Comparison of three procedures for the rapid identification of bacteraemia-causing microorganisms. Evaluation of their effectiveness and applicability to microbiology laboratories

• Published in: Enfermedades infecciosas y microbiologia clinica (English ed.) Vol. 37; no. 5; pp. 319 - 323
• Main Authors: Martín-Pujol, Oriol, Tosco-Nuñez, Tomas, de Miguel-Martinez, Isabel
• Format: Journal Article
• Language: English
• Published: Elsevier España, S.L.U 01.05.2019
• Subjects: Bacteraemia; Bacteriemia; Blood cultures; Hemocultivos; Identificación; Identification; MALDI-TOF; Métodos rápidos; Rapid methods; Bacteriemia; Rapid methods; MALDI-TOF; Hemocultivos; Identificación; Métodos rápidos; Bacteraemia; Identification; Blood cultures
• ISSN: 2529-993X; 2529-993X
• DOI: 10.1016/j.eimce.2018.06.009

Three procedures for rapid identification of microorganisms in positive blood cultures were evaluated. We performed two methods based on direct extraction from a blood culture: Sepsityper® (Bruker Daltonics) (ST) and a non-commercial saponin method (MCS), and another method consisting of a short incubation subculture (SIC). Identification values obtained by spectrometry Matrix-Assisted Laser Desorption Ionization-Time of Flight (EM MALDI-TOF) were compared by applying the manufacturer's interpretation criteria and corrected cut-off points. According to the manufacturer, 65.8%, 45.8% and 57.4% of microorganisms were identified at the species level by using ST, MCS and SIC, respectively. When applying corrected cut-off points, the values increased to 92.3%, 80.6% and 85.2%, respectively. ST offered significantly better results than MCS, and no significant differences were found between ST and SIC, except for with respect to yeast. Better identification rates were obtained by using ST and SIC, which are easily applicable in any laboratory. Evaluamos tres procedimientos de identificación rápida de microorganismos a partir de hemocultivos positivos. Aplicamos dos métodos basados en la extracción directa desde el frasco de hemocultivo: Sepsityper® (Bruker Daltonics) (ST) y un método casero con saponina (MCS), y un tercer método basado en un subcultivo con incubación corta (SIC). Se comparan las identificaciones por espectrometría de masas Matrix-Assisted Laser Desorption Ionization-Time of Flight (EM-MALDI-TOF) aplicando los criterios de interpretación del fabricante y los puntos de corte corregidos (PCC). Aplicando los criterios del fabricante se identificaron a nivel de especie el 65,8%, el 45,8% y el 57,4% con ST, MCS y SIC, respectivamente. Aplicando los PCC, estos resultados fueron del 92,3%, del 80,6%, y del 85,2%, respectivamente. La identificación con ST fue significativamente mejor que el MCS. ST y SIC no mostraron diferencias significativas, excepto en levaduras. ST y SIC obtienen buenas tasas de identificación y pueden integrarse fácilmente en cualquier laboratorio.