Host Iron Binding Proteins Acting as Niche Indicators for Neisseria meningitidis

Neisseria meningitidis requires iron, and in the absence of iron alters its gene expression to increase iron acquisition and to make the best use of the iron it has. During different stages of colonization and infection available iron sources differ, particularly the host iron-binding proteins haemoglobin, transferrin, and lactoferrin. This study compared the transcriptional responses of N. meningitidis, when grown in the presence of these iron donors and ferric iron, using microarrays

Dog bite prevention:Effect of a short educational intervention for preschool children

This study aimed to investigate whether preschool children can learn how to interpret dogs' behaviours, with the purpose of helping avoid dog bites. Three- to five-year-old children (N = 70) were tested on their ability to answer questions about dogs' emotional states before and after participating in either an educational intervention about dog behaviour (intervention group) or an activity about wild animals (control group). Children who had received training about dog behaviour (intervention group) were significantly better at judging the dogs' emotional states after the intervention compared to before. The frequency with which they referred to relevant behaviours in justifying their judgements also increased significantly. In contrast, the control group's performance did not differ significantly between the two testing times. These results indicate that preschool children can be taught how to correctly interpret dogs' behaviours. This implies that incorporating such training into prevention programmes may contribute to reducing dog bite incidents

Panel 4 : Report of the Microbiology Panel

Objective. To perform a comprehensive review of the literature from July 2011 until June 2015 on the virology and bacteriology of otitis media in children. Data Sources. PubMed database of the National Library of Medicine. Review Methods. Two subpanels comprising experts in the virology and bacteriology of otitis media were created. Each panel reviewed the relevant literature in the fields of virology and bacteriology and generated draft reviews. These initial reviews were distributed to all panel members prior to meeting together at the Post-symposium Research Conference of the 18th International Symposium on Recent Advances in Otitis Media, National Harbor, Maryland, in June 2015. A final draft was created, circulated, and approved by all panel members. Conclusions. Excellent progress has been made in the past 4 years in advancing our understanding of the microbiology of otitis media. Numerous advances were made in basic laboratory studies, in animal models of otitis media, in better understanding the epidemiology of disease, and in clinical practice. Implications for Practice. (1) Many viruses cause acute otitis media without bacterial coinfection, and such cases do not require antibiotic treatment. (2) When respiratory syncytial virus, metapneumovirus, and influenza virus peak in the community, practitioners can expect to see an increase in clinical otitis media cases. (3) Biomarkers that predict which children with upper respiratory tract infections will develop otitis media may be available in the future. (4) Compounds that target newly identified bacterial virulence determinants may be available as future treatment options for children with otitis media.Peer reviewe

Proteome of a Moraxella catarrhalis Strain under Iron-Restricted Conditions

Moraxella catarrhalis is a leading cause of otitis media and exacerbations of chronic obstructive pulmonary disease; however, its response to iron starvation during infection is not completely understood. Here, we announce a sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) data set describing the differential expression of the M. catarrhalis CCRI-195ME proteome under iron-restricted versus iron-replete conditions

An Overview of Neisseria meningitidis

Neisseria meningitidis (the meningococcus) is a member of the normal nasopharyngeal microbiome in healthy individuals, but can cause septicemia and meningitis in susceptible individuals. In this chapter we provide an overview of the disease caused by N. meningitidis and the schemes used to type the meningococcus. We also review the adhesions, virulence factors, and phase variable genes that enable it to successfully colonize the human host. Finally, we outline the history and current status of meningococcal vaccines and highlight the importance of continued molecular investigation of the epidemiology and the structural analysis of the antigens of this pathogen to aid future vaccine development

Transcriptome RNA Sequencing Data Set of Gene Expression in Moraxella catarrhalis On- and Off-Phase Variants of the Type III DNA Methyltransferase ModM3

Moraxella catarrhalis is a leading bacterial cause of otitis media and exacerbations of chronic obstructive pulmonary disease. Here, we announce a transcriptome RNA sequencing data set detailing global gene expression in two M. catarrhalis CCRI-195ME variants with expression of the DNA methyltransferase ModM3 phase varied either on or off

The Moraxella catarrhalis phase-variable DNA methyltransferase ModM3 is an epigenetic regulator that affects bacterial survival in an in vivo model of otitis media

BACKGROUND: Moraxella catarrhalis is a leading cause of otitis media (OM) and chronic obstructive pulmonary disease (COPD). M. catarrhalis contains a Type III DNA adenine methyltransferase (ModM) that is phase-variably expressed (i.e., its expression is subject to random, reversible ON/OFF switching). ModM has six target recognition domain alleles (modM1-6), and we have previously shown that modM2 is the predominant allele, while modM3 is associated with OM. Phase-variable DNA methyltransferases mediate epigenetic regulation and modulate pathogenesis in several bacteria. ModM2 of M. catarrhalis regulates the expression of a phasevarion containing genes important for colonization and infection. Here we describe the phase-variable expression of modM3, the ModM3 methylation site and the suite of genes regulated within the ModM3 phasevarion. RESULTS: Phase-variable expression of modM3, mediated by variation in length of a 5'-(CAAC)n-3' tetranucleotide repeat tract in the open reading frame was demonstrated in M. catarrhalis strain CCRI-195ME with GeneScan fragment length analysis and western immunoblot. We determined that ModM3 is an active N6-adenine methyltransferase that methylates the sequence 5'-ACm6ATC-3'. Methylation was detected at all 4446 5'-ACATC-3' sites in the genome when ModM3 is expressed. RNASeq analysis identified 31 genes that are differentially expressed between modM3 ON and OFF variants, including five genes that are involved in the response to oxidative and nitrosative stress, with potential roles in biofilm formation and survival in anaerobic environments. An in vivo chinchilla (Chinchilla lanigera) model of otitis media demonstrated that transbullar challenge with the modM3 OFF variant resulted in an increased middle ear bacterial load compared to a modM3 ON variant. In addition, co-infection experiments with NTHi and M. catarrhalis modM3 ON or modM3 OFF variants revealed that phase variation of modM3 altered survival of NTHi in the middle ear during early and late stage infection. CONCLUSIONS: Phase variation of ModM3 epigenetically regulates the expression of a phasevarion containing multiple genes that are potentially important in the progression of otitis media

Neisseria meningitidis: Methods and protocols

This volume provides methods to analyze the meningococcus and its interactions with biologically relevant host cells and sites, to interrogate the population structure and biology of the meningococcus that defines its capacity to cause disease, and to aid in vaccine development and surveillance. Many of these methods are applicable to the close relative, Neisseria gonorrhoeae, and several of the methods described can also be used in investigating host-pathogen interactions for a range of other organisms. Written for the highly successful Methods in Molecular Biology series, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, Neisseria meningitidis: Methods and Protocols will allow for the use of these methods by more laboratories and foster collaboration and consistency in investigations of this enigmatic and dangerous pathogen

Moraxella catarrhalisphase-variable loci show differences in expression during conditions relevant to disease

Moraxella catarrhalis is a human-adapted, opportunistic bacterial pathogen of the respiratory mucosa. Although asymptomatic colonization of the nasopharynx is common, M. catarrhalis can ascend into the middle ear, where it is a prevalent causative agent of otitis media in children, or enter the lower respiratory tract, where it is associated with acute exacerbations of chronic obstructive pulmonary disease in adults. Phase variation is the high frequency, random, reversible switching of gene expression that allows bacteria to adapt to different host microenvironments and evade host defences, and is most commonly mediated by simple DNA sequence repeats. Bioinformatic analysis of five closed M. catarrhalis genomes identified 17 unique simple DNA sequence repeat tracts that were variable between strains, indicating the potential to mediate phase variable expression of the associated genes. Assays designed to assess simple sequence repeat variation under conditions mimicking host infection demonstrated that phase variation of uspA1 (ubiquitous surface protein A1) from high to low expression occurs over 72 hours of biofilm passage, while phase variation of uspA2 (ubiquitous surface protein A2) to high expression variants occurs during repeated exposure to human serum, as measured by mRNA levels. We also identify and confirm the variable expression of two novel phase variable genes encoding a Type III DNA methyltransferase (modO), and a conserved hypothetical permease (MC25239_RS00020). These data reveal the repertoire of phase variable genes mediated by simple sequence repeats in M. catarrhalis and demonstrate that modulation of expression under conditions mimicking human infection is attributed to changes in simple sequence repeat length