scholarly journals Immunoglobulins to Surface-Associated Biofilm Immunogens Provide a Novel Means of Visualization of Methicillin-Resistant Staphylococcus aureus Biofilms

2007 ◽  
Vol 73 (20) ◽  
pp. 6612-6619 ◽  
Author(s):  
Rebecca A. Brady ◽  
Jeff G. Leid ◽  
Jennifer Kofonow ◽  
J. William Costerton ◽  
Mark E. Shirtliff
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Protein Production ◽  
Specific Protein ◽  
Biofilm Growth ◽  
Methicillin Resistant ◽  
Associated Proteins ◽  
Space Function

ABSTRACT Antigens from the methicillin-resistant Staphylococcus aureus (MRSA) cell wall have been shown to be immunogenic in vivo and upregulated during biofilm growth. In this study, we created purified, recombinant forms of selected antigens and biofilm-upregulated, cell wall-associated proteins. These proteins were shown to cause a robust polyclonal immunoglobulin G (IgG) response when used to immunize rabbits. Antibodies against these recombinant proteins bound to the native forms of each protein as harvested from in vitro grown biofilms of MRSA, as determined both via Western blot analysis and immunofluorescence confocal microscopy. These IgGs could be utilized as imaging tools that localize to areas of specific protein production within a biofilm. This work illustrates that immunogenic, cell wall-associated, biofilm-upregulated proteins are promising for in vitro visualization of biofilm growth, architecture, and space-function relationships.

scholarly journals Impact of Bicarbonate-β-Lactam Exposures on Methicillin-Resistant Staphylococcus aureus (MRSA) Gene Expression in Bicarbonate-β-Lactam-Responsive vs. Non-Responsive Strains

Genes ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1650
Author(s):  
Selvi C. Ersoy ◽  
Blake M. Hanson ◽  
Richard A. Proctor ◽  
Cesar A. Arias ◽  
Truc T. Tran ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Ex Vivo ◽  
In Vivo Models ◽  
Methicillin Resistant ◽  
Genetic Perturbations ◽  
Functional Relevance

Methicillin-resistant Staphylococcus aureus (MRSA) infections represent a difficult clinical treatment issue. Recently, a novel phenotype was discovered amongst selected MRSA which exhibited enhanced β-lactam susceptibility in vitro in the presence of NaHCO3 (termed ‘NaHCO3-responsiveness’). This increased β-lactam susceptibility phenotype has been verified in both ex vivo and in vivo models. Mechanistic studies to-date have implicated NaHCO3-mediated repression of genes involved in the production, as well as maturation, of the alternative penicillin-binding protein (PBP) 2a, a necessary component of MRSA β-lactam resistance. Herein, we utilized RNA-sequencing (RNA-seq) to identify genes that were differentially expressed in NaHCO3-responsive (MRSA 11/11) vs. non-responsive (COL) strains, in the presence vs. absence of NaHCO3-β-lactam co-exposures. These investigations revealed that NaHCO3 selectively repressed the expression of a cadre of genes in strain 11/11 known to be a part of the sigB-sarA-agr regulon, as well as a number of genes involved in the anchoring of cell wall proteins in MRSA. Moreover, several genes related to autolysis, cell division, and cell wall biosynthesis/remodeling, were also selectively impacted by NaHCO3-OXA exposure in the NaHCO3-responsive strain MRSA 11/11. These outcomes provide an important framework for further studies to mechanistically verify the functional relevance of these genetic perturbations to the NaHCO3-responsiveness phenotype in MRSA.

scholarly journals Mutations inmmpLand in the Cell Wall Stress Stimulon Contribute to Resistance to Oxadiazole Antibiotics in Methicillin-Resistant Staphylococcus aureus

2014 ◽  
Vol 58 (10) ◽  
pp. 5841-5847 ◽  
Author(s):  
Qiaobin Xiao ◽  
Sergei Vakulenko ◽  
Mayland Chang ◽  
Shahriar Mobashery
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Wall Stress ◽  
Methicillin Resistant ◽  
Content Type ◽  
Cell Wall Stress ◽  
A Cell ◽  
Putative Member

ABSTRACTStaphylococcus aureusis a leading cause of hospital- and community-acquired infections, which exhibit broad resistance to various antibiotics. We recently disclosed the discovery of the oxadiazole class of antibiotics, which hasin vitroandin vivoactivities against methicillin-resistantS. aureus(MRSA). We report herein that MmpL, a putative member of the resistance, nodulation, and cell division (RND) family of proteins, contributes to oxadiazole resistance in theS. aureusstrain COL. Through serial passages, we generated twoS. aureusCOL variants that showed diminished susceptibilities to an oxadiazole antibiotic. The MICs for the oxadiazole against one strain (designatedS. aureusCOLI) increased reproducibly 2-fold (to 4 μg/ml), while against the other strain (S. aureusCOLR), they increased >4-fold (to >8 μg/ml, the limit of solubility). The COLRstrain was derived from the COLIstrain. Whole-genome sequencing revealed 31 mutations inS. aureusCOLR, of which 29 were shared with COLI. Consistent with our previous finding that oxadiazole antibiotics inhibit cell wall biosynthesis, we found 13 mutations that occurred either in structural genes or in promoters of the genes of the cell wall stress stimulon. Two unique mutations inS. aureusCOLRwere substitutions in two genes that encode the putative thioredoxin (SACOL1794) and MmpL (SACOL2566). A role formmpLin resistance to oxadiazoles was discerned from gene deletion and complementation experiments. To our knowledge, this is the first report that a cell wall-acting antibiotic selects for mutations in the cell wall stress stimulon and the first to implicate MmpL in resistance to antibiotics inS. aureus.

scholarly journals Reduced Vancomycin Susceptibility in anIn VitroCatheter-Related Biofilm Model Correlates with Poor Therapeutic Outcomes in Experimental Endocarditis Due to Methicillin-Resistant Staphylococcus aureus

2013 ◽  
Vol 57 (3) ◽  
pp. 1447-1454 ◽  
Author(s):  
Wessam Abdelhady ◽  
Arnold S. Bayer ◽  
Kati Seidl ◽  
Cynthia C. Nast ◽  
Megan R. Kiedrowski ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Wall Thickness ◽  
Biofilm Formation ◽  
Methicillin Resistant ◽  
Content Type ◽  
Biofilm Model ◽  
Mrsa Strains

ABSTRACTStaphylococcus aureusis the most common cause of endovascular infections, including catheter sepsis and infective endocarditis (IE). Vancomycin (VAN) is the primary choice for treatment of methicillin-resistantS. aureus(MRSA) infections. However, high rates of VAN treatment failure in MRSA infections caused by VAN-susceptible strains have been increasingly reported. Biofilm-associated MRSA infections are especially prone to clinical antibiotic failure. The present studies examined potential relationships between MRSA susceptibility to VAN in biofilmsin vitroand nonsusceptibility to VAN in endovascular infectionin vivo. Using 10 “VAN-susceptible” MRSA bloodstream isolates previously investigated for VAN responsiveness in experimental IE, we studied the mechanism(s) of suchin vivoVAN resistance, including: (i) VAN binding to MRSA organisms; (ii) the impact of VAN on biofilm formation and biofilm composition; (iii) VAN efficacy in anin vitrocatheter-related biofilm model; (iv) effects on cell wall thickness. As a group, the five strains previously categorized as VAN nonresponders (non-Rsp) in the experimental IE model differed from the five responders (Rsp) in terms of lower VAN binding, increased biofilm formation, higher survival in the presence of VAN within biofilms in the presence or absence of catheters, and greater biofilm reduction upon proteinase K treatment. Interestingly, sub-MICs of VAN significantly promoted biofilm formation only in the non-Rsp isolates. Cell wall thickness was similar among all MRSA strains. These results suggest that sublethal VAN levels that induce biofilm formation and reduce efficacy of VAN in thein vitrocatheter-associated biofilms may contribute to suboptimal treatment outcomes for endovascular infections caused by “VAN-susceptible” MRSA strains.

scholarly journals Group V Phospholipase A2 Mediates Endothelial Dysfunction and Acute Lung Injury Caused by Methicillin-Resistant Staphylococcus aureus

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1731
Author(s):  
Yu Maw Htwe ◽  
Huashan Wang ◽  
Patrick Belvitch ◽  
Lucille Meliton ◽  
Mounica Bandela ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Acute Lung Injury ◽  
Endothelial Dysfunction ◽  
Lung Injury ◽  
Phospholipase A2 ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Group V ◽  
Methicillin Resistant

Lung endothelial dysfunction is a key feature of acute lung injury (ALI) and clinical acute respiratory distress syndrome (ARDS). Previous studies have identified the lipid-generating enzyme, group V phospholipase A2 (gVPLA2), as a mediator of lung endothelial barrier disruption and inflammation. The current study aimed to determine the role of gVPLA2 in mediating lung endothelial responses to methicillin-resistant Staphylococcus aureus (MRSA, USA300 strain), a major cause of ALI/ARDS. In vitro studies assessed the effects of gVPLA2 inhibition on lung endothelial cell (EC) permeability after exposure to heat-killed (HK) MRSA. In vivo studies assessed the effects of intratracheal live or HK-MRSA on multiple indices of ALI in wild-type (WT) and gVPLA2-deficient (KO) mice. In vitro, HK-MRSA increased gVPLA2 expression and permeability in human lung EC. Inhibition of gVPLA2 with either the PLA2 inhibitor, LY311727, or with a specific monoclonal antibody, attenuated the barrier disruption caused by HK-MRSA. LY311727 also reduced HK-MRSA-induced permeability in mouse lung EC isolated from WT but not gVPLA2-KO mice. In vivo, live MRSA caused significantly less ALI in gVPLA2 KO mice compared to WT, findings confirmed by intravital microscopy assessment in HK-MRSA-treated mice. After targeted delivery of gVPLA2 plasmid to lung endothelium using ACE antibody-conjugated liposomes, MRSA-induced ALI was significantly increased in gVPLA2-KO mice, indicating that lung endothelial expression of gVPLA2 is critical in vivo. In summary, these results demonstrate an important role for gVPLA2 in mediating MRSA-induced lung EC permeability and ALI. Thus, gVPLA2 may represent a novel therapeutic target in ALI/ARDS caused by bacterial infection.

scholarly journals In Vitro and In Vivo Activities of DA-7867, a New Oxazolidinone, against Aerobic Gram-Positive Bacteria

2005 ◽  
Vol 49 (6) ◽  
pp. 2498-2500 ◽  
Author(s):  
Eun Jeong Yoon ◽  
Yeong Woo Jo ◽  
Sung Hak Choi ◽  
Tae Ho Lee ◽  
Jae Keol Rhee ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Infection Models ◽  
Vancomycin Resistant

ABSTRACT In vitro and in vivo activities of DA-7867 were assessed against methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and penicillin-resistant Streptococcus pneumoniae. All isolates were inhibited by DA-7867 at ≤0.78 μg/ml, a four-times-lower concentration than that of inhibition by linezolid. For murine infection models, DA-7867 also exhibited greater efficacy than linezolid against all isolates tested.

scholarly journals Sanguiin H-6 Fractionated from Cloudberry (Rubus chamaemorus) Seeds Can Prevent the Methicillin-Resistant Staphylococcus aureus Biofilm Development during Wound Infection

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1481
Author(s):  
John Jairo Aguilera-Correa ◽  
Sara Fernández-López ◽  
Iskra Dennisse Cuñas-Figueroa ◽  
Sandra Pérez-Rial ◽  
Hanna-Leena Alakomi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Wound Infection ◽  
Preventive Measure ◽  
Surgical Site Infections ◽  
Infection Model ◽  
Growth Media ◽  
Methicillin Resistant ◽  
Biofilm Development

Staphylococcus aureus is the most common cause of surgical site infections and its treatment is challenging due to the emergence of multi-drug resistant strains such as methicillin-resistant S. aureus (MRSA). Natural berry-derived compounds have shown antimicrobial potential, e.g., ellagitannins such as sanguiin H-6 and lambertianin C, the main phenolic compounds in Rubus seeds, have shown antimicrobial activity. The aim of this study was to evaluate the effect of sanguiin H-6 and lambertianin C fractionated from cloudberry seeds, on the MRSA growth, and as treatment of a MRSA biofilm development in different growth media in vitro and in vivo by using a murine wound infection model where sanguiin H-6 and lambertianin C were used to prevent the MRSA infection. Sanguiin H-6 and lambertianin C inhibited the in vitro biofilm development and growth of MRSA. Furthermore, sanguiin H-6 showed significant anti-MRSA effect in the in vivo wound model. Our study shows the possible use of sanguiin H-6 as a preventive measure in surgical sites to avoid postoperative infections, whilst lambertianin C showed no anti-MRSA activity.

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