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Biomedical subjects

H Leclerc

Publications and source records attributed to H Leclerc.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Bacteriological monitoring of the treatment of Pseudomonas aeruginosa infections with amikacin administrated at once-daily dosis in patients with cystic fibrosis].

The interest of the treatment with a single daily dose of amikacin (AMK) in cystic fibrosis (CF) patients with P. aeruginosa infections has been much debated. The aim of work was to study the efficiency of this treatment on (CF) patients with chronic bronchopulmonary P. aeruginosa infections previously treated for two weeks with the combination ceftazidime (CAZ 200 mg/day in 3 inj. IVD) and AMK (35 mg/day in one IV perf. of 30 minutes). The bacteriological supervision of this treatment was performed 1: by the determination of MICs before and after treatment, 2: by the decrease of P. aeruginosa colonization immediately after this treatment and during 11 months, 3: by the identification of P. aeruginosa strains with phenotypic methods (serotyping and antibiotyping) and with genotypic method (pulsed field gel electrophoresis). The use of AMK in a single daily dose in order to treat chronic lung infections colonized with P. aeruginosa susceptible to this antibiotic shows encouraging results as far as bacteriology is concerned: this treatment has given means to reduce colonization for a month in 15 of 18 patients. For 9 of the 18 patients, no P. aeruginosa strains were isolated for nine months. The serotyping and antibiotyping systems do not enable us to study the P. aeruginosa epidemiology. Genome macrorestriction fingerprinting of P. aeruginosa in pulsed field gel electrophoresis confirms that patient with CF were colonized with one or several clones. In our study no variation of these clones was noticed for the first eleven months. Genome macrorestriction fingerprinting appears to be one of the most effective methods for delineate strains of P. aeruginosa colonizing CF patients.

Adolescent↗
PubMed1994

Assessment of the marker value of various components of the coli-aerogenes group of Enterobacteriaceae and of a selection of Enterococcus spp. for the official monitoring of drinking water supplies.

The traditional indicators Escherichia coli (in practice currently, though ecologically inaccurately, represented by 'thermotolerant coliforms' at 44 degrees C) and Enterococcus spp. proved to be suitable for the diagnosis of heavy and frequent faecal pollution observed in potentially dangerous waters, especially those originating from karstic aquifers. On the other hand, natural and treated waters, slightly and inconsistently contaminated, occasionally showed a variable Gram-negative flora, difficult to classify by routine tests. In that case, complete identification of isolates may be necessary to ensure a valid decision on the potability of the supply. At any rate some of the Enterobacteriaceae contained in the 'faecal coliform' group and many other 'coliforms', distinct from E. coli, lack sanitary significance although their presence at certain levels may indicate inadequate disinfection, hiatuses in the integrity of the distribution system or both.

Biomarkers↗
PubMed1994

High prevalence of Helicobacter pylori infection in cohabiting children. Epidemiology of a cluster, with special emphasis on molecular typing.

Intrafamilial cases of infection with the same strain of Helicobacter pylori (H pylori) have been reported but these clusters were too small to distinguish between person to person spread or coinfection from a common environmental source. To gain more information on the mode of transmission of H pylori, an epidemiological survey with bacterial strain differentiation by restriction endonuclease analysis of chromosomal DNA was carried out in an institution of 117 children with encephalopathy (aged 3.5 to 19 years). All children with antibodies against H pylori had gastroscopy to obtain gastric biopsy specimens. The prevalence of infection (confirmed histologically or microbiologically, or both) was 38% (45/117), and rose to 67% in one of the five sections of the institution. H pylori was isolated in 34/45 cases, and 22 different strains were found of which five strains were present in more than one child. Up to seven children were infected by the same strain, five of them were living in the same section. Analysis of the characteristics of infected children showed the predominant role of living conditions and the period of time cohabiting in this unexpectedly high prevalence of H pylori infection in children living in good sanitary conditions.

Adolescent↗
PubMed1994

[Buruli ulcer in a Zairian woman with HIV infection].

INTRODUCTION: Isolated cutaneous mycobacterial infection is exceptional in the acquired immunodeficiency syndrome (AIDS). We report a case of Buruli ulcer observed in a Zairan female infected with the human immunodeficiency virus (HIV). CASE REPORT: An HIV positive female patient was hospitalized for deep skin ulceration with detached and necrotic borders on the posterior aspect of the lower limb. Histological examination of a surgical biopsy showed numerous acid-fast bacilli identified as Mycobacterium ulcerans by thin layer gas chromatography. The clinical course was favourable with a three-drug antibiotic therapy replaced by rifampicin-clarithromycin after three months. The patient's immune status did not change for two years with a CD4 count of 500/mm3. The patient was negative for P24 antigen. DISCUSSION: While it is relatively easy to diagnose Buruli ulcers, identifying the causal bacteria is sometimes quite difficult requiring long culture periods. New techniques such as gas phase chromatography have been very useful in particularly low-count sub-cultures. Surgery remains the predominant therapy in endemic areas but antibiotic combinations are also effective. HIV-related immunosuppression did not change the clinical aspect of cutaneous mycobacteriosis in this patient whose immunological status was not modified.

Adult↗
PubMed1993

Serodiagnosis of tuberculosis. Evaluation of a sulpholipid antigen.

In order to evaluate the suitability of serology in the diagnosis of tuberculosis the Mycobacterium tuberculosis anti-sulpholipidic IV IgG were assayed, using the ELISA test, in 41 healthy controls, 121 hospitalized but non-tuberculous patients and 142 tuberculous persons including 46 cured patients. At the 150 and 300 O.D. thresholds proposed in previous studies using the same antigen, the specificity was 88.27% and 98.76%, respectively, and the sensitivity 25% and 11.45%. These results were not related to different potential factors (age, background, associated pathology) but to infection intensity which enhanced the IgG reaction. This may explain discrepancies observed in previous studies made under other epidemiological conditions. Therefore, in this European population from a universitarity hospital, it appears that too many tuberculous patients have such a low IgG reaction that serology cannot be an effective assay in the diagnostic step.

Adult↗
PubMed1993

Detection of H. pylori in saliva using a monoclonal antibody.

The presence of Helicobacter pylori in saliva specimens collected from infected children examined before and after specific therapy and from a non-infected pediatric population was detected by indirect immunofluorescence assay (IIF) using a specific monoclonal antibody. Among the 25 children with H. pylori-negative antral biopsies, 4 had in their salivas bacterial cells similar to H. pylori, but a retrospectively performed serologic test showed a positive response. No false-positive reaction was observed among non-infected and seronegative children. The observation of bacterial cells with H. pylori morphology in saliva by IIF was consistent with the presence of this bacterium in antral biopsies. A person-to-person transmission of H. pylori by saliva thus appeared to be possible.

Adolescent↗
PubMed1993

Biological specificity of bottled natural mineral waters: characterization by ribosomal ribonucleic acid gene restriction patterns.

The organisms from heterotrophic plate counts of four brands of bottled non-carbonated mineral waters were analysed by ribosomal ribonucleic acid gene restriction patterns in addition to identification by customary techniques. Five commercialized bottles of each brand were examined once in the year 1989-90. The total bacterial flora was divided into two main groups: the pseudomonads and the unidentified strains. Whereas phenotypic results did not reveal any significant differences between the four brands, rRNA gene restriction patterns were discriminatory. Among the 73 strains studied, 45 distinct patterns were observed, with only three common to several springs. These results reveal, at one determined time, a remarkable biological specificity of each brand of water.

Bacteria↗
PubMed1993

Iron acquisition by Helicobacter pylori: importance of human lactoferrin.

Helicobacter pylori is known to be an etiologic agent of gastritis and peptic ulcer disease in humans. However, the mechanism by which this organism acquires iron has not been studied. For this investigation, H. pylori was grown in iron-restricted medium. Siderophore production was not detected by chemical assays, and the strains were unable to use enterochelin and pyochelin for growth in low-iron media. Human lactoferrin supported full growth of the bacteria in media lacking other iron sources, but neither human transferrin, bovine lactoferrin, nor hen ovotransferrin served as a source for iron. Since lactoferrin was found in significant amounts in human stomach resections with superficial or atrophic gastritis, the iron acquisition system of H. pylori by the human lactoferrin receptor system may play a major role in the virulence of H. pylori infection.

Animals↗
PubMed1993

[Mycobacterium kansasii cutaneous infection].

The authors report a case of cutaneous infection caused by Mycobacterium kansasii in an immunocompetent woman. The mycobacterium was identified after a search for mycolic acids and the species-specific phenol-glycolipid K1. As minocycline followed by ciprofloxacin were ineffective, a conventional antituberculous treatment was prescribed and was fully successful.

Ciprofloxacin↗
PubMed1992

Rapid detection of members of the family Enterobacteriaceae by a monoclonal antibody.

Six monoclonal antibodies directed against enterobacteria were produced and characterized. The specificity of one of these antibodies (CX9/15; immunoglobulin G2a) was studied by indirect immunofluorescence against 259 enterobacterial strains and 125 other gram-negative bacteria. All of the enterobacteria were specifically recognized, the only exception being Erwinia chrysanthemi (one strain tested). Bacteria not belonging to members of the family Enterobacteriaceae were not detected, except for Plesiomonas shigelloides (two strains tested), Aeromonas hydrophila (five strains tested), and Aeromonas sobria (one strain tested). This recognition spectrum strongly suggested that CX9/15 recognized the enterobacterial common antigen. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) experiments, the six antienterobacteria antibodies presented similar specificities; they all revealed only one band with an apparent molecular weight of about 20,000 from the crude extract of an enterobacterium. The six monoclonal antibodies, and especially CX9/15, can be used to develop new tests for rapid and specific detection of enterobacteria.

Antibodies, Monoclonal↗
PubMed1992

[Bacterial flora of two sources of natural mineral waters; characterization by restriction patterns of the genes coding for ribosomal RNA; specificity and biological stability].

The bacterial flora of natural mineral waters was analysed using ribosomal ribonucleic acid gene restriction patterns in addition to customary identification techniques. Two springs were studied between 1989 and 1990 and six water samples per source were examined. Among the 206 bacterial strains collected at the spring, 91 (49%) were identified at species level using the API system and 99 representative strains from the two sampling points were selected for ribosomal ribonucleic acid gene restriction analysis. Forty six patterns were detected without common patterns to two springs. The bacterial association of each mineral water has a specific character (100% of specific patterns) shown by a series of patterns, not common to the other spring. This bacteriological specificity is preserved over a marked period of time, as, for each source, a great number of characteristics patterns was repeatedly found.

Bacteria↗
PubMed1991

Detection of Helicobacter pylori in stomach tissue by use of a monoclonal antibody.

Monoclonal antibodies were produced against an acid glycine extract of Helicobacter pylori ATCC 43504T. One of these appeared to be specific for H. pylori; it recognized all H. pylori isolates by an indirect immunofluorescence assay (IIF) but it did not cross-react with the other strains tested, including different species of the genera Helicobacter, Campylobacter, and Wolinella. Different strains of members of the families Enterobacteriaceae and Pseudomonadaceae or other gram-negative bacteria tested also gave negative reactions. Indirect immunofluorescence assay of antral biopsy specimens identified 54 of 56 infected patients (96.4%), and it may be able to detect nonviable organisms after antibiotic therapy.

Acridines↗
PubMed1991

[Nitrates in the drinking water and cancer].

Nitrates originating from food and particularly from water are supposedly precursors of carcinogenic N-nitroso compound (NOC) formed within the organism. According to Correa and al. these transformations could be a consequence of bacterial gastric pullulation resulting from certain hypochlorhydric conditions. Much epidemiological research has tried to establish a relationship between exposure to nitrates in drinking water and cases of gastric cancer. The present article deals with research into this relationship in France, in a region where the rate of nitrates in water supplies is among the highest. Death statistics (from cancers of the digestive and urinal tracts) are issued by INSERM and these of the population by INSEE. Towns are classified according to nitrate concentration and the number of deaths is established according to tumour detection by sex and age. Research into death rate divergencies is found by chi 2 and the correlated coefficient. The average relative risk for any age group is calculated for all types of cancer. Research on frequency is carried out from tumour records. Comparative frequency rates are established by direct standardisation according to the structural age of any one European population. Results are analysed in relation to (1) mortality rates and (2) incidence rates. (1) None of the cancers studied, of the digestive or urinary systems, whatever the age on sex, is significantly linked to the quantity of nitrates in water supplies. When all these cancers are taken into account, the death rate does not vary significantly for increasing concentration of nitrates. Towns exceeding the maximum concentration permitted by law do not have a higher mortality rate than other towns.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Anti-Helicobacter pylori IgG levels in abattoir workers.

The aim of our study was to detect antibodies against Helicobacter pylori (H. pylori) in abattoir workers whose activity was variable (pig, poultry-carcasses, poultry-intestinal organs treatment). An adsorption of all sera with H. pylori and Campylobacter species known to be ubiquitous and responsible for zoonosis was included in the ELISA reaction to eliminate possible cross-reactions between these species. Statistically higher specific titres of IgG antibodies against H. pylori were observed in men and women who had only worked for 1 or 2 years versus matched controls, indicating a possible transmission of H. pylori from animal to man. The role of poultry or pigs as contaminants alone or in association remains to be determined.

Abattoirs↗
PubMed1991

[Nitrates in drinking water and cancer].

Nitrates originating from food and particularly from water are supposedly precursors of carcinogenic N-nitroso compound (NOC) formed within the organism. According to Correa and al. these transformations could be a consequence of bacterial gastric pollution resulting from certain hypochlorhydric conditions. Much epidemiological research has tried to establish a relationship between exposure to nitrates in drinking water and cases of gastric cancer. The present article deals with research into this relationship in France, in a region where the rate of nitrates in water supplies is among the highest. Death statistics (from cancers of the digestive and urinal tracts) are issued by INSERM and these of the population by INSEE. Towns are classified according to nitrate concentration and the number of deaths is established according to tumour detection by sex and age. Research into death rate divergencies is found by chi 2 and the correlated coefficient. The average relative risk for any age group is calculated for all types of cancer. Research on frequency is carried out from tumour records. Comparative frequency rates are established by direct standardisation according to the structural age of any one European population. Results are analysed in relation to (1) mortality rates and (2) incidence rates. (1) None of the cancers studied, be they of the digestive or urinary systems, whatever the age on sex, is significantly linked to the quantity of nitrates in water supplies. When all these cancers are taken into account, the death rate does not vary significantly for increasing concentration of nitrates. Towns exceeding the maximum concentration permitted by law do not have a higher mortality rate than other towns. The overall can incidence rate in the Nord-Pas-de-Calais regions of France is 11.8 per 100,000 inhabitants. The average European rate is 18.3 per 100,000 for men in the Nord region and 20.5 in the Pas-de-Calais; for women, 5.9 and 7.2 respectively. These rates are comparable to those in other French regions. The incidence rate for gastric cancer is not significantly different for inhabitants of towns exposed to water containing more or less than 50 mg/l. The absence of links between cancer and nitrates water research into possible methodological expedients necessary. A certain number of factors (consumer habits, diet, population mobility) can, for the same concentration of nitrates, modify the actual quantity consumed, and so the corresponding long-term risk. However, no inverse effect of these factors which would be susceptible to counter the link to the extent of concealing it, is know for the moment.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗