Comparative evaluation of the Vitek-2 Compact and Phoenix systems for rapid identification and antibiotic susceptibility testing directly from blood cultures of Gram-negative and Gram-positive isolates.
We performed a comparative evaluation of the Vitek-2 Compact and Phoenix systems for direct identification and antimicrobial susceptibility testing (AST) from positive blood culture bottles in comparison to the standard methods. Overall, 139 monomicrobial blood cultures, comprising 91 Gram-negative and 48 Gram-positive isolates, were studied. Altogether, 100% and 92.3% of the Gram-negative isolates and 75% and 43.75% of the Gram-positive isolates showed concordant identification between the direct and the standard methods with Vitek and Phoenix, respectively. AST categorical agreements of 98.7% and 99% in Gram-negative and of 96.2% and 99.5% in Gram-positive isolates with Vitek and Phoenix, respectively, were observed. In conclusion, direct inoculation procedures for Gram-negative isolates showed an excellent performance with both automated systems, while for identification of Gram-positive isolates they proved to be less reliable, although Vitek provided acceptable results. This approach contributes to reducing the turnaround time to result of blood cultures, with a positive impact on patient care.
Centro Integrato di Ricerche, Laboratory of Clinical Microbiology, University Campus Bio-medico, 00128 Rome, Italy. g.gherardi@unicampus.it
Giovanni
G
Gherardi
Silvia
S
Angeletti
Miriam
M
Panitti
Arianna
A
Pompilio
Giovanni
G
Di Bonaventura
Francesca
F
Crea
Alessandra
A
Avola
Laura
L
Fico
Carlo
C
Palazzo
Genoveffa Francesca
GF
Sapia
Daniela
D
Visaggio
Giordano
G
Dicuonzo
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000175:diagnosis* / Q000382:microbiology; D001769:Blood / Q000382:microbiology*; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods
D000900:Anti-Bacterial Agents