Biomedical subjects

B Picard

Publications and source records attributed to B Picard.

At least 91 records · Page 5Linked to original sources

PubMed1991

Clonal relationships among Escherichia coli serogroup 06 isolates from human and animal infections.

The clonal relationship of thirty E. coli strains of 0 antigen serotype 06 isolated from human, dog, pig or cow infections were investigated. Two main clones with serotypes 06 : H1 or 06 : H31, H- were identified. Isolates from humans, dogs, pigs and cows were found in both clones, indicating that animals are a possible source for human extraintestinal Escherichia coli strains. Two human ETEC (06 : H16) and two pig isolates (06 : H10) were not related to the 06 : H1 or 06 : H31, H- E. coli clones.

Animals↗

PubMed1991

Pseudomonas aeruginosa isolate typing by esterase electrophoresis.

Esterase electrophoretic typing was used to classify clinical isolates of Pseudomonas aeruginosa. One hundred and twenty-seven P. aeruginosa strains belonging to 16 serotypes (including 16 non-typeable strains) and isolated from diverse human infections in three hospitals, and the type strain ATCC 10 145, were tested. Four main kinds of esterase and 4 additional esterases were distinguished by their spectra of hydrolytic activity toward synthetic substrates and by their sensitivity or resistance to di-isopropyl fluorophosphate. The electrophoretic variations of these enzymes were used to define 42 zymotypes. Electrophoretic typing of esterase appeared to be more sensitive than serotyping and the results of the two methods did not correlate. When the two typing methods were used in parallel, 78 different combinations of serotype and zymotype were obtained.

Bacterial Typing Techniques↗

PubMed1991

Computer-assisted statistical analyses of enzyme and ribosomal DNA electrophoretic polymorphism in Yersinia.

The intra- and inter-species differentiation of 90 strains of Yersinia belonging to six species were studied independently by computer-assisted statistical analysis of data from enzyme electrophoretic polymorphism and ribosomal DNA (rDNA) restriction fragment length polymorphism. Two correspondence analyses (CA) demonstrated the concordance between the bacterial classification obtained from enzymatic and genomic data. This concordance was reinforced by an algorithm of the correspondence established between the two dendrograms drawn from previous computations. Comparison of CA with similarity analysis (also called "numerical taxonomy") indicated that the intra- and inter-species differentiation obtained by the two methods are similar. The advantage of CA is that it gives a synthetic geometrical representation of the results (factorial planes), displaying both the main features of the clusters of strains (location and dispersion) and their essential character (i.e.: enzyme electrophoretic variant, rDNA fragment size).

Algorithms↗

PubMed1991

Comparison of molecular epidemiological tools for Branhamella catarrhalis typing.

Twenty-one Branhamella catarrhalis strains selected for their diversity by esterase electrophoretic polymorphism, and belonging to 20 distinct zymotypes, were studied by restriction fragment length polymorphism (RFLP) of total DNA after ethidium bromide staining and of ribosomal DNA regions (ribotyping). The former analysis allowed the distinction of 20 patterns and the latter the delineation of 19 ribotypes. The three methods were correlated and showed a clonal diversity of the species. Esterase electrophoresis and Hinfl RFLP patterns after ethidium bromide staining appeared to be simple tools for use in B. catarrhalis epidemiology.

Bacterial Typing Techniques↗

PubMed1991

Complexity of Pseudomonas aeruginosa infection in cystic fibrosis: combined results from esterase electrophoresis and rDNA restriction fragment length polymorphism analysis.

Esterase electrophoretic typing and restriction fragment length polymorphism of ribosomal DNA regions (ribotyping) were used to differentiate 102 Pseudomonas aeruginosa clinical isolates obtained from chronic lung infection in 23 patients with cystic fibrosis (CF) and two reference strains (including the type strain ATCC 10145). Twenty-five zymotypes were obtained with the former method and 16 ribotypes with the latter. Combination of the two typing systems led to the finding of 30 different types. Our data highlights the physiopathological complexity of P. aeruginosa infection in CF as, in six individual cases, several types were found among isolates from a given patient. On the other hand, two unique types were found in two and three patients respectively, raising the possibility of cross-infections.

Cystic Fibrosis↗

PubMed1991

Association of carboxylesterase B electrophoretic pattern with presence and expression of urovirulence factor determinants and antimicrobial resistance among strains of Escherichia coli that cause urosepsis.

We determined the carboxylesterase B electrophoretic profiles of 74 blood isolates of Escherichia coli from patients with urosepsis. Most strains (64%) exhibited the B2 electrophoretic pattern. P fimbrial and hemolysin genetic determinants were present and expressed significantly more often among strains with the B2 than with the B1 electrophoretic pattern. In contrast, aerobactin determinants were significantly more prevalent and more commonly expressed among the B1 strains; this difference was attributable to the presence of plasmid-encoded aerobactin in one-third of the B1 strains (P = 0.02, B1 versus B2). The prevalence and extent of antimicrobial resistance was significantly greater among the B1 strains, and the B1 electrophoretic pattern was more often found in isolates from patients with urinary tract abnormalities. We conclude that the carboxylesterase B electrophoretic pattern differentiates two groups of E. coli isolates from patients with urosepsis: strains with the B1 electrophoretic pattern are associated with urologically impaired hosts, characteristically lack P fimbrial and hemolysin determinants, and often carry a plasmid-encoded aerobactin system (possibly on multiple antimicrobial resistance plasmids), whereas B2 strains more commonly invade noncompromised hosts, express P fimbriae and hemolysin, carry chromosomal aerobactin determinants, and lack antimicrobial resistance.

Carboxylesterase↗

PubMed1990

Electrophoresis of gliadins in long acrylamide gels: method and nomenclature.

Gliadins, defined as wheat kernel storage proteins soluble in 70% ethanol, possess an electrophoretic diversity permitting us to identify different varieties. Because of genetic proximity, however, it sometimes proves impossible to distinguish between different varieties using standard methods. An electrophoresis method, utilizing a discontinuous buffer system with aluminum lactate and potassium lactate in the gel and sodium lactate in the electrode vessels, is described for two types of gels 18 cm and 32 cm in length. The number of bands is higher than with standard methods, and is significantly increased with long gels, facilitating the distinction between varieties. A nomenclature for the new bands is presented for several widely different cultivars.

Buffers↗

PubMed1990

An analysis of molecular polymorphism of esterase M produced by motile Aeromonas strains.

The high levels of electrophoretic polymorphism of esterase M detected in eight distinct hybridization groups of motile Aeromonas raise questions of genetic homogeneity of the electromorphs. The 40 electromorphs detected fall in four Mr classes--75, 80, 90, and 110 kD--and one typical variant belonging to each of these classes was purified. The four purified esterases exhibited the same resistance to heat, to pH and to diisopropyl fluorophosphate, the same Km values for 1-naphthyl acetate and 1-naphthyl propionate (1 mM), and immunological cross-reactions. Within each class, the electromorphs appeared to be related in term of single amino acid substitutions as estimated from their comparative titration patterns. The titration curves of the four purified esterases were strictly parallel suggesting close structural similarities. Thus, despite considerable variation in their pI, MF, and Mr values, it seems likely that the variants of esterase M are the products of closely related loci originating from a common ancestral gene.

Aeromonas↗

PubMed1990

Nosocomial Serratia marcescens individualized by five typing methods in a regional hospital.

The relationships between 69 isolates obtained from 26 patients who were affected by two Serratia marcescens hospital outbreaks occurring in the urology and postnatal wards, were examined by five typing methods for epidemiological purposes. Serotyping, antibiotic resistance profile and electrophoretic analysis of enzymes identified three groups of isolates, while biotyping and bacteriocin typing identified only two. These surveys allowed us to demonstrate the existence of independent episodes of cross-infection among patients of each ward.

Bacterial Typing Techniques↗

PubMed1990

Epidemiological typing of Acinetobacter strains by esterase electrophoresis.

Fifty-three strains of Acinetobacter, belonging to the species A baumannii, A. haemolyticus and A. johnsonii, were differentiated by electrophoretic typing of their esterases, on the basis of both the enzyme specific activity profiles and their electrophoretic mobilities. Each esterase was defined by its spectrum of hydrolytic activity toward five synthetic substrates and its sensitivity to di-isopropyl fluorophosphate. Since each enzyme was not detected in all strains of a given species, several zymotypes could be defined by the patterns of combinations of esterases. Thus, 24 zymotypes were defined in the 32 A. baumannii strains, 4 were defined in the 10 A. haemolyticus strains and 6 were defined in the 11 A. johnsonii strains. When the electrophoretic mobilities of the various esterases were included, each of the 53 strains of Acinetobacter (with the exception of three A. haemolyticus strains) showed a distinct electrotype.

Acinetobacter↗

PubMed1990

Characterization of enterobacteria by esterase specific-activity profiles.

The spectrum of specific activities and the electrophoretic mobilities of esterases produced by 550 strains of Enterobacteriaceae belonging to 36 species and subclassified into six groups (group 1, Escherichia coli, Shigella and Escherichia hermanii; group 2, genus Salmonella and genus Citrobacter; group 3, genus Klebsiella and genus Enterobacter; group 4, genus Serratia and Serratia fonticola; group 5, genus Proteus, genus Providencia and genus Morganella; and group 6, genus Yersinia) were analysed by acrylamide/agarose gel electrophoresis using standardized methods for staining and mobility comparisons. Nineteen types of esterase were defined by their respective esterase specific-activity profile (ESAP). A multiple correspondence analysis (MCA) of the ESAP data enabled 82% of the strains in the 36 species to be correctly classified. In each group, the species were clearly delineated after MCA on both ESAP and electrophoretic mobility data. In addition, the smallest number of characters providing species identification of Yersinia strains by esterase polymorphism was identified by means of a binary segmentation tree technique.

Enterobacteriaceae↗

PubMed1990

Correlation between ribosomal DNA polymorphism and electrophoretic enzyme polymorphism in Yersinia.

Ribosomal DNA (rDNA) polymorphism was compared with electrophoretic enzyme polymorphism for the intra- and interspecies differentiation of Yersinia enterocolitica, Y. pseudotuberculosis, Y. intermedia, Y. aldovae, Y. frederiksenii and Y. kristensenii. DNA from 90 strains previously classified into six zymotypes (Y. enterocolitica and Y. frederiksenii) and into distinct enzyme electrophoretic patterns (the four other species) was digested with EcoRI or HindIII and analysed by Southern blotting. The six species were clearly differentiated from each other. In Y. enterocolitica, the subclassification of biotype 1 into zymotypes 1A and 1B was also reflected in the rDNA and the four other bio-zymotypes gave four different classes of restriction pattern. In Y. frederiksenii, both EcoRI and HindIII gave five distinct riboclasses which correlated with the zymotypes. In the four other species, the phenotype polymorphism appeared to be better correlated with the restriction fragment length polymorphism data in some enzymes than others. The data demonstrate that the inter- and intraspecies classification by rDNA polymorphism using two restriction enzymes is similar to that based on electrophoretic enzyme polymorphism. The analysis could be refined for taxonomic and epidemiological purposes by using other restriction enzymes.

DNA, Bacterial↗

PubMed1990

Electrophoretic type B2 of carboxylesterase B for characterisation of highly pathogenic Escherichia coli strains from extra-intestinal infections.

The frequency of electrophoretic types B1 (fast mobilities) and B2 (slow mobilities) of carboxylesterase B, and alpha-haemolysin and mannose-resistant haemagglutinin (MRHA) production were compared in 705 strains of Escherichia coli isolated from cases of septicaemia, urinary tract infection (UTI) and other extra-intestinal infections from different geographical origins, in particular France, America (USA and Canada) and Oceania (Australia and New Zealand). In all groups of strains, whether classified according to their clinical or their geographical origin, electrophoretic type B2 was phenotypically linked with alpha-haemolysin and MRHA production. Haemolytic type B2 strains were isolated more frequently from France and Oceania than America whereas the proportions demonstrating production of MRHA were similar among the three groups. Type B2 strains were more frequently isolated from UTI and other infections than from septicaemia. This is attributed to the high frequency of immunocompromised subjects in the septicaemia group. Our results establish the suitability of using the type B2 of carboxylesterase B as a molecular marker for highly pathogenic E. coli strains implicated in extra-intestinal infections in man.

Australia↗

PubMed1990

Factors and markers of virulence in Escherichia coli from human septicemia.

One hundred Escherichia coli isolates from human septicemia were characterized with respect to O serogroups 1, 2, 4, 6, 7, 8, 15, 18, 75 and 78, alpha-hemolysin, carboxylesterase B typing, cytotoxic necrotizing factor, F165 and CS31A fimbrial antigens, aerobactin production, colicins, and antibiotic sensitivity. A factorial analysis of correspondence and chi 2 tests indicated that most of E. coli isolates belonging to the studied O serogroups were positive for the virulence factors or markers alpha-haemolysin, carboxylesterase B2 type, cytotoxic necrotizing factor, F165 fimbrial antigen and were antibiotic-sensitive (Group I). These characteristics differentiated them from E. coli isolates from other O serogroups which were generally antibiotic resistant and negative for the cited virulence factors and markers (Group II). Aerobactin and colicin production did not differentiate the two E. coli groups. E. coli O serogroups 4 and 6 were highly represented in group I and were responsible for most of the differences between the two groups.

Anti-Bacterial Agents↗

PubMed1990

[Seal of composite resin fillings].

The daily use of composite resins, the rapid evolution in their composition and that of adhesives, as well as the defects in their dimensional stability on setting, led us to carry out this study on the sealing ability of modern bonded aesthetic fillings by measurement of the thickness of the dentine-filling hiatus. In vitro, category V dental fillings are made then sectioned, polished, dyed and observed under optic microscopy. Penetration of the dyeing agent unto the outer two-thirds of the fillings proves the lack of tightness. Enamel-composite limits are almost always acceptable. The dentine-composite hiatus measures between 4 and 8 micrometers on average with the use of new adhesives (from 1 to 10 micrometers maximum). This represents a substantial improvement in comparison to the old generation of adhesives which allowed hiatuses of 10 to 50 micrometers to show. No particular product of the new generation showed to be better in this study.

Composite Resins↗

PubMed1990

[Reconstruction of pulpectomized teeth].

The general principles governing the choice of materials for reconstruction of devitalized teeth are determined on the basis of mechanical and biological imperatives as well as degradation phenomena. In describing the various techniques for clinical implementation, particular emphasis is placed on the imperatives and limitations of each protocol. A decisive factor in the durability of restorations is their homogeneity, as well as the clinical conditions under which they are performed.

Dental Materials↗

PubMed1989

A simple, sensitive method of analyzing bacterial ribosomal DNA polymorphism.

A rapid DNA extraction procedure and random primer labelling of Escherichia coli ribosomal RNA with cloned reverse transcriptase have been used to establish a simple and highly sensitive method for studying ribosomal DNA polymorphism in bacteria. Examples of inter- and intraspecies differentiation of bacteria are given and potential applications in bacterial epidemiology and taxonomy are discussed.

Acinetobacter↗

PubMed1989

Characterization of bacterial genospecies by computer-assisted statistical analysis of enzyme electrophoretic data.

A computer-assisted statistical treatment of the electrophoretic data obtained from the analysis of two dehydrogenases and 27 kinds of esterases produced by strains belonging to the taxonomically complex genus Acinetobacter is described. The 12 genospecies were clearly separated from each other by correspondence analysis. For each genospecies the distances of the strains from their barycenter were computed and typical isolates suitable for use as reference strains were determined. This approach is suitable for the systematic study of other procaryotic or eucaryotic organisms.

Acinetobacter↗