Bacterial Infective Endocarditis Research Articles

Skin manifestations in a patient with acute bacterial infective endocarditis.

Skin manifestations in a patient with acute bacterial infective endocarditis.

Invasive Candida Infection in Patients With Bacterial Infective Endocarditis.

Over 21 months, 12 patients with invasive Candida infections detected during the course of treatment of bacterial endocarditis, including 11 with candidemia, were identified. Invasive Candida infections can occur as a complication of bacterial endocarditis and may occur more frequently in patients with injection drug use and broad-spectrum antibiotic exposure.

Emerging trends in fungal endocarditis: clinical complexity, diagnostic challenges, and therapeutic implications - a case series and literature review.

Fungal infective endocarditis (IE) is a rare, yet increasingly recognised condition associated with substantial mortality rates. Candida and Histoplasma are among the notable causative agents, presenting diverse clinical manifestations and complexities in diagnosis and management. This study was undertaken to examine the clinical profiles, diagnostic challenges, treatment modalities, and outcomes of four compelling cases involving Candida and Histoplasma endocarditis. This was a descriptive case series study conducted from July 2021 to July 2023. All patients with definite/possible endocarditis diagnosed based on modified Duke's criteria were reviewed in this study. Data on demographics, risk factors, clinical signs and symptoms, echocardiography findings, microbiological aetiology, complications, treatment, and outcomes were collected. Among 212 suspected IE cases reviewed, 54 met the modified Duke's criteria for possible or definite IE, with four instances identified as fungal endocarditis. Candida species accounted for three cases, while an uncommon instance of Histoplasma Endocarditis (HE) was also observed. Clinical presentations varied, with fever and dyspnoea being prominent symptoms. Risk factors included chronic kidney disease, prior surgeries, prosthetic valves, and immunocompromised states. Diagnosis posed challenges due to the resemblance to bacterial IE, low blood culture yields, and delayed suspicion. Various diagnostic approaches, including blood cultures, serological markers, and imaging, were employed. Therapeutic strategies involved antifungal agents and surgical intervention, where feasible. However, despite prompt treatment initiation, many patients faced rapid clinical deterioration, emphasising the severity and aggressive nature of fungal endocarditis. Mortality rates remained notably high across the cohort. This study highlights the criticality of early suspicion, prompt diagnosis, and a multidisciplinary approach to managing fungal endocarditis. While recognising the limitations in current diagnostic tools and therapeutic options, the study underscores the urgent need for enhanced diagnostic modalities and novel treatment strategies to improve outcomes in these challenging cases.

Combined Bacterial Meningitis and Infective Endocarditis: When Should We Search for the Other When Either One is Diagnosed?

IntroductionWe aimed to describe patients with coexisting infective endocarditis (IE) and bacterial meningitis (BM).MethodsWe merged two large prospective cohorts, an IE cohort and a BM cohort, with only cases of definite IE and community-acquired meningitis. We compared patients who had IE and BM concurrently to patients with IE only and BM only.ResultsAmong the 1030 included patients, we identified 42 patients with IE–BM (4.1%). Baseline characteristics of patients with IE–BM were mostly similar to those of patients with IE, but meningitis was the predominant presentation at admission (39/42, 92.3%). Causative pathogens were predominantly Streptococcus pneumoniae (18/42, 42.9%) and Staphylococcus aureus (14/42, 33.3%). All pneumococcal IE were associated with BM (18/18). BM due to oral and group D streptococci, Streptococcus agalactiae, and S. aureus were frequently associated with IE (14/30, 46.7%). Three-month mortality was 28.6% in patients with IE–BM, 20.5% in patients with IE, and 16.6% in patients with BM.ConclusionsPatients with pneumococcal IE or altered mental status during IE must be investigated for BM. Patients with S. aureus, oral and group D streptococcal or enterococcal BM, or unfavorable outcome in pneumococcal meningitis would benefit from an echocardiography. Patients with the dual infection have the worst prognosis. Their identification is mandatory to initiate appropriate treatment.

Streptococcus constellatus Left Ventricular Apical Mural Infective Endocarditis With Acute Stroke, Septic and Cardiogenic Shock

Infective endocarditis (IE) is a severe infection of the endocardium and cardiac valves by multiple etiologic agents. Clinical presentation can be acute or subacute based on the host immunity and the causative agent’s virulence. Although Streptococci are responsible for most community-acquired native valve bacterial IE, Streptococcus constellatus is an infrequent cause. S. constellatus can rarely infect prosthetic cardiac valves. A middle-aged white male with poorly controlled type 2 diabetes mellitus was transferred to our facility for suspected stroke with an initial presentation of acute encephalopathy of uncertain duration. Transthoracic echocardiogram revealed a left ventricular apical mural vegetation, and brain imaging displayed multiple white matter hypodensities indicative of numerous small strokes. Blood cultures were positive for S. constellatus. Clinical presentation was unusual with an acute encephalopathy due to multiple septic emboli and primary mural IE with high-grade bacteremia due to S. constellatus. PubMed medical literature review reveals this to be a rare clinical presentation by an uncommon etiological agent with an infrequent echocardiogram finding.

Infective endocarditis due to Erysipelothrix rhusiopathiae in a dog \u2013 a case report

BackgroundInfective endocarditis is a rare but severe condition associated with a high mortality rate in small animal patients. This condition is caused by a microbial (most often bacterial) infection of the valvular portion of the endocardium, from which proliferative and/or erosive lesions on the cardiac valves or immediately adjacent structures develop. The two most commonly affected cardiac valves are the aortic and mitral valves.Case presentationWe report the clinical case of a 4-year old male neutered Bull terrier, 27.6 kg, body condition score 4/9, that presented with a 3-months history of pyrexia and general weakness. The patient history also revealed a transient left hind limb lameness (grade 2/4), which coincided with the onset of clinical signs about 3 months before presentation. On physical examination, a left-sided systolic heart murmur (grade 3/6) with the same intensity at the left heart base and apex, and an irregularly irregular heart rhythm were noted. Electrocardiography showed ventricular premature complexes, and echocardiography revealed lesions consistent with endocarditis involving the aortic and mitral valve. Bacterial culture of blood yielded a positive result, and the organism isolated was identified as Erysipelothrix rhusiopathiae. The extended patient history revealed that the dog lived close to a farm housing pigs and other livestock.ConclusionWe report a rare case of the premortal diagnosis of infective bacterial endocarditis in a dog due to E. rhusiopathiae infection. Most reports about this condition are from necropsy series. This clinical case report emphasizes that E. rhusiopathiae infection and bacteremia should be considered as a differential diagnosis in dogs with suspected infective endocarditis, especially in dogs living in rural areas with access to livestock and particularly farm pigs. Also, particular emphasis should be placed on the zoonotic potential of this infectious disease.

A Tale of Two Valves: Bioprosthetic Aortic Valve Obstruction in Systemic Lupus Erythematosus and Antiphospholipid Antibody Syndrome

Patients with systemic lupus erythematosus (SLE) and antiphospholipid antibody syndrome (APLAS) are at risk for cardiac manifestations, specifically valvular heart disease requiring valve replacement. Bioprosthetic valve endocarditis is an important cause of valve failure, and it is important to keep a wide differential, especially in patients with preexisting SLE and APLAS. In this E-challenge, 2 cases of bioprosthetic aortic valve endocarditis are presented; 1 case describes infective bacterial endocarditis on an aortic prosthesis and the second describes a patient with SLE and APLAS who developed bioprosthetic valve obstruction secondary to vegetations, consistent with nonbacterial endocarditis and thrombus. Etiologies for bioprosthetic valve obstruction and evaluation by echocardiography are explored. The comparison between these 2 cases specifically highlights the importance of keeping a wide differential in endocarditis, prosthetic valve vegetations, and bioprosthetic valve obstruction.

Immunosuppressive therapy to reduce mitral regurgitation in Libman-Sacks endocarditis: a case report.

BackgroundLibman–Sacks endocarditis is a cardiac manifestation of systemic lupus erythematosus (SLE) and is characterized by non-bacterial verrucous vegetations, causing valvular stenosis and/or regurgitation. The effectiveness of immunosuppressive therapy for valve dysfunction due to Libman–Sacks endocarditis has not been reported.Case summaryA 67-year-old woman with a history of chronic atrial fibrillation was emergently admitted with acute decompensated heart failure. Transoesophageal echocardiogram revealed severe mitral regurgitation (MR) due to oedematous thickening and poor coaptation of the medial edge of A2/P2 segments and the lateral edge of A3/P3 segments. Serial blood culture results were negative, suggesting bacterial infective endocarditis to be a less likely cause of valvular damage. Because the patient developed photosensitivity, livedo reticularis, and pancytopenia, Libman–Sacks endocarditis with rapidly progressive SLE was diagnosed on the basis of positive test results of anti-double-stranded DNA-IgG and its complement titer. Two months after, immunosuppressive therapy including corticosteroids, a transoesophageal echocardiogram revealed thinning of the degenerative mitral valve leaflets and a reduction of MR from severe to mild.DiscussionCorticosteroid therapy for Libman–Sacks endocarditis reportedly increases the extent of fibrosis and scarring of the valve leaflets, resulting in worse valve function. In our patient, MR decreased from severe to mild after corticosteroid therapy. Because low-echoic thickening of the mitral valve leaflets suggested acute oedematous changes without scarring and fibrosis and other clinical symptoms of SLE rapidly progressed, early initiation of immunosuppressive therapy for Libman–Sacks endocarditis lead to a benign clinical course in our patient.

A rare case of bacterial infective endocarditis caused by Streptococcus alactolyticus

Background: Streptococcus alactolyticus is a rarely isolated bacterium, which classified under DNA cluster IV of the S. Bovis/S. equinus complex. Infections, especially infective endocarditis, caused by Strep. alactolyticus are very rare in humans. Case Report: We describe a case of Strepotoccocus alactolyticus bacteriemia complicated by infective endocarditis. A 64-year-old male with a previous history of coronary artery bypass grafting applied to our cardiology outpatient clinic with complaints of dyspnea, fever, confusion and an apical holosystolic murmur. He was admitted to the intensive care unit. Transthoracic and transesophageal echocardiography showed the presence vegetation on the aortic valve. S. alactolyticus was detected on serial blood cultures. The patient was first treated with intensive antimicrobial therapy, and then underwent mitral and aortic valve replacements with uneventful follow-up. Conclusion: Streptococcus alactolyticus infective endocarditis has only been reported previously in one patient. More information is certainly needed for diagnosis and treatment of patients infected with Streptococcus alactolyticus. Key words: Streptococcus alactolyticus, endocarditis

Infective endocarditis without biological inflammatory syndrome: Description of a particular entity

Bacterial infective endocarditis (IE) is rarely suspected in patients with a low C-reactive protein (CRP) concentration. To address the incidence, characteristics and outcome of left-sided valvular IE with low CRP concentration. This was a retrospective analysis of cases of IE discharged from our institution between January 2009 and May 2017. The 10% lowest CRP concentration (<20mg/L) was used to define low CRP concentration. Right-sided cardiac device-related IE, non-bacterial IE, sequelar IE and IE previously treated by antibiotics were excluded. Of the 469 patients, 13 (2.8%; median age 68 [61-76] years) had definite (n=8) or possible (n=5) left-sided valvular IE with CRP<20mg/L (median 9.3 [4.7-14.2] mg/L). The median white blood cell count was 6.3 (5.3-7.5) G/L.The main presentations were heart failure (n=7; 54%) and stroke (n=3; 23%). Transthoracic echocardiography (TTE) showed vegetations (n=5) or isolated valvular regurgitation (n=4). Overall, eight patients (62%) had severe valvular lesions on transoesophageal echocardiography (TOE), and nine patients (69%) underwent cardiac surgery. All patients survived at 1-year follow-up. Bacterial pathogens were documented in eight patients (streptococci, coagulase-negative Staphylococcus, Corynebacteriumjeikeium, HACEK group, Coxiella burnetii, Bartonella henselae) using blood cultures, serology or valve culture and/or polymerase chain reaction analysis. Left-sided valvular IE with limited or no biological syndrome is rare, but is often associated with severe valvular and paravalvular lesions. TOE should be performed in presence of unexplained heart failure, new valvular regurgitation or cardioembolic stroke when TTE is insufficient to rule out endocarditis, even in patients with a low CRP concentration.

Prolonged fever and involuntary weight loss as manifestations of bacterial endocarditis: A case report

We reported an unusual presentation of prolonged fever and involuntary weight loss in older adult as a manifestation of infective bacterial endocarditis. The patient had pre-existing compensated asymptomatic valvular heart disease without treatment. A positive fecal occult blood test is prompting an investigation of malignancy of gastrointestinal as one of other possible cause of prolonged fever with wasting, evaluation of HIV serostatus shows seronegative. The case fulfilled criteria for definitive infective endocarditis: one major criterion of positive blood culture for Streptococcus mitis, which was one of viridans group streptococci and three minor criteria of fever at least 38°Celsius, immunologic phenomena in the form of glomerulonephritis, and a predisposing heart condition. One course of third-generation cephalosporin successfully cleared the Streptococcus mitis infection proven by culture. Infective endocarditis should be considered as one of the causes of prolonged fever with wasting, especially in cases with the previous history of heart disease.

Molecular Diagnosis of Bacterial Definite Infective Endocarditis by Real-Time Polymerase Chain Reaction.

Infective endocarditis (IE) can be diagnosed using the Duke criteria, which cannot be conclusive especially when the results of blood cultures are negative. This study aimed at using real-time polymerase chain reaction (PCR) technique to isolate bacteria present in whole blood samples of patients with definitive IE on the basis of the method designed in this study. This laboratory and test study was conducted on 20 whole blood samples taken from patients with definitive IE. Real-time PCR of the 16s rRNA was utilized to directly analyze whole blood samples to diagnose bacterial IE. Of 20 whole blood samples with definitive IE, only one blood culture (5%) was positive and the isolated bacterium belonged to Streptococci viridans group. Also, 13 whole blood samples were positive using real-time PCR technique. The isolated bacteria were Enterococcus faecalis with seven (35%) cases, Streptococcus gallolyticus with two (10%) cases, Streptococcus mutans with one (5%) case, Streptococcus sanguinis with one (5%) case, Streptococcus salivarius with one (5%) case, and Staphylococcus aureus with one (5%) case. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) using real-time PCR technique were 65%, 100%, 100%, and 74%, respectively. The developed real-time PCR method allows us to detect bacteria in whole blood samples and is much more sensitive than culturing method. It also permits the differentiation of the main group of bacteria within a few hours for IE.

Isolated Infective Endocarditis of the Left Ventricular Outflow Tract and Multiple Septic Embolisms

Infective endocarditis with isolated involvement of the left ventricular outflow tract (LVOT) and papillary muscles (PM) is very uncommon, but it can cause serious adverse events such as PM rupture or multiple embolisms [1Left ventricle outflow tract vegetation, embolism and troponin rise: an infective endocarditis case report.Intern Emerg Med. 2012; 7: S145-S147PubMed Google Scholar]. A 50-year-old woman with a history of hypertension was admitted to the emergency room because of an acute confusional syndrome with fever. Physical examination showed multiple papular erythematous spots on the trunk and lower extremities (Fig 1A) suggesting septic microembolisms. Cerebrospinal fluid analysis revealed marked leukocytosis and neutrophilia. Magnetic resonance imaging of the brain showed multiple corticosubcortical embolic lesions in both cerebral hemispheres (Fig 1B, black arrows). The echocardiogram revealed a mobile mass (0.8 ce) anchored between the LVOT wall and the anterolateral PM (Fig 2A, red arrow). Blood cultures were positive for methicillin-sensitive Staphylococcus aureus.Fig 2View Large Image Figure ViewerDownload Hi-res image Download (PPT) Surgical removal of the intracardiac mass from the LVOT and the anterolateral PM was performed (Fig 2B, red arrow). In the image, the aortic leaflets are folded over the aortic wall with a prosthetic heart valve sizer. The aortic and mitral valves were not affected. The postoperative period was uneventful, and the patient presented no neurologic deficits at discharge. Infective endocarditis was confirmed by histopathologic examination (Fig 2C, red arrow). Bacterial infective endocarditis restricted to the LVOT and the PM is exceptional. Multiple embolisms caused by large vegetations on the LVOT are difficult to control; therefore, surgical treatment should not be delayed.

Influence of Staphylococcus aureus on Outcomes after Valvular Surgery for Infective Endocarditis

BackgroundAs Staphylococcus aureus (SA) remains one of the leading cause of infective endocarditis (IE), this study evaluates whether S. aureus is associated with more severe infections or worsened outcomes compared to non-S. aureus (NSA) organisms.MethodsAll patients undergoing valve surgery for bacterial IE between 1995 and 2013 at our institution were included in this study (n = 323). Clinical data were retrospectively collected from the chart review. Patients were stratified according to the causative organism; SA (n = 85) and NSA (n = 238). Propensity score matched pairs (n = 64) of SA versus NSA were used in the analysis.ResultsSA patients presented with more severe IE compared to NSA patients, with higher rates of preoperative vascular complications, preoperative septic shock, preoperative embolic events, preoperative stroke, and annular abscess. Among the matched pairs, there were no significant differences in 30-day (9.4% SA vs. 7.8% NSA, OR = 1.20, p = 0.76) or 1-year mortality (20.3% SA vs. 14.1% NSA, OR = 1.57, p = 0.35) groups, though late survival was significantly worse in SA patients. There was also no significant difference in postoperative morbidity between the two matched groups.ConclusionsSA IE is associated with a more severe clinical presentation than IE caused by other organisms. Despite the clearly increased preoperative risk, valvular surgery may benefit SA IE patients by moderating the post-operative mortality and morbidity.

Distinct Biological Potential of Streptococcus gordonii and Streptococcus sanguinis Revealed by Comparative Genome Analysis

Streptococcus gordonii and Streptococcus sanguinis are pioneer colonizers of dental plaque and important agents of bacterial infective endocarditis (IE). To gain a greater understanding of these two closely related species, we performed comparative analyses on 14 new S. gordonii and 5 S. sanguinis strains using various bioinformatics approaches. We revealed S. gordonii and S. sanguinis harbor open pan-genomes and share generally high sequence homology and number of core genes including virulence genes. However, we observed subtle differences in genomic islands and prophages between the species. Comparative pathogenomics analysis identified S. sanguinis strains have genes encoding IgA proteases, mitogenic factor deoxyribonucleases, nickel/cobalt uptake and cobalamin biosynthesis. On the contrary, genomic islands of S. gordonii strains contain additional copies of comCDE quorum-sensing system components involved in genetic competence. Two distinct polysaccharide locus architectures were identified, one of which was exclusively present in S. gordonii strains. The first evidence of genes encoding the CylA and CylB system by the α-haemolytic S. gordonii is presented. This study provides new insights into the genetic distinctions between S. gordonii and S. sanguinis, which yields understanding of tooth surfaces colonization and contributions to dental plaque formation, as well as their potential roles in the pathogenesis of IE.

Sonobactericide: An ultrasound-mediated adjunct treatment for bacterial infective endocarditis—In vitro proof-of-principle

Infective endocarditis (IE) is a bacterial infection of the surfaces within the heart, associated with high morbidity and mortality rates. The predominant bacteria causing IE are Staphylococci, which can bind to existing thrombi on heart valves and generate vegetations (biofilms). In this in vitro study, we test a novel strategy called sonobactericide to treat IE using ultrasound and ultrasound contrast agents, in combination with an antibiotic and a thrombolytic. We simulated IE vegetations using human whole-blood clots infected with Staphylococcus aureus. Histology and live-cell imaging revealed a biofilm layer of fibrin-embedded living Staphylococci. Infected clots were treated under flow for 30 min and degradation was assessed by time-lapse microscopy imaging. Clots were exposed to human plasma flow either alone or with different combinations of therapeutics: oxacillin (172 μg/mL), recombinant tissue plasminogen activator (rt-PA; 3.15 μg/mL), intermittent (50 s on, 30 s off) continuous-wave ultrasound (120 kHz, 0.44 MPa peak-to-peak pressure), and Definity (2 μl/ml). Infected clots exposed to the combination of oxacillin, rt-PA, ultrasound, and Definity achieved 99.3 ± 1.7% clot width loss, which was greater than the other treatment arms. These results demonstrate that sonobactericide may have potential as an adjunct therapy for IE.

利奈唑胺补救治疗成人革兰阳性菌感染性心内膜炎的临床分析

目的：通过临床病例回顾性研究，评价利奈唑胺补救治疗成人革兰阳性菌(G+)感染性心内膜炎(IE)的临床疗效及安全性。方法：收集南京医科大学附属南京医院感染科在2008年1月~2012年12月期间收治的确诊G+菌感染所致IE患者36例，其中利奈唑胺治疗组15例(以下简称为L组)，其他抗感染药物治疗组21例(以下简称对照组)；分析两组患者一般情况，比较两组患者治疗效果以及预后，数据处理通过SPSS软件。结果：两组患者均取得较好的疗效，L组与对照组的病死率分别为6.7%(1例)和9.5%(2例)，预后亦无显著性差异(P > 0.05)；L组仅1例患者出现血小板下降的不良反应，停药后即好转，其他患者均耐受良好。结论：利奈唑胺用于G+菌IE的治疗可获得良好疗效，而且耐受性好。对多重耐药G+菌引起的IE，尤其对传统疗法有禁忌或治疗失败，是一个极具优势的治疗选择。 Objective: Retrospective study was carried out to evaluate the efficacy and safety of Linezolid as rescue treatment for adult gram-positive bacterial infective endocarditis. Methods: The study comprised 36 patients from department of infectious disease in Nanjing hospital affiliated to Nanjing Medical University, between 2008 and 2012. Fifteen patients enrolled in L group received Linezolid as rescue treatment for infective endocarditis which were unsuccessfully treated. Other twenty-one patients received conventional antibiotic therapy (Control group). We described baseline characteristics of the study population and compared L group with control group for the efficacy and the safety of treatment. The data were analyzed by SPSS software. Results: The thirty-three patients in two groups received effective treatment. No significant differences in the cure rate (80% vs. 81%) and in mortality (6.7% vs. 9.5%) were observed. Thrombocytopenia was present in only one patient of L group, and others were well tolerated. When we ended the Linezolid for treatment, the patients get well from thrombocytopenia. Conclusions: Linezolid was well tolerated and associated with the effective outcome as in patients with IE due to multiple resistant gram-positive, especially in patients who are fail to treated with conventional therapy or are poorly tolerated.

Structures of the Streptococcus sanguinis SrpA Binding Region with Human Sialoglycans Suggest Features of the Physiological Ligand.

Streptococcus sanguinis is a leading cause of bacterial infective endocarditis, a life-threatening infection of heart valves. S. sanguinis binds to human platelets with high avidity, and this adherence is likely to enhance virulence. Previous studies suggest that a serine-rich repeat adhesin termed SrpA mediates the binding of S. sanguinis to human platelets via its interaction with sialoglycans on the receptor GPIbα. However, in vitro binding assays with SrpA and defined sialoglycans failed to identify specific high-affinity ligands. To improve our understanding of the interaction between SrpA and human platelets, we determined cocrystal structures of the SrpA sialoglycan binding region (SrpABR) with five low-affinity ligands: three sialylated trisaccharides (sialyl-T antigen, 3'-sialyllactose, and 3'-sialyl-N-acetyllactosamine), a sialylated tetrasaccharide (sialyl-LewisX), and a sialyl galactose disaccharide component common to these sialoglyans. We then combined structural analysis with mutagenesis to further determine whether our observed interactions between SrpABR and glycans are important for binding to platelets and to better map the binding site for the physiological receptor. We found that the sialoglycan binding site of SrpABR is significantly larger than the sialoglycans cocrystallized in this study, which suggests that binding of SrpA to platelets either is multivalent or occurs via a larger, disialylated glycan.

StreptoBase: An Oral Streptococcus mitis Group Genomic Resource and Analysis Platform.

The oral streptococci are spherical Gram-positive bacteria categorized under the phylum Firmicutes which are among the most common causative agents of bacterial infective endocarditis (IE) and are also important agents in septicaemia in neutropenic patients. The Streptococcus mitis group is comprised of 13 species including some of the most common human oral colonizers such as S. mitis, S. oralis, S. sanguinis and S. gordonii as well as species such as S. tigurinus, S. oligofermentans and S. australis that have only recently been classified and are poorly understood at present. We present StreptoBase, which provides a specialized free resource focusing on the genomic analyses of oral species from the mitis group. It currently hosts 104 S. mitis group genomes including 27 novel mitis group strains that we sequenced using the high throughput Illumina HiSeq technology platform, and provides a comprehensive set of genome sequences for analyses, particularly comparative analyses and visualization of both cross-species and cross-strain characteristics of S. mitis group bacteria. StreptoBase incorporates sophisticated in-house designed bioinformatics web tools such as Pairwise Genome Comparison (PGC) tool and Pathogenomic Profiling Tool (PathoProT), which facilitate comparative pathogenomics analysis of Streptococcus strains. Examples are provided to demonstrate how StreptoBase can be employed to compare genome structure of different S. mitis group bacteria and putative virulence genes profile across multiple streptococcal strains. In conclusion, StreptoBase offers access to a range of streptococci genomic resources as well as analysis tools and will be an invaluable platform to accelerate research in streptococci. Database URL: http://streptococcus.um.edu.my.

Development and evaluation of a novel fast broad-range 16S ribosomal DNA PCR and sequencing assay for diagnosis of bacterial infective endocarditis: multi-year experience in a large Canadian healthcare zone and a literature review.

BackgroundThe study aimed to explore the sensitivity and specificity of a novel fast 16S rDNA PCR and sequencing assay for the improved diagnosis of infective endocarditis (IE) in patients with suspected native or prosthetic heart valve (HV) infection over a multi-year period at our cardiovascular center.MethodsSixty-eight patients were prospectively enrolled who underwent HV replacement for suspected or confirmed IE between February 1, 2009 and September 1, 2014. Patient demographics, medical co-morbidities, Duke’s criteria, culture results, and antibiotic therapy were collected by detailed chart reviews. Dual-priming oligonucleotide primers targeted to 500 bps of the V1-V3 region of the 16S rRNA gene were used to perform fast broad-range 16S rDNA PCR and Sanger sequencing on ribosomal DNA extracted from HV tissues. The performance/diagnostic efficiency of the molecular test was evaluated against blood cultures and Gram stain and culture of HV tissue in patients’ with definite IE according to Duke’s criteria.ResultsFifty patients (73.5 %) had definite IE and another 8 (11.8 %) had possible IE according to Duke’s criteria. Cardiac surgery was delayed an average of 15.4 days from the time of the patient’s last positive blood culture, and appropriate antibiotic therapy was given in the pre-operative period. While 44/50 (88 %) patients had a positive blood culture, HV tissue culture was only positive in 23 (46 %) of them. Molecular testing of all HV tissues had sensitivity, specificity, NPV and PPV of 92, 77.8, 77.8 and 92 % compared to 44, 100, 39.1 and 100 % respectively for culture for diagnosis of definite IE. For prosthetic HV tissue, 16S rDNA PCR had sensitivity of 93 % and specificity of 83 % compared to 35 and 100 % respectively for culture. A literature review showed that the diagnostic accuracy of our novel fast broad-range 16S rDNA PCR assay was similar or better than that of previously published studies.ConclusionsThis novel fast broad-range 16S rDNA PCR/sequencing test had superior sensitivity compared to tissue Gram stain and culture for identifying underlying bacterial pathogen in both native and prosthetic valve endocarditis.