How Infectious Is Gonorrhœa ?

Bernfeld, W. K.

doi:10.1016/s0140-6736(72)92260-x

Cited by 3 publications

(1 citation statement)

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“…2 indicate that the piliated variants attached to epithelial cells faster than their nonpiliated counterparts, since within 5 min, a significantly greater number of piliated organisms had attached compared with the nonpiliated gonococci. This is highly relevant to the natural situation as shown by the finding that micturition immediately after intercourse does not protect against infection in naturally acquired gonorrhoea (1). That the infectious dose for gonorrhoea is low was shown by Brinton et al (2).…”

Section: Resultsmentioning

confidence: 99%

Comparative virulence of opacity variants of Neisseria gonorrhoeae strain P9

Virji¹,

Everson²

1981

Infect Immun

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The invasive properties of nine variants of Neisseria gonorrhoeae strain P9 known to vary in their surface composition have been investigated. Relative virulence was evaluated by their cytotoxic effect on Chang epithelial cell monolayers. Piliated variants P9-2 (with a pili) and P9-20 (with pili plus protein II) showed increased ability to kill the target cells compared with the prototype P9-1 (lacking pili and additional outer membrane proteins). Two nonpiliated variants, P9-11 (with proteins IIa and Ild) and P9-19 (with proteins II and IIc), were also relatively more virulent compared with P9-1. Enhanced attachment was exhibited by both piliated and some nonpiliated variants: fl-piliated P9-20 (with protein II; molecular weight, 29,000) and nonpiliated P9-16 (with protein Ilb; molecular weight, 28,000) were the most effective in adherence to the target monolayers.Neisseria gonorrhoeae is specialized to invade mucosal surfaces ofhumans and possesses mechanisms which enable it, first, to anchor to the mucosal surfaces despite the constant washes of mucus and other secretions and, second, to penetrate and subsequently multiply in these cells (17). The initiation of the process of pathogenesis therefore depends on the efficiency of the processes of binding and penetration.There is evidence that surface morphological features such as pili (13) and certain outer membrane proteins (8) may confer to bacteria an increased ability to bind to certain human cells. But the attributes important in the process of bacterial entry into the host cell are not understood.Recently, nine variants of N. gonorrhoeae strain P9 were described (8,9). Two of these possess pili: P9-2 (a pili) and P9-20 (,B pili).Purified pili from these variants show different pH optima for attachment to buccal cells (9). Other nonpiliated forms possess a variety of related outer membrane proteins (7). The role of these proteins in attachment to cells and resistance to serum killing and to the action of antibiotics has been reported (8). Our aim is to investigate whether and how these distinguishing surface features confer selective advantages to the variants by influencing the processes of attachment and invasion. For this purpose, the Chang conjunctiva epithelial cell line was chosen as a model, since in nature N. gonorrhoeae is known to cause infection of the eye.MATERIALS AND METHODS Gonococcal variants. Opacity variants of N. gon-orrhoeae strain P9 were isolated and purified on clear typing medium (14) by single colony isolation as previously described (7). For each experiment, pure colonies were reisolated from stock cultures stored in liquid nitrogen. Briefly, colonies plated on solid medium from the liquid nitrogen stocks were examined by using a stereomicroscope equipped with a plane polished substage reflector adjusted to differentiate between transparent and opaque colonies (14). Differences in colonial opacities were best seen when colonies were 20 to 24 h old. Single colonies were picked and subcultured on solid media for use in experiments th...

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Section: Resultsmentioning

confidence: 99%