influenzae is an exclusively human pathogen. Phosphoryl choline may participate in pathogenesis in several ways.Phosphoryl choline decreases the susceptibility of H. influenzae to antimicrobial peptides [61].Hong et al [62, 63] demonstrated that phosphoryl choline promotes infection and persistence in an animal model by reducing the host inflammatory response and by promoting the formation and maturation of stable biofilm communities.Several indirect lines of evidence suggest that H. influenzae persists in the airway by forming biofilms that resist host immunity.The observation that the licD gene product

is abundantly expressed in sputum suggests that addition of phosphoryl choline to lipooligosaccharide is important for persistence, perhaps by protecting the bacterial cell from antimicrobial peptides and/or by promoting the formation FG-4592 of biofilms. Conclusions Proteomic expression profiling of a prototype COPD strain of H. influenzae was performed on bacteria that were grown in pooled human sputum in comparison

to the same strain grown in defined chemical media.The sequence of the genome of the prototype strain was determined by pyrosequencing yielding 53 contigs.A method involving precipitation and on-pellet digestion of a whole bacterial cell lysate was optimized to solubilize proteins of varying solubilities from a complex mixture of proteins. Proteomic profiling was accomplished using a Nano-LC/MS system and 1402 proteins were identified with high confidence using a set of strict criteria.These proteins

Aldol condensation represent 79.7% of the ORFs predicted from the genome sequence, PF-04929113 nmr including 170 proteins that are encoded by genes that are annotated as conserved hypothetical proteins.A total of 31 proteins were present in a ratio of > 1.5 in sputum grown compared to media grown bacteria.Analysis of these proteins reveal 8 antioxidant proteins and 5 stress response proteins, suggesting that expression of antioxidant activity and stress responses is important for survival of H. influenzae in the human airways.In addition, proteins involved in uptake of nutrients and MK-4827 solubility dmso adherence highlight the role of these possible functions for H. influenzae to survive in the human respiratory tract. The results of proteomic expression profiling of H. influenzae grown in pooled human sputum from adults with COPD are revealing in understanding the adaptations that H. influenzae makes during colonization and infection of the human respiratory tract.These observations have the potential to reveal critical virulence factors that enable survival of H. influenzae in its ecological niche and may present opportunities for the development of novel approaches to interrupt infection. Methods Bacterial strain Nontypeable H. influenzae strain 11P6H is a prototype exacerbation strain that was isolated from the sputum of an adult with chronic obstructive pulmonary disease (COPD).