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

Author(s):  
Tugce Unalan-Altintop ◽  
Alper Karagoz ◽  
Gulsen Hazirolan

Abstract MALDI-TOF MS provides fast, easy to perform and cost-effective diagnosis in clinical microbiology laboratories, however in some cases results of MALDI-TOF MS should be confirmed with additional tests. This confirmation is especially important for causes of life-threatening infections like Neisseria meningitidis. In our laboratory, three isolates were identified as N. meningitidis by Bruker MALDI Biotyper (BD, USA) between April 2018 and March 2019 from clinical specimens of blood, sputum, and urine. 16S rRNA sequencing was performed for further investigation. Two of the isolates were identified as Neisseria subflava and only one was confirmed as N. meningitidis by sequencing. These results show that MALDI-TOF MS is not always reliable in the diagnosis of N. meningitidis and clinical microbiologists should confirm these results with additional tests. Also, clinical correlations should be determined. Accurate identification of this microorganism is very important because of the necessity of prophylactic antimicrobial usage and biosafety precautions. Enlarged databases of Neisseria species are needed to overcome this problem.

2021 ◽  
Vol 9 (4) ◽  
pp. 708
Author(s):  
Jéssica Costa ◽  
Eugénio C. Ferreira ◽  
Cledir Santos

COVID-19 and arboviruses (ARBOD) epidemics co-occurrence is a great concern. In tropical and subtropical regions, ARBOD diseases such as chikungunya, dengue, and Zika are frequent. In both COVID-19 and ARBOD cases, an accurate diagnosis of infected patients is crucial to promote adequate treatment and isolation measures in COVID-19 cases. Overlap of clinical symptoms and laboratory parameters between COVID-19 and ARBOD present themselves as an extra challenge during diagnosis. COVID-19 diagnosis is mainly performed by quantitative reverse polymerase chain reaction (RT-qPCR), while ARBOD diagnosis is performed by serology, detection of antigen or antibody, and molecular diagnosis. In this review, the epidemiologic profile of arboviruses and SARS-CoV-2 is analyzed, and potential risks of symptom overlap is addressed. The implementation of an analytical platform based on infrared (IR) spectroscopy, MALDI-TOF mass spectrometry, and RT-qPCR is discussed as an efficient strategy for a fast, robust, reliable, and cost-effective diagnosis system even during the co-occurrence of virus outbreaks. The spectral data of IR spectroscopy and MALDI-TOF MS obtained from COVID-19 infected and recovered patients can be used to build up an integrated spectral database. This approach can enable us to determine quickly the groups that have been exposed and have recovered from COVID-19 or ARBOD, avoiding misdiagnoses.


2020 ◽  
Vol 5 (3) ◽  
pp. 454-466
Author(s):  
Grace R Williams ◽  
Leanne Cook ◽  
Lionel D Lewis ◽  
Gregory J Tsongalis ◽  
Robert D Nerenz

Abstract Background Laboratorians have the opportunity to help minimize the frequency of adverse drug reactions by implementing pharmacogenomic testing and alerting care providers to possible patient/drug incompatibilities before drug treatment is initiated. Methods combining PCR with MALDI-ToF MS have allowed for sensitive, economical, and multiplexed pharmacogenomic testing results to be delivered in a timely fashion. Method This study evaluated the analytical performance of the Agena Biosciences iPLEX® PGx 74 panel and a custom iPLEX panel on a MassARRAY MALDI-TOF MS instrument in a clinical laboratory setting. Collectively, these panels evaluate 112 SNVs across 34 genes implicated in drug response. Using commercially available samples (Coriell Biorepository) and in-house extracted DNA, we determined ideal reaction conditions and assessed accuracy, precision, and robustness. Results Following protocol optimization, the Agena PGx74 and custom panels demonstrated 100% concordance with the 1000 Genomes Project Database and clinically validated hydrolysis probe genotyping assays. 100% concordance was also observed in all assessments of assay precision when appropriate QC metrics were applied. Conclusions Significant development time was required to optimize sample preparation and instrumental analysis and 3 assays were removed due to inconsistent performance. Following modification of the manufacturer’s protocol and instituting manual review of each assay plate, the Agena PGx74 and custom panel constitute a cost-effective, robust, and accurate method for clinical identification of 106 SNVs involved in drug response.


2019 ◽  
Vol 57 (11) ◽  
Author(s):  
Matthew C. Canver ◽  
Tsigereda Tekle ◽  
Samantha T. Compton ◽  
Katrina Callan ◽  
Eileen M. Burd ◽  
...  

ABSTRACT The Staphylococcus intermedius group (SIG) is a collection of coagulase-positive staphylococci consisting of four distinct species, namely, Staphylococcus cornubiensis, Staphylococcus delphini, Staphylococcus intermedius, and Staphylococcus pseudintermedius. SIG members are animal pathogens and rare causes of human infection. Accurate identification of S. pseudintermedius has important implications for interpretation of antimicrobial susceptibility testing data and may be important for other members of the group. Therefore, we sought to evaluate the performance of five commercially available identification platforms with 21 S. delphini isolates obtained from a variety of animal and geographic sources. Here, we show that automated biochemical platforms were unable to identify S. delphini to the species level, a function of its omission from their databases, but could identify isolates to the SIG level with various degrees of success. However, all automated systems misidentified at least one isolate as Staphylococcus aureus. One matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) system was able to identify S. delphini to the species level, suggesting that MALDI-TOF MS is the best option for distinguishing members of the SIG. With the exception of S. pseudintermedius, it is unclear if other SIG members should be routinely identified to the species level; however, as our understanding of their role in animal and human diseases increases, it may be necessary and important to do so.


2012 ◽  
Vol 27 (1) ◽  
Author(s):  
Romano Mattei ◽  
Claudia Vicario ◽  
Maria Nardone ◽  
Arnaldo Savarino

2021 ◽  
Author(s):  
kwenrich not provided

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) can accurately identify bloodstream pathogens directly from positive blood culture bottles without the need to wait for agar plate growth. In this study, 2% sodium dodecyl sulfate (SDS) detergent was assessed to determine its benefit in the removal of interfering cellular components for testing on the Bruker Microflex LT MALDI-TOF MS instrument with the Biotyper® CA system. Additionally, the use of a heat-drying step was evaluated for performance improvement over conventional air-drying of samples on the MALDI steel target plate. The modified method with 2% SDS outperformed the in-house protocol in overall success with percentage scores of 91% and 55% ( respectively). The data results support the potential of applying a simple lysing step to an existing in-house extraction method and the use of modified drying methods. The modified techniques evaluated in this study proved beneficial for identifying most blood culture pathogens encountered in the clinical laboratory, and they can allow for reduced turnaround times and more appropriate antibiotic treatments.


2014 ◽  
Vol 7 (1) ◽  
Author(s):  
Constentin Dieme ◽  
Amina Yssouf ◽  
Anubis Vega-Rúa ◽  
Jean-Michel Berenger ◽  
Anna-Bella Failloux ◽  
...  

2019 ◽  
Vol 57 (5) ◽  
Author(s):  
Lisa M. T. Lam ◽  
Philippe J. Dufresne ◽  
Jean Longtin ◽  
Jacqueline Sedman ◽  
Ashraf A. Ismail

ABSTRACT Invasive fungal infections by opportunistic yeasts have increased concomitantly with the growth of an immunocompromised patient population. Misidentification of yeasts can lead to inappropriate antifungal treatment and complications. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy is a promising method for rapid and accurate identification of microorganisms. ATR-FTIR spectroscopy is a standalone, inexpensive, reagent-free technique that provides results within minutes after initial culture. In this study, a comprehensive spectral reference database of 65 clinically relevant yeast species was constructed and tested prospectively on spectra recorded (from colonies taken from culture plates) for 318 routine yeasts isolated from various body fluids and specimens received from 38 microbiology laboratories over a 4-month period in our clinical laboratory. ATR-FTIR spectroscopy attained comparable identification performance with matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). In a preliminary validation of the ATR-FTIR method, correct identification rates of 100% and 95.6% at the genus and species levels, respectively, were achieved, with 3.5% unidentified and 0.9% misidentified. By expanding the number of spectra in the spectral reference database for species for which isolates could not be identified or had been misidentified, we were able to improve identification at the species level to 99.7%. Thus, ATR-FTIR spectroscopy provides a new standalone method that can rival MALDI-TOF MS for the accurate identification of a broad range of medically important yeasts. The simplicity of the ATR-FTIR spectroscopy workflow favors its use in clinical laboratories for timely and low-cost identification of life-threatening yeast strains for appropriate treatment.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Anastasia Pavelkovich ◽  
Arta Balode ◽  
Petra Edquist ◽  
Svetlana Egorova ◽  
Marina Ivanova ◽  
...  

The spread of carbapenemase-producing Enterobacteriaceae is a global problem; however, no exact data on the epidemiology of carbapenemase in the Baltic countries and St. Petersburg area is available. We aimed to evaluate the epidemiology of carbapenemase-producingEscherichia coliandKlebsiella pneumoniaein the Baltic States and St. Petersburg, Russia, and to compare the different methods for carbapenemase detection. From January to May 2012, allK. pneumoniae  n=1983andE. coli  n=7774clinical isolates from 20 institutions in Estonia, Latvia, Lithuania, and St. Petersburg, Russia were screened for carbapenem susceptibility. The IMP, VIM, GIM, NDM, KPC, and OXA-48 genes were detected using real-time PCR and the ability to hydrolyze ertapenem was determined using MALDI-TOF MS. Seventy-seven strains were found to be carbapenem nonsusceptible. From these, 15K. pneumoniaestrains hydrolyzed ertapenem and carried theblaNDMgene. All of these strains carried integron 1 and most carried integron 3 as well as genes of the CTX-M-1 group. No carbapenemase-producingE. coliorK. pneumoniaestrains were found in Estonia, Latvia, or Lithuania; however, NDM-positiveK. pneumoniaewas present in the hospital in St. Petersburg, Russia. A MALDI-TOF MS-based assay is a suitable and cost-effective method for the initial confirmation of carbapenemase production.


2019 ◽  
Vol 440 ◽  
pp. 32-36 ◽  
Author(s):  
Maya Azrad ◽  
Victoria Freidus ◽  
Riad Kassem ◽  
Avi Peretz

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