scholarly journals Serotyping and electron microscopy studies of Staphylococcus aureus clinical isolates with monoclonal antibodies to capsular polysaccharide types 5 and 8.

1987 ◽  
Vol 25 (3) ◽  
pp. 526-530 ◽  
Author(s):  
H K Hochkeppel ◽  
D G Braun ◽  
W Vischer ◽  
A Imm ◽  
S Sutter ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Monoclonal Antibodies ◽  
Capsular Polysaccharide ◽  
Clinical Isolates

scholarly journals Identification of Anti-Alpha Toxin Monoclonal Antibodies That Reduce the Severity of Staphylococcus aureus Dermonecrosis and Exhibit a Correlation between Affinity and Potency

2012 ◽  
Vol 19 (3) ◽  
pp. 377-385 ◽  
Author(s):  
C. Tkaczyk ◽  
L. Hua ◽  
R. Varkey ◽  
Y. Shi ◽  
L. Dettinger ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Monoclonal Antibodies ◽  
Dissociation Constants ◽  
Lesion Size ◽  
Lung Epithelial Cells ◽  
Clinical Isolates ◽  
Dependent Manner ◽  
Alpha Toxin ◽  
Binding Studies ◽  
Content Type

ABSTRACTStaphylococcus aureusalpha toxin (AT) is an important virulence determinant and may be a valid target for immunoprophylaxis against staphylococcal disease. Here we report the identification of potent inhibitory anti-AT monoclonal antibodies (MAbs) derived using B-cell hybridoma technology from VelocImmune mice engineered to produce IgG with a human variable domain. A small panel of inhibitory MAbs blocked AT-mediated lysis of rabbit red blood cells, A549 human lung epithelial cells, and THP-1 human monocytic cells, in a dose-dependent manner. Binding studies indicated that these MAbs recognize a similar epitope on AT and exhibit dissociation constants (KD) ranging from 0.50 to 15 nM. In anS. aureusdermonecrosis model, mice passively immunized with anti-AT inhibitory MAbs exhibited significant reductions of lesion size relative to mice treated with an irrelevant IgG control. Interestingly, there was a correlation between MAb affinity for a single epitope, the 50% inhibitory concentration (IC50) in the AT hemolytic assay, and lesion size reduction in the dermonecrosis model. A representative high-affinity MAb, 2A3.1, was demonstrated to significantly reduce lesion size following infection with three different clinical isolates (USA300, CC30, and CC5). Taken together, these results indicate thatin vitropotency of anti-AT MAbs predictsin vivopotency in this model, supporting their continued preclinical evaluation as molecules for immunoprophylaxis against staphylococcal skin and soft tissue infections caused by diverse clinical isolates.

scholarly journals Isolation and Chemical Characterization of a Capsular Polysaccharide Antigen Shared by Clinical Isolates ofEnterococcus faecalis and Vancomycin-ResistantEnterococcus faecium

1999 ◽  
Vol 67 (3) ◽  
pp. 1213-1219 ◽  
Author(s):  
Johannes Huebner ◽  
Ying Wang ◽  
Wolfgang A. Krueger ◽  
Lawrence C. Madoff ◽  
Gayane Martirosian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Capsular Polysaccharide ◽  
Clinical Isolates ◽  
Proteinase K ◽  
Capsular Polysaccharides ◽  
Opsonic Activity ◽  
Killing Activity ◽  
Homologous Strain ◽  
Vancomycin Resistant ◽  
Immune Rabbit

ABSTRACT Enterococci are a common cause of serious infections, especially in newborns, severely immunocompromised patients, and patients requiring intensive care. To characterize enterococcal surface antigens that are targets of opsonic antibodies, rabbits were immunized with various gentamicin-killed Enterococcus faecalis strains, and immune sera were tested in an opsonophagocytic assay against a selection of clinical isolates. Serum raised against one strain killed the homologous strain (12030) at a dilution of 1:5,120 and mediated opsonic killing of 33% of all strains tested. In addition, this serum killed two (28%) of seven vancomycin-resistant Enterococcus faecium strains. Adsorption of sera with the homologous strain eliminated killing activity. The adsorbing antigens were resistant to treatment with proteinase K and to boiling for 1 h, but were susceptible to treatment with sodium periodate, indicating that the antigen inducing opsonic activity is a polysaccharide. Antibodies in immune rabbit sera reacted with a capsule-like structure visualized by electron microscopy both on the homologous E. faecalisstrain and on a vancomycin-resistant E. faecium strain. The capsular polysaccharides from E. faecalis 12030 andE. faecium 838970 were purified, and chemical and structural analyses indicated they were identical glycerol teichoic acid-like molecules with a carbohydrate backbone structure of 6-α-d-glucose-1-2 glycerol-3-PO4 with substitution on carbon 2 of the glucose with an α-2-1-d-glucose residue. The purified antigen adsorbed opsonic killing activity from immune rabbit sera and elicited high titers of antibodies (when used to immunize rabbits) that both mediated opsonic killing of bacteria and bound to a capsule-like structure visualized by electron microscopy. These results indicate that approximately one-third of a sample of 15 E. faecalisstrains and 7 vancomycin-resistant E. faecium strains possess shared capsular polysaccharides that are targets of opsonophagocytic antibodies and therefore are potential vaccine candidates.

Assessment of the Multifactorial Effect on Antimicrobial Sensitivity in Positive Staphylococcus Aureus Clinical Isolates from Assir Region, Saudi Arabia

2012 ◽  
Vol 13 (2) ◽  
pp. 152-159 ◽  
Author(s):  
Nazar M Abdalla ◽  
Waleed O Haimour ◽  
Amani A Osman ◽  
Hassan Abdul Aziz
Keyword(s):  
Staphylococcus Aureus ◽  
Saudi Arabia ◽  
Culture Media ◽  
Meca Gene ◽  
Laboratory Data ◽  
Age Groups ◽  
Clinical Isolates ◽  
Diabetic Patients ◽  
Staph Aureus ◽  
Antimicrobial Sensitivity

General objectives: This study aimed at assessment of factors affecting antimicrobial sensitivity in Staphylococcus aureus clinical isolates from Assir region, Saudi Arabia. Materials and Methods: In this study, eighty one patients presented with Staph. aureus infections either nosocomial or community acquired infections were involved by collecting nasal swabs from them at Aseer Central Hospital General Lab. These patients were from all age groups and from males and females during the period of Jan 2011- Jun 2011. These samples were undergone variable laboratory procedures mainly; bactech, culture media, antibiotics sensitivity test using diffusion disc test (MIC) and molecular (PCR) for detection of mec A gene. Clinical and laboratory data were recorded in special formats and analyzed by statistical computer program (SPSS). Results: Showed that; Descriptive and analytical statistical analysis were performed and final results were plotted in tables. In Staph aureus MecA gene positive cases (50) showed: Oxacillin/ Mithicillin, Ciprofloxacin and Fusidin resistant in diabetic patients were 13, 26.0%, 9, 18% and 7, 14% respectively and in non diabetic patients were 37, 74.0%, 22, 44% and 20, 40% respectively. While no sensitivity in diabetic and non diabetic patients using Oxacillin/ Mithicillin. In Staph aureus MecA gene negative cases (31) showed: Oxacillin/ Mithicillin, sensitivity in diabetic patients (5, 16.1%) and in non diabetic were (26, 83.9%). While no resistant in diabetic and non diabetic patients. In Ciprofloxacin and Fusidin resistant in diabetic patients were 1, 3.2% and 1, 3.2% respectively and in non diabetic patients were 12, 38.7% and 7, 22.6%respectively. Erythromycin in Staph aureus ( MecA gene) positive cases (50) showed: resistant in age (0-15) years were (5, 10%), (16-50) years were (16, 32%) and ( ›50 years) were (12, 24%). Erythromycin in Staph aureus (MecA gene) negative cases (31) showed: resistant in age (0-15) years were (6, 19.3%), (16-50) years were (5, 16.1%) and ( ›50 years) were (3, 9.7%). Conclusion: Drugs resistance is a major progressive multifactorial problem facing the treatment of Staph aureus infections. DOI: http://dx.doi.org/10.3329/jom.v13i2.12750 J Medicine 2012; 13 : 152-159

Biological Evaluation of Selected 1,2,3-triazole Derivatives as Antibacterial and Antibiofilm Agents

2020 ◽  
Vol 20 (24) ◽  
pp. 2186-2191
Author(s):  
Lialyz Soares Pereira André ◽  
Renata Freire Alves Pereira ◽  
Felipe Ramos Pinheiro ◽  
Aislan Cristina Rheder Fagundes Pascoal ◽  
Vitor Francisco Ferreira ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Public Health Problem ◽  
Biological Evaluation ◽  
Major Public Health Problem ◽  
Community Environments ◽  
Scanning Electron

Background: Resistance to antimicrobial agents is a major public health problem, being Staphylococcus aureus prevalent in infections in hospital and community environments and, admittedly, related to biofilm formation in biotic and abiotic surfaces. Biofilms form a complex and structured community of microorganisms surrounded by an extracellular matrix adhering to each other and to a surface that gives them even more protection from and resistance against the action of antimicrobial agents, as well as against host defenses. Methods: Aiming to control and solve these problems, our study sought to evaluate the action of 1,2,3- triazoles against a Staphylococcus aureus isolate in planktonic and in the biofilm form, evaluating the activity of this triazole through Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) tests. We have also performed cytotoxic evaluation and Scanning Electron Microscopy (SEM) of the biofilms under the treatment of the compound. The 1,2,3-triazole DAN 49 showed bacteriostatic and bactericidal activity (MIC and MBC 128 μg/mL). In addition, its presence interfered with the biofilm formation stage (1/2 MIC, p <0.000001) and demonstrated an effect on young preformed biofilm (2 MICs, p <0.05). Results: Scanning Electron Microscopy images showed a reduction in the cell population and the appearance of deformations on the surface of some bacteria in the biofilm under treatment with the compound. Conclusion: Therefore, it was possible to conclude the promising anti-biofilm potential of 1,2,3-triazole, demonstrating the importance of the synthesis of new compounds with biological activity.

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