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Biomedical subjects

J Fleurette

Publications and source records attributed to J Fleurette.

At least 109 records · Page 6Linked to original sources

Carbon substrate assimilation patterns of clinical and environmental strains of Aeromonas hydrophila, Aeromonas sobria and Aeromonas caviae observed with a micromethod.

The assimilation of carbon substrates by 103 strains of Aeromonas of different origin identified by conventional methods was studied by means of a standardized micromethod containing 147 tests (API system). Six distinct groups could be recognized and the discriminating substrates were determined. 3 species of Aeromonas can be identified by means of conventional method: A. hydrophila, A. sobria and A. caviae. The method has a number of drawbacks: Some media are unreliable, others are difficult to read, strict preservation conditions are essential. The proposed micromethod for carbon substrate assimilation allows, in most cases, a simple separation of the 3 motile Aeromonas species.

Aeromonas↗

Comparative efficacy of five antibiotics on experimental airborne legionellosis in guinea-pigs.

The efficacy of preventive and curative treatment of experimental airborne legionellosis in guinea-pigs was studied for erythromycin, rifampicin, minocycline, doxycycline and pefloxacin. The aerosol was produced from a strain of Legionella pneumophila serogroup 1 and dispersed in a chamber maintained below atmospheric pressure. Guinea-pigs were exposed for 30 min to 1 or 10 LD50 (10(3) or 10(4) viable inhaled organisms). Treatment was preventive or curative. Antibiotic concentrations in lungs and serum were evaluated during treatment. The action of the antibiotics on guinea-pigs infected by 1 LD50 resulted in 100% survival. For the 10 LD50 infection, pefloxacin, minocycline and erythromycin were more active (with 87.5% survivors) than doxycycline (75%) and rifampicin (62.5%). Preventive treatment with pefloxacin or doxycycline gave 100% protection, compared with 87.5% for rifampicin, 50% for erythromycin and 37.5% for minocycline. In this study, treatment of experimental legionellosis was improved, compared with previous publications, by early administration of antibiotics and increased dosage and duration.

Animals↗

Efficacy of spiramycin on experimental airborne legionellosis in guinea pigs.

The effect of preventive and curative spiramycin therapy was studied in guinea pigs infected by aerosol with the experimental model previously tested. The infectious aerosol was obtained from a virulent strain of Legionella pneumophila (Philadelphia ATCC 33 152). Male guinea pigs (Dunkin-Hartley) weighing 250-300 g were exposed for 30 min to an aerosol of 1 or 10 LD50 (10(3) or 10(4) viable inhaled organisms). Spiramycin was administered intraperitoneally (150 mg/kg/day) 18 h after infection for five days for curative therapy; for preventive therapy it was administered on the day before and on the day of aerosol administration (10 LD50). The animals were observed during seven days for weight and temperature and 28 days for survival; bacterial (lungs, spleen) and serological tests were performed. Spiramycin levels (lungs, serum) were evaluated during treatment by a microbiological method. The survival rate in the treated guinea pigs after inhalation of 1 LD50 was 100%. For the 10 LD50 aerosol, curative and preventive therapy gave a survival rate of 87.5%; these results are significant when compared with results of non-treated animals, P less than 0.05. Spiramycin merits further study in experimental and human legionellosis.

Animals↗

Susceptibilities to antibiotics and antiseptics of new species of the family Enterobacteriaceae.

One hundred and sixty-nine strains of new species of the family Enterobacteriaceae, isolated mainly from the environment, were tested to determine their susceptibilities to 13 antibiotics and 4 antiseptics or disinfectants. All the species were susceptible to aminoglycosides, doxycycline, and trimethoprim but were resistant to chloramphenicol. Susceptibility to beta-lactams varied more among the strains. However, all the strains were cefotaxime susceptible, apart from some Buttiauxella agrestis strains for which MICs were greater than 256 micrograms/ml. The antiseptic MBCs were similar to those published elsewhere for species of the Enterobacteriaceae of clinical origin. No resistance to chlorhexidine was observed. On the other hand, the environmental strains presented a greater resistance to active chlorine than did the reference strains.

Anti-Bacterial Agents↗

Characterization of clinically significant isolates of Staphylococcus epidermidis from patients with endocarditis.

Biotyping, slime production, bacteriophage typing, serotyping, antibiograms, and plasmid profiles were used to characterize 19 Staphylococcus epidermidis strains isolated from 12 patients with prosthetic valve endocarditis and from 7 patients with native valve endocarditis. With the API Staph battery, 12 different biocodes with, at the most, three differences were obtained. Slime production was found for 10 strains (53%). Agglutinogens investigated by agglutination with two specific sera were found for 12 strains (63.1%). Three strains were phage typable (15.2%). Against a panel of nine antimicrobial agents, 15 different profiles were found. Multiply antibiotic-resistant strains were isolated from patients with prosthetic valve endocarditis when disease onset occurred less than 18 months after heart surgery and from patients with native valve endocarditis who received antibiotics immediately prior to their illness. All of the strains were available for plasmid analysis, and all the DNA profiles were distinct. On gels run in Tris-borate buffer, 73.7% of the strains had large plasmids of more than 30 megadaltons. A small plasmid of 2.8 megadaltons was found in multiply resistant strains and in strains resistant only to tetracyclines. None of the isolates appeared to be the same strain, and the bacteriological differences between the strains were confirmed mainly by the antibiotic susceptibility profile and the plasmid pattern analysis. These bacteriological results were in agreement with the clinical data.

Bacteriophage Typing↗

Postoperative infant septicemia caused by Pseudomonas luteola (CDC group Ve-1) and Pseudomonas oryzihabitans (CDC group Ve-2).

Pseudomonas luteola (CDC group Ve-1) and Pseudomonas oryzihabitans (CDC group Ve-2) were both isolated from the same blood culture of a 5-month-old infant, 8 days after open-heart surgery. He quickly responded to appropriate antibiotics. Carbon substrate assimilation tests and fatty acid analysis clearly differentiated these two rarely pathogenic organisms.

Humans↗

Restriction endonuclease analysis of Staphylococcus epidermidis DNA may be a useful epidemiological marker.

We compared the epidemiological markers of 13 Staphylococcus epidermidis strains isolated from an adult inpatient during a febrile episode and 23 S. epidermidis strains isolated during a presumptive outbreak of nosocomial infection in a neonatal ward. The total DNA restriction endonuclease analysis (REA) was processed along with the following conventional markers: biotyping, serotyping, phage typing, antibiotic susceptibility profiles, and plasmid profiles. The REA method was reproducible, giving stable results both in vitro and in vivo. For the hospitalized adult patient, the conventional markers of the 13 strains were concordant and the restriction profiles were identical. Five restriction groups were demonstrated during the course of the outbreak. Within two of the groups, the identities of all of the markers were used to verify whether all of the isolates belonged to the same cell clone. In a third group, combined analysis of the conventional markers and REA had to be used to demonstrate isolate similarity. On the other hand, in another group, none of the markers were similar; interpretation was not easy. An epidemiological study of S. epidermidis infections in hospitals must take into account all of the epidemiological markers: biotypes, serotypes, phage types, antibiograms, plasmid profiles, and REA.

Bacterial Typing Techniques↗

Susceptibilities of streptococcal strains associated with infective endocarditis to nine antibiotics.

The susceptibilities of 121 streptococcal strains isolated from patients with infective endocarditis to mezlocillin, piperacillin, ceftizoxime, ceftriaxone, ceftazidime, imipenem, ciprofloxacin, ofloxacin and pefloxacin were determined by the agar dilution technique. Viridans streptococci, Streptococcus bovis and Enterococcus faecalis were susceptible to imipenem, mezlocillin and piperacillin. All the strains, except E. faecalis were sensitive to ceftriaxone, ceftizoxime and ceftazidime and resistant to ciprofloxacin, ofloxacin and pefloxacin. E. faecalis strains were moderately resistant to the new quinolons.

Anti-Bacterial Agents↗

[In vitro activity of roxithromycin compared to 5 other macrolides against staphylococci].

This study aimed to compare the bacteriostatic activity of roxithromycin (RU) to those of erythromycin (ERY), troleandomycin (TAO), spiramycin (SPI), josamycin (JOS) and midekamycin (MID) against staphylococci strains. 239 strains of hospital origin were analysed: S. aureus (139), coagulase negative staphylococci (CNS) (100). The MIC were determined by the agar dilution method. The modal MIC, the MIC 50 and 90 observed for the both groups of strains are given according to species and antibiotics. This study gives the opportunity to classify the 6 antibiotics in a decreasing order considering their antistaphylococcal activity: RU = ERY, TAO = SPI, JOS = MID. No difference was noticeable between S. aureus and CNS strains.

Anti-Bacterial Agents↗

[Early bacterial infections after allogenic bone marrow grafts].

The bacterial infections occurring during the period of neutropenia have been reviewed in a series of 100 allogeneic bone marrow transplant patients. Forty episodes of septicaemia were observed, in 37 patients, with a large majority of Gram positive organisms (thirty cases). Only one case of major local infection occurred (Gram negative meningitis). A non-bacterial infection was seen in 10 patients, and 36 patients presented with fever of unknown origin. Three patients who failed to engraft died of bacterial infection. Surveillance cultures showed that upper respiratory tract was a frequent site of invasion, not only for Gram positive, but also for Gram negative organisms (Pseudomonas aeruginosa).

Adolescent↗

[Identification of Legionella by gas phase chromatography of fatty acids and high performance liquid chromatography of ubiquinones].

The fatty acids and ubiquinones of 44 reference strains corresponding to species of Legionella and 3 strains of Legionella isolated in the environment have been evaluated. The analysis of fatty acids profiles allows a classification of 22 species into 4 groups depending on the predominance of some branched-chain fatty acids of linear fatty acids. As for ubiquinones our results for the 22 species corroborate the classification in 5 groups established by Moss in 1983 based on the study of 10 species of Legionella. The analysis of fatty acids composition combined with ubiquinones content has allowed us to identify the antigenically similar strains which cannot be differentiated by direct immunofluorescence on one hand (strain 1) and on the other a more precise approach to the identification, before DNA-ADN hybridization of strains of new species (strains 2).

Chromatography, Gas↗

[Use of cultured epidermis of human origin for demonstrating the acantholytic action of staphylococcal exfoliatin A].

Cultured human epithelia obtained from epidermal cells in vitro were used to assay the activity of staphylococcal epidermolytic toxin and develop an in vitro experimental model for the staphylococcal scalded skin syndrome. Human epidermal cells were grown from single epidermal cell suspensions obtained through trypsinization of adult normal skin into multilayered epithelia (with a basal cell layer, several intermediate and one or two upper layers) on mouse 3T3 feeder cells. First passage cultures were incubated with exfoliative toxin A from phage Group II staphylococci at various concentrations in DMEM. They were examined at various time intervals by direct microscopic and histological examination of respectively the culture plates or the epidermal sheets after their detachment from the plates with dispase grad II. A total exfoliation could be obtained at 24 hour at concentrations of Img and 500 micrograms/ml, only local areas of epidermolysis noted at 100 micrograms/ml. The intraepithelial separation was noted to occur between the basal layer and the lowest intermediate layer. No exfoliation could be observed at lower concentrations. Up to 4-5 hours few changes were evident, but at this time small areas of epidermolysis developed. With exfoliatin 100 micrograms/ml, intraepidermal blisters were clearly visible, occurring either between the basal cells and the lowest intermediate layer or between the first two intermediate cell layers. At the ultrastructural level, desmosomes were sparse and altered, with enlargement of the intercellular spaces and condensation of tonofilaments. These data indicate that human epidermal cell cultures, although their differentiation in culture only mimics what occurs in vivo, can be used as an in vitro model of the staphylococcal TEN to further investigate the site of action of such a toxin and the cellular mechanism responsible for the syndrome.

Adult↗

Prevalence of legionellosis among adults: a study of community-acquired pneumonia in France.

Over a 24-month period, 274 patients with community-acquired pneumonia were hospitalized in Departments of Medicine at hospitals in Bordeaux, Lyon, Marseille, and Toulouse. Etiology of the pneumonia was determined either by organism identification or by indirect immunofluorescence in only 139 cases (51%). The most frequently isolated etiological agents were Streptococcus pneumoniae (34 cases), Legionella pneumophila (29 cases) and Mycoplasma pneumoniae (24 cases). The majority of patients with legionellosis were male (79%), middle aged (mean age: 53 years), and living in urban areas (69%). Their clinical features were atypical and did not differ from those of other pneumonias. Four patients with legionellosis (13.8%) died. L. pneumophila was isolated directly in only three instances. The study confirms the high prevalence of legionellosis (20%) among pneumonias of identified etiology. The fact that these cases had an atypical clinical presentation and that isolation of the organism was difficult reinforce the need to apply the CDC criteria for the interpretation of positive serological titers.

Age Factors↗

Bacteriological and serological diagnosis of community-acquired acute pneumonia, specially Legionnaire's disease. Multicentric prospective study of 274 hospitalized patients.

In 1982 and 1983 a prospective study was carried out involving 274 adult patients hospitalized with community-acquired acute pneumonia. The results of the bacteriological and serological diagnoses are presented here. Conventional and standardized bacteriological methods were used. All the serodiagnoses of LD were carried out with the 13 antigens produced by the "Centre National de Référence" (L. pneumophila 1, 2, 3, 4, 5, 6; L. micdadei; L. bozemanii, L. dumoffii, L. jordanis; L. gormanii; L. longbeachae 1 and 2). Standardized criteria were used for the interpretation of results. Conventional methods were used for the other serodiagnoses. Because the laboratory results had been interpreted very rigorously, an etiological diagnosis was established only in 51% of pneumonia cases. Other reasons, such as the frequent prescription of antibiotics prior to hospitalization, may explain why no aetiology could be determined in 49% of cases. The microbial agents responsible were: S. pneumoniae, Legionella and M. pneumoniae in 62% of cases; H. influenzae, K. pneumoniae, Chlamydia and S. aureus in 21.6%; and viruses in 8.6%. 29 (10%) of the 274 pneumonia cases were caused by Legionella, being second to S. pneumoniae. The preponderance of L. pneumophila was striking (22 cases), 3 Legionella strains were isolated (L. pneumophila serogroup 1:2 strains, serogroup 6:1 strain). Three associated or successive infections were observed (influenza, Leptospirosis, Coxiella infection). As regards the other bacteria, implication of the strain isolated was based on its multiple occurrence in several samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

Effect of culture medium on morphology and virulence of Legionella pneumophila serogroup 1.

In a preliminary study, the preparation of a modified charcoal yeast extract by predialysis of yeast extract (CDYE) allowed us to obtain short non filamentous forms of Legionella pneumophila ser 1 (Philadelphia) found to be more virulent in the chick embryo than the long forms grown on conventional media. We confirmed these findings in guinea pigs inoculated by either intraperitoneal injection or aerosol inhalation. LD50s were calculated using the method of Reed and Muench. Survival curves were established using Liddell's method. If for chick embryo the most virulent organisms were those derived from yolk sac culture, organisms grown on CDYE agar were more virulent than those grown on the other media. There was a significant positive correlation between the mean length of the bacilli and the log 10 of the LD50 (r = 0.96; 0.02 less than p less than 0.05). For guinea pigs by either intraperitoneal injection or inhalation we confirmed that the bacteria cultured on CDYE were more virulent than those grown on other solid media. Thus for the guinea pig inoculated intraperitoneally, the LD50s of the CDYE and BCYE cultures were 1.4 X 10(7) and greater than 3 X 10(9) CFU, respectively. The mortality of guinea pigs inoculated by aerosol with CDYE cultures was significantly higher than that of guinea pigs infected with BCYE cultures using suspensions of 10(8) and 10(9) CFU/ml (p less than 0.01) and 10(10) CFU/ml (p less than 0.05).

Aerosols↗

Recovery of pefloxacin in saliva and feces and its action on oral and fecal floras of healthy volunteers.

Pefloxacin, a new fluoroquinolone, was given to 10 volunteers in single 400-mg oral doses repeated at 12-h intervals during 7 days. Serum, saliva, and feces samples were collected before and at appropriate intervals after the initiation of treatment. Drug concentrations were determined by bioassay. Qualitative and quantitative analyses of the saliva and fecal floras were performed. Mean concentrations in saliva (3.46 micrograms/ml on day 1 and 7.54 micrograms/ml on day 7) were closely related to levels in serum. High concentrations of pefloxacin were found in the feces (645 micrograms/g on day 8). No modification of oral flora was observed. In the fecal flora, members of the family Enterobacteriaceae were eliminated between days 2 and 8. The alterations in streptococci and anaerobic flora were not significant; Bacteroides fragilis was more resistant to pefloxacin after treatment. Clostridium difficile was not detected, and there was no overgrowth by yeasts. No side effects were observed.

Bacteria↗

Septicemia caused by Sphingobacterium multivorum.

Sphingobacterium multivorum was isolated in pure culture from the blood of a man undergoing chemotherapy for a lymphoma. He responded to appropriate antibiotics and later showed a significant rise in specific serum antibodies. Carbon substrate assimilation tests and fatty acid analysis proved useful in identifying the organism precisely.

Anti-Bacterial Agents↗