Identification and susceptibility testing of microorganism by direct inoculation from positive blood culture bottles by combining MALDI-TOF and Vitek-2 Compact is rapid and effective.

The objective of this study was to evaluate the reliability and accuracy of the combined use of MALDI-TOF MS bacterial identification and the Vitek-2 Compact antimicrobial susceptibility testing (AST) directly from positive blood cultures. Direct identification by MALDI-TOF MS and AST were performed in parallel to the standard methods in all positively flagged blood cultures bottles during the study period. Three hundred and twenty four monomicrobial positive blood cultures were included in the present study, with 257 Gram-negative and 67 Gram-positive isolates. MALDI-TOF MS identification directly from blood bottles reported the correct identification for Enterobacteriaceae in 97.7%, non-fermentative Gram-negative bacilli 75.0%, Staphylococcus aureus 75.8%, coagulase negative staphylococci 63.3% and enterococci 63.3%. A total 6156 isolate/antimicrobial agent combinations were tested. Enterobacteriaceae group and non-fermentative Gram-negative Bacilli showed an agreement of 96.67% and 92.30%, respectively, for the Gram-positive cocci the overall agreement found was 97.84%. We conclude that direct identification by MALDI-TOF and inoculation of Vitek-2 Compact AST with positive blood culture bottles yielded very good results and decreased time between initial inoculation of blood culture media and determination of the antibiotic susceptibility for Gram-negative rods and Gram-positive cocci causing bacteremia.

Romero-Gómez MP ，Gómez-Gil R ，Paño-Pardo JR ，Mingorance J ... -  《-》

A new rapid method for direct antimicrobial susceptibility testing of bacteria from positive blood cultures.

Barnini S ，Brucculeri V ，Morici P ，Ghelardi E ，Florio W ，Lupetti A ... -  《BMC MICROBIOLOGY》

Direct Identification and Antimicrobial Susceptibility Testing of Bacteria From Positive Blood Culture Bottles by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry and the Vitek 2 System.

Jo SJ ，Park KG ，Han K ，Park DJ ，Park YJ ... -  《-》

Clinical performance of ASTA SepsiPrep kit in direct bacterial identification and antimicrobial susceptibility test using MicroIDSys Elite and VITEK-2 system.

Rapid and accurate microbial identification and antimicrobial susceptibility testing (AST) are essential for timely use of appropriate antimicrobial agents for bloodstream infection. To shorten the time for isolating colonies from the positive blood culture, various preparation methods for direct identification using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) system were developed. Here, we evaluated the SepsiPrep kit (ASTA Corp.) for direct identification of microorganisms and AST from positive blood cultures using MicroIDSys Elite MALDI-TOF MS system (ASTA Corp.) and VITEK-2 system (bioMérieux). For direct identification, a total of 124 prospective monomicrobial positive blood culture bottles were included. For direct identification, the pellet was prepared by centrifugation and washing twice. For direct AST, the pellet was suspended in 0.45% saline and adjusted to McFarland 0.5. The results from the direct identification and AST using MicroIDSys Elite and VITEK-2 system were compared to those from the conventional method performed with pure colony subcultured on agar plate. Compared to the conventional method using pure colony, correct direct identification rate was 96.5% and 98.5% for 57 gram-positive isolates and 67 gram-negative isolates, respectively. For direct AST, among the 55 gram-positive isolates, the categorical agreement (CA) for staphylococci, streptococci, and enterococci was 96.7%, 98.4%, and 94.1%, respectively. For 66 gram-negative isolates, the CA for Enterobacterales and non-fermentative gram-negative rods was 99.0% and 96.6%, respectively. The SepsiPrep kit was easy to use combined with MicroIDSys Elite and VITEK-2 system and also, the correct identification and AST rate were very high.

Yoo IY ，Han J ，Ha SI ，Cha YJ ，Pil SD ，Park YJ ... -  《-》

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.

Gherardi G ，Angeletti S ，Panitti M ，Pompilio A ，Di Bonaventura G ，Crea F ，Avola A ，Fico L ，Palazzo C ，Sapia GF ，Visaggio D ，Dicuonzo G ... -  《-》