Accuracy of the VITEK® 2 system for a rapid and direct identification and susceptibility testing of Gramnegative rods and Gram-positive cocci in blood samples

• Published in: Eastern Mediterranean health journal Vol. 22; no. 3; pp. 193 - 200
• Main Authors: Nimer, N A, Al-Saa'da, R J, Abuelaish, O
• Format: Journal Article
• Language: English
• Published: Egypt 15.06.2016
• Subjects: Bacteremia - diagnosis; Gram-Positive Cocci - isolation & purification; Humans; Jordan; Microbial Sensitivity Tests - methods; Sensitivity and Specificity
• ISSN: 1020-3397
• DOI: 10.26719/2016.22.3.193

The performance of the VITEK® 2 system for direct rapid identification and antimicrobial susceptibility testing of the bacteria responsible for blood infections was determined. The isolates studied included 166 Gram-negative rods and 74 Gram-positive cocci from inpatients. Specially treated monomicrobial samples from positive blood culture bottles were directly inoculated into the VITEK 2 system and the results were compared with those from cards inoculated with standardized bacterial suspensions. Compared with the standard method, 95.8% of Gram-negative rods were correctly identified by VITEK 2 and the overall level of agreement between the two methods in susceptibility testing was 92.0%. For Gram-positive bacteria, 89.2% were correctly identified by VITEK 2 and susceptibility testing revealed an overall agreement rate of 91.3%. These results suggest that VITEK 2 cards inoculated with fluids sampled directly from positive blood culture bottles are suitable for speedy identification and susceptibility testing of Gram-negative bacilli and Gram-positive cocci.