scholarly journals The Papain Inhibitor (SPI) of Streptomyces mobaraensis Inhibits Bacterial Cysteine Proteases and Is an Antagonist of Bacterial Growth

2013 ◽  
Vol 57 (7) ◽  
pp. 3388-3391 ◽  
Author(s):  
Stephan Zindel ◽  
Wendy E. Kaman ◽  
Sabrina Fröls ◽  
Felicitas Pfeifer ◽  
Anna Peters ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bacillus Anthracis ◽  
Pathogenic Bacteria ◽  
Cysteine Proteases ◽  
Inhibitory Effect ◽  
Inhibitory Protein ◽  
Content Type ◽  
Cysteine Protease Activity ◽  
Streptomyces Mobaraensis ◽  
Culture Supernatants

ABSTRACTA novel papain inhibitory protein (SPI) fromStreptomyces mobaraensiswas studied to measure its inhibitory effect on bacterial cysteine protease activity (Staphylococcus aureusSspB) and culture supernatants (Porphyromonas gingivalis,Bacillus anthracis). Further, growth ofBacillus anthracis,Staphylococcus aureus,Pseudomonas aeruginosa, andVibrio choleraewas completely inhibited by 10 μM SPI. At this concentration of SPI, no cytotoxicity was observed. We conclude that SPI inhibits bacterial virulence factors and has the potential to become a novel therapeutic treatment against a range of unrelated pathogenic bacteria.

scholarly journals Lytic Activity of LysH5 Endolysin Secreted by Lactococcus lactis Using the Secretion Signal Sequence of Bacteriocin Lcn972

2012 ◽  
Vol 78 (9) ◽  
pp. 3469-3472 ◽  
Author(s):  
Lorena Rodríguez-Rubio ◽  
Dolores Gutiérrez ◽  
Beatriz Martínez ◽  
Ana Rodríguez ◽  
Pilar García
Keyword(s):  
Staphylococcus Aureus ◽  
Lactococcus Lactis ◽  
Signal Peptide ◽  
Signal Sequence ◽  
Content Type ◽  
Inducible Promoters ◽  
Secretion Signal ◽  
Cell Extracts ◽  
Culture Supernatants ◽  
Secretion Signal Sequence

ABSTRACTBacteriophage endolysins have an interesting potential as antimicrobials. The endolysin LysH5, encoded byStaphylococcus aureusphage vB_SauS-phi-IPLA88, was expressed and secreted inLactococcus lactisusing the signal peptide of bacteriocin lactococcin 972 and lactococcal constitutive and inducible promoters. Up to 80 U/mg of extracellular active endolysin was detected in culture supernatants, but most of the protein (up to 323 U/mg) remained in the cell extracts.

scholarly journals Manganese Detoxification by MntE Is Critical for Resistance to Oxidative Stress and Virulence of Staphylococcus aureus

mBio ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Caroline M. Grunenwald ◽  
Jacob E. Choby ◽  
Lillian J. Juttukonda ◽  
William N. Beavers ◽  
Andy Weiss ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Staphylococcus Aureus ◽  
Pathogenic Bacteria ◽  
Efflux Pump ◽  
Uptake System ◽  
Cation Diffusion ◽  
Intracellular Iron ◽  
Cation Diffusion Facilitator ◽  
Mn Toxicity ◽  
Content Type

ABSTRACT Manganese (Mn) is an essential micronutrient critical for the pathogenesis of Staphylococcus aureus, a significant cause of human morbidity and mortality. Paradoxically, excess Mn is toxic; therefore, maintenance of intracellular Mn homeostasis is required for survival. Here we describe a Mn exporter in S. aureus, MntE, which is a member of the cation diffusion facilitator (CDF) protein family and conserved among Gram-positive pathogens. Upregulation of mntE transcription in response to excess Mn is dependent on the presence of MntR, a transcriptional repressor of the mntABC Mn uptake system. Inactivation of mntE or mntR leads to reduced growth in media supplemented with Mn, demonstrating MntE is required for detoxification of excess Mn. Inactivation of mntE results in elevated levels of intracellular Mn, but reduced intracellular iron (Fe) levels, supporting the hypothesis that MntE functions as a Mn efflux pump and Mn efflux influences Fe homeostasis. Strains inactivated for mntE are more sensitive to the oxidants NaOCl and paraquat, indicating Mn homeostasis is critical for resisting oxidative stress. Furthermore, mntE and mntR are required for full virulence of S. aureus during infection, suggesting S. aureus experiences Mn toxicity in vivo. Combined, these data support a model in which MntR controls Mn homeostasis by balancing transcriptional repression of mntABC and induction of mntE, both of which are critical for S. aureus pathogenesis. Thus, Mn efflux contributes to bacterial survival and virulence during infection, establishing MntE as a potential antimicrobial target and expanding our understanding of Mn homeostasis. IMPORTANCE Manganese (Mn) is generally viewed as a critical nutrient that is beneficial to pathogenic bacteria due to its function as an enzymatic cofactor and its capability of acting as an antioxidant; yet paradoxically, high concentrations of this transition metal can be toxic. In this work, we demonstrate Staphylococcus aureus utilizes the cation diffusion facilitator (CDF) family protein MntE to alleviate Mn toxicity through efflux of excess Mn. Inactivation of mntE leads to a significant reduction in S. aureus resistance to oxidative stress and S. aureus-mediated mortality within a mouse model of systemic infection. These results highlight the importance of MntE-mediated Mn detoxification in intracellular Mn homeostasis, resistance to oxidative stress, and S. aureus virulence. Therefore, this establishes MntE as a potential target for development of anti-S. aureus therapeutics.

scholarly journals Livestock Origin for a Human Pandemic Clone of Community-Associated Methicillin-Resistant Staphylococcus aureus

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Laura E. Spoor ◽  
Paul R. McAdam ◽  
Lucy A. Weinert ◽  
Andrew Rambaut ◽  
Henrik Hasman ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pathogenic Bacteria ◽  
Control Measures ◽  
Human Populations ◽  
Epidemic Spread ◽  
Human Pathogens ◽  
Methicillin Resistant ◽  
Content Type ◽  
Evolutionary Origins ◽  
Healthy Humans

ABSTRACTThe importance of livestock as a source of bacterial pathogens with the potential for epidemic spread in human populations is unclear. In recent years, there has been a global increase in community-associated methicillin-resistantStaphylococcus aureus(CA-MRSA) infections of healthy humans, but an understanding of the different evolutionary origins of CA-MRSA clones and the basis for their recent expansion is lacking. Here, using a high-resolution phylogenetic approach, we report the discovery of two emergent clones of human epidemic CA-MRSA which resulted from independent livestock-to-human host jumps by the major bovineS. aureuscomplex, CC97. Of note, one of the new clones was isolated from human infections on four continents, demonstrating its global dissemination since the host jump occurred over 40 years ago. The emergence of both humanS. aureusclones coincided with the independent acquisition of mobile genetic elements encoding antimicrobial resistance and human-specific mediators of immune evasion, consistent with an important role for these genetic events in the capacity to survive and transmit among human populations. In conclusion, we provide evidence that livestock represent a reservoir for the emergence of new human-pathogenicS. aureusclones with the capacity for pandemic spread. These findings have major public health implications highlighting the importance of surveillance for early identification of emergent clones and improved transmission control measures at the human-livestock interface.IMPORTANCEAnimals are the major source of new pathogens affecting humans. However, the potential for pathogenic bacteria that originally were found in animals to switch hosts and become widely established in human populations is not clear. Here, we report the discovery of emergent clones of methicillin-resistantStaphylococcus aureus(MRSA) that originated in livestock and switched to humans, followed by host-adaptive evolution and epidemic spread in global human populations. Our findings demonstrate that livestock can act as a reservoir for the emergence of new human bacterial clones with potential for pandemic spread, highlighting the potential role of surveillance and biosecurity measures in the agricultural setting for preventing the emergence of new human pathogens.

scholarly journals Cysteine Protease Activity of Feline Tritrichomonas foetus Promotes Adhesion-Dependent Cytotoxicity to Intestinal Epithelial Cells

2014 ◽  
Vol 82 (7) ◽  
pp. 2851-2859 ◽  
Author(s):  
M. K. Tolbert ◽  
S. H. Stauffer ◽  
M. D. Brand ◽  
J. L. Gookin
Keyword(s):  
Intestinal Epithelium ◽  
Cysteine Protease ◽  
Intestinal Tract ◽  
Intestinal Epithelial Cells ◽  
Cysteine Proteases ◽  
Intestinal Epithelial ◽  
Tritrichomonas Foetus ◽  
Cellular Mechanisms ◽  
Content Type ◽  
Cysteine Protease Activity

ABSTRACTTrichomonads are obligate protozoan parasites most renowned as venereal pathogens of the reproductive tract of humans and cattle. Recently, a trichomonad highly similar to bovine venerealTritrichomonas foetusbut having a unique tropism for the intestinal tract was recognized as a significant cause of colitis in domestic cats. Despite a high prevalence, worldwide distribution, and lack of consistently effective drugs for treatment of the infection, the cellular mechanisms ofT. foetuspathogenicity in the intestinal tract have not been examined. The aims of this study were to determine the pathogenic effect of felineT. foetuson porcine intestinal epithelial cells, the dependence ofT. foetuspathogenicity on adhesion ofT. foetusto the intestinal epithelium, and the identity of mediators responsible for these effects. Using anin vitrococulture approach to model felineT. foetusinfection of the intestinal epithelium, these studies demonstrate thatT. foetuspromotes a direct contact-dependent activation of intestinal epithelial cell apoptosis signaling and progressive monolayer destruction. Moreover, these pathological effects were demonstrated to be largely dependent onT. foetuscell-associated cysteine protease activity. Finally,T. foetuscysteine proteases were identified as enabling cytopathic effects by promoting adhesion ofT. foetusto the intestinal epithelium. The present studies are the first to examine the cellular mechanisms of pathogenicity ofT. foetustoward the intestinal epithelium and support further investigation of the cysteine proteases as virulence factorsin vivoand as potential therapeutic targets for ameliorating the pathological effects of intestinal trichomonosis.

scholarly journals Revisiting the Concept of Targeting Only Bacillus anthracis Toxins as a Treatment for Anthrax

2016 ◽  
Vol 60 (8) ◽  
pp. 4878-4885 ◽  
Author(s):  
Itai Glinert ◽  
Elad Bar-David ◽  
Assa Sittner ◽  
Shay Weiss ◽  
Josef Schlomovitz ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Protein Fraction ◽  
Neutralizing Antibodies ◽  
Pathogenic Bacteria ◽  
Protective Antigen ◽  
Lethal Factor ◽  
Immunofluorescence Assay ◽  
Secreted Protein ◽  
Content Type

ABSTRACTProtective antigen (PA)-based vaccines are effective in preventing the development of fatal anthrax disease both in humans and in relevant animal models. TheBacillus anthracistoxins lethal toxin (lethal factor [LF] plus PA) and edema toxin (edema factor [EF] plus PA) are essential for the establishment of the infection, as inactivation of these toxins results in attenuation of the pathogen. Since the toxins reach high toxemia levels at the bacteremic stages of the disease, the CDC's recommendations include combining antibiotic treatment with antitoxin (anti-PA) immunotherapy. We demonstrate here that while treatment with a highly potent neutralizing monoclonal antibody was highly efficient as postexposure prophylaxis treatment, it failed to protect rabbits with any detectable bacteremia (≥10 CFU/ml). In addition, we show that while PA vaccination was effective against a subcutaneous spore challenge, it failed to protect rabbits against systemic challenges (intravenous injection of vegetative bacteria) with the wild-type Vollum strain or a toxin-deficient mutant. To test the possibility that additional proteins, which are secreted by the bacteria under pathogenicity-stimulating conditionsin vitro, may contribute to the vaccine's potency, we immunized rabbits with a secreted protein fraction from a toxin-null mutant. The antiserum raised against the secreted fraction reacts with the bacteria in an immunofluorescence assay. Immunization with the secreted protein fraction did not protect the rabbits against a systemic challenge with the fully pathogenic bacteria. Full protection was obtained only by a combined vaccination with PA and the secreted protein fraction. Therefore, these results indicate that an effective antiserum treatment in advanced stages of anthrax must include toxin-neutralizing antibodies in combination with antibodies against bacterial cell targets.

scholarly journals Aerosol and Surface Deposition Characteristics of Two Surrogates for Bacillus anthracis Spores

2016 ◽  
Vol 82 (22) ◽  
pp. 6682-6690 ◽  
Author(s):  
Alistair H. Bishop ◽  
Helen L. Stapleton
Keyword(s):  
Bacillus Anthracis ◽  
Pathogenic Bacteria ◽  
Human Infection ◽  
Solid Surfaces ◽  
Surface Deposition ◽  
Content Type ◽  
Hazard Management ◽  
Bacillus Anthracis Spores ◽  
Air Blower ◽  
Set Up

ABSTRACTSpores of an acrystalliferous derivative ofBacillus thuringiensissubsp.kurstaki, termedBtcry−, are morphologically, aerodynamically, and structurally indistinguishable fromBacillus anthracisspores.Btcry− spores were dispersed in a large, open-ended barn together with spores ofBacillus atrophaeussubsp.globigii, a historically used surrogate forBacillus anthracis. Spore suspensions (2 × 1012CFU each ofB. atrophaeussubsp.globigiiandBtcry−) were aerosolized in each of five spray events using a backpack misting device incorporating an air blower; a wind of 4.9 to 7.6 m s−1was also flowing through the barn in the same direction. Filter air samplers were situated throughout the barn to assess the aerosol density of the spores during each release. Trays filled with a surfactant in aqueous buffer were placed on the floor near the filter samplers to assess spore deposition. Spores were also recovered from arrays of solid surfaces (concrete, aluminum, and plywood) that had been laid on the floor and set up as a wall at the end of the barn.B. atrophaeussubsp.globigiispores were found to remain airborne for significantly longer periods, and to be deposited on horizontal surfaces at lower densities, thanBtcry− spores, particularly near the spray source. There was a 6-fold-higher deposition ofBtcry− spores than ofB. atrophaeussubsp.globigiispores on vertical surfaces relative to the surrounding airborne density. This work is relevant for selecting the bestB. anthracissurrogate for the prediction of human exposure, hazard assessment, and hazard management following a malicious release ofB. anthracis.IMPORTANCEThere is concern that pathogenic bacteria could be maliciously disseminated in the air to cause human infection and disruption of normal life. The threat from spore-forming organisms, such as the causative agent of anthrax, is particularly serious. In order to assess the extent of this risk, it is important to have a surrogate organism that can be used to replicate the dispersal characteristics of the threat agent accurately. This work compares the aerosol dispersal and deposition behaviors of the surrogatesBtcry− andB. atrophaeussubsp.globigii.Btcry− spores remained in the air for a shorter time, and were markedly more likely to adhere to vertical surfaces, thanB. atrophaeussubsp.globigiispores.

scholarly journals Staphopains Modulate Staphylococcus aureus Biofilm Integrity

2013 ◽  
Vol 81 (9) ◽  
pp. 3227-3238 ◽  
Author(s):  
Joe M. Mootz ◽  
Cheryl L. Malone ◽  
Lindsey N. Shaw ◽  
Alexander R. Horswill
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Cysteine Proteases ◽  
Cysteine Protease Inhibitor ◽  
Content Type ◽  
Sigma Factor B ◽  
Biofilm Structure ◽  
Microtiter Assay ◽  
Negative Phenotype

ABSTRACTStaphylococcus aureusis a known cause of chronic biofilm infections that can reside on medical implants or host tissue. Recent studies have demonstrated an important role for proteinaceous material in the biofilm structure. TheS. aureusgenome encodes many secreted proteases, and there is growing evidence that these enzymes have self-cleavage properties that alter biofilm integrity. However, the specific contribution of each protease and mechanism of biofilm modulation is not clear. To address this issue, we utilized a sigma factor B (ΔsigB) mutant where protease activity results in a biofilm-negative phenotype, thereby creating a condition where the protease(s) responsible for the phenotype could be identified. Using a plasma-coated microtiter assay, biofilm formation was restored to the ΔsigBmutant through the addition of the cysteine protease inhibitor E-64 or by using Staphostatin inhibitors that specifically target the extracellular cysteine proteases SspB and ScpA (called Staphopains). Through construction of gene deletion mutants, we determined that ansspB scpAdouble mutant restored ΔsigBbiofilm formation, and this recovery could be replicated in plasma-coated flow cell biofilms. Staphopain levels were also found to be decreased under biofilm-forming conditions, possibly allowing biofilm establishment. The treatment ofS. aureusbiofilms with purified SspB or ScpA enzyme inhibited their formation, and ScpA was also able to disperse an established biofilm. The antibiofilm properties of ScpA were conserved acrossS. aureusstrain lineages. These findings suggest an underappreciated role of the SspB and ScpA cysteine proteases in modulatingS. aureusbiofilm architecture.

scholarly journals Topical Antimicrobial Treatments Can Elicit Shifts to Resident Skin Bacterial Communities and Reduce Colonization by Staphylococcus aureus Competitors

2017 ◽  
Vol 61 (9) ◽  
Author(s):  
Adam J. SanMiguel ◽  
Jacquelyn S. Meisel ◽  
Joseph Horwinski ◽  
Qi Zheng ◽  
Elizabeth A. Grice
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Communities ◽  
Pathogenic Bacteria ◽  
Skin Surface ◽  
Skin Microbiome ◽  
Antimicrobial Drugs ◽  
Bacterial Populations ◽  
Content Type ◽  
Topical Antibiotics ◽  
The Impact

ABSTRACT The skin microbiome is a complex ecosystem with important implications for cutaneous health and disease. Topical antibiotics and antiseptics are often employed to preserve the balance of this population and inhibit colonization by more pathogenic bacteria. However, despite their widespread use, the impact of these interventions on broader microbial communities remains poorly understood. Here, we report the longitudinal effects of topical antibiotics and antiseptics on skin bacterial communities and their role in Staphylococcus aureus colonization resistance. In response to antibiotics, cutaneous populations exhibited an immediate shift in bacterial residents, an effect that persisted for multiple days posttreatment. By contrast, antiseptics elicited only minor changes to skin bacterial populations, with few changes to the underlying microbiota. While variable in scope, both antibiotics and antiseptics were found to decrease colonization by commensal Staphylococcus spp. by sequencing- and culture-based methods, an effect which was highly dependent on baseline levels of Staphylococcus. Because Staphylococcus residents have been shown to compete with the skin pathogen S. aureus, we also tested whether treatment could influence S. aureus levels at the skin surface. We found that treated mice were more susceptible to exogenous association with S. aureus and that precolonization with the same Staphylococcus residents that were previously disrupted by treatment reduced S. aureus levels by over 100-fold. In all, the results of this study indicate that antimicrobial drugs can alter skin bacterial residents and that these alterations can have critical implications for cutaneous host defense.

scholarly journals Pharmacological Properties of the Marine Natural Product Marinopyrrole A against Methicillin-Resistant Staphylococcus aureus

2011 ◽  
Vol 55 (7) ◽  
pp. 3305-3312 ◽  
Author(s):  
Nina M. Haste ◽  
Chambers C. Hughes ◽  
Dan N. Tran ◽  
William Fenical ◽  
Paul R. Jensen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bactericidal Effect ◽  
Inhibitory Effect ◽  
Marine Natural Product ◽  
Methicillin Resistant ◽  
Content Type ◽  
Mammalian Cell Lines ◽  
Antistaphylococcal Activity ◽  
New Antibiotics ◽  
Mrsa Strains

ABSTRACTThe ongoing spread of methicillin-resistantStaphylococcus aureus(MRSA) strains in hospital and community settings presents a great challenge to public health and illustrates the urgency of discovering new antibiotics. Marinopyrrole A is a member of a structurally novel class of compounds identified from a species of marine-derived streptomycetes with evidence of antistaphylococcal activity. We show that marinopyrrole A has potent concentration-dependent bactericidal activity against clinically relevant hospital- and community-acquired MRSA strains, a prolonged postantibiotic effect superior to that of the current first-line agents vancomycin and linezolid, and a favorable resistance profile. Marinopyrrole A showed limited toxicity to mammalian cell lines (at >20× MIC). However, its antibiotic activity against MRSA was effectively neutralized by 20% human serum. A variety of marinopyrrole analogs were isolated from culture or synthetically produced to try to overcome the inhibitory effect of serum. While many of these compounds retained potent bactericidal effect against MRSA, their activities were also inhibited by serum. Marinopyrrole A has significant affinity for plastic and may therefore have potential as a potent anti-MRSA agent in cutaneous, intracatheter, or antibiotic-lock applications.

scholarly journals Methicillin-Resistant Staphylococcus aureus in Hospitals: Latest Trends and Treatments Based on Bacteriophages

2019 ◽  
Vol 57 (12) ◽  
Author(s):  
Andrea Álvarez ◽  
Lucía Fernández ◽  
Diana Gutiérrez ◽  
Beatriz Iglesias ◽  
Ana Rodríguez ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Pathogenic Bacteria ◽  
World Health ◽  
Natural Phenomenon ◽  
Methicillin Resistant ◽  
Content Type ◽  
Wide Range ◽  
Mrsa Strains ◽  
Health Organization

ABSTRACT Even though antibiotic resistance in bacteria is a natural phenomenon, the alarming increase in pathogenic bacteria refractory to a wide range of antimicrobials is attracting attention worldwide. Indeed, the World Health Organization (WHO) has recently published a list of priority pathogens for which new antimicrobial alternatives are urgently needed. Among these pathogens, methicillin-resistant Staphylococcus aureus (MRSA) strains are perhaps the best known by the general public. In addition to its potential to acquire antibiotic resistance, S. aureus can produce a large number of virulence factors, such as hemolysins, enterotoxins, and proteases, and exhibits the ability to form biofilms as well as to evolve into different clones that can spread and colonize new environments. This review provides a brief overview of the latest options in antibacterial therapies, mainly focusing on phage therapy. In this regard, the current stage of research about antimicrobial compounds based on bacteriophages and endolysins against MRSA infections is shown and discussed.

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