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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 -
Indian Journal of Medical Microbiology 2016The viridans group streptococci are a heterogeneous group of organisms which exist as commensals in the oropharynx and the gut. They cause serious infections when they... (Review)
Review
The viridans group streptococci are a heterogeneous group of organisms which exist as commensals in the oropharynx and the gut. They cause serious infections when they gain entry into sterile sites particularly in patients with predisposing conditions. Classification and species differentiation of these organisms has always been a challenge because of phenotypic differences between strains of the same species. Facklam's typing scheme based on six metabolic properties has been the most widely used and many commercial identification systems are based on it. Due to the ambiguity in species differentiation based on phenotypic tests, nucleic acid-based methods have been developed to improve the identification of these organisms. Results using genotypic methods such as 16S rRNA and sodA gene sequencing have been promising. Multilocus sequence analysis of seven house-keeping genes map, pfl, pyk, ppaC, rpoB, soda and tuf amplified by polymerase chain reaction was found to be an accurate alternative to other methods and could be useful in the characterisation of larger collections of isolates.
Topics: Bacterial Proteins; Bacterial Typing Techniques; Humans; Molecular Diagnostic Techniques; Multilocus Sequence Typing; RNA, Bacterial; RNA, Ribosomal, 16S; Streptococcal Infections; Viridans Streptococci
PubMed: 27934818
DOI: 10.4103/0255-0857.195371 -
PloS One 2020The purpose of this study was to evaluate the adherence of streptococci to disks of titanium (commercially pure titanium: CpTi) and zirconia (tetragonal zirconia...
The purpose of this study was to evaluate the adherence of streptococci to disks of titanium (commercially pure titanium: CpTi) and zirconia (tetragonal zirconia polycrystals: TZP). CpTi and yttria-stabilized TZP disks with a mirror-polished surface were used as specimens. The arithmetic mean surface roughness (Ra and Sa) and the surface wettability of the experimental specimens were measured. For analyzing the outermost layer of the experimental specimens, X-ray photoelectron spectroscopy (XPS) analysis was performed. Streptococcus sanguinis, S. gordonii, S. oralis, and S. mutans were used as streptococcal bacterial strains. These bacterial cultures were grown for 24 h on CpTi and TZP. The number of bacterial adhesions was estimated using an ATP-bioluminescent assay, and scanning electron microscope (SEM) observation of the adhered bacterial specimens was performed. No significant differences in surface roughness or wettability were found between CpTi and TZP. In XPS analyses, outermost layer of CpTi included Ti0 and Ti4+, and outermost layer of TZP included Zr4+. In the cell adhesion assay, the adherences of S. sanguinis, S. gordonii, and S. oralis to TZP were significantly lower than those to CpTi (p < 0.05); however, significant difference was not observed for S. mutans among the specimens. The adherence to CpTi and TZP of S. mutans was significantly lower than that of S. sanguinis, S. gordonii, and S. oralis. These results were confirmed by SEM. S. sanguinis, S. gordonii, and S. oralis adhered less to TZP than to CpTi, but the adherence of S. mutans was similar to both surfaces. S. mutans was less adherent compare with the other streptococci tested in those specimens.
Topics: Bacterial Adhesion; Materials Testing; Microscopy, Electron, Scanning; Photoelectron Spectroscopy; Streptococcus sanguis; Surface Properties; Titanium; Yttrium; Zirconium
PubMed: 32579584
DOI: 10.1371/journal.pone.0234524 -
Infection and Immunity Mar 2024Oral streptococci, key players in oral biofilm formation, are implicated in oral dysbiosis and various clinical conditions, including dental caries, gingivitis,...
Oral streptococci, key players in oral biofilm formation, are implicated in oral dysbiosis and various clinical conditions, including dental caries, gingivitis, periodontal disease, and oral cancer. Specifically, is associated with esophageal, gastric, and pharyngeal cancers, while is linked to oral cancer. However, no study has investigated the mechanistic links between these species and cancer-related inflammatory responses. As an initial step, we probed the innate immune response triggered by and in RAW264.7 macrophages. These bacteria exerted time- and dose-dependent effects on macrophage morphology without affecting cell viability. Compared with untreated macrophages, macrophages infected with exhibited a robust proinflammatory response characterized by significantly increased levels of inflammatory cytokines and mediators, including TNF, IL-6, IL-1β, NOS2, and COX2, accompanied by enhanced NF-κB activation. In contrast, -infected macrophages failed to elicit a robust inflammatory response. Seahorse Xfe96 analysis revealed an increased extracellular acidification rate in macrophages infected with compared with . At the 24-h time point, the presence of led to reduced extracellular itaconate, while triggered increased itaconate levels, highlighting distinct metabolic profiles in macrophages during infection in contrast to aconitate decarboxylase expression observed at the 6-h time point. This initial investigation highlights how and , two Gram-positive bacteria from the same genus, can prompt distinct immune responses and metabolic shifts in macrophages during infection.IMPORTANCEThe surge in head and neck cancer cases among individuals devoid of typical risk factors such as Human Papilloma Virus (HPV) infection and tobacco and alcohol use sparks an argumentative discussion around the emerging role of oral microbiota as a novel risk factor in oral squamous cell carcinoma (OSCC). While substantial research has dissected the gut microbiome's influence on physiology, the oral microbiome, notably oral streptococci, has been underappreciated during mucosal immunopathogenesis. , a viridans streptococci group, has been linked to abscess formation and an elevated presence in esophageal cancer and OSCC. The current study aims to probe the innate immune response to compared with the early colonizer as an important first step toward understanding the impact of distinct oral species on the host immune response, which is an understudied determinant of OSCC development and progression.
Topics: Humans; Streptococcus anginosus; Carcinoma, Squamous Cell; Mouth Neoplasms; Dental Caries; Streptococcus; Macrophages; Succinates
PubMed: 38289109
DOI: 10.1128/iai.00536-23 -
Microbiology (Reading, England) Mar 2013Despite the enormous contributions of the bacterial paradigms Escherichia coli and Bacillus subtilis to basic and applied research, it is well known that no single... (Review)
Review
Despite the enormous contributions of the bacterial paradigms Escherichia coli and Bacillus subtilis to basic and applied research, it is well known that no single organism can be a perfect representative of all other species. However, given that some bacteria are difficult, or virtually impossible, to cultivate in the laboratory, that some are recalcitrant to genetic and molecular manipulation, and that others can be extremely dangerous to manipulate, the use of model organisms will continue to play an important role in the development of basic research. In particular, model organisms are very useful for providing a better understanding of the biology of closely related species. Here, we discuss how the lifestyle, the availability of suitable in vitro and in vivo systems, and a thorough understanding of the genetics, biochemistry and physiology of the dental pathogen Streptococcus mutans have greatly advanced our understanding of important areas in the field of bacteriology such as interspecies biofilms, competence development and stress responses. In this article, we provide an argument that places S. mutans, an organism that evolved in close association with the human host, as a novel Gram-positive model organism.
Topics: Biofilms; DNA Transformation Competence; Humans; Streptococcus mutans; Stress, Physiological
PubMed: 23393147
DOI: 10.1099/mic.0.066134-0 -
The ISME Journal Jul 2023During oral biofilm development, interspecies interactions drive species distribution and biofilm architecture. To understand what molecular mechanisms determine these...
During oral biofilm development, interspecies interactions drive species distribution and biofilm architecture. To understand what molecular mechanisms determine these interactions, we used information gained from recent biogeographical investigations demonstrating an association of corynebacteria with streptococci. We previously reported that Streptococcus sanguinis and Corynebacterium durum have a close relationship through the production of membrane vesicle and fatty acids leading to S. sanguinis chain elongation and overall increased fitness supporting their commensal state. Here we present the molecular mechanisms of this interspecies interaction. Coculture experiments for transcriptomic analysis identified several differentially expressed genes in S. sanguinis. Due to its connection to fatty acid synthesis, we focused on the glycerol-operon. We further explored the differentially expressed type IV pili genes due to their connection to motility and biofilm adhesion. Gene inactivation of the glycerol kinase glpK had a profound impact on the ability of S. sanguinis to metabolize C. durum secreted glycerol and impaired chain elongation important for their interaction. Investigations on the effect of type IV pili revealed a reduction of S. sanguinis twitching motility in the presence of C. durum, which was caused by a decrease in type IV pili abundance on the surface of S. sanguinis as determined by SEM. In conclusion, we identified that the ability to metabolize C. durum produced glycerol is crucial for the interaction of C. durum and S. sanguinis. Reduced twitching motility could lead to a closer interaction of both species, supporting niche development in the oral cavity and potentially shaping symbiotic health-associated biofilm communities.
Topics: Glycerol; Streptococcus; Streptococcus sanguis; Biofilms; Symbiosis; Streptococcus mutans
PubMed: 37169870
DOI: 10.1038/s41396-023-01426-9 -
Virulence 2015Streptococcus tigurinus is a novel species of viridans streptococci, shown to cause severe invasive infections such as infective endocarditis, spondylodiscitis and... (Review)
Review
Streptococcus tigurinus is a novel species of viridans streptococci, shown to cause severe invasive infections such as infective endocarditis, spondylodiscitis and meningitis. S. tigurinus belongs to the Streptococcus mitis group and is most closely related to Streptococcus mitis, Streptococcus oralis, Streptococcus pneumoniae, Streptococcus pseudopneumoniae and Streptococcus infantis. The presence of S. tigurinus in the human oral cavity has been documented, including in patients with periodontal disease. This review addresses the available scientific knowledge on S. tigurinus and its association with closely related streptococci, and discusses its putative involvement in common oral infections. While there is as yet no strong evidence on the involvement of S. tigurinus with oral infections, its presence in the oral cavity and its association with endocarditis warrants special attention for a link between oral and systemic infection.
Topics: DNA, Bacterial; Endocarditis, Bacterial; Humans; Microbiota; Mouth; Periodontal Diseases; Periodontitis; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Streptococcal Infections; Streptococcus; Streptococcus mitis
PubMed: 25483862
DOI: 10.4161/21505594.2014.970472 -
BMJ Case Reports Jan 2013
Topics: Endocarditis, Subacute Bacterial; Hand Dermatoses; Humans; Male; Middle Aged; Streptococcal Infections; Tooth Extraction; Viridans Streptococci
PubMed: 23302546
DOI: 10.1136/bcr-2012-007564 -
Infection, Genetics and Evolution :... Sep 2022The aim of the present study is to establish a method, based on sequence analysis of the helix 54 of 23S rRNA gene, to identify clinical relevant strains belonging to...
The aim of the present study is to establish a method, based on sequence analysis of the helix 54 of 23S rRNA gene, to identify clinical relevant strains belonging to viridans group streptococci (VGS). A set of 25 randomly selected clinical isolates of alpha-hemolytic streptococci from upper respiratory tract were characterized by the routine phenotypic methods (API 20 Strep test). Molecular characterization was assessed by genotypic analysis of the nucleotide sequence of the helix 54 of 23S rRNA and Intergenic spacer region 16S23S. Partial sequencing of the gdh gene was used on 10 strains of mitis group. Sequence variations of the helix 54 allowed the identification of strains to group level and even to species level for certain strains within sanguinis and anginosus groups. Infact, species identification was ambiguous for some strains belonged to the salivarius group (of VGS16 to VGS20) and the mitis group (of VGS1 to VGS14). These results are almost similar to those obtained by sequencing the 16S23S intergenic region. Thus, we use the gdh gene sequencing for the identification of strains, not recognized, within the mitis group. The results generated herein indicate that no single methodology can be used to provide an accurate identification to the species level of all VGS, although nucleotide sequence analysis of the helix 54 of 23S rRNA gene proved to be a reliable method for the identification of VGS to the group level and even to the species level within sanguinis and anginosus groups.
Topics: DNA, Ribosomal; RNA, Ribosomal, 16S; RNA, Ribosomal, 23S; Streptococcus; Viridans Streptococci
PubMed: 35753621
DOI: 10.1016/j.meegid.2022.105321 -
BMC Oral Health Jun 2023Streptococcus, Bifidobacteria, Lactobacillus and Actinomyces are acidogenic aciduria that may be associated with root caries (RC). The aim of the study was to analyze...
BACKGROUND
Streptococcus, Bifidobacteria, Lactobacillus and Actinomyces are acidogenic aciduria that may be associated with root caries (RC). The aim of the study was to analyze Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Bifidobacterium spp., Lactobacillus spp. and Actinomyces naeslundii (A. naeslundii) in the saliva of nursing home elderly, to assess the correlation between bacterial composition and RC for five putative catiogenic organisms.
METHODS
In this study, we collected 43 saliva samples and divided into two groups: the root caries group (RCG, n = 21) and the caries-free group (CFG, n = 22). Bacterial DNA was extracted from the saliva samples. The presence and abundance of the five microorganisms were detected by Quantitative real-time PCR (qPCR). Spearman correlation test was performed to evaluate the relationship between the numbers of root decayed filled surfaces (RDFS) and root caries index (RCI) and salivary levels of the bacteria.
RESULTS
The salivary levels of S. mutans, S. sobrinus, Bifidobacterium spp. and Lactobacillus spp. were significantly higher in RCG than in CFG (p < 0.05). RDFS and RCI (RDFS/RCI) were positively associated with salivary levels of S. mutans, S. sobrinus and Bifidobacterium spp. (r = 0.658/0.635, r = 0.465/0.420 and r = 0.407/0.406, respectively). No significant differences in presence and amounts of A. naeslundii was observed between the two groups (p > 0.05).
CONCLUSION
S. mutans, S. sobrinus and Bifidobacterium spp. in saliva appear to be associated with RC in the elderly. Taken together, the findings indicate that specific salivary bacteria may be involved in the progression of RC.
Topics: Humans; Aged; Root Caries; Streptococcus mutans; Streptococcus sobrinus; Dental Caries; Saliva; Nursing Homes
PubMed: 37270529
DOI: 10.1186/s12903-023-02953-9