D-test


Also found in: Acronyms.

D-test

(de'test?)
A method of assessing erythromycin-resistant strains of Staphylococcus aureus for their susceptibility to the antibiotic clindamycin. Erythromycin-impregnated disks are placed near clindamycin, or lincomycin-impregnated disks on a growth medium, and the effect of inducible erythromycin resistance on the inhibition of bacterial growth around the clindamycin disk is assessed. A flattening of the zone of inhibition around the clindamycin disk is indicative of clindamycin drug resistance.
Synonym: disk diffusion induction test
References in periodicals archive ?
[19,20] The cost benefit of routinely performing the D-test must be evaluated in each laboratory setting after first determining the incidence of the MLSBi.
Patterns of Constitutive and Inducible Clindamycin Resistance in Staphylococcus aureus Isolated from Clinical Samples by D-test Method, Shiraz, Southwest of Iran.
De las cepas D-test positivo, 22 (36,67%) demostraron conjuntamente resistencia a oxacilina (Tabla 2).
Puesto que el mecanismo de resistencia inducible no es reconocido utilizando los metodos de susceptibilidad estandar, aunado a que su prevalencia varia segun la ubicacion geografica, el D-test se convierte en una parte imprescindible de la prueba de susceptibilidad antimicrobiana rutinaria para todos los aislados clinicos de S.
These two contributions complement the Martinez and Ruiz's (2011) work on measurement invariance in rating scales, because D-test is applied to analyze within group data, and does not take uncertainty into account.
D-test: Anew test for analyzing scale invariance using symbolic dynamics and symbolic entropy.
Coupling of mefA and ermB genes (efflux with constitutive ribosomal modification) suggests a greater presence of constitutive [MLS.sub.B] phenotype will be seen in clinical settings when testing for mechanisms using the D-test. Knowing the mechanisms of resistance is useful in determining how to counteract the resistance and will influence the development and future administration of antimicrobials.
A possible confounder in calculating clindamycin resistance rates is the 2004 CLSI guideline stating that each isolate that initially tests susceptible to clindamycin and resistant to erythromycin should be tested for inducible clindamycin resistance by the D-test; if the test result is positive, that isolate should be considered resistant (35).
Our policy is to abandon clindamycin when susceptibility testing or D-test results suggest the possibility of treatment failure, usually 2-4 days into the treatment course or, as mentioned, for severe illness when CA-MRSA is suspected.
On antibiotic susceptibility testing, 59% (680) isolates were erythromycin resistant which were then subjected to D-Test, where 212 (18.4%) isolates showed Inducible Phenotype, 255 (22.1%) isolates showed MS Phenotype and 212 (18.4%) isolates showed Constitutive Phenotype.
(10,11,12) thus necessitating the need to detect such resistance by a simple 'D-Test' on a routine basis, so as to ensure safe and effective use of Clindamycin, only in those patients with truly susceptible strains.
aureus is identified and the organism is MRSA, check for the erythromycin / clindamycin susceptibility discordance and make sure your lab is doing the D-test. If it's positive, an alternative choice of therapy would be trimethoprim-sulfamethoxazole and rifampin.