scholarly journals Early biofilm formation on microtiter plates is not correlated with the invasive disease potential of Streptococcus pneumoniae

2010 ◽  
Vol 48 (3-4) ◽  
pp. 124-130 ◽  
Author(s):  
Anel Lizcano ◽  
Tiffany Chin ◽  
Karin Sauer ◽  
Elaine I. Tuomanen ◽  
Carlos J. Orihuela
Keyword(s):  
Streptococcus Pneumoniae ◽  
Biofilm Formation ◽  
Invasive Disease ◽  
Microtiter Plates

DiiA is a novel dimorphic cell wall protein of Streptococcus pneumoniae involved in invasive disease

2016 ◽  
Vol 73 (1) ◽  
pp. 71-81 ◽  
Author(s):  
María S. Escolano-Martínez ◽  
Arnau Domenech ◽  
José Yuste ◽  
María I. Cercenado ◽  
Carmen Ardanuy ◽  
...  
Keyword(s):  
Cell Wall ◽  
Streptococcus Pneumoniae ◽  
Invasive Disease ◽  
Cell Wall Protein

scholarly journals A pneumococcal controlled human infection model in Malawi: Transfer of an established pneumococcal carriage model from Liverpool, UK to Blantyre, Malawi – A feasibility study

2020 ◽  
Vol 5 ◽  
pp. 25
Author(s):  
Ben Morton ◽  
Sarah Burr ◽  
Kondwani Jambo ◽  
Jamie Rylance ◽  
Marc Y.R. Henrion ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Feasibility Study ◽  
Invasive Disease ◽  
Community Acquired Pneumonia ◽  
Human Infection ◽  
Infection Model ◽  
Endpoint Detection ◽  
Pneumococcal Carriage ◽  
Sampling Protocols ◽  
Classical Culture

Streptococcus pneumoniae is the leading cause of morbidity and mortality due to community acquired pneumonia, bacterial meningitis and bacteraemia worldwide. Pneumococcal conjugate vaccines protect against invasive disease, but are expensive to manufacture, limited in serotype coverage, associated with serotype replacement and demonstrate reduced effectiveness against mucosal colonisation.  As asymptomatic colonisation of the human nasopharynx is a prerequisite for pneumococcal disease, this is proposed as a marker for novel vaccine efficacy. Our team established a safe and reproducible pneumococcal controlled human infection model at Liverpool School of Tropical Medicine (LSTM). This has been used to test vaccine induced protection against nasopharyngeal carriage for ten years in over 1000 participants. We will transfer established standardised operating procedures from LSTM to Malawi and test in up to 36 healthy participants. Primary endpoint: detection of the inoculated pneumococci by classical culture from nasal wash recovered from the participants after pneumococcal challenge. Secondary endpoints: confirmation of robust clinical and laboratory methods for sample capture and processing. Tertiary endpoints: participant acceptability of study and methods. We will test three doses of pneumococcal inoculation (20,000, 80,000 and 160,000 colony forming units [CFUs] per naris) using a parsimonious study design intended to reduce unnecessary exposure to participants. We hypothesise that 80,000 CFUs will induce nasal colonisation in approximately half of participants per established LSTM practice. The aims of the feasibility study are: 1) Establish Streptococcus pneumoniae experimental human pneumococcal carriage in Malawi; 2) Confirm optimal nasopharyngeal pneumococcal challenge dose; 3) Confirm safety and measure potential symptoms; 4) Confirm sampling protocols and laboratory assays; 5) Assess feasibility and acceptability of consent and study procedures. Confirmation of pneumococcal controlled human infection model feasibility in Malawi will enable us to target pneumococcal vaccine candidates for an at-risk population who stand the most to gain from new and improved vaccine strategies.

scholarly journals Toxin-Antitoxin Genes of the Gram-Positive Pathogen Streptococcus pneumoniae: So Few and Yet So Many

2012 ◽  
Vol 76 (4) ◽  
pp. 773-791 ◽  
Author(s):  
Wai Ting Chan ◽  
Inma Moreno-Córdoba ◽  
Chew Chieng Yeo ◽  
Manuel Espinosa
Keyword(s):  
Streptococcus Pneumoniae ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Host Cells ◽  
Molecular Characteristics ◽  
Type Ii ◽  
Pneumococcal Infections ◽  
Interesting Phenomenon ◽  
Content Type ◽  
Toxin Protein

SUMMARYPneumococcal infections cause up to 2 million deaths annually and raise a large economic burden and thus constitute an important threat to mankind. Because of the increase in the antibiotic resistance ofStreptococcus pneumoniaeclinical isolates, there is an urgent need to find new antimicrobial approaches to triumph over pneumococcal infections. Toxin-antitoxin (TA) systems (TAS), which are present in most living bacteria but not in eukaryotes, have been proposed as an effective strategy to combat bacterial infections. Type II TAS comprise a stable toxin and a labile antitoxin that form an innocuous TA complex under normal conditions. Under stress conditions, TA synthesis will be triggered, resulting in the degradation of the labile antitoxin and the release of the toxin protein, which would poison the host cells. The three functional chromosomal TAS fromS. pneumoniaethat have been studied as well as their molecular characteristics are discussed in detail in this review. Furthermore, a meticulous bioinformatics search has been performed for 48 pneumococcal genomes that are found in public databases, and more putative TAS, homologous to well-characterized ones, have been revealed. Strikingly, several unusual putative TAS, in terms of components and genetic organizations previously not envisaged, have been discovered and are further discussed. Previously, we reported a novel finding in which a unique pneumococcal DNA signature, the BOX element, affected the regulation of the pneumococcalyefM-yoeBTAS. This BOX element has also been found in some of the other pneumococcal TAS. In this review, we also discuss possible relationships between some of the pneumococcal TAS with pathogenicity, competence, biofilm formation, persistence, and an interesting phenomenon called bistability.

scholarly journals Isolation, Characterization, and Comparison of Efficiencies of Bacteriophages to Reduce Planktonic and Biofilm-Associated Staphylococcus aureus

2020 ◽  
Vol 10 (03) ◽  
pp. 102-108
Author(s):  
Anoopkrishna Rai ◽  
Rajeshwari V. Vittal ◽  
Juliet R. Mohan Raj
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Viable Cell ◽  
Viable Count ◽  
Dna Fingerprint ◽  
Planktonic Cells ◽  
Microtiter Plates ◽  
Reduction Assay ◽  
Need To Evaluate

Abstract Introduction In the present era, wherein occurrence of antimicrobial resistance compounded with biofilms in disease conditions has rendered present antibiotic therapy ineffective, the need for alternative strategies to treat bacterial infections has brought bacteriophages to the forefront. The antimicrobial activity of phages is often determined by a viable cell reduction assay which focuses only on planktonic forms. The physiology of an organism in biofilm differs from those that are planktonic; hence, there is a need to evaluate the activity of phages both on planktonic forms, as well as on biofilms, to select candidate therapeutic phages. Materials and Methods Bacteriophages for Staphylococcus aureus were isolated from environmental samples and characterized based on growth kinetics and DNA fingerprint patterns. Activity of isolated phages on planktonic forms was determined by viable count reduction assay. Phage ability to prevent biofilm formation and ability to disperse formed biofilms were performed in 96-well microtiter plates and biofilm estimated by crystal violet assay. Results Four bacteriophages designated, that is, P3, PD1, PE1, and PE2, were isolated and characterized. Planktonic cells of S. aureus were found to be sensitive to phages PD1, PE1, and PE2. Phages PD1 and PE2 were efficient in preventing biofilm formation and phages PD1, PE1, and P3 were efficient in dispersing formed biofilms. Conclusion The ability of some phages to disperse biofilms effectively, while unable to show the same efficiency on planktonic cells, indicates that viable count reduction assay alone may not be a sufficient tool to imply bactericidal activity of bacteriophages, especially while trying to eradicate biofilms.

scholarly journals The relative invasive disease potential of Streptococcus pneumoniae among children after PCV introduction: A systematic review and meta-analysis

2018 ◽  
Vol 77 (5) ◽  
pp. 368-378 ◽  
Author(s):  
Evelyn Balsells ◽  
Ron Dagan ◽  
Inci Yildirim ◽  
Prabhu P. Gounder ◽  
Anneke Steens ◽  
...  
Keyword(s):  
Systematic Review ◽  
Streptococcus Pneumoniae ◽  
Meta Analysis ◽  
Invasive Disease

scholarly journals Effect of Coriander Oil (Coriandrum sativum) on Planktonic and Biofilm Cells of Acinetobacter baumannii

2013 ◽  
Vol 8 (5) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Andreia F. Duarte ◽  
Susana Ferreira ◽  
Rosário Oliveira ◽  
Fernanda C. Domingues
Keyword(s):  
Essential Oil ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Antimicrobial Properties ◽  
Hospital Acquired Infections ◽  
Microtiter Plates ◽  
Crystal Violet Assay ◽  
Hospital Acquired ◽  
Microdilution Broth ◽  
Susceptibility Assay

The increasing incidence of hospital-acquired infections caused by multi-drug resistant pathogens, such as Acinetobacter baumannii, coupled with the low efficacy of drugs and rising treatment costs has created interest in the potential antimicrobial properties of natural products. The main objective of this work was to determine the effect of coriander essential oil on Acinetobacter baumannii in different growth phases, as well as its ability to inhibit the formation or eradication of biofilms. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of coriander oil using a microdilution broth susceptibility assay was determined. The effects of different concentrations of coriander oil (ranging from 0.125 to 4×MIC) on biofilm formation and on established biofilm were tested using 96-well microtiter plates. Crystal violet assay was used as indicator of total biofilm biomass and the biofilm viability was assessed with a XTT staining method. It was found that coriander oil presented significant antibacterial activity against all tested strains of A. baumannii, with MIC values between 1 and 4 μL/mL. The MBC values were the same as the MIC, being an indicator of the bactericidal activity of this essential oil. In what concerns the effect of this essential oil on biofilm formation inhibition was observed of at least 85% of biomass formation by all A. baumannii strains using 2×MIC of coriander oil, in addition to a decrease in the metabolic activity of the cells. After exposure to coriander oil, a decrease in 24 h and 48 h-old biofilm biomass and metabolism was seen for all tested concentrations, even with sub-inhibitory concentrations. Coriander essential oil proved to have a significant antibacterial and anti-biofilm activity and should be considered in the development of future disinfectants to control A. baumannii dissemination.

scholarly journals The N-Acetylglucosaminidase LytB of Streptococcus pneumoniae Is Involved in the Structure and Formation of Biofilms

2020 ◽  
Vol 86 (10) ◽  
Author(s):  
Mirian Domenech ◽  
Ernesto García
Keyword(s):  
Streptococcus Pneumoniae ◽  
Biofilm Formation ◽  
Single Gene ◽  
Extracellular Polysaccharide ◽  
Extracellular Dna ◽  
Nasopharyngeal Colonization ◽  
Content Type ◽  
Daughter Cells ◽  
Biofilm Matrix

ABSTRACT The N-acetylglucosaminidase LytB of Streptococcus pneumoniae is involved in nasopharyngeal colonization and is responsible for cell separation at the end of cell division; thus, ΔlytB mutants form long chains of cells. This paper reports the construction and properties of a defective pneumococcal mutant producing an inactive LytB protein (LytBE585A). It is shown that an enzymatically active LytB is required for in vitro biofilm formation, as lytB mutants (either ΔlytB or producing the inactive LytBE585A) are incapable of forming substantial biofilms, despite that extracellular DNA is present in the biofilm matrix. Adding small amounts (0.5 to 2.0 μg/ml) of exogenous LytB or some LytB constructs restored the biofilm-forming capacity of lytB mutants to wild-type levels. The LytBE585A mutant formed biofilm more rapidly than ΔlytB mutants in the presence of LytB. This suggests that the mutant protein acted in a structural role, likely through the formation of complexes with extracellular DNA. The chain-dispersing capacity of LytB allowed the separation of daughter cells, presumably facilitating the formation of microcolonies and, finally, of biofilms. A role for the possible involvement of LytB in the synthesis of the extracellular polysaccharide component of the biofilm matrix is also discussed. IMPORTANCE It has been previously accepted that biofilm formation in S. pneumoniae must be a multigenic trait because the mutation of a single gene has led to only to partial inhibition of biofilm production. In the present study, however, evidence that the N-acetylglucosaminidase LytB is crucial in biofilm formation is provided. Despite the presence of extracellular DNA, strains either deficient in LytB or producing a defective LytB enzyme formed only shallow biofilms.

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