The isolate 7236-07 <i>cps</i> locus does not contain capsular biosynthetic or novel surface protein genes.

<p>Schematic of the <i>cps</i> locus between primers 5419 and 3419 from isolate 7236-07 (deposited to GenBank, accession no. KJ363164). Genes and spacing are to scale. <i>dexB</i> and <i>aliA</i> are truncated at their 5′ and 3′ ends, respectively, in the sequence coverage. Annotations of <i>tnp</i> pseudogenes were assigned corresponding to the serotype 5 <i>cps</i> locus (GenBank no. CR931637).</p

Population-Based Analysis of Invasive Nontypeable Pneumococci Reveals That Most Have Defective Capsule Synthesis Genes

<div><p>Since nasopharyngeal carriage of pneumococcus precedes invasive pneumococcal disease, characteristics of carriage isolates could be incorrectly assumed to reflect those of invasive isolates. While most pneumococci express a capsular polysaccharide, nontypeable pneumococci are sometimes isolated. Carriage nontypeables tend to encode novel surface proteins in place of a capsular polysaccharide synthetic locus, the <i>cps</i> locus. In contrast, capsular polysaccharide is believed to be indispensable for invasive pneumococcal disease, and nontypeables from population-based invasive pneumococcal disease surveillance have not been extensively characterized. We received 14,328 invasive pneumococcal isolates through the Active Bacterial Core surveillance program during 2006–2009. Isolates that were nontypeable by Quellung serotyping were characterized by PCR serotyping, sequence analyses of the <i>cps</i> locus, and multilocus sequence typing. Eighty-eight isolates were Quellung-nontypeable (0.61%). Of these, 79 (89.8%) contained <i>cps</i> loci. Twenty-two nontypeables exhibited serotype 8 <i>cps</i> loci with defects, primarily within <i>wchA</i>. Six of the remaining nine isolates contained previously-described <i>aliB</i> homologs in place of <i>cps</i> loci. Multilocus sequence typing revealed that most nontypeables that lacked capsular biosynthetic genes were related to established non-encapsulated lineages. Thus, invasive pneumococcal disease caused by nontypeable pneumococcus remains rare in the United States, and while carriage nontypeables lacking <i>cps</i> loci are frequently isolated, such nontypeable are extremely rare in invasive pneumococcal disease. Most invasive nontypeable pneumococci possess defective <i>cps</i> locus genes, with an over-representation of defective serotype 8 <i>cps</i> variants.</p></div

Mutations in PCR-serotype 8 Isolates.

a<p>Sequence numbers correspond to GenBank accession No. AJ239004.</p>b<p>Polymorphisms present in an alternative serotype 8 sequence (accession No. CR931644) were ignored.</p>c<p>Residue numbers correspond to amino acid sequence deduced from <i>cap8C</i> (Wzd), <i>cap8D</i> (Wze), or <i>cap8E</i> (WchA) in GenBank accession No. AJ239004.</p>d<p>FS, frameshift;</p><p>*, stop.</p>e<p>Residue previously identified as a site of inactivating mutation <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097825#pone.0097825-Xayarath1" target="_blank">[29]</a>.</p

Multi-locus sequence types of Group II Nontypeable Isolates, 2006–2009.

1<p>Data obtained from MLST.net, accessed January 26, 2014.</p

PCR-8 nontypeable isolates contain inactivating mutations in <i>wchA</i>.

<p>A. Schematic of the serotype 8 <i>cps</i> locus (GenBank accession No. AJ239004). Alternative nomenclature is shown for regulatory genes. B. Molecular model of WchA as predicted by TMPRED (<a href="http://www.ch.embnet.org/software/TMPRED_form.html" target="_blank">http://www.ch.embnet.org/software/TMPRED_form.html</a>). Black arrows indicate nonsense (*) and frameshift (**) mutations; gray arrows indicate missense mutations. Residue numbers correspond to the predicted primary amino acid sequence for WchA.</p

PCR-serotype Distribution of Nontypeable Pneumococci, 2006–2009.

<p>PCR-serotype Distribution of Nontypeable Pneumococci, 2006–2009.</p

Data_Sheet_1.PDF

<p>High-mobility group box 1 (HMGB1), a well-known danger-associated molecular pattern molecule, acts as a pro-inflammatory molecule when secreted by activated immune cells or released after necrotic cell damage. HMGB1 binds to immunogenic bacterial components and augments septic inflammation. In this study, we show how HMGB1 mediates complement activation, promoting sterile inflammation. We show that HMGB1 activates the classical pathway of complement system in an antibody-independent manner after binding to C1q. The C3a complement activation product in human plasma and C5b-9 membrane attack complexes on cell membrane surface are detected after the addition of HMGB1. In an acetaminophen (APAP)-induced hepatotoxicity model, APAP injection reduced HMGB1 levels and elevated C3 levels in C1q-deficient mouse serum samples, compared to that in wild-type (WT) mice. APAP-induced C3 consumption was inhibited by sRAGE treatment in WT mice. Moreover, in a mouse model of brain ischemia–reperfusion injury based on middle cerebral arterial occlusion, C5b-9 complexes were deposited on vessels where HMGB1 was accumulated, an effect that was suppressed upon HMGB1 neutralization. We propose that the HMGB1 released after cell necrosis and in ischemic condition can trigger the classical pathway of complement activation to exacerbate sterile inflammation.</p