scholarly journals Rapid identification of Nocardia cyriacigeorgica from a brain abscess patient using MALDI-TOF-MS

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Mohammed AlMogbel ◽  
Mohammed AlBolbol ◽  
Noura Elkhizzi ◽  
Hisham AlAjlan ◽  
John Philip Hays ◽  
...  

Abstract Nocardia cyriacigeorgica (N. cyriacigeorgica) is most frequently associated with human infections, including chronic bronchitis, pulmonary disease and brain abscesses. In general, N. cyriacigeorgica causes infections in immunocompromised individuals and has been reported in clinical samples worldwide. However, the isolation and speciation of N. cyriacigeorgica in the routine diagnostic microbiology laboratory are complicated and time consuming. Recent mass spectrometry techniques such as matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI-TOF-MS) have been successfully integrated into many routine diagnostic microbiology laboratories, allowing for the rapid, accurate and simple identification and speciation of many different microorganisms, including difficult-to-identify bacterial species. Here, we present a case report of a 65-year-old female patient from the neurology ward of Prince Sultan Military Medical City in Riyadh, Saudi Arabia, who was infected with N. cyriacigeorgica. The bacterium was successfully identified by MALDI-TOF-MS, with species identification subsequently confirmed by sequence analysis of the 16S ribosomal RNA.

Parasite ◽  
2020 ◽  
Vol 27 ◽  
pp. 28 ◽  
Author(s):  
Basma Ouarti ◽  
Maureen Laroche ◽  
Souad Righi ◽  
Mohamed Nadir Meguini ◽  
Ahmed Benakhla ◽  
...  

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is now routinely used for the rapid identification of microorganisms isolated from clinical samples and has been recently successfully applied to the identification of arthropods. In the present study, this proteomics tool was used to identify lice collected from livestock and poultry in Algeria. The MALDI-TOF MS spectra of 408 adult specimens were measured for 14 species, including Bovicola bovis, B. ovis, B. caprae, Haematopinus eurysternus, Linognathus africanus, L. vituli, Solenopotes capillatus, Menacanthus stramineus, Menopon gallinae, Chelopistes meleagridis, Goniocotes gallinae, Goniodes gigas, Lipeurus caponis and laboratory reared Pediculus humanus corporis. Good quality spectra were obtained for 305 samples. Spectral analysis revealed intra-species reproducibility and inter-species specificity that were consistent with the morphological classification. A blind test of 248 specimens was performed against the in-lab database upgraded with new spectra and validated using molecular tools. With identification percentages ranging from 76% to 100% alongside high identification scores (mean = 2.115), this study proposes MALDI-TOF MS as an effective tool for discriminating lice species.


2014 ◽  
Vol 8 (09) ◽  
pp. 1081-1088 ◽  
Author(s):  
Elena De Carolis ◽  
Antonietta Vella ◽  
Luisa Vaccaro ◽  
Riccardo Torelli ◽  
Teresa Spanu ◽  
...  

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently emerged as a powerful technique for identification of microorganisms, changing the workflow of well-established laboratories so that its impact on microbiological diagnostics has been unparalleled. In comparison with conventional identification methods that rely on biochemical tests and require long incubation procedures, MALDI-TOF MS has the advantage of identifying bacteria and fungi directly from colonies grown on culture plates in a few minutes and with simple procedures. Numerous studies on different systems available demonstrate the reliability and accuracy of the method, and new frontiers have been explored besides microbial species level identification, such as direct identification of pathogens from positive blood cultures, subtyping, and drug susceptibility detection.


2010 ◽  
Vol 59 (3) ◽  
pp. 273-284 ◽  
Author(s):  
Claire Moliner ◽  
Christophe Ginevra ◽  
Sophie Jarraud ◽  
Christophe Flaudrops ◽  
Marielle Bedotto ◽  
...  

Legionella species are facultative, intracellular bacteria that infect macrophages and protozoa, with the latter acting as transmission vectors to humans. These fastidious bacteria mostly cause pulmonary tract infections and are routinely identified by various molecular methods, mainly PCR targeting the mip gene and sequencing, which are expensive and time-consuming. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has emerged as a rapid and inexpensive method for identification of bacterial species. This study evaluated the use of MALDI-TOF-MS for rapid species and serogroup identification of 21 Legionella species recognized as human pathogens. To this end, a reference MS database was developed including 59 Legionella type strains, and a blind test was performed using 237 strains from various species. Two hundred and twenty-three of the 237 strains (94.1 %) were correctly identified at the species level, although ten (4.2 %) were identified with a score lower than 2.0. Fourteen strains (5.9 %) from eight species were misidentified at the species level, including seven (3.0 %) with a significant score, suggesting an intraspecific variability of protein profiles within some species. MALDI-TOF-MS was reproducible but could not identify Legionella strains at the serogroup level. When compared with mip gene sequencing, MALDI-TOF-MS exhibited a sensitivity of 99.2 and 89.9 % for the identification of Legionella strains at the genus and species level, respectively. This study demonstrated that MALDI-TOF-MS is a reliable tool for the rapid identification of Legionella strains at the species level.


2009 ◽  
Vol 58 (9) ◽  
pp. 1154-1159 ◽  
Author(s):  
Pierre-Edouard Fournier ◽  
Carine Couderc ◽  
Sylvain Buffet ◽  
Christophe Flaudrops ◽  
Didier Raoult

Bacteria of the genus Bartonella are emerging zoonotic bacteria recognized in a variety of human diseases. Due to their poor chemical reactivity, these fastidious bacteria are poorly characterized using routine phenotypic laboratory tests. Identification is usually achieved using molecular techniques that are time-consuming, expensive and technically demanding. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as a new technique for bacterial species identification. This study evaluated the use of MALDI-TOF MS for rapid genus and species identification of Bartonella species. Reference strains representing 17 recognized Bartonella species were studied. For each species, MS spectra for four colonies were analysed. The consensus spectrum obtained for each species was unique among spectra obtained for 2843 bacteria within the Bruker database, including 109 alphaproteobacteria. Thirty-nine additional blind-coded Bartonella strains were correctly identified at the species level, including 36 with a significant score. Altogether, these data demonstrate that MS is an accurate and reproducible tool for rapid and inexpensive identification of Bartonella species.


2020 ◽  
Author(s):  
Patharapol Piamsomboon ◽  
Janthima Jaresitthikunchai ◽  
Tran Quang Hung ◽  
Sittiruk Roytrakul ◽  
Janenuj Wongtavatchai

Abstract Background: The majority of infectious diseases of cultured fish is caused by bacteria. Rapid identification of bacterial pathogens is necessary for immediate management. The present study developed a custom Main Spectra Profile (MSP) database and validate the method using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for rapid identification of fish bacterial pathogens. Streptococcus agalactiae, Streptococcus iniae, Aeromonas hydrophila, Aeromonas veronii, and Edwardsiella tarda obtained from diseased fish were used as representative bacterial pathogens in this study. Bacterial peptides were extracted to create a Main Spectra Profile (MSP), and the MSPs of each bacterial species was added into the MALDI Biotyper database. Fifteen additional isolates of each bacterial species were tested to validate the utilized technique. Results: The MSPs of all field isolates were clearly distinguishable, and the MSPs of the same species were clustered together. The identification methodology was validated with 75 bacterial isolates. The reliability and specificity of the method were determined with MALDI Biotyper log score values and matching results with 16s rDNA sequencing. The species identification using the public MALDI Biotyper library (Bruker MALDI Biotyper) showed unreliable results (log score <2.000) with 42.67% matching result with the reference method. In contrast, accurate identification was obtained when using the custom-made database, giving log score > 2.115, and a 100% matching result. Conclusion: This study demonstrates an effective identification of fish bacterial pathogens when a complete custom-made MSP database is applied. Further applications require a broad, well-established database to accommodate prudent identification of many fish bacterial pathogens by MALDI-TOF MS.


Author(s):  
Xue Wan ◽  
Shuang Wang ◽  
Min Wang ◽  
Jinhua Liu ◽  
Yu Zhang

Gram-positive anaerobic cocci (GPAC) are a commensal part of human flora but are also opportunistic pathogens. This is possibly the first study to report a case of Peptoniphilus harei bacteremia in an abdominal aortic aneurysm (AAA) patient. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) failed to identify the isolate and molecular analysis confirmed it as P. harei. A comprehensive literature review revealed that P. harei is an emergent pathogen. This study serves as a reminder for practicing clinicians to include anaerobic blood cultures as part of their blood culture procedures; this is particularly important situations with a high level of suspicion of infection factors in some noninfectious diseases, as mentioned in this publication. Clinical microbiologists should be aware that the pathogenic potential of GPAC can be greatly underestimated leading to incorrect diagnosis on using only one method for pathogen identification. Upgradation and correction of the MALDI-TOF MS databases is recommended to provide reliable and rapid identification of GPAC at species level in medical diagnostic microbiology laboratories.


2013 ◽  
Vol 24 (4) ◽  
pp. 191-194 ◽  
Author(s):  
Manal Tadros ◽  
Astrid Petrich

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) can be used to identify bacteria directly from positive blood and sterile fluid cultures. The authors evaluated a commercially available kit – the Sepsityper Kit (Bruker Daltonik, Germany) – and MALDI-TOF MS for the rapid identification of organisms from 80 flagged positive blood culture broths, of which 73 (91.2%) were blood culture specimens and seven (8.7%) were cerebrospinal fluid specimens, in comparison with conventional identification methods. Correct identification to the genus and species levels was obtained in 75 of 80 (93.8%) and 39 of 50 (78%) blood culture broths, respectively. Applying the blood culture analysis module, a newly developed software tool, improved the species identification of Gram-negative organisms from 94.7% to 100% and of Gram-positive organisms from 66.7% to 70%.MALDI-TOF MS is a promising tool for the direct identification of organisms cultured from sterile sites.


2020 ◽  
Author(s):  
Patharapol Piamsomboon ◽  
Janthima Jaresitthikunchai ◽  
Tran Quang Hung ◽  
Sittiruk Roytrakul ◽  
Janenuj Wongtavatchai

Abstract Background: The majority of infectious diseases of cultured fish is caused by bacteria. Rapid identification of bacterial pathogens is necessary for immediate management. The present study developed a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for rapid identification of fish bacterial pathogens. Streptococcus agalactiae, Streptococcus iniae, Aeromonas hydrophila, Aeromonas veronii, and Edwardsiella tarda obtained from diseased fish were used as representative bacterial pathogens in this study. Bacterial peptides were extracted to create a Main Spectra Profile (MSP), and the MSPs of each bacterial species was added into the MALDI Biotyper database. Fifteen additional isolates of each bacterial species were tested to validate the utilized technique. Results: The MSPs of all field isolates were clearly distinguishable, and the MSPs of the same species were clustered together. However, the species identification when matched with the public MALDI Biotyper library (Bruker MALDI Biotyper) showed unreliable results. Accurate identification was only obtained when using the custom-made database, giving a 100% matching result with the reference method. Conclusion: This study demonstrates an alternative technique for effective identification of fish bacterial pathogens. Further applications require a broad, well-established database to accommodate prudent identification of many fish bacterial pathogens by MALDI-TOF MS.


2010 ◽  
Vol 31 (3) ◽  
pp. 111
Author(s):  
Stephen A Neville ◽  
Iain B Gosbell

Although the application of mass spectrometry to bacterial identification was proposed as far back as 1975 by John Anhalt, it was not until 1987 when Professor Franz Hillenkamp and Dr Michael Karas first pioneered Matrix Assisted Laser Desorption/Ionisation Time-of-Flight mass spectrometry (MALDI-TOF MS) for truly rapid microbial identification in diagnostic microbiology laboratories. Conventional phenotypic methods of identifying isolates of bacteria, yeasts and filamentous fungi require hours to several days to complete, depending on the type of organism involved, and may be prone to error due to bias or inexperience. Even the more recent molecular innovations have their limitations that place them outside the scope and budget of many routine laboratories. However, MALDI-TOF MS technology has changed the way we think about microbial identifications and strain differentiation by providing results from plate to name in approximately five minutes for one isolate and around 90 minutes for 60 isolates at under $2 an identification. It is likely to be particularly helpful clinically for identification of species in positive blood culture broths and for organisms that are hard to identify quickly.


2021 ◽  
Vol 12 ◽  
Author(s):  
Keyi Yu ◽  
Zhenzhou Huang ◽  
Ying Li ◽  
Qingbo Fu ◽  
Lirong Lin ◽  
...  

Shewanella species are widely distributed in the aquatic environment and aquatic organisms. They are opportunistic human pathogens with increasing clinical infections reported in recent years. However, there is a lack of a rapid and accurate method to identify Shewanella species. We evaluated here matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for rapid identification of Shewanella. A peptide mass reference spectra (PMRS) database was constructed for the type strains of 36 Shewanella species. The main spectrum projection (MSP) cluster dendrogram showed that the type strains of Shewanella species can be effectively distinguished according to the different MS fingerprinting. The PMRS database was validated using 125 Shewanella test strains isolated from various sources and periods; 92.8% (n = 116) of the strains were correctly identified at the species level, compared with the results of multilocus sequence analysis (MLSA), which was previously shown to be a method for identifying Shewanella at the species level. The misidentified strains (n = 9) by MALDI-TOF MS involved five species of two groups, i.e., Shewanella algae–Shewanella chilikensis–Shewanella indica and Shewanella seohaensis–Shewanella xiamenensis. We then identified and defined species-specific biomarker peaks of the 36 species using the type strains and validated these selected biomarkers using 125 test strains. Our study demonstrated that MALDI-TOF MS was a reliable and powerful tool for the rapid identification of Shewanella strains at the species level.


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