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Article ; Online: Methicillin-Resistant Staphylococci and Macrococci at the Interface of Human and Animal Health

Karsten Becker

Toxins, Vol 13, Iss 1, p

2021 Volume 61

Abstract: The global impact of methicillin-resistant Staphylococcus aureus (MRSA) clonal lineages on human and animal health continues, even considering the decreasing MRSA rates in some parts of the world [.] ...

Abstract	The global impact of methicillin-resistant Staphylococcus aureus (MRSA) clonal lineages on human and animal health continues, even considering the decreasing MRSA rates in some parts of the world [.]
Keywords	n/a ; Medicine ; R
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Investigation of In-Vitro Adaptation toward Sodium Bituminosulfonate in Staphylococcus aureus

Marko Blisse / Evgeny A. Idelevich / Karsten Becker

Microorganisms, Vol 8, Iss 1962, p

2020 Volume 1962

Abstract: The global increase in antimicrobial resistance has revived the interest in "old" substances with antimicrobial activity such as sodium bituminosulfonate. However, for those “old” compounds, scientific studies are still sparse and the ones available do ... ...

Abstract	The global increase in antimicrobial resistance has revived the interest in "old" substances with antimicrobial activity such as sodium bituminosulfonate. However, for those “old” compounds, scientific studies are still sparse and the ones available do not mostly meet the current standards. Since this compound is used for topical applications, investigation of a potential increase in minimal inhibitory concentrations (MICs) is of particular importance. For selection of phenotypes with decreased susceptibility, a collection of 30 genetically diverse methicillin-susceptible (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) strains were cultured on bi-layered linear gradient agar plates containing sub-inhibitory concentrations of the active agents. The stability of phenotypes with increased MICs was determined by serial passage on agent-free medium. Within 10 passages, only slight and, in most cases, reversible increases in MSSA and MRSA MIC levels toward sodium bituminosulfonate were obtained. Fusidic acid, used as a control, showed exponential expansions in MIC based on mutations in the fusA gene (elongation factor G or EF-G) with no reduction during the recovery phase. The only marginal and largely reversible changes of S. aureus MICs after exposition to sodium bituminosulfonate indicate a low potential for resistance development.
Keywords	sodium bituminosulfonate ; fusidic acid ; antimicrobial resistance ; susceptibility testing ; sub-inhibitory concentrations ; linear gradient ; Biology (General) ; QH301-705.5
Language	English
Publishing date	2020-12-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Role of SrtA in Pathogenicity of Staphylococcus lugdunensis

Muzaffar Hussain / Christian Kohler / Karsten Becker

Microorganisms, Vol 8, Iss 1975, p

2020 Volume 1975

Abstract: Among coagulase-negative staphylococci (CoNS), Staphylococcus lugdunensis has a special position as causative agent of aggressive courses of infectious endocarditis (IE) more reminiscent of IEs caused by Staphylococcus aureus than those by CoNS. To ... ...

Abstract	Among coagulase-negative staphylococci (CoNS), Staphylococcus lugdunensis has a special position as causative agent of aggressive courses of infectious endocarditis (IE) more reminiscent of IEs caused by Staphylococcus aureus than those by CoNS. To initiate colonization and invasion, bacterial cell surface proteins are required; however, only little is known about adhesion of S. lugdunensis to biotic surfaces. Cell surface proteins containing the LPXTG anchor motif are covalently attached to the cell wall by sortases. Here, we report the functionality of Staphylococcus lugdunensis sortase A (SrtA) to link LPXTG substrates to the cell wall. To determine the role of SrtA dependent surface proteins in biofilm formation and binding eukaryotic cells, we generated SrtA-deficient mutants (Δ srtA ). These mutants formed a smaller amount of biofilm and bound less to immobilized fibronectin, fibrinogen, and vitronectin. Furthermore, SrtA absence affected the gene expression of two different adhesins on transcription level. Surprisingly, we found no decreased adherence and invasion in human cell lines, probably caused by the upregulation of further adhesins in Δ srtA mutant strains. In conclusion, the functionality of S. lugdunensis SrtA in anchoring LPXTG substrates to the cell wall let us define it as the pathogen’s housekeeping sortase.
Keywords	Staphylococcus lugdunensis ; sortase A ; surface proteins ; LPXTG ; Biology (General) ; QH301-705.5
Language	English
Publishing date	2020-12-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Exploration of Bacterial Re-Growth as In Vitro Phenomenon Affecting Methods for Analysis of the Antimicrobial Activity of Chimeric Bacteriophage Endolysins

Ursula Kaspar / Nina Schleimer / Evgeny A. Idelevich / Sonja Molinaro / Karsten Becker

Microorganisms, Vol 10, Iss 445, p

2022 Volume 445

Abstract: Drug alternatives to combat methicillin-resistant Staphylococcus aureus (MRSA) in human and animal healthcare are urgently needed. Recently, the recombinant bacteriophage endolysins, PRF-119 and its successor substance HY-133, have proven to be highly ... ...

Abstract	Drug alternatives to combat methicillin-resistant Staphylococcus aureus (MRSA) in human and animal healthcare are urgently needed. Recently, the recombinant bacteriophage endolysins, PRF-119 and its successor substance HY-133, have proven to be highly active against various S. aureus clonal lineages and to exhibit a very rapid bactericidal effect when standard methods for susceptibility testing are applied. Along with subsequent growth curve experiments, a re-growth phenomenon was observed in vitro necessitating its clarification for the assessment of the agent’s stability and activity as well as for methodological aspects of endolysin testing in general. Distinct in vitro parameters were comparatively examined applying also scanning electron microscopy, fluorescence assays and SDS-PAGE analysis. The shape and material of the culture vessels as well as the shaking conditions were identified as factors influencing the in vitro stability and activity of HY-133. The highest function maintenance was observed in plain centrifuge tubes. Based on this, the conditions and parameters of assays for testing the antimicrobial activities of phage endolysins were determined and adjusted. In particular, shear forces should be kept to a minimum. Our results form the basis for both future test standardization and re-growth-independent experiments as prerequisites for exact determination of the antimicrobial activities of engineered endolysins.
Keywords	endolysin ; bacteriophage ; Staphylococcus aureus ; re-growth ; in vitro stability ; susceptibility testing ; Biology (General) ; QH301-705.5
Language	English
Publishing date	2022-02-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: The Porcine Nasal Microbiota with Particular Attention to Livestock-Associated Methicillin-Resistant Staphylococcus aureus in Germany—A Culturomic Approach

Andreas Schlattmann / Knut von Lützau / Ursula Kaspar / Karsten Becker

Microorganisms, Vol 8, Iss 514, p

2020 Volume 514

Abstract: Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) remains a serious public health threat. Porcine nasal cavities are predominant habitats of LA-MRSA. Hence, components of their microbiota might be of interest as putative ... ...

Abstract	Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) remains a serious public health threat. Porcine nasal cavities are predominant habitats of LA-MRSA. Hence, components of their microbiota might be of interest as putative antagonistically acting competitors. Here, an extensive culturomics approach has been applied including 27 healthy pigs from seven different farms; five were treated with antibiotics prior to sampling. Overall, 314 different species with standing in nomenclature and 51 isolates representing novel bacterial taxa were detected. Staphylococcus aureus was isolated from pigs on all seven farms sampled, comprising ten different spa types with t899 ( n = 15, 29.4%) and t337 ( n = 10, 19.6%) being most frequently isolated. Twenty-six MRSA (mostly t899) were detected on five out of the seven farms. Positive correlations between MRSA colonization and age and colonization with Streptococcus hyovaginalis , and a negative correlation between colonization with MRSA and Citrobacter spp. were found ( p < 0.05). Of 209 non- S. aureus members of the Staphylococcaceae family, 25 isolates (12.0%) from three out of the seven farms exhibited methicillin resistance, including two Macrococcus goetzii isolates carrying the mecB gene. Among 125 Enterobacterales , none tested positive for extended-spectrum beta-lactamase (ESBL) and carbapenemase production. The high frequency of methicillin-resistant staphylococci supports the need for enhanced efforts within the “One Health” concept to manage the antibiotic resistance crisis in the human and veterinary medicine sector.
Keywords	Staphylococcus ; MRSA ; microbiota ; pig ; Macrococcus ; ESBL ; Biology (General) ; QH301-705.5
Subject code	630
Language	English
Publishing date	2020-04-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Development of a novel MALDI-TOF MS-based bile solubility test for rapid discrimination of Streptococcus pneumoniae

Evgeny A. Idelevich / Andreas Schlattmann / Markus Kostrzewa / Karsten Becker

International Journal of Medical Microbiology, Vol 310, Iss 3, Pp 151413- (2020)

2020

Abstract: Differentiation of Streptococcus pneumoniae from other Streptococcus mitis group streptococci (SMGS) remains challenging despite the introduction of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). While the ... ...

Abstract	Differentiation of Streptococcus pneumoniae from other Streptococcus mitis group streptococci (SMGS) remains challenging despite the introduction of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). While the bile solubility test (BST) provides most reliable discrimination of pneumococci, its practical implementation is limited by subjective visual interpretation and frequent inconclusive results. We aimed to develop a rapid confirmation BST based on direct-on-target MALDI-TOF MS assay. After establishment of optimal test conditions, test performance was evaluated on 36 consecutive clinical SMGS isolates. Colony material was suspended and pipetted onto a MALDI target. After drying, sodium deoxycholate in different concentrations (2%, 5%, and 10 %) was added. Incubation for 30 min (at room temperature or 35 °C) was followed by liquid removal and spot washing. After adding 70 % formic acid, spots were overlaid with matrix and measured (MALDI Biotyper smart, Bruker). The absence of microbial spectra (Biotyper score <1.7) in samples with sodium deoxycholate indicated efficient removal of bacterial biomass due to bile solubility, thus, identifying pneumococci. In contrast, scores ≥1.7 were interpreted as lack of bile solubility and confirmation as viridans streptococci other than S. pneumoniae. Highest test accuracy was achieved applying 5% sodium deoxycholate at 35 °C and 10 % sodium deoxycholate at room temperature. These test conditions provided 100 % sensitivity and 100 % specificity for discrimination of S. pneumoniae. The developed MALDI-TOF MS-based BST is an easy-to-perform assay with minimum hands-on time and objective readout. The promising results of this proof-of-principle study warrant confirmation with large collections of epidemiologically diverse strains.
Keywords	Streptococcus pneumoniae ; MALDI-TOF mass spectrometry ; Bile solubility test ; Rapid test ; Microbiology ; QR1-502 ; Other systems of medicine ; RZ201-999
Subject code	500
Language	English
Publishing date	2020-04-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Correlations of Host and Bacterial Characteristics with Clinical Parameters and Survival in Staphylococcus aureus Bacteremia

Hannah Wächter / Erdal Yörük / Karsten Becker / Dennis Görlich / Barbara C. Kahl

Journal of Clinical Medicine, Vol 10, Iss 1371, p

2021 Volume 1371

Abstract: Staphylococcus aureus bacteremia (SAB) is a frequent, severe condition that occurs in patients of all age groups and affects clinical departments of all medical fields. It is associated with a high mortality rate of 20–30%. In this study, we analyzed ... ...

Abstract	Staphylococcus aureus bacteremia (SAB) is a frequent, severe condition that occurs in patients of all age groups and affects clinical departments of all medical fields. It is associated with a high mortality rate of 20–30%. In this study, we analyzed patient mortality associated with SAB at our tertiary care university hospital, assessed the clinical management in terms of administered antimicrobial therapy, and determined which factors have an impact on the clinical course and outcome of patients with this disease. We collected clinical data and blood culture isolates of 178 patients diagnosed with SAB between May 2013 and July 2015. For this study, bacteria were cultured and analyzed concerning their phenotype, hemolysis activity, biofilm formation, nuclease activity, prevalence of toxin genes, spa and agr type. Overall mortality was 24.2% and 30-day mortality was 14.6%. Inadequate initial therapy was administered to 26.2% of patients and was associated with decreased survival ( p = 0.041). Other factors associated with poor survival were patient age ( p = 0.003), agr type 4 ( p ≤ 0.001) and pathological leukocyte counts ( p = 0.029 if elevated and p = 0.003 if lowered). The type of infection focus, spa clonal complex and enterotoxin genes seg and sei had an impact on severity of inflammation. Our results indicate that mortality and burden of disease posed by SAB are high at our university hospital.
Keywords	Staphylococcus aureus ; bacteremia ; mortality ; toxin genes ; agr type ; spa type ; Medicine ; R
Subject code	610
Language	English
Publishing date	2021-03-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: The Virulence Potential of Livestock-Associated Methicillin-Resistant Staphylococcus aureus Cultured from the Airways of Cystic Fibrosis Patients

Janina Treffon / Sarah Ann Fotiadis / Sarah van Alen / Karsten Becker / Barbara C. Kahl

Toxins, Vol 12, Iss 360, p

2020 Volume 360

Abstract: Staphylococcus aureus is one of the most common pathogens that infects the airways of patients with cystic fibrosis (CF) and contributes to respiratory failure. Recently, livestock-associated methicillin-resistant S. aureus (LA-MRSA), usually cultured in ...

Abstract	Staphylococcus aureus is one of the most common pathogens that infects the airways of patients with cystic fibrosis (CF) and contributes to respiratory failure. Recently, livestock-associated methicillin-resistant S. aureus (LA-MRSA), usually cultured in farm animals, were detected in CF airways. Although some of these strains are able to establish severe infections in humans, there is limited knowledge about the role of LA-MRSA virulence in CF lung disease. To address this issue, we analyzed LA-MRSA, hospital-associated (HA-) MRSA and methicillin-susceptible S. aureus (MSSA) clinical isolates recovered early in the course of airway infection and several years after persistence in this hostile environment from pulmonary specimens of nine CF patients regarding important virulence traits such as their hemolytic activity, biofilm formation, invasion in airway epithelial cells, cytotoxicity, and antibiotic susceptibility. We detected that CF LA-MRSA isolates were resistant to tetracycline, more hemolytic and cytotoxic than HA-MRSA, and more invasive than MSSA. Despite the residence in the animal host, LA-MRSA still represent a serious threat to humans, as such clones possess a virulence potential similar or even higher than that of HA-MRSA. Furthermore, we confirmed that S. aureus individually adapts to the airways of CF patients, which eventually impedes the success of antistaphylococcal therapy of airway infections in CF.
Keywords	LA- ; HA-MRSA ; MSSA ; cystic fibrosis ; virulence ; hemolysis ; biofilm ; Medicine ; R
Subject code	610
Language	English
Publishing date	2020-05-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Design and validation of Dolosigranulum pigrum specific PCR primers using the bacterial core genome

Maliha Aziz / Amber Palmer / Søren Iversen / Juan E. Salazar / Tony Pham / Kelsey Roach / Karsten Becker / Ursula Kaspar / Lance B. Price / Sharmin Baig / Marc Stegger / Paal Skytt Andersen / Cindy M. Liu

Scientific Reports, Vol 13, Iss 1, Pp 1-

2023 Volume 6

Abstract: Abstract Dolosigranulum pigrum—a lactic acid bacterium that is increasingly recognized as an important member of the nasal microbiome. Currently, there are limited rapid and low-cost options for confirming D. pigrum isolates and detecting D. pigrum in ... ...

Abstract	Abstract Dolosigranulum pigrum—a lactic acid bacterium that is increasingly recognized as an important member of the nasal microbiome. Currently, there are limited rapid and low-cost options for confirming D. pigrum isolates and detecting D. pigrum in clinical specimens. Here we describe the design and validation of a novel PCR assay targeting D. pigrum that is both sensitive and specific. We designed a PCR assay targeting murJ, a single-copy core species gene identified through the analysis of 21 D. pigrum whole genome sequences. The assay achieved 100% sensitivity and 100% specificity against D. pigrum and diverse bacterial isolates and an overall 91.1% sensitivity and 100% specificity using nasal swabs, detecting D. pigrum at a threshold of 1.0 × 104 D. pigrum 16S rRNA gene copies per swab. This assay adds a reliable and rapid D. pigrum detection tool to the microbiome researcher toolkit investigating the role of generalist and specialist bacteria in the nasal environment.
Keywords	Medicine ; R ; Science ; Q
Subject code	572
Language	English
Publishing date	2023-04-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Hypervirulent Klebsiella pneumoniae Sequence Type 420 with a Chromosomally Inserted Virulence Plasmid

Elias Eger / Stefan E. Heiden / Karsten Becker / Andrea Rau / Katharina Geisenhainer / Evgeny A. Idelevich / Katharina Schaufler

International Journal of Molecular Sciences, Vol 22, Iss 9196, p

2021 Volume 9196

Abstract: Background: Klebsiella pneumoniae causes severe diseases including sepsis, pneumonia and wound infections and is differentiated into hypervirulent (hvKp) and classic (cKp) pathotypes. hvKp isolates are characterized clinically by invasive and multiple ... ...

Abstract	Background: Klebsiella pneumoniae causes severe diseases including sepsis, pneumonia and wound infections and is differentiated into hypervirulent (hvKp) and classic (cKp) pathotypes. hvKp isolates are characterized clinically by invasive and multiple site infection and phenotypically in particular through hypermucoviscosity and increased siderophore production, enabled by the presence of the respective virulence genes, which are partly carried on plasmids. Methods: Here, we analyzed two K. pneumoniae isolates of a human patient that caused severe multiple site infection. By applying both genomic and phenotypic experiments and combining basic science with clinical approaches, we aimed at characterizing the clinical background as well as the two isolates in-depth. This also included bioinformatics analysis of a chromosomal virulence plasmid integration event. Results: Our genomic analysis revealed that the two isolates were clonal and belonged to sequence type 420, which is not only the first description of this K. pneumoniae subtype in Germany but also suggests belonging to the hvKp pathotype. The latter was supported by the clinical appearance and our phenotypic findings revealing increased siderophore production and hypermucoviscosity similar to an archetypical, hypervirulent K. pneumoniae strain. In addition, our in-depth bioinformatics analysis suggested the insertion of a hypervirulence plasmid in the bacterial chromosome, mediated by a new IS 5 family sub-group IS 903 insertion sequence designated IS Kpn74 . Conclusion: Our study contributes not only to the understanding of hvKp and the association between hypervirulence and clinical outcomes but reveals the chromosomal integration of a virulence plasmid, which might lead to tremendous public health implications.
Keywords	K. pneumoniae ; ST420 ; IS Kpn74 ; chromosomally inserted plasmid ; Biology (General) ; QH301-705.5 ; Chemistry ; QD1-999
Subject code	572
Language	English
Publishing date	2021-08-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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