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Prof. Dr. Monika Ehling-Schulz
University of Veterinary Medicine Vienna

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0 Pathophysiology
0 Persistence
0 Bacillus sp.
0 FTIR spectroscopy
0 pathogenic bacteria

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FTIR spectroscopy
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bacterial toxins
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pathogenic bacteria

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Journal article
Published: 17 August 2021 in International Journal of Molecular Sciences
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Within-host adaptation is a typical feature of chronic, persistent Staphylococcus aureus infections. Research projects addressing adaptive changes due to bacterial in-host evolution increase our understanding of the pathogen’s strategies to survive and persist for a long time in various hosts such as human and bovine. In this study, we investigated the adaptive processes of S. aureus during chronic, persistent bovine mastitis using a previously isolated isogenic strain pair from a dairy cow with chronic, subclinical mastitis, in which the last variant (host-adapted, Sigma factor SigB-deficient) quickly replaced the initial, dominant variant. The strain pair was cultivated under specific in vitro infection-relevant growth-limiting conditions (iron-depleted RPMI under oxygen limitation). We used a combinatory approach of surfaceomics, molecular spectroscopic fingerprinting and in vitro phenotypic assays. Cellular cytotoxicity assays using red blood cells and bovine mammary epithelial cells (MAC-T) revealed changes towards a more cytotoxic phenotype in the host-adapted isolate with an increased alpha-hemolysin (α-toxin) secretion, suggesting an improved capacity to penetrate and disseminate the udder tissue. Our results foster the hypothesis that within-host evolved SigB-deficiency favours extracellular persistence in S. aureus infections. Here, we provide new insights into one possible adaptive strategy employed by S. aureus during chronic, bovine mastitis, and we emphasise the need to analyse genotype–phenotype associations under different infection-relevant growth conditions.

ACS Style

Katharina Mayer; Martin Kucklick; Helene Marbach; Monika Ehling-Schulz; Susanne Engelmann; Tom Grunert. Within-Host Adaptation of Staphylococcus aureus in a Bovine Mastitis Infection Is Associated with Increased Cytotoxicity. International Journal of Molecular Sciences 2021, 22, 8840 .

AMA Style

Katharina Mayer, Martin Kucklick, Helene Marbach, Monika Ehling-Schulz, Susanne Engelmann, Tom Grunert. Within-Host Adaptation of Staphylococcus aureus in a Bovine Mastitis Infection Is Associated with Increased Cytotoxicity. International Journal of Molecular Sciences. 2021; 22 (16):8840.

Chicago/Turabian Style

Katharina Mayer; Martin Kucklick; Helene Marbach; Monika Ehling-Schulz; Susanne Engelmann; Tom Grunert. 2021. "Within-Host Adaptation of Staphylococcus aureus in a Bovine Mastitis Infection Is Associated with Increased Cytotoxicity." International Journal of Molecular Sciences 22, no. 16: 8840.

Communication
Published: 28 July 2021 in Toxins
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Bacillus cereus is frequently associated with food-borne intoxications, and its emetic toxin cereulide causes emesis and nausea after consumption of contaminated foods. The major source for contamination is found within contaminated raw materials containing the highly chemically resistant cereulide, independent of vegetative bacteria cells. Up to date, non-existing removal strategies for cereulide evoke the question of how the toxin is distributed within a food sample, especially cow milk. Milk samples with different milk fat contents were incubated with purified cereulide, separated by centrifugation into a lipid and an aqueous phase, and cereulide was quantified in both fractions by SIDA-LC-MS/MS. By artificially increasing the milk fat content from 0.5% to 50%, the amount of cereulide recovered in the lipid phase and could be augmented from 13.3 to 78.6%. Further, the ratio of cereulide increased in the lipid phase of milk with additional plant-based lipid (sunflower oil) to 47.8%. This demonstrated a clear affinity of cereulide towards the hydrophobic, lipid phase, aligning with cereulide’s naturally strong hydrophobic properties. Therefore, an intensified cereulide analysis of lipid enriched dairy products to prevent severe cereulide intoxications or cross-contamination in processed foods is suggested.

ACS Style

Veronika Walser; Markus Kranzler; Corinna Dawid; Monika Ehling-Schulz; Timo Stark; Thomas Hofmann. Distribution of the Emetic Toxin Cereulide in Cow Milk. Toxins 2021, 13, 528 .

AMA Style

Veronika Walser, Markus Kranzler, Corinna Dawid, Monika Ehling-Schulz, Timo Stark, Thomas Hofmann. Distribution of the Emetic Toxin Cereulide in Cow Milk. Toxins. 2021; 13 (8):528.

Chicago/Turabian Style

Veronika Walser; Markus Kranzler; Corinna Dawid; Monika Ehling-Schulz; Timo Stark; Thomas Hofmann. 2021. "Distribution of the Emetic Toxin Cereulide in Cow Milk." Toxins 13, no. 8: 528.

Journal article
Published: 04 March 2021 in Molecules
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The emetic Bacillus cereus toxin cereulide presents an enormous safety hazard in the food industry, inducing emesis and nausea after the consumption of contaminated foods. Additional to cereulide itself, seven structurally related isoforms, namely the isocereulides A–G, have already been elucidated in their chemical structure and could further be identified in B. cereus contaminated food samples. The newly performed isolation of isocereulide A allowed, for the first time, 1D- and 2D-NMR spectroscopy of a biosynthetically produced isocereulide, revealing results that contradict previous assumptions of an l-O-Leu moiety within its chemical structure. By furthermore applying posthydrolytical dipeptide analysis, amino acid and α-hydroxy acid analysis by means of UPLC-ESI-TOF-MS, as well as MSn sequencing, the structure of previously reported isocereulide A could be corrected. Instead of the l-O-Leu as assumed to date, one l-O-Ile unit could be verified in the cyclic dodecadepsipeptide, revising the structure of isocereulide A to [(d-O-Leu-d-Ala-l-O-Val-l-Val)2(d-O-Leu-d-Ala-l-O-Ile-l-Val)].

ACS Style

Veronika Walser; Markus Kranzler; Monika Ehling-Schulz; Timo Stark; Thomas Hofmann. Structure Revision of Isocereulide A, an Isoform of the Food Poisoning Emetic Bacillus cereus Toxin Cereulide. Molecules 2021, 26, 1360 .

AMA Style

Veronika Walser, Markus Kranzler, Monika Ehling-Schulz, Timo Stark, Thomas Hofmann. Structure Revision of Isocereulide A, an Isoform of the Food Poisoning Emetic Bacillus cereus Toxin Cereulide. Molecules. 2021; 26 (5):1360.

Chicago/Turabian Style

Veronika Walser; Markus Kranzler; Monika Ehling-Schulz; Timo Stark; Thomas Hofmann. 2021. "Structure Revision of Isocereulide A, an Isoform of the Food Poisoning Emetic Bacillus cereus Toxin Cereulide." Molecules 26, no. 5: 1360.

Journal article
Published: 04 March 2021 in Toxins
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The human intestine is regularly exposed to ingested food contaminants, such as fungal and bacterial toxins, which have been described to co-occur in a mixed diet. Thus, it is of utmost importance to understand possible interactions between contaminants of different origin. Hence, we investigated the single and combined effects of one of the most abundant mycotoxins, deoxynivalenol (DON; 0.1 to 10 µg/mL), and the bacterial toxin cereulide (CER; 1 to 100 ng/mL) on differentiated human Caco-2 (C2BBe1) cells cultured in a transwell system. We tested the capacity of the two toxins to alter the intestinal integrity and further investigated the uptake of both compounds and the formation of selected DON metabolites. CER alone (10 and 100 ng/mL) and in combination with DON (10 ng/mL CER with 1 µg/mL DON) was found to alter the barrier function by increasing the transepithelial electrical resistance and the expression of the tight junction protein claudin-4. For the first time, DON-3-sulfate was identified as a metabolite of human intestinal cells in vitro. Moreover, co-incubation of CER and DON led to an altered ratio between DON and DON-3-sulfate. Hence, we conclude that co-exposure to CER and DON may alter the intestinal barrier function and biotransformation of intestinal cells.

ACS Style

Julia Beisl; Elisabeth Varga; Dominik Braun; Benedikt Warth; Monika Ehling-Schulz; Giorgia Del Favero; Doris Marko. Assessing Mixture Effects of Cereulide and Deoxynivalenol on Intestinal Barrier Integrity and Uptake in Differentiated Human Caco-2 Cells. Toxins 2021, 13, 189 .

AMA Style

Julia Beisl, Elisabeth Varga, Dominik Braun, Benedikt Warth, Monika Ehling-Schulz, Giorgia Del Favero, Doris Marko. Assessing Mixture Effects of Cereulide and Deoxynivalenol on Intestinal Barrier Integrity and Uptake in Differentiated Human Caco-2 Cells. Toxins. 2021; 13 (3):189.

Chicago/Turabian Style

Julia Beisl; Elisabeth Varga; Dominik Braun; Benedikt Warth; Monika Ehling-Schulz; Giorgia Del Favero; Doris Marko. 2021. "Assessing Mixture Effects of Cereulide and Deoxynivalenol on Intestinal Barrier Integrity and Uptake in Differentiated Human Caco-2 Cells." Toxins 13, no. 3: 189.

Communication
Published: 04 February 2021 in Toxins
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The emetic toxin cereulide is a 1.2 kDa dodecadepsipeptide produced by the food pathogen Bacillus cereus. As cereulide poses a serious health risk to humans, sensitive and specific detection, as well as toxin purification and quantification, methods are of utmost importance. Recently, a stable isotope dilution assay tandem mass spectrometry (SIDA–MS/MS)-based method has been described, and an method for the quantitation of cereulide in foods was established by the International Organization for Standardization (ISO). However, although this SIDA–MS/MS method is highly accurate, the sophisticated high-end MS equipment required for such measurements limits the method’s suitability for microbiological and molecular research. Thus, we aimed to develop a method for cereulide toxin detection and isolation using equipment commonly available in microbiological and biochemical research laboratories. Reproducible detection and relative quantification of cereulide was achieved, employing reversed phase chromatography (RPC). Chromatographic signals were cross validated by ultraperformance liquid chromatography–mass spectrometry (UPLC–MS/MS). The specificity of the RPC method was tested using a test panel of strains that included non-emetic representatives of the B. cereus group, emetic B. cereus strains, and cereulide-deficient isogenic mutants. In summary, the new method represents a robust, economical, and easily accessible research tool that complements existing diagnostics for the detection and quantification of cereulide.

ACS Style

Eva Kalbhenn; Tobias Bauer; Timo Stark; Mandy Knüpfer; Gregor Grass; Monika Ehling-Schulz. Detection and Isolation of Emetic Bacillus cereus Toxin Cereulide by Reversed Phase Chromatography. Toxins 2021, 13, 115 .

AMA Style

Eva Kalbhenn, Tobias Bauer, Timo Stark, Mandy Knüpfer, Gregor Grass, Monika Ehling-Schulz. Detection and Isolation of Emetic Bacillus cereus Toxin Cereulide by Reversed Phase Chromatography. Toxins. 2021; 13 (2):115.

Chicago/Turabian Style

Eva Kalbhenn; Tobias Bauer; Timo Stark; Mandy Knüpfer; Gregor Grass; Monika Ehling-Schulz. 2021. "Detection and Isolation of Emetic Bacillus cereus Toxin Cereulide by Reversed Phase Chromatography." Toxins 13, no. 2: 115.

Review
Published: 28 January 2021 in Toxins
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Bacillus cereus is a ubiquitous soil bacterium responsible for two types of food-associated gastrointestinal diseases. While the emetic type, a food intoxication, manifests in nausea and vomiting, food infections with enteropathogenic strains cause diarrhea and abdominal pain. Causative toxins are the cyclic dodecadepsipeptide cereulide, and the proteinaceous enterotoxins hemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe) and cytotoxin K (CytK), respectively. This review covers the current knowledge on distribution and genetic organization of the toxin genes, as well as mechanisms of enterotoxin gene regulation and toxin secretion. In this context, the exceptionally high variability of toxin production between single strains is highlighted. In addition, the mode of action of the pore-forming enterotoxins and their effect on target cells is described in detail. The main focus of this review are the two tripartite enterotoxin complexes Hbl and Nhe, but the latest findings on cereulide and CytK are also presented, as well as methods for toxin detection, and the contribution of further putative virulence factors to the diarrheal disease.

ACS Style

Richard Dietrich; Nadja Jessberger; Monika Ehling-Schulz; Erwin Märtlbauer; Per Granum. The Food Poisoning Toxins of Bacillus cereus. Toxins 2021, 13, 98 .

AMA Style

Richard Dietrich, Nadja Jessberger, Monika Ehling-Schulz, Erwin Märtlbauer, Per Granum. The Food Poisoning Toxins of Bacillus cereus. Toxins. 2021; 13 (2):98.

Chicago/Turabian Style

Richard Dietrich; Nadja Jessberger; Monika Ehling-Schulz; Erwin Märtlbauer; Per Granum. 2021. "The Food Poisoning Toxins of Bacillus cereus." Toxins 13, no. 2: 98.

Article
Published: 27 October 2020 in mBio
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This study revealed a novel, potentially conserved mechanism involved in the biosynthesis of microbial natural products, exemplified by the mitochondrial active depsipeptide cereulide. Similar to other bioactive substances, such as the last-resort antibiotics vancomycin and daptomycin, the antitumor drug cryptophycin or the cholesterol-lowering agent lovastatin, cereulide is synthesized nonribosomally by multienzyme machinery, requiring the concerted actions of multiple proteins to ensure correct product assembly. Given the importance of microbial secondary metabolites in human and veterinary medicine, it is critical to understand how these processes are orchestrated within the host cells. By revealing that tethering of a biosynthetic enzyme to the cell membrane by an ABC transporter is essential for nonribosomal peptide production, our study provides novel insights into synthesis of microbial secondary metabolites, which could contribute to isolation of novel compounds from cryptic secondary metabolite clusters or improve the yield of produced pharmaceuticals.

ACS Style

A. Gacek-Matthews; Z. Chromiková; M. Sulyok; G. Lücking; I. Barák; M. Ehling-Schulz. Beyond Toxin Transport: Novel Role of ABC Transporter for Enzymatic Machinery of Cereulide NRPS Assembly Line. mBio 2020, 11, 1 .

AMA Style

A. Gacek-Matthews, Z. Chromiková, M. Sulyok, G. Lücking, I. Barák, M. Ehling-Schulz. Beyond Toxin Transport: Novel Role of ABC Transporter for Enzymatic Machinery of Cereulide NRPS Assembly Line. mBio. 2020; 11 (5):1.

Chicago/Turabian Style

A. Gacek-Matthews; Z. Chromiková; M. Sulyok; G. Lücking; I. Barák; M. Ehling-Schulz. 2020. "Beyond Toxin Transport: Novel Role of ABC Transporter for Enzymatic Machinery of Cereulide NRPS Assembly Line." mBio 11, no. 5: 1.

Journal article
Published: 16 July 2020 in Biomolecules
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The unabated global increase of allergic patients leads to an unmet need for rapid and inexpensive tools for the diagnosis of allergies and for monitoring the outcome of allergen-specific immunotherapy (SIT). In this proof-of-concept study, we investigated the potential of Fourier-Transform Infrared (FTIR) spectroscopy, a high-resolution and cost-efficient biophotonic method with high throughput capacities, to detect characteristic alterations in serum samples of healthy, allergic, and SIT-treated mice and humans. To this end, we used experimental models of ovalbumin (OVA)-induced allergic airway inflammation and allergen-specific tolerance induction in BALB/c mice. Serum collected before and at the end of the experiment was subjected to FTIR spectroscopy. As shown by our study, FTIR spectroscopy, combined with deep learning, can discriminate serum from healthy, allergic, and tolerized mice, which correlated with immunological data. Furthermore, to test the suitability of this biophotonic method for clinical diagnostics, serum samples from human patients were analyzed by FTIR spectroscopy. In line with the results from the mouse models, machine learning-assisted FTIR spectroscopy allowed to discriminate sera obtained from healthy, allergic, and SIT-treated humans, thereby demonstrating its potential for rapid diagnosis of allergy and clinical therapeutic monitoring of allergic patients.

ACS Style

Elke Korb; Murat Bağcıoğlu; Erika Garner-Spitzer; Ursula Wiedermann; Monika Ehling-Schulz; Irma Schabussova. Machine Learning-Empowered FTIR Spectroscopy Serum Analysis Stratifies Healthy, Allergic, and SIT-Treated Mice and Humans. Biomolecules 2020, 10, 1058 .

AMA Style

Elke Korb, Murat Bağcıoğlu, Erika Garner-Spitzer, Ursula Wiedermann, Monika Ehling-Schulz, Irma Schabussova. Machine Learning-Empowered FTIR Spectroscopy Serum Analysis Stratifies Healthy, Allergic, and SIT-Treated Mice and Humans. Biomolecules. 2020; 10 (7):1058.

Chicago/Turabian Style

Elke Korb; Murat Bağcıoğlu; Erika Garner-Spitzer; Ursula Wiedermann; Monika Ehling-Schulz; Irma Schabussova. 2020. "Machine Learning-Empowered FTIR Spectroscopy Serum Analysis Stratifies Healthy, Allergic, and SIT-Treated Mice and Humans." Biomolecules 10, no. 7: 1058.

Journal article
Published: 26 June 2020 in Biomolecules
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Peritoneal dialysis (PD) offers specific advantages over hemodialysis, enabling increased autonomy of patients with end-stage renal disease, but PD-related complications need to be detected in a timely manner. Fourier transform infrared (FTIR) spectroscopy could provide rapid and essential insights into the patients’ risk profiles via molecular fingerprinting of PD effluent, an abundant waste material that is rich in biological information. In this study, we measured FTIR spectroscopic profiles in PD effluent from patients taking part in a randomized controlled trial of alanyl-glutamine addition to the PD-fluid. Principal component analysis of FTIR spectra enabled us to differentiate between effluent samples from patients immediately after completion of instillation of the PD-fluid into the patients’ cavity and 4 h later as well as between patients receiving PD-fluid supplemented with 8 mM alanyl-glutamine compared with control. Moreover, feasibility of FTIR spectroscopy coupled to supervised classification algorithms to predict patient-, PD-, as well as immune-associated parameters were investigated. PD modality (manual continuous ambulatory PD (CAPD) vs. cycler-assisted automated PD (APD)), residual urine output, ultrafiltration, transport parameters, and cytokine concentrations showed high predictive potential. This study provides proof-of-principle that molecular signatures determined by FTIR spectroscopy of PD effluent, combined with machine learning, are suitable for cost-effective, high-throughput diagnostic purposes in PD.

ACS Style

Tom Grunert; Rebecca Herzog; Florian M. Wiesenhofer; Andreas Vychytil; Monika Ehling-Schulz; Klaus Kratochwill. Vibrational Spectroscopy of Peritoneal Dialysis Effluent for Rapid Assessment of Patient Characteristics. Biomolecules 2020, 10, 965 .

AMA Style

Tom Grunert, Rebecca Herzog, Florian M. Wiesenhofer, Andreas Vychytil, Monika Ehling-Schulz, Klaus Kratochwill. Vibrational Spectroscopy of Peritoneal Dialysis Effluent for Rapid Assessment of Patient Characteristics. Biomolecules. 2020; 10 (6):965.

Chicago/Turabian Style

Tom Grunert; Rebecca Herzog; Florian M. Wiesenhofer; Andreas Vychytil; Monika Ehling-Schulz; Klaus Kratochwill. 2020. "Vibrational Spectroscopy of Peritoneal Dialysis Effluent for Rapid Assessment of Patient Characteristics." Biomolecules 10, no. 6: 965.

Journal article
Published: 01 June 2020 in International Journal of Systematic and Evolutionary Microbiology
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A Gram-stain-positive bacterial isolate, designated LMM-1652T, was isolated from an intrauterine cytobrush sample originating from a postpartum Holstein Friesian dairy cow. The strain had a rod to coccoid-shape, was catalase-positive and oxidase-negative. 16S rRNA gene sequence similarity analyses revealed that its closest relatives were Corynebacterium falsenii (97.05 % similarity), Corynebacterium jeikeium (96.83 %) and Corynebacterium urealyticum (96.82 %). Subsequent whole genome analysis showed that the genome-to-genome distance of strain LMM-1652T to its closest relatives was in the range of 23.2–24.8 %, while the average nucleotide identity values ranged from 73.7 to 74.3%, thus confirming that this isolate represents a novel species. Strain LMM-1652T was characterized by a quinone system mainly consisting of MK-9(H2) and MK-10(H2). The polar lipids profile of the strain consisted mainly of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol-mannoside, as well as one unidentified lipid lacking any functional group. Smaller amounts of four unidentified phospholipids, four unidentified glycolipids, β-gentiobiosyl diacylglycerol and four unidentified lipids lacking a functional group were also found. The cell wall contained meso-diaminopimelic acid as the diagnostic diamino acid of the peptidoglycan. The fatty acid profile was mainly composed of C18 : 1 ω9c, C18 : 0 and C16 : 0. We propose a novel species of the genus Corynebacterium with the name Corynebacterium urogenitale LMM-1652T (=LMG 31163T=DSM 108747T).

ACS Style

Panagiotis Ballas; Christian Rückert; Karen Wagener; Marc Drillich; Peter Kampfer; Hans-Jürgen Busse; Monika Ehling-Schulz. Corynebacterium urogenitale sp. nov. isolated from the genital tract of a cow. International Journal of Systematic and Evolutionary Microbiology 2020, 70, 3625 -3632.

AMA Style

Panagiotis Ballas, Christian Rückert, Karen Wagener, Marc Drillich, Peter Kampfer, Hans-Jürgen Busse, Monika Ehling-Schulz. Corynebacterium urogenitale sp. nov. isolated from the genital tract of a cow. International Journal of Systematic and Evolutionary Microbiology. 2020; 70 (6):3625-3632.

Chicago/Turabian Style

Panagiotis Ballas; Christian Rückert; Karen Wagener; Marc Drillich; Peter Kampfer; Hans-Jürgen Busse; Monika Ehling-Schulz. 2020. "Corynebacterium urogenitale sp. nov. isolated from the genital tract of a cow." International Journal of Systematic and Evolutionary Microbiology 70, no. 6: 3625-3632.

Journal article
Published: 05 May 2020 in Veterinary Microbiology
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Streptococcus uberis is an opportunistic pathogen involved in various infections of cattle. It is a well-known etiological agent of bovine mastitis and has recently also been linked to postpartum endometritis in dairy cows. S. uberis is frequently isolated from the uterus of postpartum cows but its actual contribution to host pathophysiology is unknown and information on S. uberis virulence factors potentially involved in the disease is lacking. To gain first insights into the role of S. uberis in the pathology of bovine endometritis, a cell-culture-based infection model was employed to study inflammatory host responses and investigate cytotoxic effects. A comprehensive strain panel, comprising 53 strains previously isolated from bovine uteri, was compiled and screened for known virulence factor genes. Isolates showing distinct virulence gene patterns were used to study their impact on cellular viability and influence on mRNA expression of pro-inflammatory factors in endometrial epithelial cells. Our study revealed that S. uberis negatively impacts the viability of endometrial epithelial cells and provokes an upregulation of specific pro-inflammatory factors, although with certain strains having a greater effect than others. Especially, mRNA expression of IL1A and CXCL8 as well as CXCL1/2 and PTGS2 was found to be stimulated by S. uberis. These results suggest that S. uberis might indeed contribute to the establishment of bovine endometritis.

ACS Style

Panagiotis Ballas; Christoph Gabler; Karen Wagener; Marc Drillich; Monika Ehling-Schulz. Streptococcus uberis strains originating from bovine uteri provoke upregulation of pro-inflammatory factors mRNA expression of endometrial epithelial cells in vitro. Veterinary Microbiology 2020, 245, 108710 .

AMA Style

Panagiotis Ballas, Christoph Gabler, Karen Wagener, Marc Drillich, Monika Ehling-Schulz. Streptococcus uberis strains originating from bovine uteri provoke upregulation of pro-inflammatory factors mRNA expression of endometrial epithelial cells in vitro. Veterinary Microbiology. 2020; 245 ():108710.

Chicago/Turabian Style

Panagiotis Ballas; Christoph Gabler; Karen Wagener; Marc Drillich; Monika Ehling-Schulz. 2020. "Streptococcus uberis strains originating from bovine uteri provoke upregulation of pro-inflammatory factors mRNA expression of endometrial epithelial cells in vitro." Veterinary Microbiology 245, no. : 108710.

In vitro systems
Published: 17 February 2020 in Archives of Toxicology
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Deoxynivalenol (DON), one of the most abundant mycotoxins in cereal products, was recently detected with other mycotoxins and the emetic bacterial toxin cereulide (CER) in maize porridge. Within a cereal-based diet, co-exposure to these toxins is likely, hence raising the question of combinatory toxicological effects. While the toxicological evaluation of DON has quite progressed, consequences of chronic, low-dose CER exposure are still insufficiently explored. Information about the combinatory toxicological effects of these toxins is lacking. In the present study, we investigated how CER (0.1–100 ng/mL) and DON (0.01–10 µg/mL) alone and in a constant ratio of 1:100 (CER:DON) affect the cytotoxicity and immune response of differentiated human intestinal Caco-2 cells. While DON alone reduced cell viability only in the highest concentration (10 µg/mL), CER caused severe cytotoxicity upon prolonged incubation (starting from 10 ng/mL after 24 h and 48 h, 2.5 ng/mL and higher after 72 h). After 72 h, synergistic effects were observed at 2.5 ng/mL CER and 0.25 µg/mL DON. Different endpoints of inflammation were investigated in interleukin-1β-stimulated Caco-2 cells. Notably, DON-induced interleukin-8 transcription and secretion were diminished by the presence of 10 and 25 ng/mL CER after short-term (5 h) incubation, indicating immunosuppressive properties. We hypothesise that habitual consumption of cereal-based foods co-contaminated with CER and DON may cause synergistic cytotoxic effects and an altered immune response in the human intestine. Therefore, further research concerning effects of co-occurring bacterial toxins and mycotoxins on the impairment of intestinal barrier integrity, intestinal inflammation and the promotion of malnutrition is needed.

ACS Style

Julia Beisl; Gudrun Pahlke; Helen Abeln; Monika Ehling-Schulz; Giorgia Del Favero; Elisabeth Varga; Benedikt Warth; Michael Sulyok; Wilfred Abia; Chibundu N. Ezekiel; Doris Marko. Combinatory effects of cereulide and deoxynivalenol on in vitro cell viability and inflammation of human Caco-2 cells. Archives of Toxicology 2020, 94, 833 -844.

AMA Style

Julia Beisl, Gudrun Pahlke, Helen Abeln, Monika Ehling-Schulz, Giorgia Del Favero, Elisabeth Varga, Benedikt Warth, Michael Sulyok, Wilfred Abia, Chibundu N. Ezekiel, Doris Marko. Combinatory effects of cereulide and deoxynivalenol on in vitro cell viability and inflammation of human Caco-2 cells. Archives of Toxicology. 2020; 94 (3):833-844.

Chicago/Turabian Style

Julia Beisl; Gudrun Pahlke; Helen Abeln; Monika Ehling-Schulz; Giorgia Del Favero; Elisabeth Varga; Benedikt Warth; Michael Sulyok; Wilfred Abia; Chibundu N. Ezekiel; Doris Marko. 2020. "Combinatory effects of cereulide and deoxynivalenol on in vitro cell viability and inflammation of human Caco-2 cells." Archives of Toxicology 94, no. 3: 833-844.

Journal article
Published: 01 January 2020 in International Journal of Systematic and Evolutionary Microbiology
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A Gram-stain-positive bacterial strain, designated LMM-1653T, was isolated from a uterus swab from a Holstein Frisian dairy cow in the frame of a clinical sampling trial. The isolated strain, which showed a rod to coccoid shape, was catalase-positive and oxidase-negative. Based on 16S rRNA gene sequence similarity, its closest relatives were Corynebacterium flavescens and Corynebacterium argatoratense (96.50 % similarity each), suggesting that this isolate represents a novel species. Strain LMM-1653T had a quinone system consisting mainly of menaquinones MK-8(H2) and MK-9(H2). The polar lipid profile showed presence of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol-mannoside as well as one unidentified glycolipid and one unidentified aminoglycolipid. Moderate to minor amounts of three unidentified glycolipids, β-gentiobiosyl diacylglycerol, one unidentified aminoglycolipid and three unidentified lipids without a functional group were also found. The cell wall contained meso-diaminopimelic acid and the strain also contained corynemycolic acids. The fatty acid profile was predominantly composed of straight-chain, saturated and mono-unsaturated fatty acids, dominated by C18 : 1ω9c and C16 : 0. Since this isolate differs from the nearest related established Corynebacterium species in its genetic and phenotypic traits, a novel species named Corynebacterium endometrii LMM-1653T (=LMG-31164T=CCM 8952T) of the genus Corynebacterium is proposed.

ACS Style

Panagiotis Ballas; Christian Rückert; Karen Wagener; Marc Drillich; Peter Kampfer; Hans-Jürgen Busse; Monika Ehling-Schulz. Corynebacterium endometrii sp. nov., isolated from the uterus of a cow with endometritis. International Journal of Systematic and Evolutionary Microbiology 2020, 70, 146 -152.

AMA Style

Panagiotis Ballas, Christian Rückert, Karen Wagener, Marc Drillich, Peter Kampfer, Hans-Jürgen Busse, Monika Ehling-Schulz. Corynebacterium endometrii sp. nov., isolated from the uterus of a cow with endometritis. International Journal of Systematic and Evolutionary Microbiology. 2020; 70 (1):146-152.

Chicago/Turabian Style

Panagiotis Ballas; Christian Rückert; Karen Wagener; Marc Drillich; Peter Kampfer; Hans-Jürgen Busse; Monika Ehling-Schulz. 2020. "Corynebacterium endometrii sp. nov., isolated from the uterus of a cow with endometritis." International Journal of Systematic and Evolutionary Microbiology 70, no. 1: 146-152.

Journal article
Published: 18 December 2019 in Antibiotics
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The present study was conducted from July to August 2018 on milk samples taken at dairy farms in the Northern Province and Kigali District of Rwanda in order to identify Staphylococcus spp. associated with bovine intramammary infection. A total of 161 staphylococcal isolates originating from quarter milk samples of 112 crossbred dairy cattle were included in the study. Antimicrobial susceptibility testing was performed and isolates were examined for the presence of various resistance genes. Staphylococcus aureus isolates were also analyzed for the presence of virulence factors, genotyped by spa typing and further phenotypically subtyped for capsule expression using Fourier Transform Infrared (FTIR) spectroscopy. Selected S. aureus were characterized using DNA microarray technology, multi-locus sequence typing (MLST) and whole-genome sequencing. All mecA-positive staphylococci were further genotyped using dru typing. In total, 14 different staphylococcal species were detected, with S. aureus being most prevalent (26.7%), followed by S. xylosus (22.4%) and S. haemolyticus (14.9%). A high number of isolates was resistant to penicillin and tetracycline. Various antimicrobial and biocide resistance genes were detected. Among S. aureus, the Panton–Valentine leukocidin (PVL) genes, as well as bovine leukocidin (LukM/LukF-P83) genes, were detected in two and three isolates, respectively, of which two also carried the toxic shock syndrome toxin gene tsst-1 bovine variant. t1236 was the predominant spa type. FTIR-based capsule serotyping revealed a high prevalence of non-encapsulated S. aureus isolates (89.5%). The majority of the selected S. aureus isolates belonged to clonal complex (CC) 97 which was determined using DNA microarray based assignment. Three new MLST sequence types were detected.

ACS Style

Fruzsina Irén Antók; Rosa Mayrhofer; Helene Marbach; Jean Claude Masengesho; Helga Keinprecht; Vedaste Nyirimbuga; Otto Fischer; Sarah Lepuschitz; Werner Ruppitsch; Monika Ehling-Schulz; Andrea T. Feßler; Stefan Schwarz; Stefan Monecke; Ralf Ehricht; Tom Grunert; Joachim Spergser; Igor Loncaric. Characterization of Antibiotic and Biocide Resistance Genes and Virulence Factors of Staphylococcus Species Associated with Bovine Mastitis in Rwanda. Antibiotics 2019, 9, 1 .

AMA Style

Fruzsina Irén Antók, Rosa Mayrhofer, Helene Marbach, Jean Claude Masengesho, Helga Keinprecht, Vedaste Nyirimbuga, Otto Fischer, Sarah Lepuschitz, Werner Ruppitsch, Monika Ehling-Schulz, Andrea T. Feßler, Stefan Schwarz, Stefan Monecke, Ralf Ehricht, Tom Grunert, Joachim Spergser, Igor Loncaric. Characterization of Antibiotic and Biocide Resistance Genes and Virulence Factors of Staphylococcus Species Associated with Bovine Mastitis in Rwanda. Antibiotics. 2019; 9 (1):1.

Chicago/Turabian Style

Fruzsina Irén Antók; Rosa Mayrhofer; Helene Marbach; Jean Claude Masengesho; Helga Keinprecht; Vedaste Nyirimbuga; Otto Fischer; Sarah Lepuschitz; Werner Ruppitsch; Monika Ehling-Schulz; Andrea T. Feßler; Stefan Schwarz; Stefan Monecke; Ralf Ehricht; Tom Grunert; Joachim Spergser; Igor Loncaric. 2019. "Characterization of Antibiotic and Biocide Resistance Genes and Virulence Factors of Staphylococcus Species Associated with Bovine Mastitis in Rwanda." Antibiotics 9, no. 1: 1.

Preprint content
Published: 10 December 2019
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1.AbstractBacillus cereus plays an often unrecognized role in food borne diseases. Food poisoning caused by this pathogen is manifested by either diarrhea or emesis. While different enterotoxins have been linked to the diarrheal type of B. cereus infections, the emetic toxin cereulide is responsible for the second type. Due to the relatively high prevalence of cereulide associated food poisoning, methods for simple and reliable detection of cereulide producing strains are of utmost importance. Currently, liquid-chromatography coupled to mass spectrometry (LC-MS) is used for sensitive, specific and quantitative cereulide detection, but this technique requires specialized LC-MS equipment, which is often not available in microbiology routine diagnostic laboratories.The last decade has witnessed the advent of matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-ToF MS) as a simple, rapid and cost-efficient technique for identification of microbial pathogens in routine diagnostics. Just recently, two different studies reported on the application of MALDI-ToF MS for either the differentiation of emetic and non-emetic strains of B. cereus or for direct detection of cereulide from bacterial colony smears. However, no method evaluation and optimization was performed in frame of these studies. Thus, additional investigations on the selectivity and sensitivity of MALDI-TOF MS for cereulide detection are needed before implementation of this method in routine diagnostics can be considered. These aspects prompted us to investigate open or controversial issues and to systematically test sample preparation methods, commonly used for microbial identification for their suitability to detect the emetic toxin directly from bacteria.Based on our experimental findings we propose a MALDI-ToF MS workflow that allows identification of B. cereus and sensitive detection of cereulide in parallel, using standard, linear-mode MALDI-ToF MS equipment. The experimental protocol is based on the well-established ethanol/formic acid extraction method and offers, if required, possibilities for further characterization by more sophisticated LC-MS-based methods. In summary, the ease of use and the achieved level of analytical sensitivity as well as the wide-spread availability of standard MALDI-ToF MS equipment in clinical microbiological laboratories provides a promising tool to improve and to facilitate routine diagnostics of B. cereus associated food intoxications.

ACS Style

Joerg Doellinger; Andy Schneider; Timo Stark; Monika Ehling-Schulz; Peter Lasch. Evaluation of MALDI-ToF Mass Spectrometry for Rapid Detection of Cereulide from Bacillus cereus Cultures. 2019, 869958 .

AMA Style

Joerg Doellinger, Andy Schneider, Timo Stark, Monika Ehling-Schulz, Peter Lasch. Evaluation of MALDI-ToF Mass Spectrometry for Rapid Detection of Cereulide from Bacillus cereus Cultures. . 2019; ():869958.

Chicago/Turabian Style

Joerg Doellinger; Andy Schneider; Timo Stark; Monika Ehling-Schulz; Peter Lasch. 2019. "Evaluation of MALDI-ToF Mass Spectrometry for Rapid Detection of Cereulide from Bacillus cereus Cultures." , no. : 869958.

Journal article
Published: 17 September 2019 in Scientific Reports
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Staphylococcus aureus is a major cause of bovine mastitis, commonly leading to long-lasting, persistent and recurrent infections. Thereby, S. aureus constantly refines and permanently adapts to the bovine udder environment. In this work, we followed S. aureus within-host adaptation over the course of three months in a naturally infected dairy cattle with chronic, subclinical mastitis. Whole genome sequence analysis revealed a complete replacement of the initial predominant variant by another isogenic variant. We report for the first time within-host evolution towards a sigma factor SigB-deficient pathotype in S. aureus bovine mastitis, associated with a single nucleotide polymorphism in rsbU (G368A → G122D), a contributor to SigB-functionality. The emerged SigB-deficient pathotype exhibits a substantial shift to new phenotypic traits comprising strong proteolytic activity and poly-N-acetylglucosamine (PNAG)-based biofilm production. This possibly unlocks new nutritional resources and promotes immune evasion, presumably facilitating extracellular persistence within the host. Moreover, we observed an adaptation towards attenuated virulence using a mouse infection model. This study extends the role of sigma factor SigB in S. aureus pathogenesis, so far described to be required for intracellular persistence during chronic infections. Our findings suggest that S. aureus SigB-deficiency is an alternative mechanism for persistence and underpin the clinical relevance of staphylococcal SigB-deficient variants which are consistently isolated during human chronic infections.

ACS Style

Helene Marbach; Katharina Mayer; Claus Vogl; Jean Y. H. Lee; Ian R. Monk; Daniel Oscar Sordelli; Fernanda R. Buzzola; Monika Ehling-Schulz; Tom Grunert. Within-host evolution of bovine Staphylococcus aureus selects for a SigB-deficient pathotype characterized by reduced virulence but enhanced proteolytic activity and biofilm formation. Scientific Reports 2019, 9, 1 -12.

AMA Style

Helene Marbach, Katharina Mayer, Claus Vogl, Jean Y. H. Lee, Ian R. Monk, Daniel Oscar Sordelli, Fernanda R. Buzzola, Monika Ehling-Schulz, Tom Grunert. Within-host evolution of bovine Staphylococcus aureus selects for a SigB-deficient pathotype characterized by reduced virulence but enhanced proteolytic activity and biofilm formation. Scientific Reports. 2019; 9 (1):1-12.

Chicago/Turabian Style

Helene Marbach; Katharina Mayer; Claus Vogl; Jean Y. H. Lee; Ian R. Monk; Daniel Oscar Sordelli; Fernanda R. Buzzola; Monika Ehling-Schulz; Tom Grunert. 2019. "Within-host evolution of bovine Staphylococcus aureus selects for a SigB-deficient pathotype characterized by reduced virulence but enhanced proteolytic activity and biofilm formation." Scientific Reports 9, no. 1: 1-12.

Review article
Published: 26 July 2019 in Food Microbiology
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Cereulide, a potent toxin produced by Bacillus cereus, is a small, highly heat- and acid-resistant depsipeptide toxin, which confronts food industry with several challenges. Due to the ubiquitous presence of B. cereus in the environment, this opportunistic pathogen can enter food production and processing at almost any stage. Although the bacteria itself might be removed during food processing, the cereulide toxin will most likely not be destroyed or inactivated by these processes. Because of the high toxicity of cereulide and the high incidence rates often observed in connection with foodborne outbreaks, the understanding of the mechanisms of toxin production as well as accurate data on contamination sources and factors promoting toxin formation are urgently needed to prevent contamination and toxin production in food production processes. Over the last decade, considerable progress had been made on the understanding of cereulide toxin biosynthesis in emetic B. cereus, but an overview of current knowledge on this toxin with regards to food industry perspective is lacking. Thus, we aim in this work to summarize data available on extrinsic parameters acting on cereulide toxin synthesis in emetic B. cereus and to discuss the food industry specific challenges related to this toxin. Furthermore, we emphasize how identification of the cardinals in food production processes can lead to novel effective strategies for prevention of toxin formation in the food processing chain and could contribute to the improvement of existing HACCP studies.

ACS Style

Katia Rouzeau-Szynalski; Katharina Stollewerk; Ute Messelhäusser; Monika Ehling-Schulz. Why be serious about emetic Bacillus cereus: Cereulide production and industrial challenges. Food Microbiology 2019, 85, 103279 .

AMA Style

Katia Rouzeau-Szynalski, Katharina Stollewerk, Ute Messelhäusser, Monika Ehling-Schulz. Why be serious about emetic Bacillus cereus: Cereulide production and industrial challenges. Food Microbiology. 2019; 85 ():103279.

Chicago/Turabian Style

Katia Rouzeau-Szynalski; Katharina Stollewerk; Ute Messelhäusser; Monika Ehling-Schulz. 2019. "Why be serious about emetic Bacillus cereus: Cereulide production and industrial challenges." Food Microbiology 85, no. : 103279.

Journal article
Published: 22 July 2019 in Food Microbiology
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The diarrheal type of food poisoning caused by enteropathogenic Bacillus cereus has been linked to various exotoxins. Best described are the non-hemolytic enterotoxin (Nhe), hemolysin BL (Hbl), and cytotoxin K (CytK). Due to the ubiquitous prevalence of B. cereus in soil and crops and its ability to form highly resistant endospores, contaminations during food production and processing cannot be completely avoided. Although phylogenetically closely related, enteropathogenic B. cereus strains show a high versatility of their toxic potential. Thus, functional tools for evaluating the pathogenic potential are urgently needed in order to predict hazardous food contaminations. As the diarrheal syndrome is the result of a toxico-infection with enterotoxin production in the intestine, the entire passage of the bacteria within the host, from spore survival in the stomach, spore germination, host cell adherence, and motility, to enterotoxin production under simulated intestinal conditions was compared in a panel of 20 strains, including high pathogenic as well as apathogenic ones. This approach resulted in an overarching virulence analysis scheme. In parallel, we searched for potential toxico-specific secreted markers to discriminate low and high pathogenic strains. To this end, we targeted known exotoxins using an easy to implement immunoblotting approach as well as a caseinolytic exoprotease activity assay. Overall, Nhe component B, sphingomyelinase, and exoproteases showed good correlation with the complex virulence analysis scheme and can serve as a template for future fast and easy risk assessment tools to be implemented in routine diagnostic procedures and HACCP studies.

ACS Style

Nadja Jessberger; Markus Kranzler; Claudia Da Riol; Valerie Schwenk; Tanja Buchacher; Richard Dietrich; Monika Ehling-Schulz; Erwin Märtlbauer. Assessing the toxic potential of enteropathogenic Bacillus cereus. Food Microbiology 2019, 84, 103276 .

AMA Style

Nadja Jessberger, Markus Kranzler, Claudia Da Riol, Valerie Schwenk, Tanja Buchacher, Richard Dietrich, Monika Ehling-Schulz, Erwin Märtlbauer. Assessing the toxic potential of enteropathogenic Bacillus cereus. Food Microbiology. 2019; 84 ():103276.

Chicago/Turabian Style

Nadja Jessberger; Markus Kranzler; Claudia Da Riol; Valerie Schwenk; Tanja Buchacher; Richard Dietrich; Monika Ehling-Schulz; Erwin Märtlbauer. 2019. "Assessing the toxic potential of enteropathogenic Bacillus cereus." Food Microbiology 84, no. : 103276.

Review
Published: 31 May 2019 in Microbiology Spectrum
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The Bacillus cereus group includes several Bacillus species with closely related phylogeny. The most well-studied members of the group, B. anthracis , B. cereus , and B. thuringiensis , are known for their pathogenic potential. Here, we present the historical rationale for speciation and discuss shared and unique features of these bacteria. Aspects of cell morphology and physiology, and genome sequence similarity and gene synteny support close evolutionary relationships for these three species. For many strains, distinct differences in virulence factor synthesis provide facile means for species assignment. B. anthracis is the causative agent of anthrax. Some B. cereus strains are commonly recognized as food poisoning agents, but strains can also cause localized wound and eye infections as well as systemic disease. Certain B. thuringiensis strains are entomopathogens and have been commercialized for use as biopesticides, while some strains have been reported to cause infection in immunocompromised individuals. In this article we compare and contrast B. anthracis , B. cereus , and B. thuringiensis , including ecology, cell structure and development, virulence attributes, gene regulation and genetic exchange systems, and experimental models of disease.

ACS Style

Monika Ehling-Schulz; Didier Lereclus; Theresa M. Koehler. The Bacillus cereus Group: Bacillus Species with Pathogenic Potential. Microbiology Spectrum 2019, 7, 1 .

AMA Style

Monika Ehling-Schulz, Didier Lereclus, Theresa M. Koehler. The Bacillus cereus Group: Bacillus Species with Pathogenic Potential. Microbiology Spectrum. 2019; 7 (3):1.

Chicago/Turabian Style

Monika Ehling-Schulz; Didier Lereclus; Theresa M. Koehler. 2019. "The Bacillus cereus Group: Bacillus Species with Pathogenic Potential." Microbiology Spectrum 7, no. 3: 1.

Original research article
Published: 26 April 2019 in Frontiers in Microbiology
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The Bacillus cereus group comprises genetical closely related species with variable toxigenic characteristics. However, detection and differentiation of the B. cereus group species in routine diagnostics can be difficult, expensive and laborious since current species designation is linked to specific phenotypic characteristic or the presence of species-specific genes. Especially the differentiation of Bacillus cereus and Bacillus thuringiensis, the identification of psychrotolerant Bacillus mycoides and Bacillus weihenstephanensis, as well as the identification of emetic B. cereus and Bacillus cytotoxicus, which are both producing highly potent toxins, is of high importance in food microbiology. Thus, we investigated the use of a machine learning approach, based on artificial neural network (ANN) assisted Fourier transform infrared (FTIR) spectroscopy, for discrimination of B. cereus group members. The deep learning tool box of Matlab was employed to construct a one-level ANN, allowing the discrimination of the aforementioned B. cereus group members. This model resulted in 100% correct identification for the training set and 99.5% correct identification overall. The established ANN was applied to investigate the composition of B. cereus group members in soil, as a natural habitat of B. cereus, and in food samples originating from foodborne outbreaks. These analyses revealed a high complexity of B. cereus group populations, not only in soil samples but also in the samples from the foodborne outbreaks, highlighting the importance of taking multiple isolates from samples implicated in food poisonings. Notable, in contrast to the soil samples, no bacteria belonging to the psychrotolerant B. cereus group members were detected in the food samples linked to foodborne outbreaks, while the overall abundancy of B. thuringiensis did not significantly differ between the sample categories. None of the isolates was classified as B. cytotoxicus, fostering the hypothesis that the latter species is linked to very specific ecological niches. Overall, our work shows that machine learning assisted (FTIR) spectroscopy is suitable for identification of B. cereus group members in routine diagnostics and outbreak investigations. In addition, it is a promising tool to explore the natural habitats of B. cereus group, such as soil.

ACS Style

Murat Bağcıoğlu; Martina Fricker; Sophia Johler; Monika Ehling-Schulz. Detection and Identification of Bacillus cereus, Bacillus cytotoxicus, Bacillus thuringiensis, Bacillus mycoides and Bacillus weihenstephanensis via Machine Learning Based FTIR Spectroscopy. Frontiers in Microbiology 2019, 10, 902 .

AMA Style

Murat Bağcıoğlu, Martina Fricker, Sophia Johler, Monika Ehling-Schulz. Detection and Identification of Bacillus cereus, Bacillus cytotoxicus, Bacillus thuringiensis, Bacillus mycoides and Bacillus weihenstephanensis via Machine Learning Based FTIR Spectroscopy. Frontiers in Microbiology. 2019; 10 ():902.

Chicago/Turabian Style

Murat Bağcıoğlu; Martina Fricker; Sophia Johler; Monika Ehling-Schulz. 2019. "Detection and Identification of Bacillus cereus, Bacillus cytotoxicus, Bacillus thuringiensis, Bacillus mycoides and Bacillus weihenstephanensis via Machine Learning Based FTIR Spectroscopy." Frontiers in Microbiology 10, no. : 902.