Abstract Non-typeable Haemophilus influenzae contains an N 6 -adenine DNA-methyltransferase (ModA) that is subject to phase-variable expression (random ON/OFF switching). Five modA alleles, modA2 , modA4, modA5 modA9 and modA10 account for over two-thirds of clinical otitis media isolates surveyed. Here, we use single molecule, real-time (SMRT) methylome analysis identify the DNA-recognition motifs all five these alleles. Phase variation alleles regulates multiple proteins including vaccine...

Significance Extracellular DNA and DNABII proteins are essential structural components of the extracellular polymeric substance, or matrix, nontypeable Haemophilus influenzae biofilm; however, mechanisms by which these elements released from bacterial cell for incorporation into biofilm matrix not yet characterized. Here, we propose a mechanism active release during formation that involves an inner-membrane complex (TraCG) ComE pore through type IV pilus is typically expressed. Knowledge how...

Cystic fibrosis (CF), one of the most common human genetic diseases worldwide, is caused by a defect in CF transmembrane conductance regulator (CFTR). Patients with are highly susceptible to infections opportunistic pathogens (including Burkholderia cenocepacia), which induce excessive lung inflammation and lead eventual loss pulmonary function. Abundant neutrophil recruitment into key characteristic bacterial patients. In response infection, inflammatory neutrophils release reactive oxygen...

Several human-adapted bacterial pathogens use a phasevarion (ie, phase-variable regulon) to rapidly and reversibly regulate the expression of many genes, which include known virulence factors, yet influence phasevarion-mediated regulation in pathogenesis remains poorly understood. Here we examine impact nontypeable Haemophilus influenzae (NTHI) ModA2 on disease severity chinchilla model experimental otitis media. Chinchillas were challenged with NTHI variant populations that either...

Otitis media (OM) is often polymicrobial, with nontypeable Haemophilus influenzae (NTHI) and Moraxella catarrhalis (Mcat) frequently cocultured from clinical specimens. Bacterial biofilms in the middle ear contribute to chronicity recurrence of OM; therefore, strategies disrupt are needed. We have focused our vaccine development efforts on majority subunit NTHI type IV pili, PilA. Antibodies against a recombinant, soluble form PilA (rsPilA) both prevent formation vitro. Moreover,...

Upper respiratory tract infections are the number one reason for a child to visit emergency department, and otitis media (middle ear infection) ranks third overall. Biofilms contribute significantly chronic nature of bacterial infections, including media, make these diseases particularly difficult treat. Several mucosa-associated human pathogens utilize mechanism rapid adaptation termed phasevarion, or phase vari able regul on , resist environmental host immune pressures. In this study, we...

Nontypeable Haemophilus influenzae (NTHI) is the causative agent of multiple respiratory tract infections. Several human pathogens, including NTHI, possess a novel genetic system, termed phasevarion, which mediates rapid and reversible change in expression many genes throughout chromosome. This occurs by phase variation single gene (modA) that encodes DNA methyltransferase results two phenotypically distinct subpopulations, ON OFF. NTHI encounters pressures within various microenvironments...

During infection, phagocytic cells pursue homeostasis in the host via multiple mechanisms that control microbial invasion. Neutrophils respond to infection by exerting a variety of cellular processes, including chemotaxis, activation, phagocytosis, degranulation and generation reactive oxygen species (ROS). Calcium (Ca2+) signaling activation specific Ca2+ channels are required for most antimicrobial effector functions neutrophils. The transient receptor potential melastatin-2 (TRPM2) cation...

Non-typeable Haemophilus influenzae (NTHi) is a human-adapted bacterial pathogen, responsible for infections of the human respiratory tract. This pathogen expresses range adhesins that mediate binding to host cells. Most NTHi strains can express related HMW1 and HMW2. Expression HMW proteins phase-variable: changes in length simple-sequence repeats located encoding genes promoter regions results expression levels these adhesins. also controlled by epigenetic regulation. has been previously...

Otitis media (OM) is one of the most common diseases childhood, and nontypeable

Our studies reveal that the oral colonizer and cause of infective endocarditis Streptococcus oralis subsp. dentisani displays a striking monolateral distribution surface fibrils. Furthermore, our data suggest these fibrils impact structure adherent bacterial chains. Mutagenesis indicate are dependent on three serine-rich repeat proteins (SRRPs), here named fibril-associated protein A (FapA), FapB, FapC, each SRRP forms different fibril with distinct distribution. SRRPs family adhesins have...

Host-adapted bacterial pathogens like NTHi have evolved specific mechanisms to colonize their restricted host niche. Relatively few of the adhesins expressed by been characterized as regards binding affinity at molecular level. In this work, we show that major adhesin Hia preferentially binds Neu5Ac-α2-6-sialyllactosamine, form sialic acid in humans. The receptors targeted human airway mirror those influenza A virus and indicates broad importance glycans for microbes airway.

Nontypeable Haemophilus influenzae (NTHi) causes multiple diseases of the human airway and is a predominant bacterial pathogen acute otitis media in which treatment fails. NTHi utilizes system phase variable epigenetic regulation, termed phasevarion, to facilitate adaptation survival within sites host. The phasevarion influences numerous disease-relevant phenotypes such as biofilm formation, antibiotic resistance opsonization. We have previously identified an advantageous selection for...

Achromobacter xylosoxidans is an opportunistic pathogen implicated in a wide variety of human infections including the ability to colonize lungs cystic fibrosis (CF) patients. The role A. pathology remains controversial due lack optimized

Achromobacter xylosoxidans (Ax) is an opportunistic pathogen and causative agent of numerous infections particularly in immunocompromised individuals with increasing prevalence cystic fibrosis (CF). To date, investigations have focused on the clinical epidemiology genomic comparisons Ax isolates, yet little known about disease pathology or role that specific virulence factors play tissue invasion damage. Here, we model acute lung infection immunocompetent C57BL/6 mice CF mice, revealing a...

Adherence of nontypeable Haemophilus influenzae (NTHi) to the host airway is an essential initial step for asymptomatic colonization nasopharynx, as well development disease. NTHi relies on strict regulation multiple adhesins adherence substrates encountered in airway. encode a phase-variable cytoplasmic DNA methyltransferase, ModA, that regulates expression genes; phasevarion (phase-variable regulon). Multiple modA alleles are present NTHi, which different methylate target, and each...

Abstract Shewanella oneidensis , a metal reducer and facultative anaerobe, expresses large number of c -type cytochromes, many which function as anaerobic reductases. All these proteins contain the typical heme-binding motif CXXCH require Ccm for maturation. Two cytochrome reductases also possess atypical sites, NrfA nitrite reductase (CXXCK) SirA sulfite (CX 12 NKGCH). S. MR-1 encodes two synthetases (CcmF SirE) apocytochrome chaperones (CcmI SirG). SirE located in sir gene cluster is...

Non-typeable Haemophilus influenzae (NTHi) causes millions of infections each year. Though it is primarily known to cause otitis media, recent studies have shown NTHi emerging as a primary pathogen for invasive infection, prompting the need new vaccines and treatments. Lipooligosaccharide (LOS) has been identified potential vaccine candidate due its immunogenic nature outer membrane localization. Yet, phase variable expression genes involved in LOS synthesis complicated development. In this...

Abstract NTHi is a human-adapted pathogen that colonises the human respiratory tract. Strains of express multiple adhesins, however there unique, mutually exclusive relationship between major adhesins Hia and HMW1/2. Approximately 25% strains Hia, phase-variable autotransporter protein, which has critical role in colonisation host nasopharynx. The remaining 75% Previous work shown HMW1 HMW2 proteins mediate binding to 2,3- 2,6-linked sialic acid glycans found Here we show high affinity...

Lav is an autotransporter protein found in pathogenic Haemophilus and Neisseria species. nontypeable influenzae (NTHi) phase-variable: the gene reversibly switches ON-OFF via changes length of a locus-located GCAA (n) simple DNA sequence repeat tract. The expression status lav was examined carriage invasive collections NTHi, where it predominantly not expressed (OFF). Phenotypic study showed (ON) results increased adherence to human lung cells denser biofilm formation.

Non-typeable Haemophilus influenzae (NTHi) is a major bacterial pathogen of the human airway. We report high-depth coverage RNA-Seq data from prototype NTHi strains 723 and R2866, encoding two most common phase-variable ModA alleles found in strains, ModA2 ModA10, respectively.

Abstract Calcium signaling is required for most antimicrobial functions of neutrophils. The transient receptor potential melastatin-2 (TRPM2) cation channel has been proposed to play important roles in modulating calcium mobilization, cell migration and oxidative stress However, the precise mechanism by which TRPM2 activation may exert a pro- or anti-inflammatory function remains unclear. In this study, we used mouse model Listeria monocytogenes infection define role regulation neutrophils’...