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Comparison of workflow and accuracy of identification and antimicrobial susceptibility testing of clinical isolates of Enterobacteriaceae , Pseudomonas aeruginosa and enterococci by Vitek 2 and routine methods
Author(s) -
RANTAKOKKOJALAVA KAISU,
ELOLEHTONEN EIJA,
MEURMAN OLLI
Publication year - 2006
Publication title -
apmis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0903-4641
DOI - 10.1111/j.1600-0463.2006.apm_338.x
Subject(s) - enterococcus faecalis , enterococcus , microbiology and biotechnology , pseudomonas aeruginosa , enterobacteriaceae , trimethoprim , antimicrobial , medicine , biology , antibiotics , escherichia coli , staphylococcus aureus , bacteria , biochemistry , gene , genetics
Three hundred and fifty‐three consecutive urine cultures growing Enterobacteriaceae , Pseudomonas aeruginosa or enterococci were subjected to parallel identification (ID) and antimicrobial susceptibility testing (AST) by Vitek 2 and routine methods, including simple screening tests or API 20 E for ID and standardized disc diffusion for AST. Accuracy of results, technician hands‐on time required by both methods and time to results were compared. Vitek 2 correctly identified 322 (94.7%) of the 340 gram‐negative isolates and 17 (81%) of the 21 Enterococcus faecalis strains. AST by Vitek 2 and disc diffusion gave category agreement for 4,058 (95.5%) of 4,248 organism‐antimicrobial agent combinations. With MIC determination by E‐test as reference, AST by Vitek 2 and disc diffusion produced 15 and 3 very major errors, respectively. Six (40%) of the fifteen very major errors by Vitek 2 were associated with trimethoprim‐sulfamethoxazole. With an average of 22 specimens processed per day, use of Vitek 2 saved 80 min per day of technician hands‐on time as compared to routine methods. Regarding the cost of hands‐on worktime and consumables, use of Vitek 2 for identification of Escherichia coli ‐screened Enterobacteriaceae saved 0.70 p per sample in comparison to API 20 E. More than 80% of Enterobacteriaceae introduced to Vitek 2 in the morning could be reported by 16:00.