Few GSI-IX Rules It Is Important To Stick With

14%). Among the 202 isolates belonging to the genus Staphylococcus (92 S. aureus; 110 coagulase-negative staphylococci), the SIR agreement of the direct and standard VITEK2-based AST was 97.72% (Table 5). Clinically important VMEs were found for the testing of cefoxitin and rifampicin (n = 1; VRE = 5%). In the species�Cdrug combination Staphylococcus spp.�Ccefoxitin VMEs were observed in three isolates (VME = 2.61%) identified as Staphylococcus epidermidis (n = 2) and Staphylococcus hominis (n = 1), respectively. With the exception of benzylpenicillin which yielded combined minor and major errors in 24% of test results, the combined minor and major errors were below 7% for all other species�Cdrug combinations. For the 136 Enterococcus isolates, the results of direct AST corresponded in 98.9% of the tests with the results derived from the reference method. The VME was below 3% for all species drug combinations NK cell of enterococci (Table 5) except for high-level gentamicin (VME = 10.87%), which occurred mostly with E. faecalis (n = 4). Enterococci showed marginally increased combined minor and major errors for the AST against ampicillin and imipenem (combined error 7.32%). Importantly, no errors occurred ZD1839 chemical structure when enterococci were tested against vancomycin. Discussion Direct AST from positive blood cultures is motivated by the considerable time saving of approximately 1 working day until results become available and by the simplicity of the test. To be clinically useful, any AST protocol has to meet certain minimal requirements. Thornsberry et al. (1980) suggested for the evaluation of new automated AST methods that the complete category agreement should be over 90% and that the total of very major errors and major errors, respectively, should not exceed 5% [15]. In the current study, testing of 538 clinical blood cultures and challenge strains in 2803 bacterium�Cdrug combinations yielded an agreement of the direct disk diffusion test and standard VITEK2-based AST of 95.47% with a combined rate of VMEs and MEs of 3.65%. Thus, the direct disk diffusion test method fulfills the requirements described above suggesting an acceptable accuracy of the test system. In 1993, Jorgensen [14] proposed a refined criteria buy GSI-IX that requires an agreement >90% of the new test compared with the reference method, a VME