Distribution of Haemophilus influenzae and Haemophilus parainfluenzae biotypes isolated from the human genitourinary tract.

A total of 3,598 genital specimens from men and women was cultured for Haemophilus spp. using a simple selective culture method. Two hundred and thirty three samples (6.5%) were positive for Haemophilus spp., 216 Haemophilus parainfluenzae and 28 Haemophilus influenzae strains being isolated. Biotyping demonstrated that Haemophilus parainfluenzae biotype II was dominant at all sites, especially the male urethra, comprising 59% of all Haemophilus strains isolated. On the other hand, Haemophilus influenzae biotype IV was isolated from only six patients and thus was not a major genital biotype. The respective proportions of the two Haemophilus spp. recovered from various mucosal sites led to the supposition that the genitourinary colonization originated either from the upper respiratory tract or the gastrointestinal tract.