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

Abstract

Burkholderia pseudomallei is not represented in the current version of Bruker Biotyper matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) system. A total of 66 isolates of B. pseudomallei, including 30 clinical isolates collected from National Taiwan University Hospital (NTUH, n = 27) and Peking Union Medical College Hospital (PUMCH, n = 3), and 36 isolates of genetically confirmed strains, including 13 from clinical samples and 23 from environmental samples, collected from southern Taiwan were included in this study. All these isolates were identified by partial 16S rDNA gene sequencing analysis and the Bruker Biotyper MALDI-TOF MS system. Among the 30 isolates initially identified as B. pseudomallei by conventional identification methods, one was identified as B. cepacia complex (NTUH) and three were identified as B. putida (PUMCH) by partial 16S rDNA gene sequencing analysis and Bruker Biotyper MALDI-TOF MS system. The Bruker Biotyper MALDI-TOF MS system misidentified 62 genetically confirmed B. pseudomallei isolates as B. thailandensis or Burkholderia species (score values, 1.803–2.063) when the currently available database (DB 5627) was used. However, using a newly created MALDI-TOF MS database (including B. pseudomallei NTUH-3 strain), all isolates were correctly identified as B. pseudomallei (score values >2.000, 100%). An additional 60 isolates of genetically confirmed B. cepacia complex and B. putida were also evaluated by the Bruker Biotyper MALDI-TOF MS system using the newly created database and none of these isolates were identified as B. pseudomallei. MALDI-TOF MS is a versatile and robust tool for the rapid identification of B. pseudomallei using the enhanced database.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the identification of Burkholderia pseudomallei from Asia and Australia and differentiation between Burkholderia species

“…Nearly all of these (62/66 isolates) were initially misidentified as B . thailandensis using an existing database (DB5627), but an enhanced database subsequently identified all correctly [34]. A limitation of this study was that most of the isolates (63/66) were from a single country (Taiwan), the remaining 3 originating from Beijing, China.…”

Research on the establishment and application of protein fingerprint spectrum database of Burkholderia pseudomallei in Hainan Province China

“…In this study, it was demonstrated that the specific peaks of Hainan were partially different from those of Thailand [3,11], Taiwan [4], Australia [3] and other endemic regions. B.pseudomallei isolates in the above areas were all found in 2049 Da, 4410 Da , 5149 Da, 6551 Da and 7169 Da, respectively.see text Fig 1. Furthermore, the specific peaks of Hainan were extremely similar to those of B. Additionally, they used 57 B.pseudomallei strains and 60 strains of B. cepacia and B. putida to verify the newly created database, in which B.pseudomallei can be correctly identified and B. cepacia and B. putida were not identified mistakenly for B.pseudomallei [4]. The largest evaluation of B. pseudomallei, to date, has been undertaken using 26 strains of B.pseudomallei from Thailand, Laos, Cambodia, Australia and 21 other Burkholderia strains to construct the database [3].…”

The Brief Case: A Traveler’s Tale—Burkholderia pseudomallei Infection in a Cystic Fibrosis Patient

“…MALDI-TOF MS incorrectly identified this organism as Burkholderia thailandensis (albeit at a suboptimal rating), which is genetically closely related to B. pseudomallei but is nonpathogenic in humans. Misidentification of B. pseudomallei by the Bruker MALDI-TOF MS has been well described in the literature (1,5,(14)(15)(16). In this case, the Public Health England UK antimicrobial resistance and health care-associated infections reference unit, opportunistic pathogens section based in Colindale, London, used a species-specific PCR to identify this organism and performed susceptibility testing in a BSL3 facility (2,3).…”

“…As B. pseudomallei can be acquired through inhalation, all culture plates for suspected or confirmed cases should be handled by trained personnel with the appropriate personal protective equipment (PPE). Respiratory protection must be used during centrifugation because of the potential to generate aerosols and transmit infection (3,5,10,(13)(14)(15)(16). Sealed cups should be used in all centrifuges, and these should be opened only in a biologic safety cabinet (5).…”