Project description:Nonencapsulated Streptococcus pneumoniae (NESp) is an emerging human pathogen that colonizes the nasopharynx and is associated with noninvasive disease such as otitis media (OM), conjunctivitis, and nonbacteremic pneumonia. For decades, expression of a polysaccharide capsule appeared to be necessary for establishment of colonization and development of invasive pneumococcal disease (IPD). Accordingly, the currently licensed pneumococcal vaccines target the polysaccharide capsule. However, NESp expressing the novel oligopeptide importer proteins AliC and AliD have been isolated during IPD. Our study reveals that NESp expressing AliC and AliD have intensified virulence compared to isogenic mutants, and we provide insight about how this pneumococcal population has become associated with IPD. Our data demonstrates that AliC and AliD enhance murine nasopharyngeal colonization and are required for OM in a chinchilla model. Furthermore, AliC and AliD increase pneumococcal survival in chinchilla whole blood and decrease deposition of human C3b on the bacterial surface. As NESp become an increasing threat to public health, our study exposes specific virulence factors to possibly target for a broadened prevention of IPD through vaccination.
Project description:Microarray analysis of Streptococcus pneumoniae TIGR4 transcriptome in response to manganese as the transcriptome changes in response to intracellular manganese accumulation via a mutation in sp1552/mntE a manganese efflux protein. Investigating role of manganese efflux and accumulation in S. pneumoniae: 3 TIGR4 in ThyB vs. TIGR4 in Mn and 3 TIGR4 in Mn vs mntE1 in Mn replicate 3
Project description:Transcriptomic analysis of Streptococcus pneumoniae TIGR4 wildtype and it's isogenic ccpA mutant, grown in chemically defined media supplemented with physiological levels of carbohydrates to mimic the human nasopharynx and bloodstream. The goal is to examine how anatomical site-specific carbohydrate availability impacts S. pneumoniae physiology and virulence.
Project description:Investigation of whole genome gene expression differences between a full (four-gene) SlrV locus 1 deletion compared to the WT PittII strain. Removal of the four SlrV genes (aka macrophage survival factors : Δmsf) results in a competetive defect with the WT strain in in vitro biofilms and in the otitis media chinchilla model. It also results in an inability to persist within macrophages long-term in vitro and to escape from the middle-ear space and infect other sites in the chinchilla model.
Project description:Microarray analysis of Streptococcus pneumoniae TIGR4 transcriptome in response to manganese as the transcriptome changes in response to intracellular manganese accumulation via a mutation in sp1552/mntE a manganese efflux protein.
Project description:TIGR4 and R6 bacterial strains of Streptococcus pneumoniae treated and not treated with the iron chelator deferoxamine mesylate (DFO)
Project description:Streptococcus pneumoniae (Spn) is the predominant causative organism of acute otitis media (AOM) in children. A human cDNA microarray comprising 30,968 human genome probes was used to evaluate the transcriptional changes that occur in peripheral blood mononuclear cells (PBMC) at the onset of clinical AOM caused by Spn infection in children after comparison of microarray results with the pre-infection healthy stage of the same children.
Project description:Investigation of whole genome gene expression differences between a full (four-gene) SlrV locus 1 deletion compared to the WT PittII strain. Removal of the four SlrV genes (aka macrophage survival factors : ?msf) results in a competetive defect with the WT strain in in vitro biofilms and in the otitis media chinchilla model. It also results in an inability to persist within macrophages long-term in vitro and to escape from the middle-ear space and infect other sites in the chinchilla model. WT and ?msf strains were grown in a chemically defined media (CDM) to early stationary phase (OD ~1.0). RNA was extracted from two separate cultures (biological replicates). 3-13 probes represent each subcluster(gene) and two replicate probe sets are included on each custom NTHi supragenome chip (technical replicates) thus under each sampling condition 4 separate values are obtained per strain and used for WT:Msf-KO comparisons.
Project description:Non-typeable Haemophilus influenzae (NTHi) contains an N6-adenine DNA-methyltransferase (ModA), that is subject to phase variable expression (random ON/OFF switching). Five modA alleles, modA2, 4, 5, 9 and 10, account for over two-thirds of clinical otitis media isolates surveyed. Single Molecule Real Time (SMRT) methylome analysis identified the DNA recognition motifs for all five of these modA alleles. Phase variation of these alleles regulated multiple proteins, including vaccine candidates. ON/OFF switching of modA alleles resulted in differential regulation of key virulence phenotypes, such as antibiotic resistance (modA2, 5, 10), biofilm formation (modA2) and immunoevasion (modA4). Analysis of the modA2 strain, 723, in the chinchilla model of otitis media showed a clear selection for switching from modA2OFF to ON in the middle ear. This is the first report of a biphasic epigenetic switch controlling bacterial virulence, immunoevasion and niche adaptation in an animal model system
Project description:Transcriptional responses of Streptococcus pneumoniae strain TIGR4 to human lung epithelial cells (A549) were investigated at the early stages of interactions (0.5 h and 1 h).
