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Biomedical subjects

A Bouvet

Publications and source records attributed to A Bouvet.

At least 19 recordsLinked to original sources
PubMed1995

[Tuberculosis in a Parisian pneumology department: 151 cases].

OBJECTIVES: The incidence of tuberculosis has risen since 1992. We studied cases observed in our department to search for factors favouring this increased incidence. METHODS: A retrospective assessment of 151 cases of tuberculosis observed over a 3 year period in a department of pneumology in Paris was performed. RESULTS: Fifty-two percent of the patients were foreigners; 66% lived in a poor socio-economic environment included 18% with no permanent residence; 29% were alcoholics. An association with human immunodeficiency virus infection was seen in 7% of the cases. Another immunodepression factor was found in 15%. Tuberculosis was discovered in a context of respiratory distress in 7% or the patients. Outcome was fatal in 6%. Three months after diagnosis 22% of the patients were lost to follow-up. CONCLUSION: This series emphasizes the major role of socio-economic factors in the rising incidence of tuberculosis and the need for urgent and adapted measures for therapeutic management in an often non-compliant and socially instable population.

AIDS-Related Opportunistic Infections↗
PubMed1995

Human endocarditis due to nutritionally variant streptococci: streptococcus adjacens and Streptococcus defectivus.

Streptococcus adjacens and S. defectivus are two recently individualized species of viridans streptococci. Both species were previously designated as nutritionally variant streptococci and characterized by their growth as small satellite colonies supported by 'helper' bacteria, or requiring complex media enriched with cysteine or with pyridoxal. Structural abnormalities were observed under these conditions and balanced growth can be obtained only with a semi-chemically defined medium, in which the cells are morphologically normal and exhibit a parietal chromophore. The two species are primarily isolated from the oral cavity, or from intestinal and genito-urinary tracts. They are likely to be responsible for most blood-culture-negative endocarditis and account for more than 4% of streptococcal strains isolated from blood cultures during this disease. Cases of endocarditis caused by these bacteria exhibit much higher rates of failure, relapse and mortality than those due to other viridans streptococci. The slow growth rate of the bacteria and the production of large amounts of exopolysaccharide in vivo may account for the difficulties encountered in treatment and suggest that a longer course of antimicrobial therapy may be required for successful cures. Results obtained from experimental models of endocarditis confirmed the efficacy of vancomycin as an alternative therapy in patients when a combination of penicillin and aminoglycoside is ineffective or contraindicated.

Animals↗
PubMed1995

Analysis of enzymatic activities for differentiation of two species of nutritionally variant streptococci, Streptococcus defectivus and Streptococcus adjacens.

Strains of nutritionally variant streptococci, Streptococcus defectivus (n = 10) and Streptococcus adjacens (n = 20), were studied for the production of glycosidic and proteolytic enzyme activities. S. defectivus strains produced neuraminidase and alpha-fucosidase, while S. adjacens strains produced only neuraminidase. The S. adjacens strains produced a very wide range of proteolytic activities with the ability to hydrolyze the majority of aminopeptidase substrates tested, while S. defectivus strains hydrolyzed only a minority of aminopeptidase substrates. These data provide additional phenotypic characteristics which may be useful in distinguishing between these two species and suggest that they may have different nutritional requirements.

Amino Acid Sequence↗
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

Restricted association between biotypes and serotypes within group A streptococci.

Investigating individual variations between different isolates of group A streptococci, we observed a close correlation between biotypes and serotypes in 46 strains from pharyngitis patients. Biotyping, carried out with a commercially available rapid identification gallery, delineated 10 different associations of characteristics, designated biotypes 1 to 10, observed both in the manufacturer's (127 strains) and our personal (98 strains) collections of group A strains. Only the most frequent biotypes (biotypes 1 to 6) were observed in the pharyngitis cohort, but the overall frequencies of the biotypes did not display striking differences compared with the control collections. Serotyping of the pharyngitis strains showed that each M type was restricted to a sole biotype. For example, M types 1, 4, and 28 were found only in biotype 1 and M type 6 was found only in biotype 6 strains. This association was not due to an epidemiologic bias, since it was also observed in a control series consisting of reference strains and isolates from distant countries (the United States and Czech Republic versus France). An exception was for M type 78, which exhibited biotype 3 or biotype 4. Investigation of the heterogeneity of the strains at the DNA level showed no significant variations of the ribotype patterns between strains of different biotypes, confirming that group A streptococci belong to a unique and homogeneous species. This previously undescribed association between serotypes and biotypes is of interest for a rapid and preliminary characterization of strains isolated in individual patients or during an outbreak. A possible pathogenic association of some biotypic characteristics with specific M proteins is envisaged.

Adolescent↗
PubMed1993

Identification of pig chromosomes in pig-mouse somatic cell hybrid bivariate flow karyotypes.

To identify pig chromosomes in pig-mouse somatic cell hybrids, dual-laser flow karyotypes and GTG-banded metaphase spreads of pig, mouse, and 7 pig-mouse hybrid cell lines were compared. Pig chromosomes no. 1, 2, 5, 6, 10, 11, 13, 14, 16, 18, X and Y were tentatively assigned to individual peaks in the pig flow karyotype on the basis of DNA content vs. relative chromosome length. In the 7 hybrid cell lines, 7 out of 8 peaks distinct from those of the mouse cell line could be correlated with the presence of pig chromosomes no. 5, 9, 10, 11 or 16, 14, 15, and 18, whereas 1 peak appeared to correspond to the presence of 1 middle-size chromosome (3, 4, or 7). Other pig chromosomes present in the hybrids could not be detected with certainty due to superposition with mouse peaks and mouse chromosome rearrangements.

Animals↗
PubMed1992

Efficacy of temafloxacin in experimental Streptococcus adjacens endocarditis and autoradiographic diffusion pattern of [14C]temafloxacin in cardiac vegetations.

Temafloxacin, a new fluoroquinolone, alone or in combination with tobramycin, was compared with penicillin, tobramycin, and their combination in the therapy of rabbits with endocarditis caused by Streptococcus adjacens GaDT, a new species of nutritionally variant streptococci. Animals were injected intramuscularly for 4 days with temafloxacin (50 mg/kg of body weight twice daily [b.i.d.]) alone or combined with tobramycin (12 mg/kg once daily), with procaine penicillin (150,000 U/kg b.i.d.) alone or combined with tobramycin (12 mg/kg once daily), or with tobramycin (12 mg/kg once daily) alone. Another group of animals was treated with a higher dose of temafloxacin (100 mg/kg b.i.d.). Temafloxacin, penicillin, and tobramycin MICs and MBCs were 1 and 2, 0.015 and 1, and 8 and 16 micrograms/ml, respectively. Time-kill curves showed that the addition of tobramycin to penicillin or temafloxacin increased the killing rate. In vivo, treatment with temafloxacin (50 and 100 mg/kg b.i.d.) alone reduced the bacterial counts in vegetations (3.9 +/- 0.9 and 3.1 +/- 0.8 log10 CFU/g of vegetation) compared with those in the vegetations of control animals (7.5 +/- 0.9 log10 CFU/g of vegetation). This result was similar to that obtained with penicillin alone (4.5 +/- 0.8 log10 CFU/g of vegetation). The combination of temafloxacin (50 mg/kg) and tobramycin was as effective as penicillin plus tobramycin (2.5 +/- 0.3 versus 2.3 +/- 0.4 log10 CFU/g of vegetation, respectively). The autoradiographic pattern of [14C]temafloxacin diffusion into infected cardiac vegetations was studied. Thirty minutes after the end of infusion of 250 microCi of [14C]temafloxacin, the [14C]temafloxacin was homogeneously distributed throughout the vegetations. These data support further evaluation of quinolones in experimental endocarditis.

Animals↗
PubMed1992

Heterosynapsis in two fertile but hypoprolific boars carriers of reciprocal translocations.

The authors report here two new cases of reciprocal translocations in two fertile and hypoprolific boars. Silver stained synaptonemal complexes in surface-spread pachytene nuclei from a boar heterozygous for a reciprocal translocation, and from another one carrying two different reciprocal translocations, were analyzed by electron microscopy. In such heterozygotes, cross-shaped quadrivalent configurations are expected to form in order to allow homologous pairing. In the same boar, the lengths of the fully synapsed arms of the quadrivalent varies from one quadrivalent to the other and heterosynapsis was obvious. Heterosynapsis was also observed with asymmetrical pairing of the non-homologous partners of the quadrivalent. This heterosynapsis is assumed to be a mechanism preventing spermatocyte loss, but inducing a secondary segregational type of impairment of fertility due to foetal wastage leading to reduced prolificacy.

Animals↗
PubMed1991

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↗
PubMed1991

Ceftriaxone diffusion into cardiac fibrin vegetation. Qualitative and quantitative evaluation by autoradiography.

Heterogeneous diffusion of some antibiotics into fibrin rich infectious processes is one explanation of the difficulty to cure infections such as endocarditis. Ceftriaxone is a beta lactam antibiotic, potentially useful due to a broad spectrum of activity and its long elimination half-life. We investigated by means of autoradiography the diffusion of labelled ceftriaxone into large infected cardiac vegetations obtained in a rabbit model of endocarditis. Ten d after infection 250 microCi 14C ceftriaxone was injected over 30 min. Thirty min after the end of infusion (T30) vegetation/blood radioactivity ratio was 0.58 +/- 0.4 (n = 3). At T200, radioactivity decreased approximatively 3-fold, in blood and in vegetations simultaneously. Autoradiography showed that at T30, ceftriaxone was 20-30 times more concentrated at the periphery of vegetation than in the core. Autoradiography obtained at T200 showed a progressive diffusion toward the core. The diffusion gradient may explain the fact that high local concentrations are necessary to sterilize vegetations. The pattern of diffusion of antibiotics in fibrin is an important pharmacokinetic parameter for predicting in vivo activity.

Animals↗
PubMed1991

[Icterohemorrhagic leptospirosis with acute respiratory distress syndrome and pulmonary hemorrhage].

We report a case of the respiratory distress syndrome occurring in a patient with leptospirosis ictero-haemorrhagica (LIH). The respiratory failure was associated with pulmonary haemorrhage. There was a rapid favourable outcome after treatment with antibiotics and artificial ventilation. The diagnosis of LIH has been confirmed by serological examination. The mechanisms of the pulmonary disorder during the course of LIH were discussed.

Adult↗
PubMed1990

Epidemiological markers for epidemic strain and carrier isolates in an outbreak of nosocomial oxacillin-resistant Staphylococcus aureus.

An outbreak of nosocomial infections occurring in a postoperative intensive care unit was caused by a single strain of oxacillin-resistant Staphylococcus aureus. Six patients were infected, or colonized, by this strain, which was traced by using the following four epidemiological markers: antibiogram, bacteriophage type, capsular polysaccharide type, and esterase electrophoretic type. This strain was compared with S. aureus isolates obtained from the noses of 13 carriers from a group of 42 staff members. A good correlation in terms of phenotypic markers was found between the epidemic strain and a strain isolated from one carrier. Both exhibited the same pattern of multiple resistance as well as the same phage type, 77, capsular polysaccharide type, 5, and esterase electrophoretic type, 6. In contrast, an oxacillin-resistant strain, isolated from another carrier, differed from the epidemic strain by susceptibility to rifampin and by susceptibility to four additional bacteriophages. The other 11 strains isolated from carriers were susceptible to oxacillin and exhibited widely different phenotypes. These results confirm the interest of using several epidemiological markers to trace the spread of epidemic S. aureus strains and to delineate the carrier strains.

Bacterial Typing Techniques↗
PubMed1990

[Value of agglutination tests for the rapid identification of isolated streptococci in medical microbiology].

The clinical need for rapidly and correctly differentiating pathogenic streptococci into Lancefield groups prompted the development of rapid agglutination techniques by the direct colony method. Pastorex Streptogroupe (Diagnostics Pasteur, France) and Streptex (Wellcome Diagnostics, USA) were tested on 90 streptococcal isolates and compared with the identification obtained by conventional procedures. No cross-reactions were observed with any of the 33 strains of enterococci and of the seven strains representative of other genus among Gram-positive bacteria. When combined with colonial morphology and hemolytic reaction, both Pastorex and Streptex were specific tests for identifying beta-hemolytic streptococci, with Pastorex being slightly faster.

Agglutination Tests↗
PubMed1989

Evaluation of antibiotic diffusion into cardiac vegetations by quantitative autoradiography.

The reason bacterial endocarditis is difficult to cure has been controversial for many years. One explanation could be that antibiotic diffusion inside the vegetations is heterogeneous. This hypothesis was investigated by means of an autoradiographic study of diffusion of labeled antibiotics into large infected cardiac vegetations of nutritionally variant Streptococcus endocarditis in rabbits. Ten days after infection, 653 microCi of [3H]penicillin, 410 microCi of [3H]tobramycin, or 174 microCi of [14C]teicoplanin were injected iv over 30 min. Thirty minutes after the end of infusion (T30), vegetation/blood radioactivity ratios were 2.48 +/- 1.27, 2.49 +/- 0.67, and 3.94 +/- 1.19 for penicillin, tobramycin, and teicoplanin, respectively. Autoradiography clearly showed that distribution of the three drugs was different: Tobramycin was homogeneously distributed; penicillin was more concentrated at the periphery but still reached the center of vegetations; teicoplanin was concentrated only at the periphery. The same distribution pattern was observed with teicoplanin at T120 (i.e., one t1/2 beta later) and also after simultaneous infusion of a therapeutic dose (15 mg/kg) of cold teicoplanin. The diffusion gradient exhibited by some antibiotics could explain the difficulty in sterilizing vegetations despite high local concentrations, and the deleterious effect of the size of the vegetations on the therapeutic response.

Animals↗
PubMed1989

Inducible, transferable resistance to vancomycin in Enterococcus faecalis A256.

A strain of Enterococcus faecalis (A256) was isolated from the urine of a patient with urinary sepsis and was found to exhibit susceptibilities (micrograms per milliliter) to various glycopeptides as follows: vancomycin, 256; teicoplanin, 16; 62208, 512; 62211, 4; and 62476, 16. As judged by growth rates before and after exposure to sub-MICs of glycopeptides, vancomycin and 62476 induced self-resistance, 62208 and 62211 induced slight self-resistance, and teicoplanin did not induce self-resistance. Vancomycin induced cross-resistance to all other glycopeptides tested, as judged both in growth experiments and by direct measurement of inhibition of peptidoglycan synthesis in cells exposed to sub-MICs of vancomycin. Thus, the spectra of activity of the glycopeptides were not correlated with their patterns of induction. There was a correlation between the increased synthesis of a 39-kilodalton (kDa) protein located in the cytoplasmic membrane and the induction of resistance. Protoplasts of A256 were susceptible to inhibition of peptidoglycan synthesis by vancomycin at levels similar to those for susceptible strains. Vancomycin resistance was transferable on filters from the parent strain to E. faecalis JH2-2 at a frequency of about 10(-7), and the 39-kDa protein was also inducible by glycopeptides in these transconjugants. We conclude that A256 is resistant to glycopeptides by virtue of the synthesis of a 39-kDa cytoplasmic membrane protein, that this protein is probably involved in preventing access of the glycopeptides to their peptidoglycan targets, and that this resistance is transferable, probably by conjugation.

Bacterial Outer Membrane Proteins↗
PubMed1989

Direct testing of blood culture for detection of the serotype 5 and 8 capsular polysaccharides of Staphylococcus aureus.

Monoclonal antibodies (MAbs) reactive with serotype 5 and 8 capsular polysaccharides of Staphylococcus aureus have been used to test, by enzyme-linked immunosorbent assay (ELISA), blood culture fluids for the presence of S. aureus. A total of 748 blood cultures from 665 patients yielding 706 bacterial isolates belonging to more than 26 bacterial species were studied. All blood cultures containing bacterial strains belonging to species other than S. aureus were negative in ELISA. All 23 blood cultures containing serotype 5 S. aureus were positive in ELISA with the corresponding MAb. Out of 20 blood cultures containing serotype 8 S. aureus, 19 were positive with the corresponding MAb. All 5 blood cultures containing nontypeable S. aureus were negative in ELISA with both MAbs. This method provides reliable identification of serotype 5 or serotype 8 S. aureus by direct testing of blood culture fluids with ELISA.

Animals↗
PubMed1989

Staphylococcus aureus strains which are not identified by rapid agglutination methods are of capsular serotype 5.

A total of 183 recent Staphylococcus aureus clinical isolates were tested with three commercially available rapid agglutination methods. The capsular polysaccharide type and resistance to oxacillin of these isolates were also determined. Seven isolates were not identified correctly by agglutination methods. All isolates not identified by the rapid methods were of capsular serotype 5, and of these isolates, six were resistant to oxacillin. The results suggest that these agglutination kits can be improved by the use of antibodies reactive with S. aureus capsular polysaccharide.

Agglutination Tests↗