Streptococcal infective endocarditis: clinical features and outcomes according to species.

PURPOSE: Infective endocarditis (IE) is frequently caused by streptococcal species, yet clinical features and mortality are poorly investigated. Our aim was to examine patients with streptococcal IE to describe clinical features and outcomes according to streptococcal species. METHODS: From 2002 to 2012, we investigated patients with IE admitted to two tertiary Danish heart centres. Adult patients with left-sided streptococcal IE were included. Adjusted multivariable logistic regression analyses were performed, to assess the association between streptococcal species and heart valve surgery or 1-year mortality. RESULTS: Among 915 patients with IE, 284 (31%) patients with streptococcal IE were included [mean age 63.5 years (SD 14.1), 69% men]. The most frequent species were S. mitis/oralis (21%) and S. gallolyticus (17%). Fever (86%) and heart murmur (81%) were common symptoms, while dyspnoea was observed in 46%. Further, 18% of all cases were complicated by a cardiac abscess/pseudoaneurysm and 25% by an embolic event. Heart valve surgery during admission was performed in 55% of all patients, and S. gallolyticus (OR 0.28 [95% CI 0.11-0.69]) was associated with less surgery compared with S. mitis/oralis. In-hospital mortality was 7% and 1-year mortality 15%, without any difference between species. CONCLUSION: S. mitis/oralis and S. gallolyticus were the most frequent streptococcal species causing IE. Further, S. gallolyticus IE was associated with less heart valve surgery during admission compared with S. mitis/oralis IE. Being aware of specific symptoms, clinical findings, and complications related to different streptococcal species, may help the clinicians in expecting different outcomes.

Induction of Apoptotic Cell Death by Oral Streptococci in Human Periodontal Ligament Cells.

Initiation and progression of oral infectious diseases are associated with streptococcal species. Bacterial infection induces inflammatory responses together with reactive oxygen species (ROS), often causing cell death and tissue damage in the host. In the present study, we investigated the effects of oral streptococci on cytotoxicity and ROS production in human periodontal ligament (PDL) cells. Streptococcus gordonii showed cell cytotoxicity in a dose- and time-dependent manner. The cytotoxicity might be due to apoptosis since S. gordonii increased annexin V-positive cells, and the cytotoxicity was reduced by an apoptosis inhibitor, Z-VAD-FMK. Other oral streptococci such as Streptococcus mitis, Streptococcus sanguinis, and Streptococcus sobrinus also induced apoptosis, whereas Streptococcus mutans did not. All streptococci tested except S. mutans triggered ROS production in human PDL cells. Interestingly, however, streptococci-induced apoptosis appears to be ROS-independent, as the cell death induced by S. gordonii was not recovered by the ROS inhibitor, resveratrol or n-acetylcysteine. Instead, hydrogen peroxide (H2O2) appears to be important for the cytotoxic effects of streptococci since most oral streptococci except S. mutans generated H2O2, and the cytotoxicity was dramatically reduced by catalase. Furthermore, streptococcal lipoproteins are involved in cytotoxicity, as we observed that cytotoxicity induced by the lipoprotein-deficient S. gordonii mutant was less potent than that by the wild-type and was attenuated by anti-TLR2-neutralizing antibody. Indeed, lipoproteins purified from S. gordonii alone were sufficient to induce cytotoxicity. Notably, S. gordonii lipoproteins did not induce H2O2 or ROS but cooperatively induced cell death when co-treated with H2O2. Taken together, these results suggest that most oral streptococci except S. mutans efficiently induce damage to human PDL cells by inducing apoptotic cell death with bacterial H2O2 and lipoproteins, which might contribute to the progression of oral infectious diseases such as apical periodontitis.

Proposal for the use of echocardiography in bloodstream infections due to different streptococcal species.

BACKGROUND: Infective endocarditis (IE) is diagnosed in 7-8% of streptococcal bloodstream infections (BSIs), yet it is unclear when to perform transthoracic (TTE) and transoesophageal echocardiography (TOE) according to different streptococcal species. The aim of this sub-study was to propose a flowchart for the use of echocardiography in streptococcal BSIs. METHODS: In a population-based setup, we investigated all patients admitted with streptococcal BSIs and crosslinked data with nationwide registries to identify comorbidities and concomitant hospitalization with IE. Streptococcal species were divided in four groups based on the crude risk of being diagnosed with IE (low-risk < 3%, moderate-risk 3-10%, high-risk 10-30% and very high-risk > 30%). Based on number of positive blood culture (BC) bottles and IE risk factors (prosthetic valve, previous IE, native valve disease, and cardiac device), we further stratified cases according to probability of concomitant IE diagnosis to create a flowchart suggesting TTE plus TOE (IE > 10%), TTE (IE 3-10%), or "wait & see" (IE < 3%). RESULTS: We included 6393 cases with streptococcal BSIs (mean age 68.1 years [SD 16.2], 52.8% men). BSIs with low-risk streptococci (S. pneumoniae, S. pyogenes, S. intermedius) are not initially recommended echocardiography, unless they have ≥3 positive BC bottles and an IE risk factor. Moderate-risk streptococci (S. agalactiae, S. anginosus, S. constellatus, S. dysgalactiae, S. salivarius, S. thermophilus) are guided to "wait & see" strategy if they neither have a risk factor nor ≥3 positive BC bottles, while a TTE is recommended if they have either ≥3 positive BC bottles or a risk factor. Further, a TTE and TOE are recommended if they present with both. High-risk streptococci (S. mitis/oralis, S. parasanguinis, G. adiacens) are directed to a TTE if they neither have a risk factor nor ≥3 positive BC bottles, but to TTE and TOE if they have either ≥3 positive BC bottles or a risk factor. Very high-risk streptococci (S. gordonii, S. gallolyticus, S. mutans, S. sanguinis) are guided directly to TTE and TOE due to a high baseline IE prevalence. CONCLUSION: In addition to the clinical picture, this flowchart based on streptococcal species, number of positive blood culture bottles, and risk factors, can help guide the use of echocardiography in streptococcal bloodstream infections. Since echocardiography results are not available the findings should be confirmed prospectively with the use of systematic echocardiography.

Acute Adult Supraglottitis: An Impending Threat to Patency of Airway and Life.

Introduction Acute adult supraglottitis (AAS) is one of the upper airway infections that can potentially cause upper airway obstruction and, if not treated promptly, can be life-threatening. The widespread use of vaccines against Hemophilus influenzae has decreased the incidence of epiglottitis in children, whereas the incidence of AAS is on the rise. We aim to highlight the presentation, diagnosis, and management in AAS with our study.  Patients and Methods A retrospective analysis was performed on all patients admitted to a tertiary health care facility surgical intensive care unit (SICU) where AAS was identified and the demographic data, duration of symptoms, imaging studies, management, and complications were recorded. In these patients, the diagnosis of AAS was confirmed by nasopharyngeal endoscopy. Data was entered in the IBM Statistical Package for Social Sciences (SPSS), version 23 (IBM SPSS Statistics, Armonk, NY), and groups were compared using student t-test and chi-square test. P values of ≤ 0.05 were considered statistically significant. Results A total of 118 patients were admitted to the SICU. The male: female ratio was 3.9: 1. Major risk factors were smoking and drinking cold liquids. The common presenting symptom was sore throat (89.8%). The thumb sign was positive in 65% of the patients. Common bacteria were the Streptococcus species (11.9%). Ceftriaxone was the most commonly prescribed inpatient antibiotic. All patients received steroids as adjuvant therapy. Adrenaline nebulization was used in 66% of the cases. Forty-six percent of patients required endotracheal intubation. In 10.2% of patients, intubation was not possible and in 12.7% of patients, a tracheostomy was done. Ludwig's angina was the most frequent complication. Patients presenting with dysphagia and fever had a significantly higher incidence of Ludwig's angina (P ≤ 0.02 and 0.005, respectively). AAS patients complicating into Ludwig's angina (severe cellulitis of submandibular, submental, and sublingual spaces) had a significantly longer duration of symptoms, a higher incidence of streptococcal infection, airway interventions, and prolonged stay in an intensive care unit (p ≤ 0.05). Conclusion Male gender, smoking, and drinking cold liquids were the risk factors associated with AAS, and thumb sign on lateral neck soft tissue x-ray was suggestive of it. AAS caused by Streptococcus species was a relatively serious condition, leading to complications like Ludwig's angina.