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P Bourlioux

Publications and source records attributed to P Bourlioux.

At least 19 recordsLinked to original sources
PubMed2002

Relations between hydrophobicity tested by three methods and surface chemical composition of Escherichia coli.

The cell surface hydrophobicity of three strains of Escherichia coli cultured in liquid medium and on solid medium was measured using various methods including adsorption to pxylene, partition of cells in a polyethylene glycol/dextran (PEG/DEX) two phase system and contact angle measurements. The percentage adsorbed to pxylene ranged from 1.6% to 67% and the percentage of cells in polyethylene glycol phase ranged from 19% to 64%. The contact angle data of less than 40 degrees C revealed a hydrophylic character of the E. coli strains studied here. No relations were found between paraxylene/water partitioning, PEG/DEX partioning and water contact angles. The linear correlation coefficients between the results of the three hydrophobicity assays and the elemental concentration ratios obtained by X-ray photoelectron spectroscopy (XPS) were calculated. A linear correlation was found between the contact angles and the O/C ratios (r=0.91) and the N/C ratios (0.67). The adsorption to pxylene correlates better with N/C ratios (0.88) but does not correlate with O/C ratios (0.46). However, this test correlates with N/P ratios (0.79). No relation was obtained between partition in PEG/DEX system and any elemental concentration ratios. The surface composition determined by XPS was converted into a molecular composition in terms of proteins, polysaccharides, and hydrocarbon-like compounds. The proteins/polysaccharides and the hydrocarbons/polysaccharides seems to determine the contact angle of E. coli but not the adsorption to paraxylene or partition in the PEG/DEX system.

Animals↗
PubMed2002

Influence of surface cell structures on physicochemical properties of Escherichia coli.

The partition of cells in a polyethylene glycol-dextran two phase system was used to compare the relative hydrophobicity of E. coli strains expressing different surface structures. The role of fimbriae and surface antigens on the behavior partition was investigated. The strains expressing PAP fimbriae and/or O-antigen showed a higher surface hydrophobicity than strains which express only type 1 fimbriae and/or R-antigen. No relation was found between K and H antigen and hydrophobicity measurements. The influence of surface structures on electrophoretic mobility has been evaluated. The polysaccharide capsules of AL 213 and AL 499 strains generated a high EPM. For non capsulated E. coli the EPM of rough strains (AL 46, 382) is higher than smooth strain (AL52).

Animals↗
PubMed2001

Bacteriological validation of a new apparatus for disinfection of hospital waste at the point of disposal.

OBJECTIVES: To evaluate the ability of a new apparatus (Dipsys 25, Société SGN, Bagnols sur Cèze, France) to disinfect biomedical waste, including both potentially infectious agents and the normal saprophytic flora of the waste. METHODS: Disinfection was assessed using standard methods (reference strains were fixed on reference carriers according to the French AFNOR methods) and nonstandard assays. Assays in conditions of hospital use, evaluations of bacterial survival during storage, sporicidal effect, and spore survival during storage were performed in parallel. Finally, bactericidal effect in extreme conditions (association of high contamination and high bacterial protection conditions) was tested with normal fecal flora. Bacterial counts were performed after treatment by the apparatus and without treatment (controls). All tests were carried out in triplicate. RESULTS: In all treated carriers, a bacterial population decrease of at least 5 log10 was obtained. Assays performed in hospital-use conditions did not show any bacterial growth. Concerning the evaluation of sporicidal effect and spore revival during conservation, a minimum reduction of 5 log10 was observed in all assays performed, without survival. Finally, concerning assays in extreme conditions, the decrease of bacterial population was between 5 log10 and 10 log10 for vegetative anaerobes of normal fecal flora. CONCLUSION: Under our study conditions, the study apparatus reduced the tested microbial populations by a minimal factor of 5 log10. The main advantage of the apparatus is the opportunity to treat contaminated waste inside hospital wards, at the point of initial collection, without pulverization, by nonspecialized staff.

Bacteria, Aerobic↗
PubMed2001

GroEL (Hsp60) of Clostridium difficile is involved in cell adherence.

Previous results have demonstrated that adherence of Clostridium difficile to tissue culture cells is augmented by various stresses; this study focussed on whether the GroEL heat shock protein is implicated in this process. The 1940 bp groESL operon of C. difficile was isolated by PCR. The 1623 bp groEL gene is highly conserved between various C. difficile isolates as determined by RFLP-PCR and DNA sequencing, and the operon is present in one copy on the bacterial chromosome. The 58 kDa GroEL protein was expressed in Escherichia coli in fusion with glutathione S:-transferase and the fusion protein was purified from IPTG-induced bacterial lysates by affinity chromatography on glutathione-Sepharose. A polyclonal, monospecific antiserum was obtained for GroEL which established by immunoelectron microscopy, indirect immunofluorescence and immunoblot analysis that GroEL is released extracellularly after heat shock and can be surface associated. Cell fractionation experiments suggest that GroEL is predominantly cytoplasmic and membrane bound. GroEL-specific antibodies as well as the purified protein partially inhibited C. difficile cell attachment and expression of the protein was induced by cell contact, suggesting a role for GroEL in cell adherence.

Amino Acid Sequence↗
PubMed2001

Characterization of a cell surface protein of Clostridium difficile with adhesive properties.

Our laboratory has previously shown that Clostridium difficile adherence to cultured cells is enhanced after heat shock at 60 degrees C and that it is mediated by a proteinaceous surface component. The present study was undertaken to identify the surface molecules of this bacterium that could play a role in its adherence to the intestine. The cwp66 gene, encoding a cell surface-associated protein of C. difficile 79-685, was isolated by immunoscreening of a C. difficile gene library with polyclonal antibodies against C. difficile heated at 60 degrees C. The Cwp66 protein (66 kDa) contains two domains, each carrying three imperfect repeats and one presenting homologies to the autolysin CwlB of Bacillus subtilis. A survey of 36 strains of C. difficile representing 11 serogroups showed that the 3' portion of the cwp66 gene is variable; this was confirmed by sequencing of cwp66 from another strain, C-253. Two recombinant protein fragments corresponding to the two domains of Cwp66 were expressed in fusion with glutathione S-transferase in Escherichia coli and purified by affinity chromatography using gluthatione-Sepharose 4B. Antibodies raised against the two domains recognized Cwp66 in bacterial surface extracts. By immunoelectron microscopy, the C-terminal domain was found to be cell surface exposed. When used as inhibitors in cell binding studies, the antibodies and protein fragments partially inhibited adherence of C. difficile to cultured cells, confirming that Cwp66 is an adhesin, the first to be identified in clostridia.

Adhesins, Bacterial↗
PubMed2001

Molecular characterization of fliD gene encoding flagellar cap and its expression among Clostridium difficile isolates from different serogroups.

The fliD gene encoding the flagellar cap protein (FliD) of Clostridium difficile was studied in 46 isolates belonging to serogroups A, B, C, D, F, G, H, I, K, X, and S3, including 30 flagellated strains and 16 nonflagellated strains. In all but three isolates, amplification by PCR and reverse transcription-PCR demonstrated that the fliD gene is present and transcribed in both flagellated and nonflagellated strains. PCR-restriction fragment length polymorphism (RFLP) analysis of amplified fliD gene products revealed interstrain homogeneity, with one of two major patterns (a and b) found in all but one of the strains, which had pattern c. A polyclonal monospecific antiserum raised to the recombinant FliD protein reacted in immunoblots with crude flagellar preparations from 28 of 30 flagellated strains but did not recognize FliD from nonflagellated strains. The fliD genes from five strains representative of the three different RFLP groups were sequenced, and sequencing revealed 100% identity between the strains with the same pattern and 88% identity among strains with different patterns. Our results show that even though FliD is a structure exposed to the outer environment, the flagellar cap protein is very well conserved, and this high degree of conservation suggests that it has a very specific function in attachment to cell or mucus receptors.

Bacterial Proteins↗
PubMed2001

[Virulence factor of Escherichia coli strains isolated during asymptomatic bacteriura among patients treated by drugs with acetylcholine antagonistic activity in a psychiatric institute].

In two successive investigations on nosocomial infections in our hospital, wa have found that asymptomatic bacteriuria is closely related to age (over 50 years) and to treatment with acetylcholine antagonistic activity. We therefore searched for the presence and expression of genes coding for the virulence factors usually present in uropathogenic E. coli in our strains, in strains isolated during asymptomatic bacteriura related to neurologic bladder, and in strains isolated during symptomatic bacteriura. We found that strains from neurologic bladders rarely carried one or two virulence factors while 50% of our strains isolated from asymptomatic bacteriuria carriea at least 3 virulence factors commonly found in strains isolated from symptomatic urinary tract infection. Consequently, it appears important to look for urinary tract infection in patients (over 50 years of age) treated with such drugs, and to look for virulence factors in case of asymptomatic bacteriura. If the stains carry no virulence factors, no antibiotic treatment shoud be instituted but the patients should be invited to drink more water than usual in order to promote elimination of the strains in the urine. Inversely, if the strains carry virulence factors, an adpted antibiotic treatment should be started.

Bacteriuria↗
PubMed2000

Effects of subinhibitory concentrations of nitroxoline on the surface properties of Escherichia coli.

Nitroxoline (5-nitro-8-quinolinol; NIQ) at subinhibitory concentrations (sub-MIC) decreased the adherence of uropathogenic Escherichia coli to catheter surface and significantly enhanced cell surface hydrophobicity. The surface hydrophobicity increased in the presence of sub-MIC of NIQ and also in an excess of Mg2+. The effect of NIQ on the cell surface was not related to the bacteriostatic effect of this agent. The increase in nitrogen and decrease in phosphate content in the cell surface was found in the presence of NIQ. NIQ did not inhibit the expression of fimbriae.

Bacterial Adhesion↗
PubMed2000

Phenotypic and genotypic diversity of the flagellin gene (fliC) among Clostridium difficile isolates from different serogroups.

Phenotypic and genotypic diversity of the flagellin gene (fliC) of Clostridium difficile was studied in 47 isolates from various origins belonging to the serogroups A, B, C, D, F, G, H, I, K, X, and S3. Electron microscopy revealed 17 nonflagellated strains and 30 flagellated strains. PCR and reverse transcription-PCR demonstrated that the flagellin gene was present in all strains and that the fliC gene was expressed in both flagellated and nonflagellated strains. Southern blotting showed the presence of only one copy of the gene and three different hybridization patterns. DNA sequence analysis of fliC from the strains belonging to serogroups C, D, and X, representative of each profile, disclosed great variability in the central domain, whereas the N- and C-terminal domains were conserved. The variability of the flagellin gene fliC was further studied in the isolates by PCR-restriction fragment length polymorphism (RFLP) analysis. Nine different RFLP groups were identified (I to IX), among which three (I, VII, and VIII) corresponded to numerous serogroups whereas the six others (II, III, IV, V, VI, and IX) belonged to a single serogroup. Flagellin gene RFLP analysis could constitute an additional typing method employable in conjunction with other typing methods currently available.

Amino Acid Sequence↗
PubMed1999

Typing of sheep clinical isolates and identification of enterotoxigenic Clostridium perfringens strains by classical methods and by polymerase chain reaction (PCR).

A simple procedure was developed to identify toxitypes of Clostridium perfringens of different origins. Ninety strains of C. perfringens were identified by classical bacteriological methods, typing of the strains was done by a seroneutralisation test on mice. Production of enterotoxin was tested and all strains were analysed by PCR using gene of toxin alpha, gene of toxin E, gene of toxin beta and gene of enterotoxin. Simple amplification (amplifying one gene), and duplex and triplex amplification (amplifying two and three genes simultaneously) were performed. In the conditions of the experiment, the PCR method has proved efficacious. The specificity and sensitivity are excellent and superior to those of the classical methods. The prophylaxis of enterotoxaemia in animals is achieved by vaccination, the PCR technique can thus become a first-choice tool for the identification and typing of the C. perfringens strains which initiate these diseases. In turn, this would simplify the development of vaccines adapted to the epidemiological situation.

Animals↗
PubMed1999

Clostridium difficile cell attachment is modified by environmental factors.

Adherence of Clostridium difficile to Vero cells under anaerobic conditions was increased by a high sodium concentration, calcium-rich medium, an acidic pH, and iron starvation. The level of adhesion of nontoxigenic strains was comparable to that of toxigenic strains. Depending on the bacterial culture conditions, Vero cells could bind to one, two, or three bacterial surface proteins with molecular masses of 70, 50, and 40 kDa.

Adhesins, Bacterial↗
PubMed1999

[Seroprevalence of hepatitis B and C viruses in a psychiatric institution].

Many patients admitted to psychiatric institutions have a history of risk factors for contamination with the hepatitis B and C viruses (HBV and HCV). Immunization policies for psychiatric institution patients are not widely know. A study conducted in a 600-bed psychiatric institution in Paris, France, to evaluate the proportion of potentially contaminating patients at admission, as well as immunization use in HBV-negative patients. Serologic markers for the HBV and HCV were looked for prospectively in all patients admitted over a two-month period. Immunization use was evaluated in the patients who had a first serologic test in 1995 or 1996 and follow-up tests until the end of 1997. The prospective part of the study demonstrated preadmission exposure to the HBV in 23.0 +/- 6.0% of patients. This proportion was larger in men (26.0%) than in women (14.8%), although the difference was not statistically significant (P = 0.10). Four patients (2.0%) tested positive for the HbS Ag. Among the HBV-negative patients, 13.0% received the vaccine; all had protective antibody levels. These patients were younger and more likely to be first-time admissions (18.4% vs 3.6%, P < 0.01). HCV seroprevalence was 6.0%. Serologic tests for the HBV were requested for 327 patients between January 1995 and december 1996. Among the patients who were seronegative at admission and received follow-up at the study hospital, only 13.8% were immunized at this hospital. Of the HCV-positive subjects, 63.3% were also HBV-positive. None of the HCV-positive HBV-negative subjects received immunization subsequently. Six to eight per cent of patients admitted to the study hospital are potentially contaminating for the HBV or HCV. The level of hepatitis B vaccine use is too low, particularly in high-risk patients. These data indicate a need for policies aimed at effectively preventing HBV and HCV transmission (information, education, immunization campaigns), both during the psychiatric institution stay and after discharge.

Adult↗
PubMed1999

[Multidrug resistant bacteria in a psychiatric milieu].

Isolation rates of multiple-drug resistant (MDR) bacteria were evaluated retrospectively in a psychiatric care facility. Over the six-year study period, 66 MDR bacterial strains were found. Methicillin-resistant Staphylococcus aureus contributed half of all MDR strains and 31% of all S. aureus strains. Among Pseudomonas aeruginosa strains, 22% were resistant to ticarcillin or imipenem, and among Enterobacteriaceae, 4.1% were MDR strains (production of a derepressed cephalosporinase or of an extended-spectrum beta-lactamase). Although most MDR strains were probably acquired during hospitalizations in short-term care facilities outside our institution, patient-to-patient transmission, either direct or via other individuals, cannot be ruled out. These data indicate that psychiatric care facilities should adopt the MDR strain monitoring strategies already used in other hospitals.

Bacteria↗
PubMed1998

Protease activity of Clostridium difficile strains.

The production of proteolytic enzymes by 10 Clostridium difficile isolates of varying toxigenicity and clinical origin was studied to determine if all isolates secreted proteases. Different protease substrates were studied: gelatin, collagen, phenylazobenzyloxycarbonyl-leucyl-glycyl-L-prolyl-D-arginine (Pz-peptide), casein, azocasein, and azocoll. All isolates degraded gelatin, collagen, and azocoll. The supernatants of all isolates contained an enzyme capable of attacking gelatin incorporated in a polyacrylamide gel (zymograms) and forming two closely spaced lytic bands with an estimated molecular mass of 35-40 kDa. Polyclonal antibodies, produced against the C. difficile gelatinase, revealed in Western blots a 35-kDa protein in the culture supernatants of all C. difficile isolates. In the same manner, Clostridium perfringens collagenase polyclonal antibodies detected a 120-kDa protein in the culture supernatants of all isolates; this suggests that at least two proteases may exist in C. difficile. The protease activities of the 10 strains examined did not seem strikingly different quantitatively but were in general weak and their role in pathogenicity is suspect.

Caseins↗
PubMed1997

Cell surface characteristics of Lactobacillus casei subsp. casei, Lactobacillus paracasei subsp. paracasei, and Lactobacillus rhamnosus strains.

Hydrophilic and electrostatic cell surface properties of eight Lactobacillus strains were characterized by using the microbial adhesion to solvents method and microelectrophoresis, respectively. All strains appeared relatively hydrophilic. The strong microbial adhesion to chloroform, an acidic solvent, in comparison with microbial adhesion to hexadecane, an apolar n-alkane, demonstrated the particularity of lactobacilli to have an important electron donor and basic character and consequently their potential ability to generate Lewis acid-base interactions with a support. Regardless of their electrophoretic mobility (EM), strains were in general slightly negatively charged at alkaline pH. A pH-dependent behavior concerning cell surface charges was observed. The EM decreased progressively with more acidic pHs for the L. casei subsp. casei and L. paracasei subsp. paracasei strains until the isoelectric point (IEP), i.e., the pH value for which the EM is zero. On the other hand, the EM for the L. rhamnosus strains was stable from pH 8 to pH 3 to 4, at which point there was a shift near the IEP. Both L. casei subsp. casei and L. paracasei subsp. paracasei strains were characterized by an IEP of around 4, whereas L. rhamnosus strains possessed a markedly lower IEP of 2. The present study showed that the cell surface physicochemical properties of lactobacilli seem to be, at least in part and under certain experimental conditions, particular to the bacterial species. Such differences detected between species are likely to be accompanied by some particular changes in cell wall chemical composition.

Acetates↗
PubMed1997

Production of a complete binary toxin (actin-specific ADP-ribosyltransferase) by Clostridium difficile CD196.

A Clostridium difficile isolate was found to produce an actin-specific ADP-ribosyltransferase (CDT) homologous to the enzymatic components of Clostridium perfringens iota toxin and Clostridium spiroforme toxin (M. R. Popoff, E. J. Rubin, D. M. Gill, and P. Boquet, Infect. Immun. 56:2299-2306, 1988). The CDT locus from C. difficile CD196 was cloned and sequenced. It contained two genes (cdtA and cdtB) which display organizations and sequences similar to those of the iota toxin gene. The deduced enzymatic (CDTa) and binding (CDTb) components have 81 and 84% identity, respectively, with the corresponding components of iota toxin. CDTa and CDTb induced actin cytoskeleton alterations similar to those caused by other clostridial binary toxins. The lower level of production of binary toxin by CD196 than of iota toxin by C. perfringens was related to a lower transcript level, possibly due to a promoter region different from that of iota toxin genes. The cdtA and cdtB genes have been detected in 3 of 24 clinical isolates examined, and cdtB alone was found in 2 additional strains. One strain (in addition to CD196) was shown by Western blotting to produce CDTa and CDTb. These results indicate that some C. difficile strains synthesize a binary toxin that could be an additional virulence factor.

Amino Acid Sequence↗