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Y Michel-Briand

Publications and source records attributed to Y Michel-Briand.

At least 19 recordsLinked to original sources
PubMed1999

Uptake of pyocin S3 occurs through the outer membrane ferripyoverdine type II receptor of Pseudomonas aeruginosa.

Pyocin S3 was found to kill exclusively Pseudomonas aeruginosa isolates producing type II pyoverdine (exemplified by strain ATCC 27853). Killing was specifically inhibited by addition of type II ferripyoverdine. All Tn5 mutants resistant to pyocin S3 were defective for pyoverdine-mediated iron uptake and failed to produce an 85-kDa iron-repressed outer membrane protein. We conclude that this protein is probably the type II ferripyoverdine receptor that is used by pyocin S3 to gain entry into the cell.

Bacterial Outer Membrane Proteins↗
PubMed1997

Dechlorination of Atrazine by a Rhizobium sp. Isolate.

A Rhizobium sp. strain, named PATR, was isolated from an agricultural soil and found to actively degrade the herbicide atrazine. Incubation of PATR in a basal liquid medium containing 30 mg of atrazine liter(sup-1) resulted in the rapid consumption of the herbicide and the accumulation of hydroxyatrazine as the only metabolite detected after 8 days of culture. Experiments performed with ring-labeled [(sup14)C]atrazine indicated no mineralization. The enzyme responsible for the hydroxylation of atrazine was partially purified and found to consist of four 50-kDa subunits. Its synthesis in PATR was constitutive. This new atrazine hydrolase demonstrated 92% sequence identity through a 24-amino-acid fragment with atrazine chlorohydrolase AtzA produced by Pseudomonas sp. strain ADP.

Journal Article↗
PubMed1997

Genotypic analysis of Burkholderia cepacia isolates from 13 French cystic fibrosis centers.

Burkholderia cepacia has been involved in outbreaks of pulmonary infection among patients with cystic fibrosis (CF), and the spread of a highly transmissible clone has been reported throughout the United Kingdom and Canada. These data prompted a DNA-based typing study of the strains recovered in French CF centers. Ninety-five isolates recovered from 71 patients attending 13 CF centers in 9 regions of France were characterized by randomly amplified polymorphic DNA (RAPD) analysis and pulsed-field gel electrophoresis (PFGE). Twenty-one genotypes were identified among the 95 isolates, and the results of RAPD and PFGE were concordant for 89 isolates (94%). Cross-colonization was demonstrated in 7 of the 13 CF centers. The investigation of serial isolates showed that most chronically colonized patients harbored a single B. cepacia strain. A geographically clustered distribution of B. cepacia genotypes was observed, except for one genotype, which was detected in four regions but was proven to be different from the genotype of the British-Canadian highly transmissible strain. The present study confirms the ability of B. cepacia to spread among CF communities in France and the importance of epidemiological surveys in the institution of prevention policies.

Bacterial Typing Techniques↗
PubMed1996

Discriminatory power and usefulness of pulsed-field gel electrophoresis in epidemiological studies of Pseudomonas aeruginosa.

We assessed the discriminatory power of pulsed-field gel electrophoresis (PFGE) for the analysis of DNA restriction fragment length polymorphism (RFLP) in Pseudomonas aeruginosa. We determined DraI PFGE-RFLP of DNA of unrelated clinical and environmental strains, and clinical strains isolated from two intensive care units of the Besançon University Hospital. The typeability and reproducibility was 100%. The discriminatory index was 0.998, and the DNA patterns were stable in vitro and in vivo. There was a very low correlation between PFGE-RFLP and traditional typing methods. The typeability, reproducibility, the high discriminatory power and the stability of PFGE-RFLP make this a valuable method to be used in conjunction with serotyping. Further standardization and quantitative interpretation are possible and should lead to this technique becoming a library typing system.

Bacterial Typing Techniques↗
PubMed1996

Pulsed-field gel electrophoresis as an epidemiological tool for clonal identification of Aeromonas hydrophila.

Pulsed-field gel electrophoresis (PFGE) was used to characterize Aeromonas hydrophila strains isolated from a cluster of hospital-acquired infections that occurred over approximately 1 month in a French hospital. Five isolates from patients and 10 isolates from the water supply were characterized by biotyping and antibiotic susceptibility patterns and compared with 10 epidemiologically unrelated strains isolated from patients and rivers, by PFGE of digests of chromosomal DNA. Five environmental and four clinical isolates belonged to the same biotype and antibiotic susceptibility pattern type. The endonucleases XbaI, SpeI and SwaI gave satisfactory profiles whereas DraI did not. The profiles were stable, reproducible and discriminatory. The 10 epidemiologically unrelated strains exhibited 10 different patterns after digestion with XbaI, the least expensive, suitable endonuclease. PFGE is a rapid and discriminatory technique for the typing of Aeromonas hydrophila where a common origin of infection is suspected.

Aeromonas hydrophila↗
PubMed1995

Molecular characterization of pyocin S3, a novel S-type pyocin from Pseudomonas aeruginosa.

The genetic determinant for the soluble pyocin S3 was isolated from a genomic library constructed in the plasmid pGV1122, of Pseudomonas aeruginosa strain P12 isolated from a cystic fibrosis patient. The nucleotide sequence of a 3270-base pair DNA fragment was determined, and the two structural genes, pyoS3A and pyoS3I, and the 3'- and 5'-flanking regions were localized. Transcription (Northern blot) analysis showed that the two genes were co-transcribed. The genes pyoS3A and pyoS3I code for polypeptides of 767 and 154 amino acids, respectively, with calculated molecular weights of 81,385 and 17,047. Pyocin S3 was produced in Escherichia coli from a plasmid and purified as a complex of two components (S3A and S3I) corresponding to the pyoS3A and pyoS3I gene products, respectively. The S3A component, like pyocin S3, had a killing effect involving DNase activity and was inhibited by the S3I protein. Comparisons of the predicted amino acid sequence of the two components of pyocin S3 to those of pyocins S1, S2, and AP41 indicate that pyocin S3 is a new type of S-type pyocin.

Amino Acid Sequence↗
PubMed1995

[Listeriosis in patients with malignant hemopathy. 3 cases in the same hospital ward].

During the listeriosis epidemic which occurred in France in the summer 1992, three patients with malignant haematopathies hospitalized in our service contracted the disease. Although the retrospective investigations were hindered by the variable incubation period and the impossibility of examining the foods eaten at the time of infection, there was a high probability that two of the patients had been infected by cooked ham and dairy products at home. The third patient was apparently infected in hospital with well-cooked food found to be contaminated. The hypothesis of coinfection has been raised.

Aged↗
PubMed1995

Risk factors for nosocomial colonization with multiresistant Acinetobacter baumannii.

A six-month prospective survey was carried out in a university hospital to assess the incidence of Acinetobacter baumannii cross-contamination and to identify risk factors for colonization. Clinical isolates obtained during the study period were biotyped and genotyped by pulsed-field gel electrophoresis after ApaI macrorestriction of total DNA. Case-control univariate and multivariate analyses were performed to identify risk factors for Acinetobacter baumannii colonization. One hundred forty-seven patients hospitalized in 36 units were colonized or infected, of whom 52 were in three intensive care units. The urinary (29%) and bronchopulmonary tracts (26%) were the most frequently colonized sites. Nine major restriction patterns were identified: two were exhibited by epidemic multi-resistant strains of biotype 9 which were isolated from 65 patients hospitalized in ten units. Multivariate analysis showed that case-patients were (a) more likely than non-infected controls to be male, to have been previously hospitalized in another unit and to have had longer stays in the unit before colonization and hyperalimentation; and (b) more likely than controls colonized with other gram-negative bacilli to be male, to have had longer hospitalization, to have received treatment with third-generation cephalosporins and to have had a urinary catheter. The high incidence of colonization with Acinetobacter baumannii can thus be attributed to frequent cross-contamination and the use of broad-spectrum antibiotics. Colonized patients appear to be the major source of cross-contamination as epidemic strains spread throughout the hospital.

Acinetobacter Infections↗
PubMed1995

Use of pulsed-field gel electrophoresis for investigation of an outbreak of Clostridium difficile infection among geriatric patients.

A six-month outbreak of Clostridium difficile infection among elderly residents of a middle-term-care facility was investigated. Pulsed-field gel electrophoresis was used to genotype 22 outbreak strains and 30 epidemiologically unrelated strains. A prospective case-control study was conducted to identify risk factors for epidemic Clostridium difficile-associated diarrhea. All epidemiologically unrelated Clostridium difficile strains of the same serogroup could be differentiated by their DNA patterns with two restriction enzymes (SmaI and KspI). Among clustered strains, two epidemic serogroups (C and K) were identified. Two different DNA patterns were identified among serogroup C strains and three among serogroup K strains. Multivariate analysis showed that the risk of Clostridium difficile infection increased with antimicrobial chemotherapy (beta-lactam agents and pristinamycin) and the presence of a feeding tube. This study confirms the high discriminative power of restriction fragment length polymorphism analysis by pulsed-field gel electrophoresis to describe Clostridium difficile epidemiology. The typing results confirm that infection was principally exogenous in this outbreak. Furthermore, they indicate the need to improve all measures limiting transmission of infection.

Aged↗
PubMed1995

Use of pulsed-field gel electrophoresis as an epidemiologic tool during an outbreak of Pseudomonas aeruginosa lung infections in an intensive care unit.

OBJECTIVE: A retrospective study was performed to evaluate the use of DNA polymorphism analysis by pulsed-field gel electrophoresis (PFGE) in assessing the rate of exogenous contamination during an outbreak of Pseudomonas aeruginosa lung infections in an intensive care unit ICU. Another goal was to determine the risk factors, involved in the outbreak. DESIGN: Rectal swabs and tracheal secretions were cultured from all patients upon admission and thereafter once a week throughout their stay in the ICU. Resistance patterns were determined in all P. aeruginosa isolates. We determined the serotypes, pyocin types, plasmid profiles and total DNA macrorestriction patterns for isolates. The restriction fragment length polymorphism (RFLP) of Dra I total DNA digest was studied by PFGE. A retrospective case-control study was performed to determine the risk factors for P. aeruginosa bronchopulmonary colonization. SETTING: The study was carried out in the medical ICU of Besancon University Hospital (France). RESULTS: The typability, stability and reproducibility of phenotypic markers were not completely satisfactory. Only the RFLP profile satisfied all the criteria for a good typing technique. In four of the 17 patients, P. aeruginosa strains with the same DNA pattern were found. Among the previously reported risk factors for hospital-acquired bronchopulmonary infections, only invasive procedures were determined by multivariate analysis to be significant in our study group. The oropharynx and the bronchial tract are the most likely endogenous sources. CONCLUSION: PFGE-RFLP is a valuable tool for the epidemiologic study of P. aeruginosa. This typing method revealed that exogenous contamination is not always the major source of P. aeruginosa lung infections in mechanically ventilated patients in ICUs.

Analysis of Variance↗
PubMed1995

Nasal carriage of Staphylococcus aureus and cross-contamination in a surgical intensive care unit: efficacy of mupirocin ointment.

A six month prospective study was carried out in a surgical intensive care unit (SICU) of a university hospital to assess the incidence and routes of exogenous colonization by Staphylococcus aureus. A total of 157 patients were included in the study. One thousand one hundred and eleven specimens (nasal, surgical wound swabs, tracheal secretions obtained on admission and once a week thereafter, and all clinical specimens) were collected over a four month period from patients without nasal decontamination (A). They were compared with 729 specimens collected over a two month period from patients treated with nasal mupirocin ointment (B). All S. aureus strains were typed by restriction fragment length polymorphism (RFLP) pulsed-field gel electrophoresis after SmaI macrorestriction. The nasal colonization rates on admission were 25.5 and 32.7% in groups A and B, respectively. Thirty-one untreated patients (31.3%) and three patients (5.1%) treated with nasal ointment, acquired the nasal S. aureus in the SICU (P = 0.00027). Nasal carriers were more frequently colonized in the bronchopulmonary tract (Bp) and surgical wound (Sw) (62%) than patients who were not nasal carriers (14%) (P < 0.00001). The patterns were identical for nasal, Bp and Sw strains from the same patient. RFLP analysis characterized seven epidemic strains of methicillin-resistant S. aureus (MRSA) which colonized 60% of group A and 9% of group B patients (P < 0.00001). The bronchopulmonary tract infection rate was reduced in group B (P = 0.032). In conclusion, in an SICU, nasal carriage of S. aureus appeared to be the source of endogenous and cross-colonization. The use of nasal mupirocin ointment reduced the incidence of Bp and Sw colonization, as well as the MRSA infection rate.

Administration, Intranasal↗
PubMed1995

[Organ culture preservation of the human cornea at +31 degrees C and risk of infection].

PURPOSE: In order to reduce the risk of infection, we analyzed each stage of conservation of human cornea in organ culture at +31 degrees C. METHODS: This epidomiological study was conducted in 266 human corneas preserved in organ culture between January 1991 and December 1993. There were 3 stages: In the period of preservation (analysis of the contaminated medium), Before clinical use of the graft (analysis of the preservation medium), After the penetrating keratoplasty (analysis of the corneo-scleral rim and the transportation medium). The bacteriological media used were thioglycolate broth, trypticase soja and Sabouraud. RESULTS: In 266 storage media, 42 (15.7%) cultures are positive. The most commonly found organism was Staphylococcus aureus (21.4%). At the end of the conservation procedure, all of the cultures of the media were sterile (n = 165). After penetrating keratoplasty, 8 cultures were positive for the transportation medium and the corneo-scleral rim (5.1%), 3 cultures were positive for the corneo-scleral rim only (1.9%) and 5 cultures were positive (3.2%) for the transportation medium without contamination of the corneo-scleral rim. CONCLUSION: Preservation at +31 degrees C in organ culture of human corneas allows elimination of the contaminated or potentially contaminant corneas before an eventual transplantation. In our experience, the risk of infection is especially situated in the period of preservation which shows the insuffiency of the decontamination procedures or the antibiotical content of the medium and probably the virulence of the organisms in donors hospitalized for long period.

Anti-Bacterial Agents↗
PubMed1994

Typing of hospital strains of Xanthomonas maltophilia by pulsed-field gel electrophoresis.

We report the use of pulsed-field gel electrophoresis (PFGE) to characterize Xanthomonas maltophilia isolates from an incident of hospital-acquired infection over a 12-day period in a haematological unit. Ten isolates from five patients (from throat, urine, stool and blood) and two isolates from environmental sites in the unit were compared with 10 epidemiologically unrelated clinical strains, isolated over a 3-month period from several units in two hospitals, by PFGE of DraI digests of chromosomal DNA. The profiles obtained were stable, reproducible and discriminatory. The 10 unrelated strains had different DNA profiles. Each of the five patients in the unit was colonized by a different strain and the isolates from a water faucet and a shower pommel had the same DNA profile as the strains of two patients who had used these fittings. A case-controlled study showed that the only factor that correlated with colonization was the origin of the patient from another unit (P = 0.0122). We conclude that PFGE is a rapid and discriminatory technique for the typing of X. maltophilia where a common origin of infection is suspected.

Adult↗
PubMed1994

Replicon typing of 71 multiresistant Serratia marcescens strains.

Replicon typing is the identification of plasmids by hybridization with specific DNA probes which contain the genes involved in plasmid maintenance. This new method has been used to classify plasmids into replicon (rep) groups which can often be correlated with incompatibility (Inc) groups. We studied 71 multiresistant Serratia marcescens strains with 19 rep probes constructed from reference plasmid replicons belonging to known Inc groups. These probes are known to react with enteric bacterial plasmids. However, they did not represent the totality of the thirty known Inc groups. For 52% of the studied strains, plasmids were identified and classified into groups FIB, FIC, FIIA, HI2, L/M, N, B/O, P, W, Y and Com9. Most (79%) of the plasmid preparations hybridized with a single rep probe, and 21% hybridized with two different probes. Electrophoretic analysis of DNA suggested that double hybridization could result from the presence of either two different Inc plasmids in the same strain (e.g. S37) or one single plasmid with a multireplicon (e.g. S113).

Bacterial Typing Techniques↗
PubMed1994

Cloning and characterization of the Inc A/C plasmid RA1 replicon.

The Inc A/C plasmids, like Inc P and Inc Q plasmids, have a broad host range. However, their maintenance functions remain to be studied. An autoreplicative region of 2.79 kb named RepA/C, able to replicate both in the family Enterobacteriaceae and in Pseudomonas spp., was isolated and sequenced. The stability, copy number, and incompatibility expression of this replicon were determined. RepA/C and a nonautoreplicative fragment of 16 kb of this replicon were used as probes and showed specific hybridizations with the Inc P3-A/C plasmids from Pseudomonas spp. and members of the Enterobacteriaceae. These probes could be used as tools for identification of the plasmids of this epidemiologically important Inc group.

Amino Acid Sequence↗