Gonococcal sensitivity to fecal lipids can be mediated by an Mtr-independent mechanism

Publisher Website
Google Scholar
Abstract
Neisseria gonorrhoeae (98 strains) from rectal, cervical and urethal cultures of homosexual men and heterosexual men and women were examined for their sensitivities to fecal lipids. Isolates were characterized according to cell envelope phenotype, auxotype and protein I serogroup. Although cell envelope phenotype was an important factor in the resistance of this organism to fecal lipids (Mtr phenotype > wild type > Env phenotype), other factors were also of importance. AHU- strains (strains requiring arginine, hypoxanthine and uracil) uniformly exhibited a wild-type envelope phenotype but were as sensitive to fecal lipids as were Env strains. The protein I serogroup was not a factor in determining the sensitivity of wild-type envelope phenotype non-AHU- strains to fecal lipids. Sexual preference and site of isolation were important factors. Wild-type envelope phenotype (non-AHU-) strains from homosexual men and heterosexual women were more resistant to fecal lipids than were similar isolated from heterosexual men. When these strains were compared by isolation site, rectal isolates from homosexual men and heterosexual women were more resistant than were cervical isolates from heterosexual women or urethral isolates from heterosexual men. Urethral isolates from homosexual men were also more resistant to fecal lipids than were urethral isolates from heterosexual men. Thus, the host environment can evidently select for increased resistance to hydrophobic molecules by an Mtr-independent mechanism. The basis for this Mtr-independent resistance is unknown, but it probably involves an alteration of the target site(s) for fecal lipid inhibition.