A DNA-binding protein implicated in transcriptional repression and chromosome organization and compaction. Binds nucleation sites in AT-rich DNA and bridges them, forming higher-order nucleoprotein complexes and condensing the chromosome. As many horizontally transferred genes are AT-rich, it plays a central role in silencing foreign genes. A subset of genes are repressed by H-NS in association with other proteins (By similarity). KcpA is involved in pathogenesis. The protein is required by invading bacteria for spread into adjacent cells (colonic epithelial cells). It is needed to establish kerato-conjunctivitis provocation (KCP) by pathogenic bacteria (PubMed:2668687). It is involved in the thermal control of epithelial cell invasion (PubMed:1406252). Homodimer that oligomerizes on DNA into higher-order complexes that form bridges between disparate regions of DNA compacting it. Interacts with Hha, Cnu and StpA. Belongs to the histone-like protein H-NS family.