The virulence of bacterial pathogens is a complex process that requires the dynamic expression of many genes for the pathogens to invade and circumvent host defenses, as well as to proliferate in vivo. In this study, we employed a large-scale screen, signature-tagged mutagenesis (STM), to identify Streptococcus pyogenes virulence genes important for pathogenesis within the host. Approximately 1,200 STM mutants were created and screened using the zebrafish infectious disease model. The transposon insertion site was identified for 29 of the 150 mutants that were considered attenuated for virulence. Previously reported streptococcal virulence genes, such as mga, hasA, amrA, smeZ, and two genes in the sil locus, were identified, confirming the utility of the model for revealing genes important for virulence. Multiple genes not previously implicated in virulence were also identified, including genes encoding putative transporters, hypothetical cytosolic proteins, and macrolide efflux pumps. The STM mutant strains display various levels of attenuation, and multiple separate insertions were identified in either the same gene or the same locus, suggesting that these factors are important for this type of acute, invasive infection. We further examined two such genes, silB and silC of a putative quorum-sensing regulon, and determined that they are significant virulence factors in our model of necrotizing fasciitis. sil locus promoter expression was examined under various in vitro conditions, as well as in zebrafish tissues, and was found to be differentially induced. This study was a unique investigation of S. pyogenes factors required for successful invasive infection.Severe Streptococcus pyogenes infections, such as streptococcal toxic shock syndrome and necrotizing fasciitis, result in high mortality rates that range from 25% to 50% (7, 43). The severity and incidence of these invasive S. pyogenes diseases have increased since the 1980s despite what had been considered near eradication of S. pyogenes infections in the previous decades of the 20th century due to the development of antibiotics (13, 43). The reasons for this resurgence remain vague, despite numerous reports indicating the prevalence of particular strains associated with severe S. pyogenes infections (9, 13). Recent studies assessed factors that are present in various serotypes, but they failed to determine specific pathogen and host factors that are common denominators of invasive S. pyogenes disease (34, 55). Moreover, from the host perspective, Kotb et al. eloquently illustrated that certain human leukocyte class II alleles confer a predisposition to severe S. pyogenes disease (29). Undoubtedly, the complexity and versatility of this organism, particularly its remarkable ability to alter its broad spectrum of virulence factors in order to survive in different environments, are the foundation for its success.Although in vitro studies have permitted analysis of virulence determinants, the conditions are selective, as the systems cannot completely mimic ho...

Early diagnosis of invasive pulmonary aspergillosis (IPA) remains difficult due to the variable performance of the tests used. We compared the performance characteristics of Aspergillus lateral flow device (LFD) in bronchoalveolar lavage (BAL) vs. BAL-galactomannan (GM), for the diagnosis of IPA. 311 BAL specimens were prospectively collected from patients who underwent bronchoscopy from January to May 2013. Patients at risk for IPA were divided into haematological malignancy (HEM) and non-HEM groups: solid organ transplants (SOT) (lung transplant (LT) and non-LT SOT); chronic steroid use (CSU); solid tumour (STU) and others. We identified 96 patients at risk for IPA; 89 patients (93%) were in the non-HEM groups: SOT 57 (LT, 46, non-LT SOT, 11); CSU 21; STU 6, other 5. Only three patients met criteria for IA (two probable; one possible). Overall sensitivity (SS) was 66% for both and specificity (SP) was 94% vs. 52% for LFD and GM respectively. LFD and GM performance was similar in the HEM group (SS 100% for both and SP 83% vs. 100% respectively). LFD performance was better than GM among non-HEM SOT patients (P = 0.02). Most false-positive GM results occurred in the SOT group (50.8%), especially among LT patients (56.5%). LFD performance was superior with an overall SP of 95.6% in SOT (P < 0.002) and 97% in LT patients (P = 0.0008). LFD is a rapid and simple test that can be performed on BAL to rule out IPA.

No abstract

Fluctuating asymmetry measures random deviations from bilateral symmetry, and thus estimates developmental instability, the loss of ability by an organism to regulate its development. There have been few rigorous tests of this proposition. Regulation of bilateral symmetry must involve either feedback between the sides or independent regulation toward a symmetric set point. Either kind of regulation should decrease asymmetry over time, but only right–left feedback produces compensatory growth across sides, seen as antipersistent growth following perturbation. Here, we describe the developmental trajectories of perturbed and unperturbed leaves of pumpkin, Cucurbita pepo L., grown at three densities. Covering one side of a leaf with aluminium foil for 24 h perturbed leaf growth. Reduced growth on the perturbed side caused leaves to become more asymmetrical than unperturbed controls. After the treatment the size‐corrected asymmetry decreased over time. In addition, rescaled range analysis showed that asymmetry was antipersistent rather than random, i.e. fluctuation in one direction was likely to be followed by fluctuations in the opposite direction. Development involves right–left feedback. This feedback reduced size‐corrected asymmetry over time most strongly in the lowest density treatment suggesting that developmental instability results from a lack of resilience rather than resistance.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 78, 27–41.

Background/Purpose: Treatment of Type 2 diabetes (T2D) remains an unmet need, particularly a medication with low toxicity. BTI320 (SugarDown®) is fractionated galactomannan with inhibitory activity on carbohydratehydrolyzing enzymes. The primary objective of this study was to investigate the efficacy and safety of BTI320 on glycemic control in T2D. Subjects/Methods: This was a double-blind, placebo-controlled, multi-center study in 60 T2D adults. Subjects ingested 4 g BTI320 or placebo 10 minutes before meals 3 times daily for 12 weeks. The primary endpoint was the change from Baseline to Week 12 in 2-hr post-prandial glucose (PPG) AUC between groups. Results/Conclusion: A consistent trend was observed in favor of BTI320 vs. placebo in change from Baseline at Week 12 in 2-hr PPG AUC (-795.00 vs. -228.75 mg/dL*min), HbA1c (-0.7% vs. +1.1%), lipids, weight/BMI, and blood pressure. At Week 12, BTI320 had more subjects with stable glucose levels (84.6% vs. 79.2%). According to CGM, the BTI320 group had more subjects with stable glucose levels (84.6 vs. 79.2%) and BTI320 subjects experienced relative hypoglycemia for shorter duration than placebo consistently across all visits. No differences were observed in AE profiles between groups. BTI320 was proven to be efficacious and safe in T2D. This study is registered at ClinicalTrials.gov (NCT03655535).