Contribution of serotype and genetic background to biofilm formation by Streptococcus pneumoniae

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.

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

Applied and Environmental Microbiology ◽

10.1128/aem.00280-20 ◽

2020 ◽

Vol 86 (10) ◽

Cited By ~ 1

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

Microbial Pathogenesis ◽

10.1016/j.micpath.2010.01.002 ◽

2010 ◽

Vol 48 (3-4) ◽

pp. 124-130 ◽

Cited By ~ 41

Author(s):

Anel Lizcano ◽

Tiffany Chin ◽

Karin Sauer ◽

Elaine I. Tuomanen ◽

Carlos J. Orihuela

Keyword(s):

Streptococcus Pneumoniae ◽

Biofilm Formation ◽

Invasive Disease ◽

Microtiter Plates

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The LuxS-Dependent Quorum-Sensing System Regulates Early Biofilm Formation by Streptococcus pneumoniae Strain D39

Infection and Immunity ◽

10.1128/iai.05186-11 ◽

2011 ◽

Vol 79 (10) ◽

pp. 4050-4060 ◽

Cited By ~ 82

Author(s):

Jorge E. Vidal ◽

Herbert P. Ludewick ◽

Rebekah M. Kunkel ◽

Dorothea Zähner ◽

Keith P. Klugman

Keyword(s):

Streptococcus Pneumoniae ◽

Quorum Sensing ◽

Biofilm Formation ◽

Single Copy ◽

Middle Ear Mucosa ◽

Transcript Levels ◽

Content Type ◽

Sensing System ◽

Quorum Sensing System

ABSTRACTStreptococcus pneumoniaeis the leading cause of death in children worldwide and forms highly organized biofilms in the nasopharynx, lungs, and middle ear mucosa. TheluxS-controlled quorum-sensing (QS) system has recently been implicated in virulence and persistence in the nasopharynx, but its role in biofilms has not been studied. Here we show that this QS system plays a major role in the control ofS. pneumoniaebiofilm formation. Our results demonstrate that theluxSgene is contained by invasive isolates and normal-flora strains in a region that contains genes involved in division and cell wall biosynthesis. TheluxSgene was maximally transcribed, as a monocistronic message, in the early mid-log phase of growth, and this coincides with the appearance of early biofilms. Demonstrating the role of the LuxS system in regulatingS. pneumoniaebiofilms, at 24 h postinoculation, two different D39ΔluxSmutants produced ∼80% less biofilm biomass than wild-type (WT) strain D39 did. Complementation of these strains withluxS, either in a plasmid or integrated as a single copy in the genome, restored their biofilm level to that of the WT. Moreover, a soluble factor secreted by WT strain D39 or purified AI-2 restored the biofilm phenotype of D39ΔluxS. Our results also demonstrate that during the early mid-log phase of growth, LuxS regulates the transcript levels oflytA, which encodes an autolysin previously implicated in biofilms, and also the transcript levels ofply, which encodes the pneumococcal pneumolysin. In conclusion, theluxS-controlled QS system is a key regulator of early biofilm formation byS. pneumoniaestrain D39.

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Biofilm Formation by Streptococcus pneumoniae: Role of Choline, Extracellular DNA, and Capsular Polysaccharide in Microbial Accretion

Journal of Bacteriology ◽

10.1128/jb.00673-06 ◽

2006 ◽

Vol 188 (22) ◽

pp. 7785-7795 ◽

Cited By ~ 213

Author(s):

Miriam Moscoso ◽

Ernesto García ◽

Rubens López

Keyword(s):

Streptococcus Pneumoniae ◽

Biofilm Formation ◽

Laser Scanning Microscopy ◽

Extracellular Dna ◽

Dimensional Structure ◽

Confocal Laser ◽

Upper Respiratory Tract ◽

Teichoic Acids ◽

Abiotic Surfaces ◽

Biofilm Development

ABSTRACTStreptococcus pneumoniaecolonizes the human upper respiratory tract, and this asymptomatic colonization is known to precede pneumococcal disease. In this report, chemically defined and semisynthetic media were used to identify the initial steps of biofilm formation by pneumococcus during growth on abiotic surfaces such as polystyrene or glass. Unencapsulated pneumococci adhered to abiotic surfaces and formed a three-dimensional structure about 25 μm deep, as observed by confocal laser scanning microscopy and low-temperature scanning electron microscopy. Choline residues of cell wall teichoic acids were found to play a fundamental role in pneumococcal biofilm development. The role in biofilm formation of choline-binding proteins, which anchor to the teichoic acids of the cell envelope, was determined using unambiguously characterized mutants. The results showed that LytA amidase, LytC lysozyme, LytB glucosaminidase, CbpA adhesin, PcpA putative adhesin, and PspA (pneumococcal surface protein A) mutants had a decreased capacity to form biofilms, whereas no such reduction was observed in Pce phosphocholinesterase or CbpD putative amidase mutants. Moreover, encapsulated, clinical pneumococcal isolates were impaired in their capacity to form biofilms. In addition, a role for extracellular DNA and proteins in the establishment ofS. pneumoniaebiofilms was demonstrated. Taken together, these observations provide information on conditions that favor the sessile mode of growth byS. pneumoniae. The experimental approach described here should facilitate the study of bacterial genes that are required for biofilm formation. Those results, in turn, may provide insight into strategies to prevent pneumococcal colonization of its human host.

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Phenotypic Characterization of Streptococcus pneumoniae Biofilm Development

Journal of Bacteriology ◽

10.1128/jb.188.7.2325-2335.2006 ◽

2006 ◽

Vol 188 (7) ◽

pp. 2325-2335 ◽

Cited By ~ 113

Author(s):

Magee Allegrucci ◽

F. Z. Hu ◽

K. Shen ◽

J. Hayes ◽

Garth D. Ehrlich ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Biofilm Formation ◽

Protein Identification ◽

Development Process ◽

Developmental Stages ◽

Developmental Process ◽

Phenotypic Characterization ◽

Biofilm Growth ◽

Cell Counts ◽

Biofilm Development

ABSTRACT Streptococcus pneumoniae is among the most common pathogens associated with chronic otitis media with effusion, which has been hypothesized to be a biofilm disease. S. pneumoniae has been shown to form biofilms, however, little is known about the developmental process, the architecture, and the changes that occur upon biofilm development. In the current study we made use of a continuous-culture biofilm system to characterize biofilm development of 14 different S. pneumoniae strains representing at least 10 unique serotypes. The biofilm development process was found to occur in three distinct stages, including initial attachment, cluster formation, and biofilm maturation. While all 14 pneumococcal strains displayed similar developmental stages, the mature biofilm architecture differed significantly among the serotypes tested. Overall, three biofilm architectural groups were detected based on biomass, biofilm thickness, and cluster size. The biofilm viable cell counts and total protein concentration increased steadily over the course of biofilm development, reaching ∼8 × 108 cells and ∼15 mg of protein per biofilm after 9 days of biofilm growth. Proteomic analysis confirmed the presence of distinct biofilm developmental stages by the detection of multiple phenotypes over the course of biofilm development. The biofilm development process was found to correlate not only with differential production of proteins but also with a dramatic increase in the number of detectable proteins, indicating that biofilm formation by S. pneumoniae may be a far more complex process than previously anticipated. Protein identification revealed that proteins involved in virulence, adhesion, and resistance were more abundant under biofilm growth conditions. A possible role of the identified proteins in biofilm formation is discussed.

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Increased Zinc Availability Enhances Initial Aggregation and Biofilm Formation of Streptococcus pneumoniae

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2017.00233 ◽

2017 ◽

Vol 7 ◽

Cited By ~ 13

Author(s):

Lindsey R. Brown ◽

Rachel C. Caulkins ◽

Tyler E. Schartel ◽

Jason W. Rosch ◽

Erin S. Honsa ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Biofilm Formation ◽

Zinc Availability

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Evaluation of antimicrobial and antibiofilm activities of stingless bee Trigona honey (Malaysia) against Streptococcus pneumoniae

The International Arabic Journal of Antimicrobial Agents ◽

10.3823/856 ◽

2021 ◽

Vol 11 (2) ◽

Author(s):

Mohammad A. Alkafaween ◽

Hamid A. Nagi Al-Jamal ◽

Abu Bakar Mohmd Hilmi

Keyword(s):

Antibacterial Activity ◽

Streptococcus Pneumoniae ◽

Biofilm Formation ◽

Stingless Bee ◽

Expression Of Genes ◽

Zones Of Inhibition

Background: The study aims to evaluate the antibacterial activity of Trigona honey against S. pneumonia. Methods: The effect of Trigona honey on S. pneumonia investigated using agar well diffusion, MIC, MBC, biofilm formation and RT-qPCR. Results: Trigona honey samples showed the larger zones of inhibition against S. pneumonia, 22.2±0.4 at 100% concentration. Trigona honey possessed the lowest MIC, MBC, MIC50 and MIC90 against S. pneumoniae, 25%, 30%, 12.5% and 25% (w/v) respectively. Trigona honey permeated established biofilms of S. pneumonia, resulting in significant decreased the cells from the biofilm. RT-qPCR revealed that the expression of genes amiF, ftsY, mvaS, pnpA, argG, mvd1, purN, miaA and pbp2a were upregulated, glcK, marR, prmA and ccpA were downregulated after exposure to honey. Conclusion: Trigona honey demonstrated the highest antibacterial activity against S. pneumoniae. By limiting study in vitro on Trigona honey, we infer that Trigona honey impacts on S. pneumoniae.

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