Haemophilus Ducreyi Research Paper

Haemophilus ducreyi (H. ducreyi) is a coccobacillus bacterium that causes the sexually transmitted disease Chancroid. Chancroid is a major cause of genital ulceration in developing countries, and is characterized by painful sores on the genitalia. (Labandeira-Rey et al., 2009) H. ducreyi is an opportunistic microorganism that infects its host through breaks in the skin. Chancroid starts as an erythematous papular lesion that becomes painful bleeding ulcers with necrotic bases and ragged edges (Alfa 2005). Due to the presence of H. ducreyi in the body, the immune system signals lymphocytes, macrophages, and granulocytes, which in turn causes inflammation. Inflammation causes regional lymphadenitis in the sexually transmitted bacillus Chancroid (Rapini et al, 2007). H.
ducreyi uses a two-component regulatory system to sense and respond to changes in the environment. These systems are basic stimulus-response coupling mechanisms that allow prokaryotic organisms to adapt to changes in many different environmental conditions (Spinola et al., 2010). Adenosine triphosphate (ATP) transfers a phosphoryl group to a specific histidine kinase, which recognizes the stimulus to create a signal transduction in the cell. Upon the auto-phosphorylation of histidine kinase, the phosphoryl group is transferred to the receiver domain located on the response regulator. Phosphorylation causes a change in the response regulator confirmation, which then leads to the stimulation or repression of target genes (Stock et al., 2000).
Since H. ducreyi encounters phagocytes in the body, it must be able to adapt in hostile environments. The bacterium uses a CpxR-CpxA two-component response system to make the adaptation. CpxR acts as a response regulator, while CpxA acts a sensor kinase. Studies have shown that CpxR represses the transcription of DsrA, the lspB-lspA2 operon, and the flp operon, which are all required for virulence in humans CpxA is needed to maintain transcription of all