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J M Fournier

Publications and source records attributed to J M Fournier.

At least 37 records · Page 2Linked to original sources
PubMed1997

Regulation of Staphylococcus aureus capsular polysaccharide type 5: CO2 inhibition in vitro and in vivo.

Staphylococcus aureus capsular polysaccharide type 5 (CP5) expression was investigated in lung tissue and nasal polyps of two cystic fibrosis (CF) patients, in rats, and in vitro using ELISA and IFA. In CF tissues, S. aureus expressed protein A and teichoic acid but only 1%-5% of cells expressed CP5. When rats were challenged with CP5-positive S. aureus in the granuloma pouch model, only 1%-5% of CP5-positive cells were detectable in pouch exudates. CF and pouch isolates, however, reexpressed CP5 (70%-90% of cells) when grown in vitro with air. Addition of > or = 1% CO2 to air or to O2/N2 gas mixtures reduced CP5 expression significantly (P < .001) in a dose-dependent manner (6%-1% CP5-positive cells). The results show that S. aureus does not produce CP5 in CF airways and in rat granuloma pouches and that CO2 is an environmental signal that regulates CP5 expression.

Animals↗
PubMed1997

[Regulation of Staphylococcus aureus capsular polysaccharide type 5: in vitro and in vivo inhibition by CO2].

Staphylococcus aureus capsular polysaccharide type 5 (CP5) expression was investigated in lung tissue and nasal polyps of two cystic fibrosis (CF) patients, in rats and in vitro using ELISA and immunofluorescence. In CF tissues, S. aureus expressed protein A and teichoic acid but only 1-5% of cells expressed CP5. When rats were challenged with CP5-positive S. aureus in the granuloma pouch model, only 1-5% CP5-positive cells were detectable in pouch exsudates. CF and pouch isolates, however, re-expressed CP5 (70-90% of cells) when grown in vitro with air. Addition of 1% CO2 or more to air or to O2/N2 gas mixtures reduced CP5 expression significantly (p < 0.001) in a dose-dependent manner (1-6% CP5-positive cells). The results show that S. aureus does not produce CP5 in CF airways and in rat granuloma pouches and that CO2 is an environmental signal which regulates CP5 expression.

Adult↗
PubMed1996

Respiratory activity is essential for post-exponential-phase production of type 5 capsular polysaccharide by Staphylococcus aureus.

Capsule formation is believed to have a significant role in bacterial virulence. To examine the possible involvement of capsular polysaccharide (CP) from Staphylococcus aureus in the pathological mechanisms associated with staphylococcal infections, we investigated the influence of respiratory activity on type 5 CP production by S. aureus grown in the presence of various concentrations of dissolved oxygen or nitrate. The effects of several metabolic inhibitors (arsenite, cyanide, azide, trimethylamine N-oxide, 2-heptyl-4-hydroxyquinoline N-oxide, and 2,4-dinitrophenol) were also tested. The metabolism of the bacteria was estimated by measuring their reductive capacity and by monitoring the pH and concentrations of fermentation products. Type 5 CP was always produced by S. aureus during the exponential phase of growth under all culture conditions tested. In contrast, post-exponential-phase CP production appeared to be strictly dependent on the respiratory activity. Since post-exponential-phase CP production contributes at least two-thirds of the total CP obtained, the influence of S. aureus respiration on CP production might be of some importance in the process of infection.

Antimetabolites↗
PubMed1994

Epidemiology of Staphylococcus aureus in patients with cystic fibrosis.

Seven hundred and thirty-four isolates of Staphylococcus aureus, recovered from the sputum of 238 cystic fibrosis patients in six French hospitals, were characterized by esterase electrophoretic typing, capsular polysaccharide serotyping and phage typing and tested against 14 antibiotics for sensitivity. Thirty-four esterase electrophoretic types were found with a genotypic diversity coefficient of 0.91. Five hundred and forty-eight (78.7%) isolates produced capsular polysaccharide and 350 (50.3%) were type 8. Four hundred and sixty isolates (66.6%) were phage typable and 202 (28.2%) were lysed by group III bacteriophages. No esterase electrophoretic type, capsular type or phage type was specific to cystic fibrosis. Isolates belonged to a wide range of types, similar to strains acquired outside hospitals. Eighty-five patients had three or more consecutive isolates over at least 6 months. The ability of S. aureus to persist for long periods of time has been demonstrated in 73% of them. Methicillin-resistance was encountered among 73 strains (9.8%) which were also multiresistant. Two hundred and eighty-nine (39.9%) strains were sensitive to all antibiotics tested except to penicillin. Pristinamycin and co-trimoxazole were the most effective antibiotics. These results could contribute to the elaboration of a rational approach to the prophylaxis and therapy of respiratory staphylococcal infections in cystic fibrosis patients.

Bacterial Capsules↗
PubMed1994

The novel epidemic strain O139 is closely related to the pandemic strain O1 of Vibrio cholerae.

A new Vibrio cholerae serogroup O139 strain of unknown origin recently emerged in India and Bangladesh, causing a major outbreak of cholera. The genetic relationship between this epidemic strain and the O1 strain responsible for the 7th pandemic of cholera was studied by analyzing the DNA polymorphism of V. cholerae by pulsed-field gel electrophoresis and arbitrarily primed polymerase chain reaction. The restriction patterns of the reference strain O139 Bengal and 10 wild O139 strains isolated early in the Indian outbreak strikingly resemble that of the pandemic O1 strain of V. cholerae El Tor, thus suggesting a close genetic relationship among these strains. This similarity contrasts with the genetic heterogeneity of sporadic non-O1 strains isolated in various parts of the world. Study results strongly suggest that the new epidemic O139 strain is closely related to and might be derived from the pandemic O1 strain of V. cholerae.

Bangladesh↗
PubMed1994

[Value of vibriocidal antibody research in endemic areas of Vibrio cholerae 0:1].

We made vibriocidal antibody titration in the serum of some populations in Algeria and in Mali either during or between cholera epidemics. The seropositivity rate was 43.3% in healthy contacts in Alger in 1990 during an epidemic of cholera. For 12/16 healthy contacts examined two times in a 25-day interval, the seropositivity rate increased during the epidemic and the mean of antibody titres rose 8.88 folds. In Constantine, 53% of 195 blood donors had significant titres of vibriocidal antibodies in 1992, 6 years after an epidemic of cholera. The seropositivity rate in population seemed decreasing during this year. In Bamako, 46% of selected patients had significant vibriocidal antibody titres 8 years after the last epidemic of cholera in Mali. Seven of 10 children born after the epidemic had vibriocidal antibodies. These data confirm the persistence of vibriocidal antibodies in population during many years. The importance of the seropositivity rate in healthy contacts and in children born during a non epidemic period shows that asymptomatic infection is frequent and that Vibrio cholerae O:1 may be circulating in population between epidemics. As part of surveillance of cholera outbreaks in endemic areas, it might be of interest to study on a regular basis the vibriocidal antibody seropositivity rate in populations.

Adolescent↗
PubMed1994

[In vitro sensitivity of Vibrio cholerae serotype 0:139 to an intestinal antiseptic tiliquinol-tilbroquinol combination].

O:139 is a new serotype of Vibrio cholerae that is not agglutinated by an O:1 antiserum but causes epidemics of cholera. Strains of O:139 serotype are resistant to O/129 compound and many antibiotics but are sensitive to tetracyclines and tiliquinol-tilbroquinol (Intétrix). The clinical management of the patients infected with serotype O:139 is identical to that of usual choleric patients. However, the immunological difference with O:1 serotype must lead to reconsider both the diagnosis and the vaccinating strategies of cholera.

Anti-Infective Agents, Local↗
PubMed1993

Involvement of the accessory gene regulator (agr) in expression of type 5 capsular polysaccharide by Staphylococcus aureus.

The effect of an agr mutation on expression of type 5 capsular polysaccharide (CP) by Staphylococcus aureus Newman was investigated in different complex and synthetic media. CP expression by the agr mutant was strongly reduced in certain media but slightly in others, indicating that CP synthesis is positively controlled by agr. CP expression occurred in the post-exponential growth phase in both wild-type and mutant strains, suggesting that other regulatory systems could act in conjunction with agr.

Bacterial Capsules↗
PubMed1993

Comparison of various methods and reagents for species identification of Staphylococcus aureus positive or negative for the mecA gene.

The reliability of various methods for species identification of Staphylococcus aureus was evaluated. A total of 135 coagulase-positive (SA) or -negative (SS) staphylococcal isolates were tested, including methicillin-resistant (MR) and -susceptible (MS) strains. When the nuc gene which encodes the S. aureus thermonuclease (TNase) was amplified in a multiplex PCR simultaneously with the mecA gene which encodes for the MR-associated penicillin-binding protein 2a of staphylococci, the nuc amplification showed full agreement with the results of the coagulase test. TNase detected by an enzymatic method or as protein in a sandwich ELISA identified S. aureus with nearly the same precision as the PCR. The Staphylase, Monostaph and Staphaurex agglutination kits were all reliable for identification of MSSA, but not for MRSA. Most of the negative MRSA strains were identified by the Pastorex agglutination kit, in which reagents for fibrinogen receptor and protein A detection have been supplemented with antibodies for capsular polysaccharides of the serotypes 5 and 8. These results show that detection of the nuc gene or its TNase product is highly reliable for identification of both MRSA and MSSA strains, while various widely used agglutination kits do not show the same reliability for identification of MRSA strains.

Agglutination Tests↗
PubMed1993

Typing of Staphylococcus aureus by pulsed-field gel electrophoresis, zymotyping, capsular typing, and phage typing: resolution of clonal relationships.

Sixty-nine Staphylococcus aureus isolates from two epidemiologically unrelated sources were typed by pulsed-field gel electrophoresis after SmaI digestion of chromosomal DNA (genome typing), and the results were compared with those obtained by other typing methods: phage typing with the international set of phages, capsular serotyping with monoclonal antibodies against capsular polysaccharides type 5 and 8, and zymotyping by polyacrylamide agarose electrophoresis for esterase polymorphism. A good correlation of S. aureus types was found by these four typing methods. Differentiation increased in the order capsular typing < zymotyping < phage typing < genome typing, yielding 2, 10, 20, and 26 different S. aureus types, respectively. Five of the 26 genome types were further divided into several subtypes revealing clonal relationships. When 36 French S. aureus isolates were compared with 33 German S. aureus isolates, 3 strains representing clonal populations were identical in both groups. S. aureus isolates from patients with cystic fibrosis were also typed at the beginning and the end of a 4-week summer camp for these patients. The results suggested a possible strain transmission during the summer camp. We conclude that genome typing by pulsed-field gel electrophoresis is a powerful tool not only for strain identification but also for the resolution of the clonal relationships of S. aureus strains.

Bacterial Typing Techniques↗
PubMed1993

New latex reagent using monoclonal antibodies to capsular polysaccharide for reliable identification of both oxacillin-susceptible and oxacillin-resistant Staphylococcus aureus.

A new latex agglutination test (Pastorex Staph-Plus, Sanofi Diagnostics Pasteur), consisting of a mixture of latex particles coated with fibrinogen and immunoglobulin G for the detection of clumping factor and protein A and latex particles sensitized with monoclonal antibodies directed to Staphylococcus aureus serotype 5 and 8 capsular polysaccharides, was compared with three commercially available rapid agglutination methods for the identification of 220 isolates of S. aureus (61 oxacillin resistant) and 128 isolates of coagulase-negative staphylococci. The sensitivity for identification of S. aureus was high with the Pastorex Staph-Plus test (98.6%) compared with those of the other tests, which ranged from 91.8 to 84.5%. Test sensitivities for the identification of oxacillin-resistant S. aureus were as follows: Pastorex Staph-Plus, 95.1%; Pastorex Staph, 73.8%; Staphyslide, 72.1%; and StaphAurex, 49.2%.

Antibodies, Monoclonal↗
PubMed1993

[Simplified vibriocidal antibody titer performed on a drop of blood].

We report a simplified technique for vibriocidal antibody test in underprivileged people in tropical area. The test is performed on a drop of blood sampled on a disc of blotting paper. It avoid taking of large quantities of blood in timid underfed people who are often solicited. Its reading is rapid and easy by the naked eye owing to staining viable germs violet by the neotetrazolium succinate. Tested in mice and humans, the simplified method gave data well correlated to those obtained with the standard test on serum for vibriocidal titres higher than (or equal to) 1/40.

Animals↗
PubMed1992

Staphylococcal skin colonization in children with atopic dermatitis: prevalence, persistence, and transmission of toxigenic and nontoxigenic strains.

Staphylococcal skin colonization is a common feature of atopic dermatitis (AD) in adults. Little is known about prevalence and persistence of staphylococci in children. Forty-one AD children (mean age, 70 months) and 41 age-matched controls were studied. S. aureus was isolated from 38 AD patients (93%; 32% of controls, P less than .001) and 37% of AD patients (5% of controls, P less than .001) harbored toxigenic (enterotoxins, toxic shock syndrome toxin) S. aureus strains. No individual biotype prevailed. On follow-up (mean interval, 9 months), 70% of S. aureus strains were reisolated. Nasal and cutaneous S. aureus strains were identical in 73% of AD patients (7% of controls, P less than .001), reflecting increased self-contamination. Identical staphylococcal strains in AD children and their mothers were observed in 38% (S. aureus) and 16% (coagulase-negative strains; P less than .001). The prevalence of staphylococcal colonization in AD children is comparable to that in adults. High rates of self-contamination, transmission to contacts, and prevalence of toxigenic strains in AD children may have clinical and epidemiologic implications.

Adolescent↗
PubMed1992

[Resistance of Vibrio cholerae 0:1 to the 0/129 compound and multiresistance to antibiotics].

The authors present a study of the in vitro susceptibility to O/129 compound and usual antibiotics of 29 strains of V. cholerae O:1 biotype El Tor isolated during epidemics in miscellaneous countries over the world from 1982 to 1991. Several identical isolates from the same epidemic are represented by one strain. Susceptibility testing by diffusion method and MICs by agar dilution method are used. The data show that the resistance to O/129 compound is often associated with the resistance to usual antibiotics such as trimethoprim, sulphonamides, chloramphenicol, ampicillin and tetracycline. This resistance to the vibrostatic compound leads to a double problem of diagnosis and therapy. The nitrofuranes derivatives and tiliquinol-tilbroquinol association, an intestinal antiseptic, are the most active antimicrobial agents as well on the strains O/129 sensitive as on the strains O/129 resistant.

Anti-Bacterial Agents↗
PubMed1991

Diagnosing Staphylococcus aureus endocarditis by detecting antibodies against S. aureus capsular polysaccharide types 5 and 8.

Consecutive serum samples from patients with Staphylococcus aureus endocarditis or septicemia or non-S. aureus endocarditis and febrile nonsepticemic controls were tested for antibodies against S. aureus capsular polysaccharide (CP) types 5 and 8 by ELISA. The upper normal antibody levels were defined as the upper 99.5% confidence limits of the values from the febrile controls. All available patient isolates were tested for the presence of CP type 5 or 8 (85% of the isolates expressed either serotype), and all five patients with S. aureus endocarditis had positive antibody levels against the corresponding serotype within the first 10 days of infection. Three other endocarditis patients lacked isolates for CP testing but two of these were positive. Positive antibody levels were found in 0 of 28 septicemia patients, in 1 of 12 non-S. aureus endocarditis patients, and in 3 of 37 febrile controls. Thus, testing for anti-CP 5 or 8 antibodies, especially together with CP serotyping of the patient's isolate, seems to provide important information in the differential diagnosis of endocarditis in patients with S. aureus septicemia.

Antibodies, Bacterial↗