Inducible resistance to clindamycin in Staphylococcus aureus: validation of Vitek-2 against CLSI D-test
| Autor: | M.L. Grayson, B.J. Gardiner, G.M. Wood |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Staphylococcus aureus
Meticillin medicine.drug_class animal diseases Erythromycin Drug resistance Microbial Sensitivity Tests medicine.disease_cause Staphylococcal infections Pathology and Forensic Medicine Microbiology Macrolide Antibiotics Predictive Value of Tests Drug Resistance Bacterial medicine Humans business.industry Clindamycin virus diseases Reproducibility of Results Gold standard (test) biochemical phenomena metabolism and nutrition Staphylococcal Infections medicine.disease Anti-Bacterial Agents Bacterial Typing Techniques Reagent Kits Diagnostic business medicine.drug |
| Zdroj: | Pathology. 45(2) |
| ISSN: | 1465-3931 |
| Popis: | Summary Aims Inducible resistance to clindamycin in Staphylococcus aureus is common but not easily identified by routine testing, and can result in treatment failure if not detected. The gold standard method is the D-test described by the Clinical and Laboratory Standards Institute (CLSI). The Vitek-2 AST-P612 card contains an ‘inducible clindamycin resistance’ (ICR) test. We aimed to determine the accuracy of the Vitek-2 ICR test compared to the D-test. Methods Isolates of erythromycin non-susceptible, clinda-mycin susceptible Staphylococcus aureus were identified. Routine antimicrobial susceptibility testing was performed using the Vitek-2 AST-P612 card, including the ICR test, and compared against the D-test. Results 217 isolates were obtained. All of the 191 isolates that were ICR positive were D-test positive. Of the 27 ICR negative isolates, 10 (37%) were D-test positive [9 methicillin-sensitive S. aureus (MSSA), 1 methicillin-resistant S. aureus (MRSA)]. This correlates with a specificity of 100%, sensitivity of 95%, positive predictive value of 100%, and negative predictive value of 72%. Conclusions The ICR test is reliable in the presence of a positive result; however there is a false negative rate of approximately one in four. This will lead to susceptibility reporting errors, with potentially serious clinical implications. A negative ICR should be confirmed by CLSI D-test before reporting clindamycin as susceptible where the organism is not susceptible to erythromycin. |
| Databáze: | OpenAIRE |
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