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Frontiers in Cellular and Infection... 2020is an oral species closely associated with dental caries. As an early oral colonizer, utilizes interspecies coaggregation to promote the colonization of subsequent...
is an oral species closely associated with dental caries. As an early oral colonizer, utilizes interspecies coaggregation to promote the colonization of subsequent species and affect polymicrobial pathogenesis. Previous studies have confirmed several adhering partner species of , including and . In this study, we discovered new intergeneric co-adherence between and the saliva isolate (GBS-SI101). Research shows that GBS typically colonizes the human gastrointestinal and vaginal tracts. It is responsible for adverse pregnancy outcomes and life-threatening infections in neonates and immunocompromised people. Our results revealed that GtfB and GtfC of , which contributed to extracellular polysaccharide synthesis, promoted coaggregation of with GBS-SI101. In addition, oral streptococci, including and , barely inhibited the growth of GBS-SI101. This study indicated that could help GBS integrate into the associated oral polymicrobial community and become a resident species in the oral cavity, increasing the risk of oral infections.
Topics: Biofilms; Dental Caries; Humans; Infant, Newborn; Streptococcus agalactiae; Streptococcus mutans; Streptococcus sanguis
PubMed: 32733820
DOI: 10.3389/fcimb.2020.00344 -
Microbiology Spectrum Aug 2023Radiation caries is one of the most common complications of head and neck radiotherapy. A shift in the oral microbiota is the main factor of radiation caries. A new form...
Radiation caries is one of the most common complications of head and neck radiotherapy. A shift in the oral microbiota is the main factor of radiation caries. A new form of biosafe radiation, heavy ion radiation, is increasingly being applied in clinical treatment due to its superior depth-dose distribution and biological effects. However, how heavy ion radiation directly impacts the oral microbiota and the progress of radiation caries are unknown. Here, unstimulated saliva samples from both healthy and caries volunteers and caries-related bacteria were directly exposed to therapeutic doses of heavy ion radiation to determine the effects of radiation on oral microbiota composition and bacterial cariogenicity. Heavy ion radiation significantly decreased the richness and diversity of oral microbiota from both healthy and caries volunteers, and a higher percentage of Streptococcus was detected in radiation groups. In addition, heavy ion radiation significantly enhanced the cariogenicity of saliva-derived biofilms, including the ratios of the genus Streptococcus and biofilm formation. In the Streptococcus mutans-Streptococcus sanguinis dual-species biofilms, heavy ion radiation increased the ratio of S. mutans. Next, S. mutans was directly exposed to heavy ions, and the radiation significantly upregulated the and cariogenic virulence genes to enhance the biofilm formation and exopolysaccharides synthesis of S. mutans. Our study demonstrated, for the first time, that direct exposure to heavy ion radiation can disrupt the oral microbial diversity and balance of dual-species biofilms by increasing the virulence of S. mutans, increasing its cariogenicity, indicating a potential correlation between heavy ions and radiation caries. The oral microbiome is crucial to understanding the pathogenesis of radiation caries. Although heavy ion radiation has been used to treat head and neck cancers in some proton therapy centers, its correlation with dental caries, especially its direct effects on the oral microbiome and cariogenic pathogens, has not been reported previously. Here, we showed that the heavy ion radiation directly shifted the oral microbiota from a balanced state to a caries-associated state by increasing the cariogenic virulence of S. mutans. Our study highlighted the direct effect of heavy ion radiation on oral microbiota and the cariogenicity of oral microbes for the first time.
Topics: Humans; Streptococcus mutans; Heavy Ions; Dental Caries; Streptococcus; Streptococcus sanguis; Microbiota; Biofilms
PubMed: 37310225
DOI: 10.1128/spectrum.01322-23 -
Clinical Microbiology Reviews Jan 1988"Streptococcus milleri" is an unofficial name that has been applied to a group of streptococci which, although basically similar, show various hemolytic, serological,... (Review)
Review
"Streptococcus milleri" is an unofficial name that has been applied to a group of streptococci which, although basically similar, show various hemolytic, serological, and physiological characteristics. The species name Streptococcus anginosus has recently been recognized as the approved name for these organisms. Streptococci known as "S. milleri" have been implicated as etiologic agents in a variety of serious purulent infections, but because of their heterogeneous characteristics, these organisms may be unrecognized or misidentified by clinical laboratorians. This review describes the bacteriological aspects of organisms known as "S. milleri," their clinical significance, and the problems encountered with their identification in the clinical laboratory.
Topics: Humans; Streptococcal Infections; Streptococcus
PubMed: 3060239
DOI: 10.1128/CMR.1.1.102 -
Microbiology Spectrum Feb 2022Streptococcus equi subsp. (SEE) is a host-restricted equine pathogen considered to have evolved from Streptococcus equi subsp. (SEZ). SEZ is promiscuous in host range...
Differences in the Accessory Genomes and Methylomes of Strains of Streptococcus equi subsp. and of Streptococcus equi subsp. Obtained from the Respiratory Tract of Horses from Texas.
Streptococcus equi subsp. (SEE) is a host-restricted equine pathogen considered to have evolved from Streptococcus equi subsp. (SEZ). SEZ is promiscuous in host range and is commonly recovered from horses as a commensal. Comparison of a single strain each of SEE and SEZ using whole-genome sequencing, supplemented by PCR of selected genes in additional SEE and SEZ strains, was used to characterize the evolution of SEE. But the known genetic variability of SEZ warrants comparison of the whole genomes of multiple SEE and SEZ strains. To fill this knowledge gap, we utilized whole-genome sequencing to characterize the accessory genome elements (AGEs; i.e., elements present in some SEE strains but absent in SEZ or vice versa) and methylomes of 50 SEE and 50 SEZ isolates from Texas. Consistent with previous findings, AGEs consistently found in all SEE isolates were primarily from mobile genetic elements that might contribute to host restriction or pathogenesis of SEE. Fewer AGEs were identified in SEZ because of the greater genomic variability among these isolates. The global methylation patterns of SEE isolates were more consistent than those of the SEZ isolates. Among homologous genes of SEE and SEZ, differential methylation was identified only in genes of SEE encoding proteins with functions of quorum sensing, exopeptidase activity, and transitional metal ion binding. Our results indicate that effects of genetic mobile elements in SEE and differential methylation of genes shared by SEE and SEZ might contribute to the host specificity of SEE. Strangles, caused by the host-specific bacterium Streptococcus equi subsp. (SEE), is the most commonly diagnosed infectious disease of horses worldwide. Its ancestor, Streptococcus equi subsp. (SEZ), is frequently isolated from a wide array of hosts, including horses and humans. A comparison of the genomes of a single strain of SEE and SEZ has been reported, but sequencing of further isolates has revealed variability among SEZ strains. Thus, the importance of this study is that it characterizes genomic and methylomic differences of multiple SEE and SEZ isolates from a common geographic region (, Texas). Our results affirm many of the previously described differences between the genomes of SEE and SEZ, including the role of mobile genetic elements in contributing to host restriction. We also provide the first characterization of the global methylome of Streptococcus equi and evidence that differential methylation might contribute to the host restriction of SEE.
Topics: Animals; DNA Methylation; Epigenome; Genetic Variation; Genome, Bacterial; Horse Diseases; Horses; Respiratory System; Streptococcal Infections; Streptococcus; Streptococcus equi; Texas
PubMed: 35019696
DOI: 10.1128/spectrum.00764-21 -
Thorax Dec 2013Molecular methods based on phylogenetic differences in the 16S rRNA gene are able to characterise the microbiota of the respiratory tract in health and disease.
BACKGROUND
Molecular methods based on phylogenetic differences in the 16S rRNA gene are able to characterise the microbiota of the respiratory tract in health and disease.
OBJECTIVES
Our goals were (1) to characterise bacterial communities in lower and upper airways of patients with interstitial lung disease (ILD) and (2) to compare the results with the microbiota of patients with Pneumocystis pneumonia (PCP) and normal controls.
METHODS
We examined the upper and lower respiratory tract of 18 patients with ILD of whom 5, 6, and 7 had idiopathic interstitial pneumonia (IIP), non-IIP and sarcoidosis, respectively. In addition, six immune-compromised patients with PCP and nine healthy subjects were included as controls. Exclusion criteria were recent bacterial/viral respiratory tract infection, HIV-positivity and subjects receiving antibiotic therapy. Bronchoalveolar lavage fluid and oropharyngeal swabs were simultaneously collected, and microbiota was characterised by ultra-deep 16S rRNA gene sequencing.
RESULTS
The microbiota in lower airways of the majority of patients (30; 90%) primarily consisted of Prevotellaceae, Streptococcaceae and Acidaminococcaceae. α and β diversity measurements revealed no significant differences in airway microbiota composition between the five different groups of patients. Comparison of bacterial populations in upper and lower respiratory tract showed significant topographical discontinuities for 7 (23%) individuals.
CONCLUSIONS
IIP, non-IIP and sarcoidosis are not associated with disordered airway microbiota and a pathogenic role of commensals in the disease process is therefore unlikely. Nevertheless, molecular analysis of the topographical microbiota continuity along the respiratory tract may provide additional information to assist management of individual patients.
Topics: Adult; Aged; Bacteria; Bacteroidetes; Bronchoalveolar Lavage Fluid; Case-Control Studies; Female; Humans; Idiopathic Interstitial Pneumonias; Male; Microbiota; Middle Aged; Pneumonia, Pneumocystis; RNA, Ribosomal, 16S; Respiratory System; Sarcoidosis, Pulmonary; Streptococcaceae; Veillonellaceae
PubMed: 23945167
DOI: 10.1136/thoraxjnl-2012-202917 -
European Journal of Clinical... Oct 2020The aim of our study was to investigate phenotypic and genotypic features of streptococci misidentified (misID) as Streptococcus pneumoniae, obtained over 20 years from...
The aim of our study was to investigate phenotypic and genotypic features of streptococci misidentified (misID) as Streptococcus pneumoniae, obtained over 20 years from hospital patients in Poland. Sixty-three isolates demonstrating microbiological features typical for pneumococci (optochin susceptibility and/or bile solubility) were investigated by phenotypic tests, lytA and 16S rRNA gene polymorphism and whole-genome sequencing (WGS). All isolates had a 6-bp deletion in the lytA 3' terminus, characteristic for Mitis streptococc and all but two isolates lacked the pneumococcal signature cytosine at nucleotide position 203 in the 16S rRNA genes. The counterparts of psaA and ply were present in 100% and 81.0% of isolates, respectively; the spn9802 and spn9828 loci were characteristic for 49.2% and 38.1% of isolates, respectively. Phylogenetic trees and networks, based on the multilocus sequence analysis (MLSA) scheme, ribosomal multilocus sequence typing (rMLST) scheme and core-genome analysis, clearly separated investigated isolates from S. pneumoniae and demonstrated the polyclonal character of misID streptococci, associated with the Streptococcus pseudopneumoniae and Streptococcus mitis groups. While the S. pseudopneumoniae clade was relatively well defined in all three analyses, only the core-genome analysis revealed the presence of another cluster comprising a fraction of misID streptococci and a strain proposed elsewhere as a representative of a novel species in the Mitis group. Our findings point to complex phylogenetic and taxonomic relationships among S. mitis-like bacteria and support the notion that this group may in fact consist of several distinct species.
Topics: Bacterial Typing Techniques; Diagnostic Errors; Female; Humans; Male; Phylogeny; Poland; RNA, Ribosomal, 16S; Streptococcal Infections; Streptococcus; Streptococcus mitis; Streptococcus pneumoniae
PubMed: 32409955
DOI: 10.1007/s10096-020-03916-6 -
Applied and Environmental Microbiology Jul 2017Integrative and conjugative elements (ICEs) are widespread chromosomal mobile genetic elements which can transfer autonomously by conjugation in bacteria. Thirteen ICEs...
Integrative and conjugative elements (ICEs) are widespread chromosomal mobile genetic elements which can transfer autonomously by conjugation in bacteria. Thirteen ICEs with a conjugation module closely related to that of ICE of were characterized in by whole-genome sequencing. Sequence comparison highlighted ICE evolution by shuffling of 3 different integration/excision modules (for integration in the 3' end of the , , or gene) with the conjugation module of the ICE subfamily. Sequence analyses also pointed out a recombination occurring at (likely mediated by the relaxase) as a mechanism of ICE evolution. Despite a similar organization in two operons including three conserved genes, the regulation modules show a high diversity (about 50% amino acid sequence divergence for the encoded regulators and presence of unrelated additional genes) with a probable impact on the regulation of ICE activity. Concerning the accessory genes, ICEs of the ICE subfamily appear particularly rich in restriction-modification systems and orphan methyltransferase genes. Other cargo genes that could confer a selective advantage to the cell hosting the ICE were identified, in particular, genes for bacteriocin synthesis and cadmium resistance. The functionality of 2 ICEs of was investigated. Autonomous conjugative transfer to other strains, to , and to was observed. The analysis of the ICE- border sequence in these transconjugants allowed the localization of the DNA cutting site of the ICE integrase. The ICE subfamily of ICEs appears to be widespread in streptococci and targets diverse chromosomal integration sites. These ICEs carry diverse cargo genes that can confer a selective advantage to the host strain. The maintenance of these mobile genetic elements likely relies in part on self-encoded restriction-modification systems. In this study, intra- and interspecies transfer was demonstrated for 2 ICEs of Closely related ICEs were also detected in other species ( and ), thus indicating that diffusion of ICE-related elements probably plays a significant role in horizontal gene transfer (HGT) occurring in the oral cavity but also in the digestive tract, where is present.
Topics: Bacterial Proteins; Conjugation, Genetic; DNA Transposable Elements; Evolution, Molecular; Gene Transfer, Horizontal; Genetic Variation; Streptococcus salivarius; Streptococcus thermophilus
PubMed: 28432093
DOI: 10.1128/AEM.00337-17 -
Applied and Environmental Microbiology Oct 2023Biofilms are complex polymicrobial communities which are often associated with human infections such as the oral disease periodontitis. Studying these complex...
Biofilms are complex polymicrobial communities which are often associated with human infections such as the oral disease periodontitis. Studying these complex communities under controlled conditions requires biofilm model systems that mimic the natural environment as close as possible. This study established a multispecies periodontal model in the drip flow biofilm reactor in order to mimic the continuous flow of nutrients at the air-liquid interface in the oral cavity. The design is engineered to enable real-time characterization. A community of five bacteria, -GFPmut3*, -GFPmut3*, -pVMCherry, , and -SNAP26 is visualized using two distinct fluorescent proteins and the SNAP-tag. The biofilm in the reactor develops into a heterogeneous, spatially uniform, dense, and metabolically active biofilm with relative cell abundances similar to those in a healthy individual. Metabolic activity, structural features, and bacterial composition of the biofilm remain stable from 3 to 6 days. As a proof of concept for our periodontal model, the 3 days developed biofilm is exposed to a prebiotic treatment with L-arginine. Multifaceted effects of L-arginine on the oral biofilm were validated by this model setup. L-arginine showed to inhibit growth and incorporation of the pathogenic species and to reduce biofilm thickness and volume. Additionally, L-arginine is metabolized by -GFPmut3* and -pVMCherry, producing high levels of ornithine and ammonium in the biofilm. In conclusion, our drip flow reactor setup is promising in studying spatiotemporal behavior of a multispecies periodontal community.ImportancePeriodontitis is a multifactorial chronic inflammatory disease in the oral cavity associated with the accumulation of microorganisms in a biofilm. Not the presence of the biofilm as such, but changes in the microbiota (i.e., dysbiosis) drive the development of periodontitis, resulting in the destruction of tooth-supporting tissues. In this respect, novel treatment approaches focus on maintaining the health-associated homeostasis of the resident oral microbiota. To get insight in dynamic biofilm responses, our research presents the establishment of a periodontal biofilm model including , , , , and . The added value of the model setup is the combination of simulating continuously changing natural mouth conditions with spatiotemporal biofilm profiling using non-destructive characterization tools. These applications are limited for periodontal biofilm research and would contribute in understanding treatment mechanisms, short- or long-term exposure effects, the adaptation potential of the biofilm and thus treatment strategies.
Topics: Humans; Bacteria; Streptococcus gordonii; Fusobacterium nucleatum; Streptococcus sanguis; Streptococcus oralis; Biofilms; Periodontitis; Arginine; Porphyromonas gingivalis
PubMed: 37768099
DOI: 10.1128/aem.01081-23 -
Antimicrobial Agents and Chemotherapy Oct 2014The linkage between the macrolide efflux gene mef(I) and the chloramphenicol inactivation gene catQ was first described in Streptococcus pneumoniae (strain Spn529),...
The linkage between the macrolide efflux gene mef(I) and the chloramphenicol inactivation gene catQ was first described in Streptococcus pneumoniae (strain Spn529), where the two genes are located in a module designated IQ element. Subsequently, two different defective IQ elements were detected in Streptococcus pyogenes (strains Spy029 and Spy005). The genetic elements carrying the three IQ elements were characterized, and all were found to be Tn5253 family integrative and conjugative elements (ICEs). The ICE from S. pneumoniae (ICESpn529IQ) was sequenced, whereas the ICEs from S. pyogenes (ICESpy029IQ and ICESpy005IQ, the first Tn5253-like ICEs reported in this species) were characterized by PCR mapping, partial sequencing, and restriction analysis. ICESpn529IQ and ICESpy029IQ were found to share the intSp 23FST81 integrase gene and an identical Tn916 fragment, whereas ICESpy005IQ has int5252 and lacks Tn916. All three ICEs were found to lack the linearized pC194 plasmid that is usually associated with Tn5253-like ICEs, and all displayed a single copy of a toxin-antitoxin operon that is typically contained in the direct repeats flanking the excisable pC194 region when this region is present. Two different insertion sites of the IQ elements were detected, one in ICESpn529IQ and ICESpy029IQ, and another in ICESpy005IQ. The chromosomal integration of the three ICEs was site specific, depending on the integrase (intSp 23FST81 or int5252). Only ICESpy005IQ was excised in circular form and transferred by conjugation. By transformation, mef(I) and catQ were cotransferred at a high frequency from S. pyogenes Spy005 and at very low frequencies from S. pneumoniae Spn529 and S. pyogenes Spy029.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Polymerase Chain Reaction; Streptococcus pneumoniae; Streptococcus pyogenes
PubMed: 25070090
DOI: 10.1128/AAC.03638-14 -
Emerging Microbes & Infections Dec 2022Owing to an increasing number of infections in adults, has gained recognition as an emerging human pathogen, causing bacteraemia and septicaemia. In September 2020,...
Owing to an increasing number of infections in adults, has gained recognition as an emerging human pathogen, causing bacteraemia and septicaemia. In September 2020, four paediatric onco-hematologic patients received a platelet concentrate from the same adult donor at Bambino Gesù Children's Hospital IRCCS, Rome. Three of four patients experienced sepsis one day after transfusion. The pediatric isolates and the donor's platelet concentrates were retrospectively collected for whole-genome sequencing and shot-gun metagenomics, respectively (Illumina HiSeq). By de novo assembly of the genomes, we found that all three pediatric isolates shared a 99.9% identity and were characterized by 440 common SNPs. Plasmid pUC11C (conferring virulence properties) and the temperate prophage Plg-Tb25 were detected in all three strains. Core SNP genome-based maximum likelihood and Bayesian trees confirmed their phylogenetic common origin and revealed their relationship with strains affecting cows and humans (bootstrap values >100 and posterior probabilities = 1.00). Bacterial reads obtained by the donor's platelet concentrate have been profiled with MetaPhlAn2 (v.2.7.5); among these, 29.9% belonged to Firmicutes, and 5.16% to Streptococcaceae (>97% identity with ), confirming the presence of in the platelet concentrate transfusion. These data showed three episodes of sepsis for the first time due to a transfusion-associated transmission of in three pediatric hospitalized hematology patients. This highlights the importance to implement the screening of platelet components with new human-defined pathogens for ensuring the safety of blood supply, and more broadly, for the surveillance of emerging pathogens.
Topics: Bayes Theorem; Child; Drug Resistance, Bacterial; Humans; Lactococcus; Phylogeny; Retrospective Studies; Sepsis
PubMed: 35475418
DOI: 10.1080/22221751.2022.2071174