15. A Novel Approach to Bacterial Vaccines: Haemophilus influenzae as a Paradigm

Background The H. influenzae type b vaccines target the type b capsule and therefore have no impact on the nontypable (unencapsulated) H. influenzae (NTHi). NTHi has become the most common cause of otitis media and is the most common isolate from patients with exacerbations of Chronic Obstructive Pulmonary Disease (COPD). Therefore, NTHi is an appropriate target for vaccine development. Methods To characterize potential vaccine targets, the core outer proteins of NTHi present in the available sequenced genomes were identified through genomic bioinformatics. The structures of the outer proteins were analyzed through comparison with the available structures of homologues characterized by X-ray crystallography. Sequenced conserved outer regions of these proteins were analyzed for their protective capacity in the infant rat model of H. influenzae infection. Results Nine peptides that were protective in the infant rat model were used in a novel vaccine to immunize chinchillas, the most established animal model of otitis media. Chinchillas (40 vaccinated and 41 controls) were infected with NTHi 86-028NP. The vaccinated group cleared infection more quickly than the control group as indicated by significantly decreased positive findings on video-otoscopy (p< 0.0001) and tympanometry (p=0.0002) on day 7, and presence of middle ear fluid obtained by aspiration (p=0.0001) on day 10 post infection. Similarly, in the mouse model of NTHi pulmonary clearance, the vaccinated group (n=5) reduced infection more rapidly than the control group (n= 5), p=0.008. Conclusion These data demonstrate the effectiveness of the Bacterial Vaccine Polypeptide methodology in development of a vaccine against NTHi with protection in relevant preclinical models of both otitis media and pulmonary clearance. The methods are applicable to other bacteria, and this approach to a Bacterial Vaccine Polypeptide against NTHi serves as a paradigm for development of similar vaccines to protect against other bacterial infections. Disclosures All Authors: No reported disclosures

The Need to Develop New Antimicrobial Molecules, as Revealed by in vitro Assessment of Drug Resistance in Staphylococcal Skin Infections Treated with Autologous Bacterial Vaccine

Staphylococcus spp. is a facultative pathogen, which can be found in the commensal microbiota of humans, most often in moist skinfolds and mucous membranes. This microorganism has the ability to cause various infections, in almost every organ of the body, with an increased frequency in the skin and soft tissues, being involved in pathologies like acne, folliculitis, furunculosis, hidradenitis suppurativa, cellulitis, abscesses, but also in secondary infections in diseases with an altered cutaneous barrier. The prolonged evolution of these diseases and severe outcome can be influenced by various factors, most importantly being the antimicrobial resistance. We have evaluated the antimicrobial susceptibility profiles, according to the Comite de l` Antibiogramme de la Societe Francaise de Microbiologie recommendations, for strains of Staphylococcus spp. isolated from acne or different types of skin and soft tissue infections in patients recommended to receive autologous bacterial vaccine. Most frequent identified species was Staphylococcus epidermidis, followed by Staphylococcus aureus. The antimicrobial resistance was higher for antibiotics usually used in the treatment of skin and soft tissue infections, with interesting differences of the resistance profile for the strains isolated from patients before receiving autologous bacterial vaccine compared with the ones from individuals already treated. Another important finding was represented by the differences in the resistance profile according to the age group of the patients. The results of this study underline the importance of antimicrobial resistance surveillance in finding new molecules and alternative therapies, the necessity of a personalized approach in medical acts and of a continuous connection between clinic and laboratory research.