterium strain within tumours. Moreover, as the genetic diversity of the All. vitis isolates is relatively narrow, this study lays the basis for further analyses on the evolution of the disease, on the dissemination of the pTi and more globally on the fate of the different genomic groups in this newly colonized environment.

Prevalence and preventability of adverse drug events in a teaching hospital: a cross-sectional study.

We determined the prevalence of adverse drug events (ADEs) in a general teaching hospital in Rabat, Morocco. We performed a 5-day cross-sectional study of hospital departments recruiting inpatients and outpatients. Among the 1390 patients surveyed, 59 (4.2%) experienced at least 1 ADE and for 20 patients (1.4%) the ADE was responsible for hospitalization or prolongation of hospitalization. The ADE was classified as serious in 28 patients. Of the total of 76 ADEs, 10 (13.2%) were categorized as preventable; 6 of these occurred during the treatment monitoring phase. Patients who experienced an ADE were more likely to be women, to be younger (< 30 years) and to be hospitalized in medical departments.

Prevalence and preventability of adverse drug events in a teaching hospital: a cross-sectional study

We determined the prevalence of adverse drug events [ADEs] in a general teaching hospital in Rabat, Morocco. We performed a 5-day cross-sectional study of hospital departments recruiting inpatients and outpatients. Among the 1390 patients surveyed, 59 [4.2%] experienced at least 1 ADE and for 20 patients [1.4%] the ADE was responsible for hospitalization or prolongation of hospitalization. The ADE was classified as serious in 28 patients. Of the total of 76 ADEs, 10 [13.2%] were categorized as preventable; 6 of these occurred during the treatment monitoring phase. Patients who experienced an ADE were more likely to be women, to be younger [< 30 years] and to be hospitalized in medical departments

Non-linear analysis of the arterial pulsatile flow: assessment of a model allowing a non-invasive ultrasonic functional exploration.

Ultrasonic measurements and modelling of blood flow in large vessels allows non-invasive evaluation of clinically interesting hemodynamic variables. To this aim, a non-linear mathematical model for the pulsatile arterial flow is proposed using the approximation of "local flow" theory. The model requires only measurements of instantaneous radius and centre-line blood velocity, and the knowledge of the tube distensibility to calculate blood velocity profiles, pressure gradient and wall shear stress. Evaluation of the proposed model using experimental data obtained from the literature proved that it can provide reliable results. In addition, as shown by assessing significance of various non-linear terms, results did not significantly change when a linear pressure-radius relationship was used instead of a non-linear relationship. Also, the model was found to be moderately sensitive to arterial tapering. Thus, the proposed model is suitable for a non-invasive clinical arterial exploration since it only requires three measurements which can be easily and precisely obtained in vivo using ultrasonic methods: the instantaneous radius, the centre-line velocity and the mean pulse wave velocity, this last variable characterizing the tube distensibility when assuming a linear pressure-radius relationship.

Immunochemical characterization of an IgG-binding protein of Streptococcus suis.

Several bacterial species express surface proteins with affinity for the constant region (Fc) of immunoglobulin (Ig) of different animal species. Previous studies from our group have reported the presence of an IgG-binding protein in various serotypes of Streptococcus suis. This molecule was also shown to bind in a non-immune fashion chicken IgY and to our knowledge this characteristic is unique. In the present study, by dot-blotting, we showed that the native protein, obtained by affinity chromatography, reacted more strongly with IgG from various animal species than the denatured material. Using a competitive enzyme-linked immunosorbent assay the affinity of the native 60-kDa protein (previously identified as a 52-kDa protein) towards IgG of various animal species was compared to pig IgG. Bovine, goat and human IgG were able to compete effectively with pig IgG whereas chicken IgY constituted a poor competitor. Peptide mapping analysis using denatured protein indicated that pig and bovine IgG recognized the same proteolytic fragment whereas chicken IgY did not. The smallest proteolytic fragment that retained the binding activity towards the IgG of the different animal species tested had a molecular mass of approximately 40 kDa. Fragments with Mr < 40 kDa showed specific binding activities. That is, the smallest fragment binding pig and bovine IgG had a Mr of 30 kDa whereas for goat and human IgG a fragment of less than 16 kDa still showed binding activity. Finally, we observed that antisera raised against a heat-shock protein of Pseudomonas aeruginosa reacted with the 60-kDa S. suis protein indicating that the S. suis 60-kDa protein is a member of the 60-kDa hsp family that possesses the characteristic of binding in a non-immune way mammalian IgG and chicken IgY.

Identification of a Streptococcus suis 60-kDa heat-shock protein using western blotting.

This study was initiated to investigate the presence of stress or heat shock proteins in Streptococcus suis. SDS-PAGE and Western blotting using polyclonal and monoclonal antibodies directed against different bacterial heat shock proteins demonstrated cross-reactivity with a protein with an apparent molecular mass of 60 kDa in all S. suis serotypes tested. The 60-kDa cross-reactive protein was present in virulent and avirulent strains of S. suis serotype 2 tested. A rabbit antiserum raised against the 60-kDa S. suis protein recognized the 60-65-kDa heat shock proteins in different Gram-positive and Gram-negative bacteria. Finally, the 60-kDa heat shock protein of S. suis was shown to be mostly secreted into the culture supernatant and, to a lesser extent, cell-associated. Growth under heat stress conditions (42 degrees C) increased the expression of the 60-kDa S. suis protein. This protein is, to our knowledge, the first common antigen found in different serotypes of S. suis.

Immunomagnetic PCR and DNA probe for detection and identification of Porphyromonas gingivalis.

The aim of the study that we describe was to combine an immunomagnetic separation and a PCR followed by dot blot hybridization with a DNA probe for the detection and identification of Porphyromonas gingivalis. Immunomagnetic particles were coated with monoclonal antibody specific for P. gingivalis and were incubated with a suspension containing seven oral bacterial species spiked with various dilutions of P. gingivalis. Beads with their load of bound bacterial were boiled in water, and the target DNA in the supernatant was amplified with a primer pair to generate a 593-bp PCR fragment specific for P. gingivalis. Finally, the product of amplification was detected by dot blot hybridization with a digoxigenin-labeled 593-bp probe. The detection limit was determined to be 100 bacterial cells per ml. The immunomagnetic-PCR/DNA probe procedure described here should be useful for the rapid, specific, and sensitive detection and identification of P. gingivalis in clinical samples.

Demonstration of lectin-like activity for the common antigen of Neisseria gonorrhoeae by quantitative immunoelectrophoretic techniques.

To overcome problems associated with Western blotting of denatured proteins, we have used quantitative immunoelectrophoretic techniques to perform functional analysis of the Neisseria gonorrhoeae common antigen. Using these techniques, we show (a) that Neisseria gonorrhoeae expresses an antigen that is cross-reactive with the common antigen of Pseudomonas aeruginosa and Legionella micdadei and with the GroEl-like protein of Chlamydia, and (b) that this N. gonorrhoeae common antigen has lectin-like activity and can be precipitated with three different sugars immobilized on agarose beads: alpha-D-glucosamine, maltose and fucose.

Purification and immunological studies of the cross-reaction between the 65-kilodalton gonococcal parietal lectin and an antigen common to a wide range of bacteria.

The 65-kDa gonococcal parietal lectin (GPL) has been purified and found to have a lectinlike activity exhibiting both structural and immunological similarities to the common antigen family. Ultrastructural localization of GPL was done by using anti-GPL monoclonal antibodies: GPL is a major component of the outer membrane and is also present in blebs formed by gonococci.