Evaluation of the Performance of the MicroScan Pos Breakpoint Combo Panel Type 28 for Susceptibility Testing of Staphylococcus aureus: Low-range Minimum Inhibitory Concentration of Vancomycin, Cefoxitin Screening, and Inducible Clindamycin Resistance Dete.
10.3343/kjlm.2010.30.6.637
- Author:
Misuk JI
1
;
Miyoung LEE
;
Sinae NOH
;
Mi Na KIM
Author Information
1. Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea. mnkim@amc.seoul.kr
- Publication Type:Original Article ; Comparative Study ; English Abstract ; Evaluation Studies ; Research Support, Non-U.S. Gov't
- Keywords:
Staphylococcus aureus;
susceptibility test;
MRSA;
clindamycin resistance;
vancomycin resistance
- MeSH:
Anti-Bacterial Agents/*pharmacology;
Bacterial Proteins/genetics;
Cefoxitin/*pharmacology;
Clindamycin/*pharmacology;
Drug Resistance, Bacterial;
Methicillin-Resistant Staphylococcus aureus/genetics/isolation & purification;
*Microbial Sensitivity Tests;
Reagent Kits, Diagnostic;
Sensitivity and Specificity;
Staphylococcus aureus/*drug effects/genetics/isolation & purification;
Vancomycin/*pharmacology
- From:The Korean Journal of Laboratory Medicine
2010;30(6):637-646
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: Susceptibility testing of Staphylococcus aureus often requires cumbersome supplementary tests. MicroScan Pos Breakpoint Combo Panel Type 28 (PBC28) (Siemens, USA) includes cefoxitin screening to detect methicillin-resistant Staphylococcus aureus (MRSA), inducible clindamycin resistance detection (ICD), and determination of low-range minimum inhibitory concentration of vancomycin (0.5-16 microgram/mL). The purpose of this study was to evaluate the performance of PBC28 in comparison with that of Pos Combo Type 1A (PC1A) (Siemens). METHODS: From December 2009 to March 2010, 500 non-duplicate clinical isolates of S. aureus were tested with PC1A and PBC28. Categorical agreements (CA) between the interpretations of the 2 panels were estimated. The presence of the mecA gene was determined by PCR, and double-disk diffusion test (D-test) was performed on the isolates resistant to erythromycin but susceptible or intermediately resistant to clindamycin. Ninety-six isolates representing various vancomycin minimum inhibitory concentrations (MICs) were tested in parallel with repeat PBC28, broth macrodilution, and epsilometer test (E test). RESULTS: The CA was 99.3% with a very major error (VME) of 0.2%, major error (ME) of 0.1%, and minor error (mE) of 0.4% in total. PBC28 showed 100% CA for 1 isolate with vancomycin MIC of 4 microgram/mL and 35 isolates (7.0%) with MIC of 2 microgram/mL. However, only 15, 27, and 35 isolates with vancomycin MIC of 2 microgram/mL showed 100% CA in repeat PBC28, broth macrodilution, and E test, respectively. PC1A and PBC28 detected all 314 mecA-positive isolates. Among the 63 isolates tested with the D-test, 58 (92.1%) were positive, and the results were 100% concordant with those of ICD. CONCLUSIONS: PBC28 can be appropriate susceptibility testing of S. aureus, including MRSA detection and ICD. However, the lower-range vancomycin MIC test was not reproducible enough to reliably differentiate MIC of 2 microgram/mL from MIC< or =1 microgram/mL.
