Effect of Culture Conditions on Microorganism Identification by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry

Valentine, Nancy B.; Wunschel, Sharon C.; Wunschel, David S.; Petersen, Catherine E.; Wahl, Karen L.

doi:10.1128/aem.71.1.58-64.2005

Cited by 209 publications

(150 citation statements)

References 23 publications

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“…Protein expression depends on a variety of environmental factors, such as culture conditions, including different growth phases, agar plates, pH and temperature, and may also have contributed to this effect. Although several studies have pointed out that differences in peak profile are dependent on environmental conditions (Longo et al, 1999;Bernardo et al, 2002;Valentine et al, 2005;Wunschel et al, 2005), the identifying algorithm and detection range of the MALDI Biotyper database allow reliable identification from a variety of agar media. A large number of clonally different strains should be analysed to get a peak profile that is reliable and appropriate for one species.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of species-specific score cut-off values for various Staphylococcus species using a MALDI Biotyper-based identification

Richter

Hollstein

Woloszyn

et al. 2012

Journal of Medical Microbiology

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Although previous studies investigating the MALDI Biotyper database (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry-based identification) have proven its high accuracy for bacterial identification, the studies differed in sample preparation, number of replicates, quantity of shots and target types used. In particular, the score cut-off values of special importance for reliable species identification varied. The aim of the present study was to identify species-specific differences in the mean score values for staphylococci. Cut-off values recommended by the manufacturer were adapted using the 20th percentile to rule out unknown score-modifying factors, even though the specificity was high and the lowest cut-off values would also yield an accurate result. Whilst correct species diagnosis was obtained in 97.32 % of samples (1382/1420), only 220 of all duplicates (15.49 %) revealed a score of ¢2.3, whilst 968 (68.17 %) had a score between 2.0 and 2.299, and 194 (13.66 %) had a score of ,2.0. Ten of 21 species had a calculated 20th percentile of ,2.0 and one species of ,1.7. In conclusion, the use of species-specific cut-off values improves the relative sensitivity of species identification in staphylococci.

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Section: Discussionmentioning

confidence: 99%

Evaluation of species-specific score cut-off values for various Staphylococcus species using a MALDI Biotyper-based identification

Richter

Hollstein

Woloszyn

et al. 2012

Journal of Medical Microbiology

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“…Recent studies demonstrated the ability of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) to permit the identification of bacteria at the species level in pure culture under carefully controlled culture and analysis conditions (Conway et al, 2001;Fenselau & Demirev, 2001;Valentine et al, 2005). Furthermore, spectra from MALDI-TOF MS reflect the phylogenetic relationship of micro-organisms, corresponding with the results of sequence analyses of conservative genes (Stackebrandt et al, 2005).…”

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confidence: 99%

Agrococcus versicolor sp. nov., an actinobacterium associated with the phyllosphere of potato plants

Behrendt

Schümann

Ulrich

2008

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

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The taxonomic position of a group of actinobacterial strains isolated from the phyllosphere of potato plants was investigated by using a polyphasic approach. Although the similarity values for their 16S rRNA gene sequences suggested an intermediate position between Microbacterium and Agrococcus, the phylogenetic tree demonstrated a clear clustering of the representative strain, K 114/01 T , within the genus Agrococcus. The presence of 2,4-diaminobutyric acid as the diagnostic diamino acid in the cell-wall peptidoglycan of strain K 114/01 T substantiated the affiliation to the genus Agrococcus. An analysis performed using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry revealed highly similar spectral patterns for the isolated strains, which, together with their conformity regarding a multitude of phenotypic features, supported their affiliation to the same species. Differences in several physiological features, peptidoglycan and menaquinone composition and whole-cell fatty acid profiles enabled discrimination of the phyllosphere isolates with respect to recognized Agrococcus species. As the 16S rRNA gene sequence similarity values were below 97 %, the strains isolated from the phyllosphere of potato plants represent a novel species of the genus Agrococcus, for which the name Agrococcus versicolor sp. nov. is proposed. The type strain is K 114/01 T (5DSM 19812 T 5LMG 24386 T ).

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“…Mass spectral analysis of intact cells has evolved to provide an efficient tool for the identification of micro-organisms on various taxonomic levels (Fenselau & Demirev, 2001) and allows dereplication of novel isolates (Dieckmann et al, 2005) and taxonomic revisions (Stackebrandt et al, 2005). The methodology is based on the detection of abundant structural proteins, such as ribosomal proteins or DNA-binding proteins (Ryzhov & Fenselau, 2001;Fagerquist et al, 2005), generating taxonspecific patterns (Valentine et al, 2005). Various mathematical methods have been developed to compare mass spectra and to construct trees based on pattern similarity (Jarman & Wahl, 2006).…”

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confidence: 99%

Microbacterium binotii sp. nov., isolated from human blood

Clermont

Diard

Bouchier

et al. 2009

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

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Two strains of non-spore-forming, rod-shaped, Gram-positive bacteria, CIP 101303 T and CIP 102116, were isolated from human blood in 1976 and 1977, respectively. These strains had chemotaxonomic markers that were consistent with classification in the genus Microbacterium, i.e. MK-10, MK-11 and MK-12 as the major menaquinones, predominant iso-and anteiso-branched cellular fatty acids, galactose, mannose and rhamnose as the cell-wall sugars and ornithine as the diamino acid in the cell-wall peptidoglycan. The DNA G+C content was 70-72 mol%. Comparative 16S rRNA gene sequence studies revealed that strains CIP 101303 T and CIP 102116 belonged to the genus Microbacterium and that they were related closely to Microbacterium halotolerans. The level of DNA-DNA relatedness showed that the two isolates represented a separate genomic species. Based on phenotypic and genotypic results, it is proposed that strains CIP 101303 T and CIP 102116 be assigned to a novel species, Microbacterium binotii sp. nov. The type strain is CIP 101303 T (5DSM 19164 T ).

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Effect of Culture Conditions on Microorganism Identification by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry

Cited by 209 publications

References 23 publications

Evaluation of species-specific score cut-off values for various Staphylococcus species using a MALDI Biotyper-based identification

Evaluation of species-specific score cut-off values for various Staphylococcus species using a MALDI Biotyper-based identification

Agrococcus versicolor sp. nov., an actinobacterium associated with the phyllosphere of potato plants

Microbacterium binotii sp. nov., isolated from human blood

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