A Egli1,2, M Osthoff3, D Goldenberger1, J Halter4, S Schaub5, J Steiger5, M Weisser3, R Frei1. 1. Division of Clinical Microbiology, University Hospital Basel, Basel, Switzerland. 2. Vaccine Research Infection Biology Lab, Department Biomedicine, University of Basel, Basel, Switzerland. 3. Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland. 4. Hematology, University Hospital Basel, Basel, Switzerland. 5. Division of Nephrology and Transplant Immunology, University Hospital Basel, Basel, Switzerland.
Abstract
INTRODUCTION: In immunosuppressed hosts, rapid identification of microorganisms of bloodstream infections is crucial to ensuring effective antimicrobial therapy. Conventional culture requires up to 72 h from sample collection to pathogen identification. METHODS: We used the SepsiTyper Kit and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF; Microflex, Bruker) directly from positive blood culture (BacT/ALERT 3D, FN/FA vials; bioMérieux) in comparison to standard culture methodology (VITEK 2; bioMérieux) for species identification. RESULTS: A total of 62 consecutive positive blood cultures from immunosuppressed patients (solid organ or hematopoietic transplant recipients, or with febrile neutropenia) were analyzed. Culture yielded gram-negative bacteria (GNB) in 27/62 (43.5%) and gram-positive (GPB) in 35/62 (56.5%) vials. For GNB, the predominant species identified by MALDI-TOF and confirmed by VITEK were Escherichia coli (16/16 correctly identified) and Enterobacter cloacae (4/4), with a sensitivity and specificity of 92.6% and 100%, respectively. For GPB, predominant species were Staphylococcus aureus (3/3), coagulase-negative staphylococci (12/24), and Enterococcus faecium (6/6) with a sensitivity of 100%, 60%, and 100%, respectively. The median time from blood collection to species identification was 27.4 h with MALDI-TOF identification and 46.6 h with conventional methodology. CONCLUSION: Using MALDI-TOF directly from positive blood cultures allowed a shorter time to identification with high sensitivity and specificity in immunosuppressed patients.
INTRODUCTION: In immunosuppressed hosts, rapid identification of microorganisms of bloodstream infections is crucial to ensuring effective antimicrobial therapy. Conventional culture requires up to 72 h from sample collection to pathogen identification. METHODS: We used the SepsiTyper Kit and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF; Microflex, Bruker) directly from positive blood culture (BacT/ALERT 3D, FN/FA vials; bioMérieux) in comparison to standard culture methodology (VITEK 2; bioMérieux) for species identification. RESULTS: A total of 62 consecutive positive blood cultures from immunosuppressed patients (solid organ or hematopoietic transplant recipients, or with febrile neutropenia) were analyzed. Culture yielded gram-negative bacteria (GNB) in 27/62 (43.5%) and gram-positive (GPB) in 35/62 (56.5%) vials. For GNB, the predominant species identified by MALDI-TOF and confirmed by VITEK were Escherichia coli (16/16 correctly identified) and Enterobacter cloacae (4/4), with a sensitivity and specificity of 92.6% and 100%, respectively. For GPB, predominant species were Staphylococcus aureus (3/3), coagulase-negative staphylococci (12/24), and Enterococcus faecium (6/6) with a sensitivity of 100%, 60%, and 100%, respectively. The median time from blood collection to species identification was 27.4 h with MALDI-TOF identification and 46.6 h with conventional methodology. CONCLUSION: Using MALDI-TOF directly from positive blood cultures allowed a shorter time to identification with high sensitivity and specificity in immunosuppressed patients.
Authors: Ingvar Ludwig Augusto de Souza; Milene Gonçalves Quiles; Bruno Cruz Boettger; Antonio Carlos Campos Pignatari; Paola Cappellano Journal: Braz J Infect Dis Date: 2018-06-28 Impact factor: 3.257