Horizontal Gene Transfer Among Neisseria Species and Humans

The genus Neisseria is included among those organisms containing a large number of foreign or exogenous genes in its genome. In most cases, the incorporation of these foreign genes is the consequence of recent events of horizontal gene transfer (HGT) occurring between different species of Neisseria but also with other bacterial genera such as Haemophilus influenzae and even with its exclusive host, the human. In this chapter, we review the transformation process as the main mechanism of HGT in Neisseria and its role in the acquisition of virulence factors and antibiotic resistance markers, mainly from commensal to pathogen Neisseria spp. In addition, we review evidence of gene exchange between both pathogenic Neisseria spp. and human, showing that HGT can occur between mammal’s host and their associated bacteria.