Identification of Microorganisms Grown in Blood Culture Flasks using Liquid Chromatography–Tandem Mass Spectrometry

Abstract

Aim:Bloodstream infections are a common cause of disease and a fast and accurate identification of the causative agent or agents of bloodstream infections would aid the start of adequate treatment. Materials & methods: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) shotgun proteomics method was developed for the identification of bacterial species directly from blood cultures that were simulated by inoculating blood culture bottles with single or multiple clinically relevant microorganisms. Results: Using LC-MS/MS, the single species were correctly identified in 100% of the blood cultures, whereas for polymicrobial infections, 78% of both species were correctly identified in blood cultures. Conclusion: The LC-MS/MS method allows for the identification of the causative agent of positive blood cultures.

Current Status of Matrix-Assisted Laser Desorption/Ionization–Time-of-Flight Mass Spectrometry (MALDI-TOF MS) in Clinical Diagnostic Microbiology

“…LC-MS/MS is an essential tool for analyzing medicinal toxicants and therapeutic drug monitoring in forensic medicine [ 83 , 84 ]. The extent of the scientific literature relating to bacterial ID using LC-MS/MS has also gradually increased [ 85 , 86 , 87 , 88 ]. A method for the simultaneous ID of staphylococci and the detection of staphylococcal antimicrobial susceptibility also has been reported, although this method is currently still in development [ 89 ].…”

Identification of Microorganisms by Liquid Chromatography-Mass Spectrometry (LC-MS1) and in silico Peptide Mass Data

“…Identification results of samples #6 (Citrobacter freundii) and #21 (Escherichia coli) reveal that two out of the three top scored bacteria were correctly identified, including both top hits. Inspection of data from sample #21 suggested, however, that differentiation between E. coli and strains of Shigella is not straightforward, an observation which is substantiated by the special taxonomy of E. coli and Shigella and additionally reflected by findings made by other techniques, such as MALDI-TOF MS (Khot and Fisher, 2013;Paauw et al, 2015), LC-MS 2 -based approaches (Berendsen et al, 2017) or whole genome sequencing, WGS (Chattaway et al, 2017). In the instance of sample #21, we found 25 strain entries of E. coli and 5 entries from 3 different Shigella species (S. sonnei, 3 × S. boydii and S. dysenteriae) among the top 30 entries present in the score ranking list (data not shown).…”

“…Finally, LC-MS 2 is much less restricted to classes of proteins with specific physicochemical properties. Even though proteomic techniques are still complex, rather cost-intensive and limited for use by well-equipped laboratories, the many advantages of LC-MS have led to an increasing number of activities aiming at evaluating potential applications of LC-MS in microbiology (Jabbour et al, 2010;Jabbour et al, 2011;Tracz et al, 2013;Berendsen et al, 2017).…”

“…In this way, TCUP allowed typing and characterizing pathogenic bacteria from pure cultures and to estimate the relative abundances of individual microbial species from mixed microbial samples (Boulund et al, 2017). In the same year Berendsen and co-workers suggested a generic LC-MS 2 method for the identification of microorganisms from positive blood cultures (Berendsen et al, 2017). A LC-MS compatible sample preparation method was developed that enabled accurate identification of bacteria grown in blood culture flasks to species level based on LC-MS 2 bottom-up proteomics, data base searches and matching with taxonspecific discriminative peptides.…”

Anti-microbial sensitivity and resistance of organisms in blood-culture samples from prolonged fever cases: evidence from a tertiary care hospital in West Bengal, India

“…Blood cultures are believed to be the "gold standard" for diagnosis in such patients with suspected systemic infection or in particular septicaemia. [5][6][7][8] Upon detection of the organism, the sensitivity profile of the organism is usually investigated. Antibiotic sensitivity and resistance are an important tool to determine the future line of treatment in patients presenting with suspected infection and fever.…”