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Titre : | Validation de la détermination du profil de sensibilité de H. pylorià différents antibiotiques par la méthode de Kirby-Bauer |
Auteurs : | Gauthier FOSSEPREZ, Auteur ; Yvette MIENDJED, Promoteur |
Type de document : | Travail de fin d'études |
Editeur : | Bruxelles : Institut Paul Lambin, 2020 |
Langues: | Français |
Index. décimale : | TFE - Biologie médicale |
Résumé : |
In a constant research of reducing the cost while maintaining the quality of the analysis, this study aims to validate the routinely used Kirby-Bauer method (disk diffusion) for the determination of H. pyloris susceptibility to six different antibiotics that can be used in the treatment of H. pylori infection, namely tetracycline, levofloxacin, metronidazole, amoxycillin, clarithromycin and rifampicin. Indeed, for the Laboratoire Hospitalier Universitaire de Bruxelles (LHUB ULB) this method is around 20 to 25 times cheaper than the MIC determination method that is currently validated by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) for H. pyloris susceptibility testing. The validation consists in the systematic comparison of diffusion disk method using ROSCO Neo-sensitabsTM disks to the equivalent Biomérieux ETEST® strips.
To achieve this comparative study, several manipulations will be conducted for each different H. pyloris strain, a microaerophilic gram-negative bacillus with a positive urease. That begins firstly, with fulfil pre-analytical conditions, by the determination of the presence of the bacteria in a patients gastric biopsy sample with the crushing of it in a saline solution and the spreading of the obtained solution on a BD Helicobacter Agar, modified (Becton, Dickinson and Company, USA) with a microaerophilic incubation (5-6%O2, 8-10%CO2, 80-85%N2). It is followed, in the case of a morphological positive culture, by a urease confirmation test. That leads to the realization of the different antibiogram needed using a 3 McFarland (McF) bacterial suspension of the concern strain and 7 Columbia Agar with 5% Horse Blood (BD). After the lecture of the results, using the naked eyes for the ETEST strips and a digital caliper VWR® TRACEABLE for the inhibition diameter, it was possible to analyze the results by the calculation of the sensitivity, specificity, positive and negative predictive values using the ETEST values as references. The study has included 78 H. pylori strains tested in parallel. It sorts out that the routinely used K-B method could be considered as validate with the use of tetracycline, levofloxacin, metronidazole and amoxycillin. The K-B method using clarithromycin could also be considered as validate using the MIC breakpoints of the European Helicobacter & Microbiota Study Group (EHMSG), these allow the suppression of intermediary values that could be present using the EUCASTs breakpoints. Unfortunately, the rifampicin disks could not be considered as validate using the K-B method. Resulting of the analysis and in order to increase the performance of certain disks, some new breakpoints could be implemented such as for the metronidazole. Other problems encountered during the study and already crippling the laboratory such as mushroom contaminations led to new considerations to resolve the problem like better data intakes of the event or new practical dispositions. |
Accès : | Identifiez-vous avant d'accéder au document électronique |
Disponible en ligne : | Oui |
Lieu du stage : | LHUB ULB (Bactériologie) |
Département : | Biologie médicale |
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TFE biologie médicale Adobe Acrobat PDF |