Misidentification of <i>Neisseria cinerea</i> as <i>Neisseria meningitidis</i> by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS)

Abstract

Communicated by Makoto OhnishiMatrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) is used as a rapid and accurate microbial diagnostic method for species identification of pathogens. At our hospital, we use MALDI-TOF MS for rapid identification of microorganisms from pathogen-positive blood cultures. In this article, we report a case where Neisseria meningitidis was confirmed via blood culture using MALDI-TOF MS, but the microbe was ultimately confirmed to be Neisseria cinerea.The 30-year-old patient received a diagnosis of Burkitt lymphoma, and chemotherapy (R-HyperCVAD MA; rituximab, cyclophosphamide, vincristine, doxorubicin, dexamethasone, methotrexate, and cytarabine) was started on day 4 of hospitalization (Day 4). On Day 15, his body temperature rose to 39.2 C without symptoms of a common cold. Two sets of blood cultures were initiated on Day 15, and a Gram-negative coccus was detected in an aerobic bottle on Day 16. The acquisition and analysis of mass spectra were performed on a Microflex LT mass spectrometer (Bruker Daltonics, Bremen, Germany) and using the MALDI Biotyper software package (ver. 3.1) with the reference database ver. 3.1.2.0 (3,995 database entries) (Bruker Daltonics).The cultivated bacterium was identified as N. meningitidis with Score Value 2.024 (best match) and Score Value 1.966 (second best match). The Score Value 2.024 of this pathogen was lower than that of a known strain, N. meningitidis (Score Value 2.437). Their MALDI-TOF MS spectra showed different wave patterns and peaks between the pathogen isolated from the patient (Fig. 1) and stocked N. meningitidis (Fig. 2).Colony morphology and microscopic morphology were also different between these microbes. The blood culture sediment of the patient showed nonspecific agglutination in a latex agglutination assay (Pastorex Meningitis; Bio-Rad, Hercules, CA, USA). The strain from

A diagnostic challenge in clinical laboratory: Misidentification of Neisseria subflava as Neisseria meningitidis by MALDI-TOF MS

“…Our findings correlate with the data presented by Hong et al in which two isolates of Neisseria polysaccharaea, two Neisseria cinerea and one Neisseria bergeri were misidentified as N. meningitidis using Bruker MALDI Biotyper [2]. In a case reported from Japan, a blood isolate of N. cinerea was named as N. meningitidis by MALDI-TOF MS [6]. Also, Cunningham et al reports five isolates of N. polysaccharea with an identification problem as meningococci [7].…”

Whole Genome Analyses Accurately Identify Neisseria spp. and Limit Taxonomic Ambiguity

“…However, other studies suspected that the number of reference spectra in the MALDI-TOF database was insufficient, resulting in poor discriminatory power for closely related non-pathogenic Neisseria spp. [ 17 , 18 ]. To resolve this issue, some studies suggested to group N. macacae and N. mucosa isolates into the N. mucosa category and N. flavescens and N. perflava into one category with N. subflava [ 10 , 19 ].…”

Recurrent Neisseria cinerea bacteremia secondary to cardiovascular implantable electronic device infection

“…Although both diplococci, N. cinerea can be differentiated from N. gonorrhoeae due to its sensitivity to colistin and its ability to proliferate on Mueller-Hinton agar [8] . The widespread implementation of matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has improved the identification of Neisseria species but remains imperfect [9] , [10] .…”