Evaluation of Etest Strips for Rapid Susceptibility Testing of Mycobacterium tuberculosis
| Autor: | Rosa Maria Carvalho Ferreira, Fátima Moreira Martins, Leila de Souza Fonseca, Maria Helena Féres Saad, I. M. Freixo, Rossana Coimbra Brito, P. C. S. Caldas |
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| Jazyk: | angličtina |
| Rok vydání: | 2002 |
| Předmět: |
Microbiology (medical)
Susceptibility testing Tuberculosis Time Factors medicine.drug_class Antibiotics Antitubercular Agents Microbial Sensitivity Tests Microbiology Mycobacterium tuberculosis medicine polycyclic compounds Humans False Negative Reactions Etest biology business.industry Isoniazid Bacteriology biochemical phenomena metabolism and nutrition biology.organism_classification medicine.disease Antimicrobial equipment and supplies bacterial infections and mycoses Culture Media Streptomycin bacteria business medicine.drug |
| Popis: | In this study, our objective was to evaluate Etest strips containing exponential gradients of isoniazid (INH), rifampin (RIF), and streptomycin (STR) for susceptibility testing of Mycobacterium tuberculosis. M. tuberculosis isolates were tested for antimicrobial susceptibilities by the standard proportion method using Löwenstein-Jensen (LJ) medium and by the Etest. The MICs determined by the Etest were obtained at 5, 7, or 10 days. In some strains with Etest-discrepant results, radiometric susceptibility testing (BACTEC) was performed to determine a consensus result. M. tuberculosis concordance between the two methods was 97% (86 of 89 isolates) for RIF, 96% for INH (84 of 87 isolates), and 80% (61 of 76 isolates) for STR. Most of the MICs determined by the Etest were easy to interpret and readable within 5 days. Results correlated well with those obtained by the LJ proportion and BACTEC methods for INH and RIF. However, a high proportion of false-sensitive and false-resistant results were observed, most often for STR. We also observed that variations in the inoculum size of M. tuberculosis isolates affected the MICs to a substantial degree. These discrepancies, along with the expense of the media, the Etest strips, and the specialized equipment required (CO 2 incubator), make this method less useful in developing countries. |
| Databáze: | OpenAIRE |
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