The Role of Streptococcal Cell-Envelope Proteases in Bacterial Evasion of the Innate Immune System

Bacteria possess the ability to evolve varied and ingenious strategies to outwit the host immune system, instigating an evolutionary arms race. Proteases are amongst the many weapons employed by bacteria, which specifically cleave and neutralize key signalling molecules required for a coordinated immune response. In this article, we focus on a family of S8 subtilisin-like serine proteases expressed as cell-envelope proteases (CEPs) by group A and group B streptococci. Two of these proteases known as Streptococcus pyogenes CEP (SpyCEP) and C5a peptidase cleave the chemokine CXCL8 and the complement fragment C5a, respectively. Both CXCL8 and C5a are potent neutrophil-recruiting chemokines, and by neutralizing their activity, streptococci evade a key defence mechanism of innate immunity. We review the mechanisms by which CXCL8 and C5a recruit neutrophils and the characterization of SpyCEP and C5a peptidase, including both in vitro and in vivo studies. Recently described structural insights into the function of this CEP family are also discussed. We conclude by examining the progress of prototypic vaccines incorporating SpyCEP and C5a peptidase in their preparation. Since streptococci-producing SpyCEP and C5a peptidase are responsible for a considerable global disease burden, targeting these proteases by vaccination strategies or by small-molecule antagonists should provide protection from and promote the resolution of streptococcal infections.     

Accidental ingestion of magnetic foreign body in a pediatric patient: A potentially fatal attraction

Foreign body ingestion is one of the most common pediatric emergencies. As part of their cognitive development, infants and toddlers are extremely curious and constantly explore their surroundings through their senses, namely taste. The ubiquity of toys containing magnetic elements consecutively meant an increase in the cases of children ingesting said magnets. While most ingested foreign bodies, including a single magnet, will spontaneously traverse the gastrointestinal tract without problems, some may give rise to grave and potentially life-threatening complications; the latter is often seen in the presence of 2 or more magnets or paramagnetic material. The diagnosis of ingestion of magnetic foreign bodies remains a challenge, given its often ambiguous history and presentation; nonetheless, their abundance, gravity, and preventability of their complications alone should render physicians vigilant and keep a low threshold of suspicion.     

Testing for anosmia and ageusia in patients presenting to the emergency department with suspected coronavirus disease 2019 in Saudi Arabia

ObjectiveThis study investigated the role of objective olfactory dysfunction (OD) and gustatory dysfunction (GD) testing among patients with suspected coronavirus disease 2019 (COVID-19) who presented with respiratory symptoms.MethodsA prospective, blinded, observational study was conducted in the emergency units of two tertiary hospitals. Participants were asked to identify scents in the pocket smell test (PST) and flavors in four different solutions in the gustatory dysfunction test (GDT). We assessed the level of agreement between objective findings and self-reported symptoms. We evaluated the diagnostic accuracy of chemosensory dysfunction for diagnosing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.ResultsOf 250 participants, 74 (29.6%) were SARS-CoV-2-positive. There was slight agreement between self-reported symptoms and objective findings (kappa = 0.13 and 0.10 for OD and GD, respectively). OD assessed by the PST was independently associated with COVID-19 (adjusted odds ratio = 1.89, 95% confidence interval, 1.04–3.46). This association was stronger when OD was combined with objective GD, cough, and fever (adjusted odds ratio = 7.33, 95% confidence interval, 1.17–45.84).ConclusionsNeither the PST nor GDT alone are useful screening tools for COVID-19. However, a diagnostic scale based on objective OD, GD, fever, and cough may help triage patients with suspected COVID-19.     

Successful term pregnancies after laparoscopic excision of poorly differentiated Sertoli-Leydig cell tumor of the ovary

Ovarian Sertoli-Leydig cell tumors are rare sex cord-stromal tumors, accounting for less than 1% of ovarian tumors. Majority of these tumors are benign and unilateral, only 3-5% are bilateral. These patients present with clinical features of virilization due to excessive secretion of testosterone from the tumor, however 50% may have no endocrine symptoms. We report a case of poorly differentiated Sertoli-Leydig cell tumour in a woman diagnosed during routine investigation of infertility. She had two spontaneous successful pregnancies after tumor excision laparoscopically.     

New methods for the estimation of Takagi–Sugeno model based extended Kalman filter and its applications to optimal control for nonlinear systems

This paper describes new approaches to improve the local and global approximation (matching) and modeling capability of Takagi–Sugeno (T‐S) fuzzy model. The main aim is obtaining high function approximation accuracy and fast convergence. The main problem encountered is that T‐S identification method cannot be applied when the membership functions are overlapped by pairs. This restricts the application of the T‐S method because this type of membership function has been widely used during the last 2 decades in the stability, controller design of fuzzy systems and is popular in industrial control applications. The approach developed here can be considered as a generalized version of T‐S identification method with optimized performance in approximating nonlinear functions. We propose a noniterative method through weighting of parameters approach and an iterative algorithm by applying the extended Kalman filter, based on the same idea of parameters’ weighting. We show that the Kalman filter is an effective tool in the identification of T‐S fuzzy model. A fuzzy controller based linear quadratic regulator is proposed in order to show the effectiveness of the estimation method developed here in control applications. An illustrative example of an inverted pendulum is chosen to evaluate the robustness and remarkable performance of the proposed method locally and globally in comparison with the original T‐S model. Simulation results indicate the potential, simplicity, and generality of the algorithm. An illustrative example is chosen to evaluate the robustness. In this paper, we prove that these algorithms converge very fast, thereby making them very practical to use. Copyright © 2011 John Wiley & Sons, Ltd.     

Simultaneous nephrectomy and coronary artery bypass grafting through extended sternotomy

A 37-year-old man with end-stage idiopathic dilated cardiomyopathy underwent an orthotopic heart transplant followed by a reoperation with mitral annuloplasty for severe mitral regurgitation. Shortly thereafter, he developed severe tricuspid regurgitation and severe recurrent mitral regurgitation due to annuloplasty ring dehiscence. The dehisced annuloplasty ring was refixated, followed by tricuspid annuloplasty through a right anterolateral thoracotomy. After four years of follow-up, there are no signs of recurrent mitral or tricupid regurgitation and the patient remains in NYHA class II. Pushing the envelope on conventional surgical procedures in marginal donor hearts (both before and after transplantation) may not only improve the patient??s functional status and reduce the need for retransplantation, but it may ultimately alleviate the chronic shortage of donor hearts.     

Intérêt du Geriatric Nutritional Risk Index dans la prédiction de mortalité chez les patients hémodialysés : étude préliminaire

IntroductionGeriatric Nutritional Risk Index (GNRI) is a simple and quantitative method (based on three objective measurements: weight, height, albumin) for screening patients at risk for malnutrition. However no data are available regarding its relation with mortality in Caucasian hemodialysis patients. We tested the predictive value of GNRI on mortality in a hemodialysis population followed up prospectively for 18 months.MethodsA total of 46 stable prevalent (mean age: 76 ± 11 years, range: 42–95) hemodialysis patients from one center were included in the study. GNRI with other nutritional parameters were evaluated for all patients.ResultsSixteen patients (35%) died during the 18 months of follow-up. Multiple logistic model showed that GNRI and Charlson co-morbidity score were significant predictors of mortality. Age and gender were not significant.ConclusionOur preliminary study carried out on a series of prevalent hemodialysis patients suggests that GNRI is predictor of mortality. To recommend the use of this index for the screening of hemodialysis patients with malnutrition at risk of mortality, our results should be confirmed by a large cohort study.     

Equine Babesiosis: Seroprevalence,Risk Factors and Comparison of Different Diagnostic Methods in Jordan

The purposes of this study were to estimate the seroprevalence and distribution of horse piroplasmosis, to evaluate risk factors associated with the occurrence of the disease and to compare the different diagnostic methods used for this disease. A total of 253 clinically normal horses were sampled, and a collection form was completed for each horse from five of six different climatic zones of Jordan. The sixth zone was not sampled because it did not include horse population. Competitive enzyme‐linked immunosorbent assay (cELISA) revealed 37 horses (14.6%) positive for Theileria equi, and none of the horses was positive for Babesia caballi. Microscopic examination of thin blood smears and PCR test revealed no positive results for either parasite. Grazing was the only risk factor that was associated with being seropositive to the disease; horses that graze are 11.5 more likely to be seropositive (P < 0.05, OR = 11.5, CI: 3.292, 39.962). This is the first study to estimate the prevalence of horse babesiosis using serological test and to identify risk factors associated with the disease in Jordan. Competitive enzyme‐linked immunosorbent assay (cELISA) test appears to be more reliable than microscopic examination and PCR in estimating the seroprevalence of the disease as well as identifying carrier horses to babesiosis.     

Molecular Study of Free‐ranging Mule Deer and White‐tailed Deer from British Columbia,Canada, for Evidence of Anaplasma spp. and Ehrlichia spp.

Twenty‐three free‐ranging white‐tailed deer (WTD; Odocoileus virginianus) and six mule deer (MD; Odocoileus hemionus) from south‐central British Columbia, Canada, were tested for Anaplasma marginale by msp5 gene‐specific PCR and Ehrlichia spp. by 16S rRNA or citrate synthase (gltA) gene‐specific PCR, as well as by PCR with universal 16S rRNA primers detecting a wide range of bacteria. No deer tested positive for A. marginale. Amplification with universal 16S rRNA primers followed by sequencing of cloned fragments detected an Anaplasma sp. in one of 23 (4.3%) WTD and six of six (100%) MD and Bartonella sp. in four of 23 (17.4%) WTD. The Anaplasma sp. was genetically distinct from A. marginale and all other recognized members of the genus. Four of six (66.7%) MD and 0 of 23 (0%) WTD were Ehrlichia positive by PCR with primers for 16S rRNA and gltA genes. The sequences of gltA PCR fragments were identical to each other and to the respective region of the gltA gene of an Ehrlichia sp. which we detected previously in naturally infected cattle from the same area, suggesting the possibility of biological transmission of this rickettsia between cattle and wild cervids. Antibodies reactive with the MSP5 protein of A. marginale were detected using a competitive enzyme‐linked immunosorbent assay in two of six (33.3%) MD, but not in WTD. The two seropositive MD were PCR positive for both the Anaplasma sp. and Ehrlichia sp. detected in this study, suggesting a reaction of antibodies against one or both of these rickettsias with the MSP5 antigen.