Studies on gonococcus infection. XIII. Occurrence of color/opacity colonial variants in clinical cultures

Abstract

Colonial variants of Neisseria gonorrhoeae differing in color and opacity characteristics are distributed differently between male urethral and female cervical cultures. Colonial characteristics of cultures isolated from female cervices differ with time of isolation within the menstrual cycle and use of oral contraceptives. These differences may reflect selective forces in the ecology of the cervix, particularly proteolytic enzymes in cervical mucus and menstrual blood. Cycle changes in the characteristics of gonococci isolated from females may have implications for pathogenesis of gonococcal infections and immune reponse to the gonococcus.

The opacity proteins of Neisseria gonorrhoeae strain MS11 are encoded by a family of 11 complete genes

“…The expression of these proteins contributes to colony opacity and to intracellular aggregation (Swanson, 1978). Opa protein expression also correlates with growth of gonococci in vivo\ Opa^ organisms predominate in some anatomical sites whereas Opa" variants abound in others (James and Swanson, 1978;Draper ef a/., 1980;Swanson etal., 1988). Experimentai urethral infections of males yielded Opaĝ onococci almost exclusively, even in individuals who had been infected with predominantly Opa" organisms (Swanson ef a/., 1988).…”

Neisseria gonorrhoeaesuppresses the oxidative burst of human polymorphonuclear leukocytes

“…The ability of Opa -Gc to suppress PMN oxidative metabolism may also allow the bacteria to ascend the urogenital tract and disseminate to secondary sites, as the majority of Gc isolates from the upper urogenital tract and those causing gonococcal arthritis lack Opa expression (O'Brien et al, 1983;Edwards and Apicella, 2004). In contrast, during active lower urogenital tract infection, the predominance of Opa + Gc (James and Swanson, 1978;Swanson et al, 1988;Jerse et al, 1994), in combination with increasing numbers of dead Gc and pro-inflammatory bacterial products, could overcome the suppression mediated by live Opa -Gc and stimulate the PMN oxidative burst. However, the intrinsically high resistance of Gc to ROS (Archibald and Duong, 1986;Hassett et al, 1990) as well as the ROS-mediated upregulation of gene products that protect Gc from PMN killing (Stohl et al, 2005) would aid Gc survival when confronted with the resulting PMN oxidative burst.…”

“…Gc suppression of PMN oxidative metabolism may also help to explain the discrepancies in disease presentation between men and women. Male urethral infection selects for Opa + Gc that are capable of inducing ROS production in PMNs and may exacerbate the potent inflammatory response that characterizes acute disease in men (James and Swanson, 1978;Zak et al, 1984). In contrast, Opa -Gc predominate in women depending on the stage of the menstrual cycle, and suppression of the PMN oxidative burst under these conditions may contribute to the preponderance of asymptomatic or subclinical disease in the female population (James and Swanson, 1978;Edwards and Apicella, 2004).…”

“…Male urethral infection selects for Opa + Gc that are capable of inducing ROS production in PMNs and may exacerbate the potent inflammatory response that characterizes acute disease in men (James and Swanson, 1978;Zak et al, 1984). In contrast, Opa -Gc predominate in women depending on the stage of the menstrual cycle, and suppression of the PMN oxidative burst under these conditions may contribute to the preponderance of asymptomatic or subclinical disease in the female population (James and Swanson, 1978;Edwards and Apicella, 2004). Given natural variations in Opa expression and the balance between viable and non-viable Gc during the course of human infection, Gc suppression of the PMN oxidative burst can be considered a dynamic process, serving at critical junctures to enhance gonorrhoeal pathogenesis in the face of the inflammatory host immune response.…”

Prevalence of gene sequences coding for hypervariable regions of Opa (protein II) in Neisseria gonorrhoeae

“…Clinical isolates of N. gonorrhoeae form opaque or transparent colonies on primary isolation (James and Swanson, 1978), but all gonococci may express Opas on primary isolation regardless of colony opacity/transparency. On examination of 75 clinical isolates from uncomplicated genital and rectal infections, each expressed from one to four Opas (Ison etai., 1991).…”