Streptococcus pneumoniae (pneumococcus), Neisseria meningitidis (meningococcus), and Haemophilus influenzae (hemophilus) are among the main bacteria responsible for invasive bacterial diseases (MBIs) that result in severe clinical pictures also characterized by a high frequency of serious complications. Surveillance of infections caused by these pathogens and their distribution by serotypes/serogroups is essential to guide public health interventions, assess epidemiologic trends, monitor any secondary cases, estimate the proportion of preventable cases, identify any vaccine failures, and evaluate the impact of vaccine strategies.The present study aims to study the epidemiology of invasive bacterial diseases, characterize the circulating strains also in order to plan treatment and prevention strategies.