pure-cultures-streak-plating-isolation-single-bacterial-colonies-from

Pure Cultures and Streak Plating: Isolation of Single Bacterial Colonies from a Mixed Sample

Source: Tilde Andersson1, Rolf Lood1
1 Department of Clinical Sciences Lund, Division of Infection Medicine, Biomedical Center, Lund University, 221 00 ...

16s-rrna-sequencing-pcr-based-technique-to-identify-bacterial

16S rRNA Sequencing: A PCR-based Technique to Identify Bacterial Species

Source: Ewa Bukowska-Faniband1, Tilde Andersson1, Rolf Lood1
1 Department of Clinical Sciences Lund, Division of Infection Medicine, Biomedical Center, ...

antibiotic-susceptibility-testing-epsilometer-tests-to-determine-mic

Antibiotic Susceptibility Testing: Epsilometer Tests to Determine MIC Values of Two Antibiotics and Evaluate Antibiotic Synergy

Source: Anna Bl&#228;ckberg1, Rolf Lood1
1 Department of Clinical Sciences Lund, Division of Infection Medicine, Biomedical Center, Lund University, 221 ...

plaque-assay-method-to-determine-viral-titer-as-plaque-forming-units

Plaque Assay: A Method to Determine Viral Titer as Plaque Forming Units (PFU)

ultrasensitive-detection-biomarkers-using-molecular-imprinting-based

Ultrasensitive Detection of Biomarkers by Using a Molecular Imprinting Based Capacitive Biosensor

The ability to detect and quantitate biomolecules in complex solutions has always been highly sought-after within natural science; being used for the ...

Lund University

Propionibacterium acnes is a commensal of human skin but is also known to be involved in certain diseases, such as acne vulgaris and infections of orthopaedic implants. Treatment of these conditions is complicated by increased resistance to antibiotics and/or biofilm formation of P. acnes bacteria. P. acnes can be infected by bacteriophages, but until recently little has been known about these viruses. The aim of this study was to identify and characterize inducible phages from P. acnes on a genetic and morphological basis.

Inducible Siphoviruses in superficial and deep tissue isolates of Propionibacterium acnes.

Finegoldia magna is a member of the normal human bacterial flora on the skin and other non-sterile body surfaces, but this anaerobic coccus is also an important opportunistic pathogen. SufA was the first F. magna proteinase to be isolated and characterized. Many bacterial pathogens interfere with different steps of blood coagulation, and here we describe how purified SufA efficiently and specifically cleaves fibrinogen in human plasma. SufA is both secreted by F. magna and associated with the bacterial surface. Successful gene targeting has previously not been performed in anaerobic cocci, but in order to study the role of the SufA that is present at the bacterial surface, we constructed an F. magna mutant that expresses a truncated SufA lacking proteolytic activity. In contrast to wild-type bacteria that delayed the coagulation of human plasma, mutant bacteria had no such effect. Wild-type and mutant bacteria adhered to keratinocytes equally well, but in a plasma environment only wild-type bacteria blocked the formation of fibrin networks surrounding adherent bacteria. The effective cleavage of fibrinogen by SufA suggests that the interference with fibrin network formation represents an adaptive mechanism of F. magna with potential implications also for pathogenicity.

SufA - a bacterial enzyme that cleaves fibrinogen and blocks fibrin network formation.

Propionibacterium acnes is a Gram positive rod inhabiting the human skin that also infects orthopaedic implants and is associated with acne vulgaris. Previously, one lytic bacteriophage, PA6, from P. acnes has been sequenced and partially characterized. We recently isolated several inducible phages from P. acnes classified as Siphoviruses based on morphology and partial genome sequencing.

Characterization and genome sequencing of two Propionibacterium acnes phages displaying pseudolysogeny.

Systemic lupus erythematosus (SLE) is an autoimmune disease with chronic or episodic inflammation in several organ systems, related to the presence of circulating and tissue-deposited immune complexes (ICs) that stimulate leukocytes through Fcγ receptors (FcγR) with subsequent inflammation. Treatment with endoglycosidase S (EndoS), an IgG glycan-hydrolyzing bacterial enzyme from Streptococcus pyogenes, has shown beneficial effects in several experimental animal models of chronic inflammatory disease. This study was undertaken to investigate whether EndoS affects the proinflammatory properties of ICs and has the potential to be developed as a therapy for SLE.

IgG glycan hydrolysis by endoglycosidase S diminishes the proinflammatory properties of immune complexes from patients with systemic lupus erythematosus: a possible new treatment?

Bacterial infections are becoming an increasing problem worldwide and there is a need for a deeper understanding of how bacteria turn pathogenic. Here, we suggest that one answer may be found by taking into account the localization of the bacteria, both at an anatomical level and at a microenvironment level. Both commensals and traditional pathogens alter their interaction with the human host depending on the local surroundings--turning either more or less virulent. These localization effects could derive from the characteristics of different anatomical sites but also from local differences within a microenvironment. In order to understand the adaptive functions of bacterial virulence factors, we need to study the bacteria in the environments where they have evolved.

Localization-triggered bacterial pathogenesis.

The role of the skin microbiota in human health is poorly understood. Here, we identified and characterized a novel antioxidant enzyme produced by the skin microbiota, designated RoxP for radical oxygenase of Propionibacterium acnes. RoxP is uniquely produced by the predominant skin bacterium P. acnes, with no homologs in other bacteria; it is highly expressed and strongly secreted into culture supernatants. We show that RoxP binds heme, reduces free radicals, and can protect molecules from oxidation. Strikingly, RoxP is crucial for the survival of P. acnes in oxic conditions and for skin colonization of P. acnes ex vivo. Taken together, our study strongly suggests that RoxP facilitates P. acnes' survival on human skin, and is an important beneficial factor for the host-commensal interaction. Thus, RoxP is the first described skin microbiota-derived mutualistic factor that potentially can be exploited for human skin protection.

A novel enzyme with antioxidant capacity produced by the ubiquitous skin colonizer Propionibacterium acnes.

Protein-protein interactions play important roles in bacterial pathogenesis. Surface-bound or secreted bacterial proteins are key in mediating bacterial virulence. Thus, these factors are of high importance to study in order to elucidate the molecular mechanisms behind bacterial pathogenesis. Here, we present a protein-based strategy that can be used to identify and isolate bacterial proteins of importance for bacterial virulence, and allow for identification of both unknown host and bacterial factors. The methods described have among others successfully been used to identify and characterize several IgG-binding proteins, including protein G, protein H, and protein L.

Protein-Based Strategies to Identify and Isolate Bacterial Virulence Factors.

The development of therapeutic and diagnostic antibodies is a rapidly growing field of research, being the fastest expanding group of products on the pharmaceutical market, and appropriate quality controls are crucial for their application. We have identified and characterized the serine protease termed BspK (Bdellovibrio serine protease K) from Bdellovibrio bacteriovorus and here show its activity on antibodies. Mutation of the serine residue at position 230 rendered the protease inactive. Further investigations of BspK enzymatic characteristics revealed autoproteolytic activity, resulting in numerous cleavage products. Two of the autoproteolytic cleavage sites in the BspK fusion protein were investigated in more detail and corresponded to cleavage after Kand Kin the N- and C-terminal parts of BspK, respectively. Further, BspK displayed stable enzymatic activity on IgG within the pH range of 6.0 to 9.5 and was inhibited in the presence of ZnClBspK demonstrated preferential hydrolysis of human IgG1 compared to other immunoglobulins and isotypes, with hydrolysis of the heavy chain at position Kgenerating two separate Fab fragments and an intact IgG Fc domain. Finally, we show that BspK preferentially cleaves its substrates C-terminally to lysines similar to the protease LysC. However, BspK displays a unique cleavage profile compared to several currently used proteases on the market.

BspK, a Serine Protease from the Predatory Bacterium Bdellovibrio bacteriovorus with Utility for Analysis of Therapeutic Antibodies.

The necessity of identifying novel methods to combat infections caused by antibiotic resistant bacteria is increasing each year. Recent advancements in the development of peptidoglycan hydrolases (e.g. lysins) from bacterial viruses (bacteriophages) have revealed the efficiency of this class of enzymes in treating serious bacterial infections. Though promising results have been obtained regarding the lethal action of lysin on bacterial pathogens both in vitro and in vivo, an often-overlooked factor in these studies is precisely identifying their peptidoglycan cleavage site. This knowledge would be useful for following the activity of the enzyme during development, without the need for whole-organism lytic assays. However, more importantly, it would enable the selection of lysins with different cleavage activities that would act synergistically for enhanced efficacy. Here, we have developed two new methods to accurately identify the cleavage site of lysins using liquid chromatography mass spectrometry (LC-MS) on peptidoglycan-like fluorophore-quencher modified synthetic peptides, as well as determining the enzymatic action and kinetics of the enzymes on modified peptides in a Förster resonance energy transfer (FRET) assay. These methods should facilitate progress within the lysin field, accelerating the development of therapeutic lysins to combat antibiotic resistant bacterial infections.

Determining bacteriophage endopeptidase activity using either fluorophore-quencher labeled peptides combined with liquid chromatography-mass spectrometry (LC-MS) or Förster resonance energy transfer (FRET) assays.

The spread of antibiotic resistance is currently a major threat to health that humanity is facing today. Novel multidrug and pandrug resistant bacteria are reported on a yearly basis, while the development of novel antibiotics is lacking. Focus to limit the spread of antibiotic resistance by reducing the usage of antibiotics in health care, veterinary applications, and meat production, have been implemented, limiting the exposure of pathogens to antibiotics, thus lowering the selection of resistant strains. Despite these attempts, the global resistance has increased significantly. A recent area of focus has been to limit the spread of resistance through wastewater treatment plants (WWTPs), serving as huge reservoirs of microbes and resistance genes. While being able to quite efficiently reduce the presence of resistant bacteria entering any of the final products of WWTPs (e.g., effluent water and sludge), the presence of resistance genes in other formats (mobile genetic elements, bacteriophages) has mainly been ignored. Recent data stress the importance of transduction in WWTPs as a mediator of resistance spread. Here we examine the current literature in the role of WWTPs as reservoirs and hotspots of antibiotic resistance with a specific focus on bacteriophages as mediators of genetic exchange.

Revisiting Antibiotic Resistance Spreading in Wastewater Treatment Plants - Bacteriophages as a Much Neglected Potential Transmission Vehicle.

Cutibacterium (Propionibacterium) acnes, considered a part of the skin microbiota, is one of the most commonly isolated anaerobic bacteria from medical implants in contact with plasma. However, the precise interaction of C. acnes with blood cells and plasma proteins has not been fully elucidated. Herein, we have investigated the molecular interaction of C. acnes with platelets and plasma proteins. We report that the ability of C. acnes to aggregate platelets is dependent on phylotype, with a significantly lower ability amongst type IB isolates, and the interaction of specific donor-dependent plasma proteins (or concentrations thereof) with C. acnes. Pretreatment of C. acnes with plasma reduces the lag time before aggregation demonstrating that pre-deposition of plasma proteins on C. acnes is an important step in platelet aggregation. Using mass spectrometry we identified several plasma proteins deposited on C. acnes, including IgG, fibrinogen and complement factors. Inhibition of IgG, fibrinogen or complement decreased C. acnes-mediated platelet aggregation, demonstrating the importance of these plasma proteins for aggregation. The interaction of C. acnes and platelets was visualized using fluorescence microscopy, verifying the presence of IgG and fibrinogen as components of the aggregates, and co-localization of C. acnes and platelets in the aggregates. Here, we have demonstrated the ability of C. acnes to activate and aggregate platelets in a bacterium and donor-specific fashion, as well as added mechanistic insights into this interaction.

ArticleTotal : 5	Year
Publication title	2023
Publication title	2023
Publication title	2023
Publication title	2023
Publication title Cited by 4	2018

Article	Year
Inducible Siphoviruses in superficial and deep tissue isolates of Propionibacterium acnes. BMC microbiology\| PubMed ID: 18702830	2008
SufA - a bacterial enzyme that cleaves fibrinogen and blocks fibrin network formation. Microbiology (Reading, England)\| PubMed ID: 19118364	2009
Characterization and genome sequencing of two Propionibacterium acnes phages displaying pseudolysogeny. BMC genomics\| PubMed ID: 21504575	2011
IgG glycan hydrolysis by endoglycosidase S diminishes the proinflammatory properties of immune complexes from patients with systemic lupus erythematosus: a possible new treatment? Arthritis and rheumatism\| PubMed ID: 22392566	2012
Localization-triggered bacterial pathogenesis. Future microbiology\| PubMed ID: 26437846	2015
A novel enzyme with antioxidant capacity produced by the ubiquitous skin colonizer Propionibacterium acnes. Scientific reports\| PubMed ID: 27805044	2016
Protein-Based Strategies to Identify and Isolate Bacterial Virulence Factors. Methods in molecular biology (Clifton, N.J.)\| PubMed ID: 27914069	2017
BspK, a Serine Protease from the Predatory Bacterium Bdellovibrio bacteriovorus with Utility for Analysis of Therapeutic Antibodies. Applied and environmental microbiology\| PubMed ID: 27940543	2017
Determining bacteriophage endopeptidase activity using either fluorophore-quencher labeled peptides combined with liquid chromatography-mass spectrometry (LC-MS) or Förster resonance energy ... PloS one\| PubMed ID: 28296948	2017
Revisiting Antibiotic Resistance Spreading in Wastewater Treatment Plants - Bacteriophages as a Much Neglected Potential Transmission Vehicle. Frontiers in microbiology\| PubMed ID: 29209304	2017
Platelet activation and aggregation by the opportunistic pathogen Cutibacterium (Propionibacterium) acnes. PloS one\| PubMed ID: 29385206	2018

Rolf Lood

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