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Biomedical subjects

F Barbut

Publications and source records attributed to F Barbut.

46 records · Page 3Linked to original sources
PubMed1995

Decreased transmission of Enterobacteriaceae with extended-spectrum beta-lactamases in an intensive care unit by nursing reorganization.

In our gastrointestinal surgical intensive care unit (SICU), the large number of patients with multiple enterostomies enhances the risk of nosocomial transmission of gut extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBLE) by health care workers. A control study performed in our SICU from June-August 1992 showed an ESBLE gut colonization rate of 70%. To reduce this rate, nursing procedures were intensified or modified, particularly handwashing, single-use equipment and waste control. To test the efficiency of these procedures, 64 patients hospitalized for more than two days from September 1992-March 1993 were screened for gut acquisition of ESBLE. Rectal samples were taken within 48 h after admission and then weekly. After nursing reorganization, the ESBLE colonization rate dropped significantly to 40% (P < 0.001). Twenty patients (31.7%) acquired a gut ESBLE, after a mean of 24.3 +/- 13.7 days. Each patient was colonized with one, two or three ESBLE (Klebsiella pneumoniae, Escherichia coli and Enterobacter aerogenes). Baseline characteristics of the 20 colonized and 39 non-colonized patients showed no significant difference (Student's t-test, P > 0.05). The nursing workload, estimated as a omega index, was greater in the colonized group (P < 0.001). These findings show that strict observance of nursing procedures can significantly reduce ESBLE acquisition in a high-risk surgical unit.

Aged↗
PubMed1994

Investigation of a nosocomial outbreak of Clostridium difficile-associated diarrhoea among AIDS patients by random amplified polymorphic DNA (RAPD) assay.

Clostridium difficile is now well-established as the main cause of antibiotic-associated diarrhoea or colitis. Nosocomial acquisition of C. difficile has been described among various immunocompromised patient populations. From January to December 1992, 19 cases of antibiotic-associated diarrhoea occurred among AIDS patients in the same ward of a hospital. They all harboured C. difficile in their stools. All the strains were retrospectively typed by the random amplified polymorphic DNA (RAPD) method using two different 10-mer oligonucleotides. Twenty-five C. difficile strains (isolated from 15 patients) yielded the same RAPD pattern, suggesting they were identical. The timing and location of infections indicated that transmission of this highly resistant spore-forming bacterium can occur not only by direct patient-patient contact but also at a distance in time and space. This is the first report of an outbreak of C. difficile-associated diarrhoea in AIDS patients. Epidemiological markers are needed to recognize and control common-source outbreaks; RAPD assay is a simple, rapid and effective way of distinguishing isolates of C. difficile.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Physiochemical and immunological comparisons between angiotensin I-converting enzymes purified from different mammalian species.

Angiotensin I-converting enzyme (ACE) was purified from lungs of pig, rat, monkey and human for comparison of its physicochemical, enzymatic and immunological properties. The protocol involved three chromatographic steps after detergent extraction, i.e. DEAE-Sphérodex ion exchange, lisinopril-Sepharose affinity and Superose 12 HPLC, plus Mono-Q HPLC for monkey ACE. Purified ACE's presented numerous homologies: in particular, closely similar specific activities, catalytic efficiencies, Km's, optimal pH and chloride activations; the molecular weights were about 170 kDa by SDS-PAGE and 320 kDa by gel-filtration on Superose 12; the isoelectric points were about 4.5-4.7. Specific polyclonal antibodies recognized the antigen (porcine ACE) as well as rat, monkey and human ACEs. In contrast, three monoclonal antibodies (F02.4.1, F01.1.3 and F03) produced against porcine ACE showed some differences: they only reacted with pig enzyme and only one (F0.2.4.1) was anticatalytic. Moreover, the cross-reactivity judged on ELISA with porcine ACE characterized different epitopes specific for the porcine enzyme. In particular, the binding of F02.4.1 was not diminished by previous treatment with saturating concentrations of synthetic competitive ACE inhibitors. Thus, the extrapolation to human of data obtained on animal models should be possible at least for pharmacological and medical trials.

Animals↗
PubMed1993

Genomic fingerprinting of Clostridium difficile isolates by using a random amplified polymorphic DNA (RAPD) assay.

This study describes the use of a new and easy method called random amplified polymorphic DNA (RAPD) assay to distinguish strains of C. difficile. We used two single short primers (AP4 and AP5) with arbitrary nucleotide sequences in a polymerase chain reaction to amplify genomic DNA. The profiles observed after electrophoretic separation were able to distinguish 20 reference C. difficile strains previously serotyped by Delmée's method. The fingerprints of 11 epidemiologically unrelated C. difficile strains clearly yielded a DNA polymorphism between all the strains. Latterly, RAPD profiles of 11 C. difficile strains isolated from 2 independent suspected outbreaks showed, in each case, a predominant banding pattern corresponding to an epidemic strain. These results suggest that RAPD assay could be a valuable tool for epidemiological studies.

Base Sequence↗
PubMed1993

Comparison of enterotoxin production, cytotoxin production, serogrouping, and antimicrobial susceptibilities of Clostridium difficile strains isolated from AIDS and human immunodeficiency virus-negative patients.

We analyzed and compared Clostridium difficile strains isolated from diarrheic stools of 49 human immunodeficiency virus (HIV)-negative and 50 AIDS patients. Our results suggest that distribution patterns of serogroups are different in these two populations. Serogroup C (which has been previously reported to be very resistant to antimicrobial agents) represents 66.0 and 18.4% of the isolates from AIDS and HIV-negative patients, respectively (P < 0.001); the selection of serogroup C could be explained by multiple antibiotic pressure to which AIDS patients have been subjected.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Comparison of three enzyme immunoassays, a cytotoxicity assay, and toxigenic culture for diagnosis of Clostridium difficile-associated diarrhea.

Enzyme immunoassays (EIAs) based on monoclonal antibodies for the detection of Clostridium difficile toxins have recently been developed for clinical use. The aim of this study was to compare three commercially available EIAs, two for toxin A (Premier C. difficile Toxin A; Meridian, Osi, Elancourt, France; and Vidas C. difficile Toxin A; bioMérieux, Marcy l'Etoile, France) and one for toxins A and B (Cytoclone A + B EIA; Cambridge Biotech Corp., Codiapharm, Evian, France), with a cytotoxicity assay and toxigenic culture for the diagnosis of C. difficile-associated diarrhea (CDAD). The study was performed with 285 fresh stools from 285 patients with suspected CDAD. In case of disagreement, the tests were repeated on a frozen aliquot of the same stool sample, and the patient's chart was reviewed. CDAD diagnosis was established in 55 cases (incidence, 19.3%). The sensitivities and specificities of the methods were, respectively, 92.7 and 100% for the cytotoxicity assay, 96.4 and 99.1% for toxigenic culture, 75.5 and 97.8% for Cytoclone, 65.4 and 99.6% for Premier, and 65.4 and 100% for Vidas. The results were uninterpretable in 3.2% of cases with Cytoclone, 0.3% with Premier, and 2.5% with Vidas. We conclude that the cytotoxicity assay and toxigenic culture remain the best methods for the diagnosis of CDAD even though they lack standardization and require 48 to 96 h to obtain the result. Despite their rapidity and simplicity, EIAs are not sensitive enough to be relied on as the sole laboratory test.

Antibodies, Monoclonal↗
PubMed1992

[Evaluation of the immunoenzyme test (Elisa) in detecting Clostiridium difficile toxin A in fecal samples].

Currently, the method of choice in diagnosis of Clostridium difficile-associated intestinal diseases is the detection of toxin B in fecal specimens. This method is long (72 h) and can be realized in laboratories which have tissue culture facilities. Commercial agglutination test have been evaluated but they lack in specificity. An immunoenzymatic test has been recently commercialized for detection of toxin A. We have compared the results of this assay on 275 fecal specimens from patients suspected of having Clostridium difficile-associated intestinal diseases with the results obtained with the cytotoxicity test and the culture. Of the 275 fecal specimens, 58 were positive in cytotoxicity and 53 in Elisa. The overall sensitivity and specificity of the Elisa compared with cytotoxicity were 89.5% and 99.0% respectively. The immunoenzymatic test detecting Clostridium difficile toxin A is an easy test to perform in 2 h 15; it displays a good correlation with detection of toxin B and can be very useful in daily laboratory diagnosis.

Bacterial Toxins↗
PubMedDate not supplied

[Epidemiology of Clostridium difficile nosocomial infections].

Clostridium difficile accounts for 15-25% of cases of antibiotic-associated diarrhea (AAD) and for virtually all cases of antibiotic-associated pseudo-membranous colitis (PMC). This anaerobic bacterium is also carried in the gastro-intestinal tract of less than 3% of the normal adult population and can be isolated from the feces of 50-70% asymptomatic neonates. Since recent years, C. difficile has been identified as the leading cause of nosocomial diarrhea in adults. Pathogenesis relies on a disruption of the normal bacteria flora of the colon, a colonization with C. difficile and the release of toxins that cause mucosal damage and inflammation. Incidence of C. difficile intestinal disorders varies between 1 to 30 per thousand patient admissions. Risk factors for C. difficile-associated diarrhea include antimicrobial therapy, older age (> 65 years), intensive care, nasogastric tube, anti-acid use, and length of hospital stay. Nosocomial transmission of C. difficile via orofecal route occurs in 3-30% of total patient admissions but it often remains asymptomatic. Environmental contamination and carriage of the organism on the hands of hospital staff are common. Measures that are recommended to reduce cross-infection rely on an accurate and rapid diagnosis, implementation of enteric isolation, use of disposable gloves, hand washing with a suitable disinfectant (e.g. chlorhexidine) and daily environmental disinfection. C. difficile is a common cause of infectious diarrhea and should be therefore systematically investigated in patients with nosocomial diarrhea.

Adult↗