Produção e extração de vesículas de membrana externa (OMV) de Escherichia coli para o tratamento de infecções nosocomiais

Abstract

Nosocomial infection it is an infection acquired by patient during the hospital stay. According to the WHO bacterial infections are a major cause of hospitalization and worldwide death. The excessive e improper use of antibiotics are elevating nosocomial infections and causes the emergence of resistant strains to these antimicrobials causing a economic impact in the country. Thus vaccines are the alternatives strategies for treating these infections. Escherichia coli is one of the leading emerging nosocomial pathogens and it’s a Gram-negative rod shaped bacterium that colonizes the gastrointestinal tract responsible for diseases such as sepsis, pneumonia, neonatal meningitis, peritonitis, and gastroenteritis. E. coli produces outer membrane vesicles (OMV) which are small spherical and highly immunogenic structures of 20-200 nm and may be an alternative vaccine against nosocomial infections. The vesicles are released during cell growth and production can be influenced by factors such as acidity, temperature, nutrient deficiency, etc. The objective of this work was to evaluate the production of OMV by E. coli strain 17/38 (provided by HU – Hospital Universitário) in shaker, using different cultivation conditions (pH, temperature and time) and extraction by tangential filtration or ultracentrifugation. For quantification and characterization of OMV, we performed protein dosage tests, electrophoresis and electron microscopy. Based on the results, we conclude that: pH, temperature and time affected the production of OMV; the OMV extraction by tangential filtration proved to be a promising technology when compared with ultracentrifugation. Despite the great knowledge regarding OMVs as mediators of virulence and to bacterial survival there are still many aspects to be elucidated regarding the impact of these OMVs on microorganisms and the human host.