Proteoglycan 4 (lubricin) is a highly sialylated glycoprotein associated with cardiac valve damage in animal models of infective endocarditis.

Streptococcus gordonii and Streptococcus sanguinis are primary colonizers of tooth surfaces and are generally associated with oral health, but can also cause infective endocarditis (IE). These species express "Siglec-like" adhesins that bind sialylated glycans on host glycoproteins, which can aid the formation of infected platelet-fibrin thrombi (vegetations) on cardiac valve surfaces. We previously determined that the ability of S. gordonii to bind sialyl T-antigen (sTa) increased pathogenicity, relative to recognition of sialylated core 2 O-glycan structures, in an animal model of IE. However, it is unclear when and where the sTa structure is displayed, and which sTa-modified host factors promote valve colonization. In this study, we identified sialylated glycoproteins in the aortic valve vegetations and plasma of rat and rabbit models of this disease. Glycoproteins that display sTa vs. core 2 O-glycan structures were identified by using recombinant forms of the streptococcal Siglec-like adhesins for lectin blotting and affinity capture, and the O-linked glycans were profiled by mass spectrometry. Proteoglycan 4 (PRG4), also known as lubricin, was a major carrier of sTa in the infected vegetations. Moreover, plasma PRG4 levels were significantly higher in animals with damaged or infected valves, as compared with healthy animals. The combined results demonstrate that, in addition to platelet GPIbα, PRG4 is a highly sialylated mucin-like glycoprotein found in aortic valve vegetations and may contribute to the persistence of oral streptococci in this protected endovascular niche. Moreover, plasma PRG4 could serve as a biomarker for endocardial injury and infection.

Intracellular Ser/Thr/Tyr phosphoproteome of the oral commensal Streptococcus gordonii DL1.

BACKGROUND: To respond and adapt to environmental challenges, prokaryotes regulate cellular processes rapidly and reversibly through protein phosphorylation and dephosphorylation. This study investigates the intracellular proteome and Ser/Thr/Tyr phosphoproteome of the oral commensal Streptococcus gordonii. Intracellular proteins from planktonic cells of S. gordonii DL1 were extracted and subjected to 2D-gel electrophoresis. Proteins in general were visualized using Coomassie Brilliant Blue and T-Rex staining. Phosphorylated proteins were visualized with Pro-Q Diamond Phosphoprotein Gel Stain. Proteins were identified by LC-MS/MS and sequence analysis. RESULTS: In total, sixty-one intracellular proteins were identified in S. gordonii DL1, many of which occurred at multiple isoelectric points. Nineteen of these proteins were present as one or more Ser/Thr/Tyr phosphorylated form. The identified phosphoproteins turned out to be involved in a variety of cellular processes. CONCLUSION: Nineteen phosphoproteins involved in various cellular functions were identified in S. gordonii. This is the first time the global intracellular Ser/Thr/Tyr phosphorylation profile has been analysed in an oral streptococcus. Comparison with phosphoproteomes of other species from previous studies showed many similarities. Proteins that are consistently found in a phosphorylated state across several species and growth conditions may represent a core phosphoproteome profile shared by many bacteria.

Fulminant gas-forming breast abscess associated with synergistic Veillonella infection.

We present a rare case of a rapidly fulminant and destructive breast abscess with gas production by the synergistic infection of Veillonella and Streptococcus species. To our knowledge, this is the first reported case of Veillonella infection in the breast. Early recognition, empiric antibiotic cover, aggressive surgical debridement, and drainage are necessary to avoid systemic septicemia. Staged reconstructive breast surgery allows for correction any resultant breast deformity.

Streptococcus gordonii-associated infective endocarditis in a girl with Barlow's mitral valve disease.

We present a case of infective endocarditis caused by Streptococcus gordonii in an 11-year-old girl with Barlow's mitral valve disease. The differential diagnosis of rheumatic carditis and infective endocarditis was difficult as the patient fulfilled the Jones criteria. Vegetation on the mitral valve which became evident later in course of the disease and positive blood culture allowed diagnosing "definite" infective endocarditis.

Satellite Atrial Septal Vegetations Secondary to Mitral Valve Endocarditis.

Infective endocarditis is a challenging clinical problem with a high rate of mortality. Early recognition of this disease, and especially its complications, remain a critical task for the cardiologist. In this scenario, atrial endocarditis is a rare and sometimes unrecognized complication of mitral valve endocarditis. Herein is reported a clinical case that shows how a satellite vegetation in the atrial septum can be produced in a patient with mitral regurgitation secondary to mitral valve endocarditis. Video 1: Transthoracic echocardiography showing the presence of vegetation in the posterior mitral leaflet, severe secondary mitral regurgitation, and satellite vegetation in the atrial septum.

Bacterial invasion into radicular dentine-an in vitro study.

OBJECTIVES: We wanted to investigate differences in invasiveness into radicular dentinal tubules by monocultured and co-cultured bacteria frequently found in infected root canals. METHODS: Fifty-one human roots were incubated for 8 weeks with monocultured Streptococcus gordonii ATCC 10558, Streptococcus sanguinis ATCC 10556, and with five capnophiles/anaerobes as well as with capnophiles/anaerobes co-cultured with a streptococcal species. Thereafter, bacterial samples were cultured from the inner, middle, and outer third of the root dentine of longitudinally broken teeth (n = 5). In addition, scanning electron microscopy (SEM) images were obtained. RESULTS: Single gram-positive species were able to penetrate into the middle and outer third of the root dentine. Fusobacterium nucleatum ATCC 25586 was not found in any of the dentine specimens. Prevotella intermedia ATCC 25611 and Porphyromonas gingivalis ATCC 33277 were found in the inner and middle third. The bacterial load of streptococci was higher in all thirds in co-cultures compared to single infections. In co-cultures with streptococci, Actinomyces oris ATCC 43146 was found in the outer third in 9/10 samples, whereas P. intermedia ATCC 25611 was not detectable inside dentine. Co-culture with S. sanguinis ATCC 10556 enabled F. nucleatum ATCC 25586 to invade dentine; SEM images showed that F. nucleatum ATCC 25586 had a swollen shape. CONCLUSIONS: Invasiveness of bacteria into dentinal tubules is species-specific and may change depending on culturing as a single species or co-culturing with other bacteria. CLINICAL RELEVANCE: Oral streptococci may promote or inhibit invasion of capnophiles/anaerobes into radicular dentine.

Cell Surface Glycoside Hydrolases of Streptococcus gordonii Promote Growth in Saliva.

UNLABELLED: The growth of the oral commensal Streptococcus gordonii in saliva may depend on a number of glycoside hydrolases (GHs), including three cell wall-anchored proteins that are homologs of pneumococcal ß-galactosidase (BgaA), ß-N-acetylglucosaminidase (StrH), and endo-ß-N-acetylglucosaminidase D (EndoD). In the present study, we introduced unmarked in-frame deletions into the corresponding genes of S. gordonii DL1, verified the presence (or absence) of the encoded proteins on the resulting mutant strains, and compared these strains with wild-type strain DL1 for growth and glycan foraging in saliva. The overnight growth of wild-type DL1 was reduced 3- to 10-fold by the deletion of any one or two genes and approximately 20-fold by the deletion of all three genes. The only notable change in the salivary proteome associated with this reduction of growth was a downward shift in the apparent molecular masses of basic proline-rich glycoproteins (PRG), which was accompanied by the loss of lectin binding sites for galactose-specific Erythrina cristagalli agglutinin (ECA) and mannose-specific Galanthus nivalis agglutinin (GNA). The binding of ECA to PRG was also abolished in saliva cultures of mutants that expressed cell surface BgaA alone or together with either StrH or EndoD. However, the subsequent loss of GNA binding was seen only in saliva cocultures of different mutants that together expressed all three cell surface GHs. The findings indicate that the growth of S. gordonii DL1 in saliva depends to a significant extent on the sequential actions of first BgaA and then StrH and EndoD on N-linked glycans of PRG. IMPORTANCE: The ability of oral bacteria to grow on salivary glycoproteins is critical for dental plaque biofilm development. Little is known, however, about how specific salivary components are attacked and utilized by different members of the biofilm community, such as Streptococcus gordonii. Streptococcus gordonii DL1 has three cell wall-anchored glycoside hydrolases that are predicted to act on host glycans. In the present study, we introduced unmarked in-frame deletions in the corresponding genes, verified the presence (or absence) of encoded proteins on the resulting mutant strains, and compared these strains with wild-type DL1 for growth and glycan foraging in saliva. The results indicate that the growth of S. gordonii DL1 depends to a significant extent on sequential action of these cell surface GHs on N-linked glycans of basic proline-rich salivary glycoproteins, which appears to be an essential first step in salivary glycan foraging.

Strains of Enterococcus faecalis differ in their ability to coexist in biofilms with other root canal bacteria.

AIM: To investigate the relationship between protease production and the ability of Enterococcus faecalis strains to coexist in biofilms with other bacteria commonly recovered from infected root canals. METHODOLOGY: Biofilms with bacteria in mono-, dual- and four-species communities were developed in flow chambers. The organisms used were Lactobacillus salivarius, Streptococcus gordonii and Actinomyces naeslundii and E. faecalis strains, GUL1 and OG1RF. Biovolume and species distribution were examined using 16S rRNA fluorescence in situ hybridization in combination with confocal microscopy and image analysis. The full proteome of the E. faecalis strains was studied using two-dimensional gel electrophoresis. Spots of interest were identified using tandem mass spectroscopy and quantified using Delta 2D software. RESULTS: All bacteria formed biofilms and an anova analysis revealed that the biofilm biomass increased significantly (P ≤ 0.01) between 6 and 24 h. L. salivarius, S. gordonii and A. naeslundii formed mutualistic biofilm communities, and this pattern was unchanged when E. faecalis GUL1 was included in the consortium. However, with OG1RF, L. salivarius and S. gordonii were outcompeted in a 24-h biofilm. Proteomic analysis revealed that OG1RF secreted higher levels of proteases, GelE (P = 0.02) and SprE (P = 0.002) and a previously unidentified serine protease (P = 0.05), than GUL1. CONCLUSIONS: Different strains of E. faecalis can interact synergistically or antagonistically with a consortium of root canal bacteria. A possible mechanism underlying this, as well as potential differences in virulence, is production of different levels of proteases, which can cause detachment of neighbouring bacteria and tissue damage.

Infective endocarditis associated superior mesenteric artery pseudoaneurysm.

BACKGROUND: Since William Osler first described mycotic aneurysms in the setting of endocarditis in 1885, few pseudoaneurysms (PAs) of the superior mesenteric artery (SMA) have been reported in the literature. We report 2 cases of SMA PA related to infective endocarditis that were managed with open surgery. RESULTS: Here we report 2 cases of SMA PAs treated with different surgical techniques. A 59-year-old male with a history of intravenous drug use presented with abdominal pain and was found to have Streptococcus viridans endocarditis and an SMA PA. A laparotomy was performed, and proximal and distal control of the SMA PA was obtained. After ensuring that Doppler signals were still present in the distal mesentery and the entirety of the bowel was viable, the SMA was ligated proximal and distal to the PA. The patient recovered uneventfully. The second case is a 35-year-old female who presented with abdominal pain and was found to have Streptococcos gordonii endocarditis and an SMA PA for which the patient was initially observed. After several weeks, the patient's condition deteriorated and the patient underwent open ligation of the SMA, proximal and distal to the PA, with a bypass from the infrarenal abdominal aorta to a distal unnamed SMA branch and resection of 3 ft of ischemic small bowel. The patient continued to have recurrent bowel ischemia over the next several weeks and ultimately died. CONCLUSIONS: SMA PAs associated with infective endocarditis are rare, but carry a high risk of rupture and associated morbidity and mortality. Delay in surgical management may increase this risk.

Development of Streptococcus gordonii-specific quantitative real-time polymerase chain reaction primers based on the nucleotide sequence of rpoB.

In this study, Streptococcus gordonii-specific quantitative real-time polymerase chain reaction (qPCR) primers, RTSgo-F2/RTSgo-R2, were developed based on the nucleotide sequences of RNA polymerase ß-subunit gene (rpoB). The specificity of the RTSgo-F2/RTSgo-R2 primers was assessed by conventional PCR on 99 strains comprising 63 oral bacterial species, including the type strain and eight clinical isolates of S. gordonii. PCR products were amplified from the genomic DNAs of only S. gordonii strains. The qPCR primers were able to detect as little as 40 fg of S. gordonii genomic DNA at a cycle threshold value of 33. These findings suggest that these qPCR primers detect S. gordonii with high specificity and sensitivity.

Hypertrophic cardiomyopathy: role of current recommendations by the american heart association for infective endocarditis.

In the past decade, there has been evolution in the diagnosis, management, and long-term care of patients with infective endocarditis and its complications. This includes the relatively new but contentious prophylactic antibiotic regimen. However, these cases still continue to pose a challenge in the adult and pediatric populations. We present a case of a teenager with hypertrophic cardiomyopathy that had an atypical presentation of infective endocarditis.

Streptococcus gordonii septic arthritis: two cases and review of literature.

BACKGROUND: Despite advances in antimicrobial and surgical therapy, septic arthritis remains a rheumatologic emergency that can lead to rapid joint destruction and irreversible loss of function. In adults, Staphylococcus aureus is the most common microorganism isolated from native joints. Streptococcus gordonii is a prominent member of the viridans group of oral bacteria and is among the bacteria most frequently identified as being primary agent of subacute bacterial endocarditis. To the best of our knowledge, Streptococcus gordonii has not yet been described as agent of septic arthritis. CASE PRESENTATION: We describe here two cases of septic arthritis due to Streptococcus gordonii. It gives us an opportunity to review epidemiology, diagnosis criteria and management of septic arthritis. CONCLUSION: Although implication of S. gordonii as aetiologic agent of subacute endocarditis is well known, this organism is a rare cause of septic arthritis. In this case, the exclusion of associated endocarditis is warranted.

Carboxypeptidase activity common to viridans group streptococci cleaves angiotensin I to angiotensin II: an activity homologous to angiotensin-converting enzyme (ACE).

We have found that Streptococcus gordonii FSS2, an infective endocarditis (IE) isolate, expresses a dipeptidyl-carboxypeptidase with activity homologous to angiotensin-converting enzyme (ACE). The carboxypeptidase activity was purified to homogeneity as a complex/aggregate from a bacterial surface extract and was also active as a 165 kDa monomer. The specific activity for the carboxypeptidase activity was eightfold higher than that for recombinant human ACE. Selected ACE inhibitors, captopril, lisinopril and enalapril, did not inhibit the ACE activity. The carboxypeptidase also hydrolysed the Aα and Bß-chains of human fibrinogen, which resulted in impaired fibrin formation by thrombin. The gene encoding ACE carboxypeptidase activity was sequenced and the inferred polypeptide product showed 99 % amino acid homology to SGO_0566, sgc, 'challisin' of S. gordonii CL1 Challis, and had no significant amino acid sequence homology to human ACE. Homologues of challisin ACE activity were commonly detected among the viridans group streptococci most often associated with IE.

Streptococcus gordonii peritonitis in a patient on CAPD.

We report the first case of Streptococcus gordonii-related continuous ambulatory peritoneal dialysis (CAPD) peritonitis. He is a 69-year-old man with end-stage renal failure due to chronic glomerulonephritis who had been put on CAPD for 1 year. He was successfully treated with a 2-week course of cefazolin. This case highlights the emerging threat that S. gordonii can be the source of infection in patients on CAPD.

Prevalence of five biofilm-related oral streptococci species from plaque.

OBJECTIVE: To examine the prevalence of five oral streptococci species of severe early childhood caries (S-ECC) and caries-free (CF) groups. STUDY DESIGN: Supra gingival plaque samples were obtainedfrom 198 Thai children with ages ranging from one to six years old Eighty-seven subjects had no caries (dmft=0), and 111 had S-ECC. After DNA extraction, S. mutans, S. sobrinus, S. sanguinis, S. oralis, and S. gordonii were identified by standard PCR using species-specific primers. Statistical analysis determined the differences among prevalence rates of each species using Pearson chi-square test. The relationship among dmft score, age, sex and caries status within each group was analyzed by logistical regression (p < or = 0.05). RESULTS: Sex was not correlated with any of the species detected in both groups (mean age =3.09, mean +/- SD of dmft = 11.04 +/- 7.89). S. mutans was found at greatest prevalence in both groups followed by S. oralis. S. gordonii was detected at a high prevalence, but S. sobrinus and S. sanguinis were lower in S-ECC when compared with those from the CF group. CONCLUSION: S. mutans was associated significantly with S-ECC (p < or = 0.05). Caries prevalence was highest (56.5%) in subjects infected by S. mutans alone. S. sanguinis prevalence was higher in the CF group, but not statiscally different. Infection with MS did not show higher caries prevalence.

Profiling of subgingival plaque biofilm microflora from periodontally healthy subjects and from subjects with periodontitis using quantitative real-time PCR.

BACKGROUND AND OBJECTIVE: Qualitative and quantitative changes of the subgingival plaque biofilm microflora in periodontal pockets are thought to be associated with the development and progression of periodontitis. The aims of the present study were to quantify the proportions of nine periodontitis-associated bacterial species and four Streptococcus species in subgingival plaque, and to evaluate their relationship with periodontitis quantitatively. MATERIAL AND METHODS: Subgingival plaque samples were obtained from 12 periodontally healthy subjects and from 28 patients with periodontitis. The amounts of total and target bacteria were measured by quantitative real-time PCR using universal and species-specific primers, respectively. RESULTS: The proportion of total obligate anaerobes was found to be higher in subjects with periodontitis than in periodontally healthy subjects (p < 0.05). Among obligate anaerobes, Tannerella forsythia (2.04 +/- 5.27%, p < 0.05), Porphyromonas gingivalis (0.54 +/- 1.41%) and Eubacterium saphenum (0.30 +/- 0.96%) were detected at high proportions in subjects with periodontitis, but not in periodontally healthy subjects. By contrast, the proportion of total streptococci was lower in subjects with periodontitis (p < 0.05). Specifically, the proportion of T. forsythia, P. gingivalis or E. saphenum increased (>or= 2.78%) and the proportion of Streptococcus species decreased to virtually undetectable levels, in subjects with periodontitis. CONCLUSION: Obligate anaerobes, including T. forthysia, P. gingivalis and E. saphenum, were identified predominantly in microflora from subjects with periodontitis, whereas Streptococcus species were identified predominantly in microflora from periodontally healthy subjects, suggesting a change in the subgingival environment that resulted in conditions more suitable for the survival of obligate anaerobes. The proportion of these obligate anaerobes in the subgingival plaque of subjects with periodontitis appears to be associated with the status of human periodontitis.

Microbiological profiles in saliva and supragingival plaque from caries-active adolescents before and after a short-term daily intake of milk supplemented with probiotic bacteria - a pilot study.

PURPOSE: The aim of the present pilot study was to investigate the microbial profile in saliva and supragingival plaque samples collected from caries-active adolescents before and after a daily short-term intake of milk supplemented with the probiotic bacteria. MATERIALS AND METHODS: The present study group consisted of 18 caries-active adolescents of both sexes who volunteered for participation giving an informed consent. The study has a randomised placebo-controlled double-blind pilot design with two parallel arms. After a 2-week run-in period, the subjects were instructed to drink 2.5 dl of milk supplemented with Lactobacillus rhamnosus LB21 (107 CFU/ml) (test) or standard control milk (placebo) once daily for a period of 2 weeks (intervention period). Samples of stimulated whole saliva and supragingival plaque were collected at baseline (after run-in) and immediately after the end of the intervention period (follow-up). The salivary levels of mutans streptococci and lactobacilli were estimated by conventional culturing on selective agar plates. The presence and level of 19 oral species associated with the caries process were determined using the checkerboard DNA-DNA hybridisation technique. Differences between the groups were assessed using the non-parametric Wilcoxon­Mann­Whitney and chi-square tests. RESULTS: The mean caries experience was high with an average of 7.0 ± 3.8 proximal enamel lesions. The most prevalent dominating species in the plaque samples were Streptococcus mitis, Veillonella parvula and Streptococcus gordonii. The saliva samples displayed a more mixed profile, with Streptococcus mitis, Rothia dentocariosa, Lactobacillus casei and Lactobacillus curvata being frequently identified species. All of the subjects harboured mutans streptococci in their saliva, with 61% of them colonised with salivary lactobacilli. No statistically significant differences in the microbial profiles or the estimated counts between the baseline and follow-up samples, or between the two study groups, were observed. CONCLUSIONS: The present study showed that a short-term daily intake of milk supplemented with the probiotic bacterium L. rhamnosus LB21 did not significantly affect the microbial profiles or the levels of caries-associated bacteria in saliva and supragingival plaque samples collected from caries-active adolescents.

Similar genomic patterns of clinical infective endocarditis and oral isolates of Streptococcus sanguinis and Streptococcus gordonii.

Streptococcus gordonii and Streptococcus sanguinis belong to the Mitis group streptococci, which mostly are commensals in the human oral cavity. Though they are oral commensals, they can escape their niche and cause infective endocarditis, a severe infection with high mortality. Several virulence factors important for the development of infective endocarditis have been described in these two species. However, the background for how the commensal bacteria, in some cases, become pathogenic is still not known. To gain a greater understanding of the mechanisms of the pathogenic potential, we performed a comparative analysis of 38 blood culture strains, S. sanguinis (n = 20) and S. gordonii (n = 18) from patients with verified infective endocarditis, along with 21 publicly available oral isolates from healthy individuals, S. sanguinis (n = 12) and S. gordonii (n = 9). Using whole genome sequencing data of the 59 streptococci genomes, functional profiles were constructed, using protein domain predictions based on the translated genes. These functional profiles were used for clustering, phylogenetics and machine learning. A clear separation could be made between the two species. No clear differences between oral isolates and clinical infective endocarditis isolates were found in any of the 675 translated core-genes. Additionally, random forest-based machine learning and clustering of the pan-genome data as well as amino acid variations in the core-genome could not separate the clinical and oral isolates. A total of 151 different virulence genes was identified in the 59 genomes. Among these homologs of genes important for adhesion and evasion of the immune system were found in all of the strains. Based on the functional profiles and virulence gene content of the genomes, we believe that all analysed strains had the ability to become pathogenic.