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Biomedical subjects

F Grimont

Publications and source records attributed to F Grimont.

At least 73 records · Page 4Linked to original sources

DNA fingerprinting of Chlamydia trachomatis by use of ribosomal RNA, oligonucleotide and randomly cloned DNA probes.

DNA fingerprinting of 15 reference strains and 24 clinical isolates of Chlamydia trachomatis, 2 strains of C. psittaci and one strain of C. pneumoniae was studied by use of universal 16 + 23S RNA from Escherichia coli, 16S rDNA-directed oligonucleotide and randomly cloned chlamydial DNA probes. The rRNA-gene restriction patterns (ribotypes) enabled the differentiation of chlamydial species. Following DNA cleavage by restriction endonuclease PvuII, lymphogranuloma venereum and trachoma biovars of C. trachomatis could be differentiated. An oligonucleotide, designed to hybridize the C. trachomatis 16S rDNA, also allowed for both species-specific identification and biovar typing of C. trachomatis human strains. Molecular typing system using 3 lambda clones containing C. trachomatis serotype E random DNA inserts, combined to ribotyping, revealed 12 groups of variable banding patterns within C. trachomatis, and could provide an alternative epidemiological tool.

Autoradiography↗

Genotypic and phenotypic methods for the investigation of a nosocomial Legionella pneumophila outbreak and efficacy of control measures.

To determine the source of a nosocomial outbreak of Legionella pneumophila serogroup 1 infection and the efficacy of control measures, clinical and environmental isolates were characterized by molecular subtyping and disease surveillance was conducted. The outbreak involved 32 cases (relative risk, 4.0; P less than .001 vs. previous period). Water colonization with L. pneumophila serogroup 1 and patients' exposure to faucet use incriminated the water system as the environmental source. Monoclonal antibody typing showed that patient isolates belonged mainly to type Pontiac and water isolates mainly to type Bellingham (P less than .001). By four genotypic techniques, outbreak-related isolates from patients and the water system were found to be clonally related and distinct from control strains (P less than .001). Heat and UV light treatment of the water system showed a protective efficacy of 88% (95% confidence interval, 75%-94%). These findings indicate that phenotypic variation may interfere with monoclonal antibody typing of legionellae and that waterborne legionellosis can be controlled by physical disinfection.

Belgium↗

Assignment of Listeria grayi and Listeria murrayi to a single species, Listeria grayi, with a revised description of Listeria grayi.

The genomic relatedness between Listeria grayi and Listeria murrayi was reevaluated by using DNA-DNA hybridization, multilocus enzyme electrophoresis, and rRNA restriction fragment length polymorphism techniques. The high levels of similarity observed between the strains of these two species confirmed the data published since 1973 and indicated that they should be considered members of a single species. On grounds of priority, the species should be named L. grayi.

DNA, Bacterial↗

Desulfovibrio longus sp. nov., a sulfate-reducing bacterium isolated from an oil-producing well.

A novel type of sulfate-reducing bacteria with unusual morphology was isolated from an oil-producing well in the Paris Basin. The cells of this bacterium, strain SEBR 2582T (T = type strain), are long, thin, flexible rods, contain desulfoviridin, and are physiologically similar to members of the genus Desulfovibrio. On the basis of 16S rRNA sequence data, this strain should be included in the genus Desulfovibrio. However, strain SEBR 2582T differs from other members of this genus morphologically, physiologically, and phylogenetically. Thus, a new species, Desulfovibrio longus sp. nov., is proposed for this organism.

Base Composition↗

Nosocomial outbreak of acute gastroenteritis in a neonatal intensive care unit in Tunisia caused by multiply drug resistant Salmonella wien producing SHV-2 beta-lactamase.

In a Tunisian hospital 27 babies, including 12 who were premature, in a single intensive care unit suffered acute gastroenteritis in the period from January to May 1988. The mean age at the onset of gastroenteritis was 8.4 days; nine babies died. Salmonella wien was isolated from stools (all babies) and blood (4 babies). It was also isolated from the stools of one nurse and from a mattress. Twelve of the babies had received cefotaxime, which was successfully replaced by oral colimycin. The outbreak was stopped by the implementation of infection control measures. All isolates of Salmonella wien were of the same biotype, and had the same antibiotic resistance pattern (third generation cephalosporins, monobactams, aminoglycosides, chloramphenicol, trimethoprim and sulphonamides) and plasmid DNA restriction pattern. The isolates were all susceptible to a combination of cefotaxime and clavulanic acid (a beta-lactamase inhibitor), which displayed synergy, suggesting the presence of a beta-lactamase (geometric mean MICs 11.24 micrograms/ml for cefotaxime alone and 0.24 micrograms/ml in combination with 0.1 micrograms/ml potassium clavulanate). All isolates produced TEM-1 and SHV-2 beta-lactamase which was not transferable to Escherichia coli by conjugation. The presence of the SHV-2 enzyme in Salmonella wien may allow it to adapt to newer beta-lactams which is a cause for concern in this hospital.

Acute Disease↗

An outbreak of pneumonia and meningitis caused by a previously undescribed gram-negative bacterium in a hot spring spa.

An outbreak of infection caused by a previously undescribed Gram-negative bacterium affected people attending a hot (37 degrees C) spring spa in France in 1987. Thirty-five case of pneumonia and two cases of meningitis occurred. None of these patients died. Attack rates were significantly higher for patients above 70 years old and for male patients. An epidemiological comparison of the 26 hospitalized cases with 52 matched controls suggests that spa treatment early on the first day (OR = 4.8) and attendance at the vapour baths (OR = 10.7) were significant risk factors for acquiring the infection. Person-to-person spread was not thought to have occurred. The same bacterium was isolated from the hot spring water. All strains studied shows a single rRNA gene restriction pattern. Epidemiological data indicated that the thermal water was the source of infection. This outbreak stresses the need for increased surveillance of infections in people attending hot spring spas.

Aged↗

Intraspecies variations in nutritionally variant streptococci: rRNA gene restriction patterns of Streptococcus defectivus and Streptococcus adjacens.

The rRNA gene restriction patterns of two species of nutritionally variant streptococci, Streptococcus defectivus and Streptococcus adjacens, were determined, and the results were compared with the electrophoretic migration profiles of penicillin-binding proteins. Reference strains belonging to various streptococcal species were used as controls. Our results correlated with the results of DNA-DNA hybridization experiments and confirmed the delineation of these two species. Moreover, they demonstrated that intraspecies variations occur and suggested that there are two subspecies of S. defectivus.

Genetic Variation↗

Outbreak of gut colonization by Pseudomonas aeruginosa in immunocompromised children undergoing total digestive decontamination: analysis by pulsed-field electrophoresis.

We analyzed an outbreak of gut colonization by Pseudomonas aeruginosa occurring in an intensive care hematology unit by using conventional typing methods and pulsed-field electrophoresis. In October and November 1989, the feces of four immunocompromised children undergoing total digestive decontamination were colonized by P. aeruginosa. Ten isolates were obtained from the gut flora in pure culture. Retrospective investigations found that one P. aeruginosa isolate from stools of one of the patients was already present at high counts 6 months before the outbreak. This patient had been discharged from the unit in May 1989 and had been readmitted concomitantly with the outbreak. Only pulsed-field electrophoresis could demonstrate that a single epidemic strain was present in the fecal flora of the children. This strain had probably been brought into the unit by the patient with chronic fecal carriage.

Anti-Bacterial Agents↗

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↗

rRNA gene restriction patterns of Leptospira: a molecular typing system.

A total of 67 serovar reference strains and 7 isolates belonging to the genus Leptospira were characterized by ribosomal ribonucleic acid (rRNA) gene restriction patterns. Fifty patterns were observed. Strains belonging to different genomic species always gave different patterns. However, genomic species were subdivided into several patterns. Forty-three serovars gave a specific pattern. Some serovars could not be separated by rRNA gene restriction patterns: strains of serovars icterohaemorrhagiae, copenhageni, lai, pyrogenes and jalna gave pattern 1; serovars birkini, mankarso and wolffi gave pattern 4; serovars canicola, gem, hebdomadis, pomona and hardjo (strain hardjoprajitno) gave pattern 12; serovars valbuzzi and zanoni gave pattern 14; serovars jonsis, malaya and sumneri gave pattern 16; serovars arborea, ballum, castellonis and kenya gave pattern 35; and serovars borincana and shermani gave pattern 43. These data provide the bases for a molecular typing system for the genus Leptospira.

Bacterial Typing Techniques↗

Two genomic species in Borrelia burgdorferi.

A total of 13 Borrelia burgdorferi strains (responsible for Lyme borreliosis) and representatives of 3 other Borrelia species (B. hermsii, B. parkeri, B. turicatae) associated with relapsing fever were studied by DNA/DNA hybridization and rRNA gene-restriction patterns. Two genomic DNA hybridization groups were observed which could be differentiated by rRNA gene-restriction patterns. Moreover, the number and size of restriction fragments suggest the existence of a single set of 16 and 23 S rRNA genes in Borrelia.

Borrelia burgdorferi Group↗

Molecular typing of nosocomial isolates of Legionella pneumophila serogroup 3.

In Paris, France, an outbreak of pneumonia due to Legionella pneumophila serogroup 3 was observed in Necker (four cases) and Pitié (six cases) hospitals. Neither the 10 clinical isolates nor 5 tap water isolates from Necker Hospital harbored plasmids. Clinical and environmental serogroup 3 isolates and serogroup 3 reference strain Bloomington 2 were analyzed by chromosomal probe fingerprinting. rRNA, 16S and 23S from Escherichia coli and a randomly cloned 15-kilobase-pair nucleotide sequence from L. pneumophila serogroup 3 were used as probes. All strains tested showed a single pattern after HindIII digestion of DNA and hybridization with the 32P-end-labeled rRNA probe, whereas three patterns were obtained after hybridization with the 32P-labeled 15-kilobase-pair DNA probe. One pattern was given by all clinical and tap water isolates from Necker Hospital, another one was given by all clinical isolates from Pitié Hospital, and a last one was given by reference strain Bloomington 2. Thus, molecular analysis showed that the two hospital outbreaks of legionellosis were unrelated and could link the outbreak in Necker Hospital to contaminated tap water.

Bacterial Typing Techniques↗

Stability of conjugative and non-conjugative R-plasmids from Serratia marcescens to gyrase inhibitors.

The stability of conjugative and non-conjugative R-plasmids was compared using two gyrase inhibitors (novobiocin and ciprofloxacin). Conjugative R-plasmids from eighteen ticarcillin resistant Serratia marcescens were more stable than non-conjugative R-plasmids from eleven ticarcillin resistant bacteria of the same species. Moreover, novobiocin (gyrase B sub-unit inhibitor) is a better curing agent than ciprofloxacin (A sub-unit inhibitor).

Ciprofloxacin↗

Acetylaminofluorene-labelled ribosomal RNA for use in molecular epidemiology and taxonomy.

The use of acetylaminofluorene-labelled 16 + 23S rRNA (from Escherichia coli) is described for determining rRNA-gene-restriction patterns. The labelled probe allowed molecular fingerprinting of bacteria belonging to diverse phylogenetic branches (Enterobacteriaceae, Haemophilus, Pseudomonas, Acinetobacter, Brucella, Leptospira, Cytophaga, Campylobacter, Methylophaga). The labelled probe can be stored frozen (-20 degrees C) for at least a year and can endure vacuum dessication, ethanol precipitation or lyophilization.

2-Acetylaminofluorene↗

Legionella gratiana sp. nov. isolated from French spa water.

During an epidemiologic survey, an unidentified strain of Legionella was isolated from water of a thermal spa in France. The strain (Lyon 8420412) had the cultural and biochemical characteristics typical of the genus Legionella. In direct immunofluorescence tests, the strain reacted weakly with fluorescein-conjugated antisera prepared against L. bozemanii serogroups 1 and 2, L. longbeachae serogroups 1 and 2 and L. anisa, and failed to react with sera prepared against 36 other species or serogroups. A fluorescein-conjugated antiserum prepared against strain Lyon 8420412 reacted strongly with the homologous strain and only weakly with the above-mentioned species. The cell-wall fatty acid profile, with a predominance of hexadecenoic (16:1) and hexadecanoic (16:0) acids, ubiquinone Q10 as the major quinone and a characteristic protein electrophoresis profile suggested that the isolate was different from other Legionella species. In DNA-DNA hybridization experiments, the strain was distinct from all named Legionella species, and from all unnamed species currently under study at the Centers for Disease Control. The name Legionella gratiana is proposed for the new species (type strain Lyon 8420412; CDC 1242). A serologic survey of antibodies reacting against L. gratiana indicated that personnel or patients at the spa therapy centre where the organism was isolated had higher antibody titres than a control population.

Antibodies↗

Characterization of Staphylococcus species by ribosomal RNA gene restriction patterns.

The rRNA gene restriction pattern sof 110 strains belonging to 12 staphylococcal species have been determined. The strains, isolated from various sources, were epidemiologically unrelated. Total DNA was cleaved with restriction enzymes HindIII and EcoRI, electrophoretically separated and probed with radiolabelled 16S rDNA from Bacillus subtilis inserted in a plasmid vector, pBR322. Fourty-four distinct HindIII patterns and 44 distinct EcoRI patterns were observed. Strains belonging to different species had different patterns. Although distinct patterns were also observed with some species, a core of common bands could be discerned within each species or subspecies. Analysis of the patterns revealed two taxa in Staphylococcus xylosus which were not evident using phenotypic characteristics. Of 18 strains which were difficult to identify using phenotypic schemes, 15 showed patterns typical of known species. The three remaining atypical strains showed unusual patterns and may belong either to a known species, not included in the study, or to a new species. Since various patterns were observed within some species (e.g.S.aureus and S. epidermidis), rRNA gene restriction patterns may have epidemiological, as well as taxonomic interest.

Animals↗

Recurrent peritonitis caused by Serratia marcescens in a diabetic patient receiving continuous ambulatory peritoneal dialysis.

A diabetic patient treated by continuous ambulatory peritoneal dialysis for end-stage renal failure had recurrent peritonitis caused by Serratia marcescens. Thirty-eight isolates of S. marcescens recovered over a 14-month period from peritoneal-dialysis effluent, catheter tips and catheter-exit sites were biotyped and serotyped. The finding that most (90%) of these isolates belonged to the same biotype and serotype suggested that the patient had relapsing infections with the same strain. Similar isolates were recovered from the peritoneal dialysates of another two patients in the same ward, neither of whom developed Serratia-associated peritonitis.

Catheters, Indwelling↗