Evaluation of the Bruker Biotyper Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Blood Isolates of Vibrio Species

Abstract

e Among 56 blood isolates of Vibrio species identified by sequencing analysis of 16S rRNA and rpoB genes, the Bruker Biotyper matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) system correctly identified all isolates of Vibrio vulnificus (n ‫؍‬ 20), V. parahaemolyticus (n ‫؍‬ 2), and V. fluvialis (n ‫؍‬ 1) but none of the isolates of serogroup non-O1/O139 (non-serogroup O1, non-O139) V. cholerae (n ‫؍‬ 33) to the species level. All of these serogroup non-O1/O139 V. cholerae isolates were correctly identified using the newly created MALDI-TOF MS database. Vibrio cholerae causes an estimated 3 to 5 million cases of cholera, which result in 100,000 to 120,000 deaths each year (1). Vibrio cholerae and non-cholerae Vibrio species, especially V. vulnificus, V. parahaemolyticus, V. fluvialis, and V. alginolyticus, have been reported to also cause severe gastroenteritis, severe skin soft tissue infection (necrotizing fasciitis), biliary tract infections, septicemia, and other serious infections in immunocompromised and immunocompetent hosts (2-9). Given the potential of V. cholerae for rapid epidemic spread and its listing as a biothreat level B agent, it is crucial for clinical microbiology laboratories to be able to correctly identify and differentiate V. cholerae from other bacterial species, particularly Aeromonas species (10).Identification of human-pathogenic Vibrio species is traditionally based on conventional biochemical reactions and commercial identification systems (11-14), including API (API 20E), Vitek 2 (ID-GN card), and Phoenix (NMIC/ID-72) systems (11)(12)(13)(14). However, the ability of these commercially available identification systems to correctly identify Vibrio species is limited because of the high phenotypic diversity of this species (12,14). Partial sequencing analysis of the 16S rRNA and rpoB genes is a commonly used identification method (15).A number of studies have shown that matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) can rapidly and accurately identify bacteria and fungi to the species level (16). Our previous study demonstrated that the Bruker Biotyper MALDI-TOF MS system, with implementation of a newly created database, can accurately identify other important human-enteropathogenic aeromonads, such as Aeromonas dhakensis, A. hydrophila, A. veronii, and A. caviae (17). However, few studies have investigated the ability of the Bruker Biotyper MALDI-TOF MS system to accurately identify pathogenic Vibrio species, particularly V. cholerae (10,(18)(19)(20). In the present study, we evaluated the ability of the Bruker Biotyper MALDI-TOF MS system to accurately identify genetically confirmed Vibrio species that were recovered from patients with bloodstream infections.A total of 50 isolates of Vibrio species that were recovered from patients with bloodstream infections at National Taiwan University Hospital (NTUH; northern Taiwan) during the period 2004 to 2013 were obtained from the hospital's microbiolog...

Detection of Acinetobacter spp. in Blood Cultures by an Improved Fluorescent in Situ Hybridization Assay

“…In the present study, we added more bacterial strains including Flavobacterium spp., B. abortus, B. melitensis, N. meningitidis, Shewanella sp., Aeromonas sp., P. shigelloides, V. parahaemolyticus, P. rettgeri, and S. pneumoniae, that may cause bacteremia and be present in blood cultures (Hall, 2015;Wellinghausen et al, 2006;Carroll and Hobden, 2016;Hochedez et al, 2010;Chen et al, 2013;Cheng et al, 2015;Choi et al, 2015;Tajbakhsh et al, 2013a) and were not examined by Frickmann et al (2011). These strains were not hybridized with probe Aci and thus we confirmed the high specificity of this probe for the detection of Acinetobacter spp.…”

Evaluation of the Bruker Biotyper Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry System for Identification of Clinical and Environmental Isolates of Burkholderia pseudomallei

“…Partial 16S rRNA gene sequencing of all 66 isolates was performed using two primers, 8FPL (5′-AGAGTTT GATCCTGGCTCAG-3′) and 1492RPL (5′-GGTTACCTTG TTACGACTT-3′; Cheng et al, 2015 ). The sequences (1425 bp) obtained were compared with published sequences in the GenBank database using the BLAST algorithm ( http://www.ncbi.nlm.nih.gov/blast ).…”

“…Samples of the 66 isolates were prepared for analysis by the Bruker Biotyper MALDI-TOF MS system as previously described (Cheng et al, 2015 ). B. thailandensis E264 (ATCC700388) was included as the control strain.…”

Direct identification of trypanosomatids by matrix-assisted laser desorption ionization-time of flight mass spectrometry (DIT MALDI-TOF MS)

“…cruzi DTUs, using this method, can be attributed to the similarity, and this results in highly similar MALDI‐TOF MS profile . Strain‐specific identification is more challenging than species because within the same species different strains are highly similar, genotypically and phenotypically, in spite of having different functions . Strain‐level characterization involves specific peaks that function as biomarkers.…”