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PloS One 2018The viridans group streptococci comprise multiple species and have gained more recognition in recent years as common etiologic agents of bacterial endophthalmitis. The...
The viridans group streptococci comprise multiple species and have gained more recognition in recent years as common etiologic agents of bacterial endophthalmitis. The purpose of this study was to identify the species of human endophthalmitis isolates of viridans streptococci and to characterize their potential virulence attributes. The species of 22 endophthalmitis strains of viridans streptococci were identified by Matrix Assisted Laser Desorption Ionization Time-of-Flight. Susceptibilities to 3 antibiotics commonly used for bacterial endophthalmitis were determined. The extracellular milieu of each strain was tested for cytotoxicity of retinal pigmented epithelial cells, hemolysis of sheep erythrocytes, and protease activity using gelatin zymography. Identified species were Streptococcus mitis/oralis, S. salivarius, S. vestibularis, S. parasanguinis, S. mutans, S. constellatus, and S. gordonii. One strain of S. pseudoporcinus was also identified. All strains were sensitive to vancomycin, 77% were resistant to amikacin, and 27% had intermediate resistance to ceftazidime. Extracellular milieu from all strains except one (S. pseudoporcinus) were largely devoid of toxicity to retinal pigmented epithelial cells and sheep erythrocytes. Twelve strains, 10 of which were S. mitis/oralis, produced protease activity. Interestingly, not all of the S. mitis/oralis strains were proteolytic. These findings highlight the diversity of virulence factor production in ocular strains of the viridans streptococci not only at the group level but also at the species level.
Topics: Animals; Anti-Bacterial Agents; Ceftazidime; Endophthalmitis; Erythrocytes; Humans; Microbial Sensitivity Tests; Sheep; Vancomycin; Viridans Streptococci; Virulence; Virulence Factors
PubMed: 30576393
DOI: 10.1371/journal.pone.0209849 -
Scientific Reports Dec 2021As a conserved defense mechanism, many bacteria produce antimicrobial peptides, called bacteriocins, which provide a colonization advantage in a multispecies...
As a conserved defense mechanism, many bacteria produce antimicrobial peptides, called bacteriocins, which provide a colonization advantage in a multispecies environment. Here the first bacteriocin of Streptococcus anginosus, designated Angicin, is described. S. anginosus is commonly described as a commensal, however it also possesses a high pathogenic potential. Therefore, understanding factors contributing to its host colonization and persistence are important. A radial diffusion assay was used to identify S. anginosus BSU 1211 as a potent bacteriocin producer. By genetic mutagenesis the background of bacteriocin production and the bacteriocin gene itself were identified. Synthetic Angicin shows high activity against closely related streptococci, listeria and vancomycin resistant enterococci. It has a fast mechanism of action and causes a membrane disruption in target cells. Angicin, present in cell free supernatant, is insensitive to changes in temperature from - 70 to 90 °C and pH values from 2 to 10, suggesting that it represents an interesting compound for potential applications in food preservation or clinical settings.
Topics: Bacterial Proteins; Bacteriocins; Gene Expression Regulation, Bacterial; Listeria; Streptococcus anginosus; Vancomycin-Resistant Enterococci
PubMed: 34934110
DOI: 10.1038/s41598-021-03797-5 -
Indian Heart Journal 2018To evaluate the role of periodontitis in viridans group streptococci (VGS) bacteremia and infective endocarditis (IE).
OBJECTIVES
To evaluate the role of periodontitis in viridans group streptococci (VGS) bacteremia and infective endocarditis (IE).
METHODS
A total of 200 subjects including two groups. Group A- 34 subjects undergoing tooth extraction with periodontitis, 46 subjects undergoing tooth extraction without periodontitis and 40 healthy controls. Group B: 40 confirmed cases of IE (17 with and 23 without periodontitis) and 40 healthy controls. Subgingival plaque and blood samples were obtained and processed by standard procedures.
RESULTS
A total of 53 blood samples (66.25%) yielded positive cultures after tooth extraction. The relationship between the presence of periodontitis and a positive blood culture was significantly higher (p=0.05) for tooth extraction cases with periodontitis (79.40%) than tooth extraction cases without periodontitis (56.50%). Periodontitis was observed in 42.5% of IE cases. Out of the 40 patients of IE, the blood samples yielded 40 different isolates, majority were viridans streptococci 15 (37.5%) and staphylococci nine (22.5%). No statistically significant difference was observed between the subgingival plaque and blood isolates of periodontitis in both the groups, indicating similarity of biotypes of viridans streptococci isolated from the blood and the subgingival plaque. Similarity was also observed between the antibiogram profiles of viridans streptococci from both the groups.
CONCLUSIONS
Periodontitis enhances viridans streptococcal bacteremia and may be a potential risk factor for IE.
Topics: Adult; Bacteremia; Endocarditis, Bacterial; Female; Gingiva; Humans; Male; Middle Aged; Periodontitis; Risk Factors; Streptococcal Infections; Viridans Streptococci
PubMed: 29716699
DOI: 10.1016/j.ihj.2017.06.019 -
Nature Chemical Biology May 2021Genome mining of clinical samples led to the identification of a structurally unique polyketide/non-ribosomal peptide, mutanofactin-697, that promotes biofilm...
Genome mining of clinical samples led to the identification of a structurally unique polyketide/non-ribosomal peptide, mutanofactin-697, that promotes biofilm formation. This study highlights the unexplored functional potential of secondary metabolites and opens new avenues for inhibiting pathogenic processes.
Topics: Biofilms; Mining; Mouth; Streptococcus mutans
PubMed: 33767389
DOI: 10.1038/s41589-021-00784-9 -
Journal of Cardiothoracic Surgery Jun 2020The aim of this study was to describe the clinical features and outcome of infective endocarditis at a general hospital in China and to identify the risk factors...
BACKGROUND
The aim of this study was to describe the clinical features and outcome of infective endocarditis at a general hospital in China and to identify the risk factors associated with in-hospital mortality.
METHODS
A retrospective study was conducted and all patients diagnosed with definite or possible infective endocarditis between January 2013 and June 2018 according to the modified Duke criteria were included.
RESULTS
A total of 381 patients were included. The mean age was 46 years old and 66.9% patients were male patients. Community acquired IE was the most common type of infective endocarditis and Viridans Group Streptococci (37.5%) was still the most common causative pathogen. The microbial etiology of infective endocarditis varied with location of acquisition. 97 (25.5%) patients had culture-negative infective endocarditis. Vegetations were detected in 85% patients and mitral valve was the most common involved valve. Operations were performed in 72.7% patients and in-hospital mortality rate was 8.4%. The risk factors of in-hospital mortality were age old than 70 years old, heart failure, stroke and medical therapy.
CONCLUSIONS
Older age, heart failure, stroke and medical therapy were risk factors of in-hospital mortality. Infective endocarditis, were mainly caused by Viridans Group Streptococci, characterized by younger patients and lower mortality rate in China.
Topics: Adult; Age Factors; Aged; China; Community-Acquired Infections; Endocarditis, Bacterial; Female; Heart Failure; Hospital Mortality; Humans; Male; Middle Aged; Retrospective Studies; Risk Factors; Streptococcal Infections; Stroke; Tertiary Care Centers; Viridans Streptococci
PubMed: 32522279
DOI: 10.1186/s13019-020-01183-2 -
Frontiers in Cellular and Infection... 2023() is the most frequent strain associated with cross-kingdom infections in the oral cavity. Clinical evidence shows the co-existence of () and in the carious lesions... (Review)
Review
() is the most frequent strain associated with cross-kingdom infections in the oral cavity. Clinical evidence shows the co-existence of () and in the carious lesions especially in children with early childhood caries (ECC) and demonstrates the close interaction between them. During the interaction, both and have evolved a complex network of regulatory mechanisms to boost cariogenic virulence and modulate tolerance upon stress changes in the external environment. The intricate relationship and unpredictable consequences pose great therapeutic challenges in clinics, which indicate the demand for emergence of potential antimicrobial therapy with multi-targets or combinatorial therapies. In this article, we present an overview of the clinical significance, and cooperative network of the cross-kingdom interaction between and Furthermore, we also summarize the current strategies for targeting cross-kingdom biofilm.
Topics: Child; Humans; Child, Preschool; Streptococcus mutans; Candida albicans; Biofilms; Dental Caries
PubMed: 37249973
DOI: 10.3389/fcimb.2023.1106231 -
Journal of Dental Research Apr 2023As oral bacteria grow and persist within biofilms attached to the tooth's surface, they interact with other species to form synergistic or antagonistic exchanges that...
As oral bacteria grow and persist within biofilms attached to the tooth's surface, they interact with other species to form synergistic or antagonistic exchanges that govern homeostasis for the overall population. One example are the interactions between the cariogenic species and oral commensal streptococci. Previously, we showed that the cell-cell signaling pathways of were inhibited during coculture with other oral streptococci species, leading us to posit that the transcriptome and behaviors are broadly altered during growth with these species. To test this hypothesis, we performed whole transcriptome sequencing (RNA-seq) on cocultures of with either , , or and a quadculture containing all 4 species in comparison to grown alone. Our results reveal that in addition to species-dependent changes to the transcriptome, a conserved response to oral streptococci in general can be observed. We monitored the behavior of by both microscopy imaging of biofilms and in a bacteriocin overlay assay and verified that acts similarly with each of these species but noted divergences in phenotypes when cocultured with another cariogenic () or with oral nonstreptococci species. RNA-seq with oral nonstreptococci showed lack of a consistent gene expression profile and overlap of differentially expressed genes found with commensal streptococci. Finally, we investigated the role of upregulated genes within our data sets to determine if they provided a fitness benefit during interspecies interactions. Eleven total genes were studied, and we found that a majority impacted the fitness of in various assays, highlighted by increased biomass of commensal streptococci in mixed-species biofilms. These results confirm a common, species-independent modification of behaviors with oral commensal streptococci that emphasizes the need to further evaluate oral bacteria within multispecies settings.
Topics: Streptococcus mutans; Streptococcus sanguis; Streptococcus gordonii; Symbiosis; Microbiota; Biofilms
PubMed: 36688378
DOI: 10.1177/00220345221145906 -
Clinical Microbiology and Infection :... Aug 2020Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is becoming the method of choice for bacterial identification. However,...
OBJECTIVES
Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is becoming the method of choice for bacterial identification. However, correct identification by MALDI-TOF of closely related microorganisms such as viridans streptococci is still cumbersome, especially in the identification of S. pneumoniae. By making use of additional spectra peaks for S. pneumoniae and other viridans group streptococci (VGS). We re-identified viridans streptococci that had been identified and characterized by molecular and phenotypic techniques by MALDI-TOF.
METHODS
VGS isolates (n = 579), 496 S. pneumoniae and 83 non-S. pneumoniae were analysed using MALDI-TOF MS and the sensitivity and specificity of MALDI-TOF MS was assessed. Hereafter, mass spectra analysis was performed. Presumptive identification of proteins represented by discriminatory peaks was performed by molecular weight matching and the corresponding nucleotides sequences against different protein databases.
RESULTS
Using the Bruker reference library, 495 of 496 S. pneumoniae isolates were identified as S. pneumoniae and one isolate was identified as non-S. pneumoniae. Of the 83 non-S. pneumoniae isolates, 37 were correctly identified as non-S. pneumoniae, and 46 isolates as S. pneumoniae. The sensitivity of the MALDI-TOF MS was 99.8% (95% confidence interval (CI) 98.9-100) and the specificity was 44.6% (95% CI 33.7-55.9). Eight spectra peaks were mostly present in one category (S. pneumoniae or other VGS) and absent in the other category and inversely. Two spectra peaks of these (m/z 3420 and 3436) were selected by logistic regression to generate three identification profiles. These profiles could differentiate between S. pneumoniae and other VGS with high sensitivity and specificity (99.4% and 98.8%, respectively).
CONCLUSIONS
Spectral peaks analysis based identification is a powerful tool to differentiate S. pneumoniae from other VGS species with high specificity and sensitivity and is a useful method for pneumococcal identification in carriage studies. More research is needed to further confirm our findings. Extrapolation of these results to clinical strains need to be deeply investigated.
Topics: Bacterial Typing Techniques; Diagnosis, Differential; Humans; Molecular Typing; Sensitivity and Specificity; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Streptococcal Infections; Streptococcus pneumoniae; Viridans Streptococci
PubMed: 31811915
DOI: 10.1016/j.cmi.2019.11.024 -
Journal of Dental Research Jan 2021is known to form polymicrobial biofilms with various spp., including mitis and mutans group streptococci. (mitis group) has been shown to bind avidly to hyphae via...
is known to form polymicrobial biofilms with various spp., including mitis and mutans group streptococci. (mitis group) has been shown to bind avidly to hyphae via direct cell-to-cell interaction, while the cariogenic pathogen (mutans group) interacts with the fungal cells via extracellular glucans. However, the biophysical properties of these cross-kingdom interactions at the single-cell level during the early stage of biofilm formation remain understudied. Here, we examined the binding forces between (or ) and in the presence and absence of in situ glucans on the fungal surface using single-cell atomic force microscopy and their influence on biofilm initiation and subsequent development under cariogenic conditions. The data show that binding force to the surface is significantly higher than that of to the fungal surface (~2-fold). However, binding forces are dramatically enhanced when the cell surface is locally coated with extracellular glucans (~6-fold vs. uncoated ), which vastly exceeds the forces between and. The enhanced binding affinity of to glucan-coated resulted in a larger structure during early biofilm initiation compared to biofilms. Ultimately, this resulted in dominance composition in the 3-species biofilm model under cariogenic conditions. This study provides a novel biophysical aspect of -streptococcal interaction whereby extracellular glucans may selectively favor binding interactions with during cariogenic biofilm development.
Topics: Biofilms; Candida albicans; Cell Communication; Streptococcus gordonii; Streptococcus mutans
PubMed: 32853527
DOI: 10.1177/0022034520950286 -
Clinical Microbiology and Infection :... Aug 2018
Meta-Analysis Review
Topics: Bacteremia; Disease Management; Endocarditis, Bacterial; Humans; Neutropenia; Streptococcal Infections; Viridans Streptococci
PubMed: 29559393
DOI: 10.1016/j.cmi.2018.03.012