Characterization of genes conferring v factor independence in haemophilus parainfluenzae and haemophilus ducreyi

Abstract

Haemophilus influenzae and Haemophilus parainfluenzae are obligate human parasites that form part of the flora of the mucous membranes. They are normally present in the mouth and upper respiratory tract of healthy individuals. H. influenzae is known as a major pathogen in children while H. parainfluenzae is an opportunistic pathogen which is also found in the urogenital tract. H. ducreyi, however, has only been isolated from genital ulcers in patients suffering from chancroid. The various species of the genus Haemophilus are characterised by their requirements for two growth factors, X factor or haemin and V factor or nicotinamide adenine dinucleotide (NAD).