Gonococci and meningococci are obligate human pathogens that can infect diverse sites within the human host. Each of these sites represents a unique niche with respect to nutrients, environmental factors, and competing microorganisms. The growth environment has a marked effect on the metabolism and cellular composition of Neisseria gonorrhoeae and N. meningitidis. Altered cellular composition is often reflected by changes in the cell surface that can ultimately affect the interaction of these microorganisms with the human host. The physiology and metabolism of the pathogenic Neisseria spp. have not been reviewed since 1979 (41). This review will discuss selected areas that have implications for the pathogenesis of these important microorganisms. IRON METABOLISMAfter entry into the human host, N. gonorrhoeae and N. meningitidis must multiply to colonize mucosal surfaces and to establish an infection. Cell growth and multiplication require essential nutrients such as iron. To obtain iron, the pathogenic Neisseria spp. must acquire it from the host. Despite the relative abundance of iron in the host, there is little free iron because of its sequestration by the ironbinding proteins transferrin (TF) and lactoferrin (LF) (19). In serum and interstitial fluid, iron is associated with TF; in breast milk, semen, and mucosal surfaces, it is associated primarily with LF. Consequently, gonococci and meningococci must possess mechanisms for utilizing the iron associated with the host iron-binding proteins as well as other potential in vivo iron sources such as heme and hemoglobin.Several studies have implicated iron in the virulence of the pathogenic Neisseria spp. Calver et al. (7) demonstrated that injection of ferrous sulfate prior to or injection of either iron sorbitol citrate or iron-dextran concomitantly with injection of N. meningitidis increased the lethality of several different meningococcal serogroups for mice by up to a 106-fold. The effect of the added iron was partially abrogated by the prior incubation of N. meningitidis with Desferal (CIBA-GEIGY Corp.), an iron chelator from which meningococci and gonococci are unable to remove iron (36). Holbein et al. (24) showed that the 50% lethal dose of N. meningitidis strains in a mouse model was decreased 109-fold by the concomitant administration of iron-dextran with the inoculum. Payne and Finkelstein (50) found that the intravenous inoculation of iron-containing compounds together with avirulent (nonpiliated) gonococci increased the lethality of these avirulent organisms for chicken embryos.Hafiz et al. (20) All strains of N. gonorrhoeae and N. meningitidis are able to grow with 25% iron-saturated TF as their sole source of iron (37). Archibald and DeVoe (1, 2) found that meningococci were capable of obtaining iron from a variety of iron-containing compounds including gastric mucin, ferric citrate, hemoglobin, myoglobin, and human TF. Iron complexed with a number of metabolic organic acids, polyphosphates, and several synthetic polycarboxylic acids was also re...
Background Several jurisdictions globally have implemented internet-based STI and HIV testing with good uptake and reach into untested populations. In British Columbia, a similar program is under development to offer online access to chlamydia, gonorrhoea, syphilis, and HIV testing. This program aims to increase the frequency of testing in individuals at risk of infection and ease demand on clinic-based services by providing an accessible option for screening asymptomatic persons. We conducted a series of focus groups in spring 2011 to determine the acceptability of various aspects of the internet testing model and of the service overall. Methods Two types of prospective internet testing clients living in the Vancouver area were recruited for focus groups: self-identified gay/bisexual/two-spirit men (hereafter "gay men") and STI clinic clients. Participants were presented with a brief description of the internet testing model, after which a structured interview guide was used to address the following domains: willingness to provide personal information online, ways to engender trust in the service, comfort with different ways of delivering results, interest in specific features, appeal of the service, and willingness to use the service. Results Most of the 31 participants to-date (ages 21e70 years) were gay men (81%) and reported post-secondary education (74%). All were self-described active internet users and had been tested previously for HIV or other STI. Overall, the concept of internet testing was thought to be acceptable and most participants expressed interest in using the service when it becomes available. Participants indicated that internet testing would be convenient and could enhance the accessibility of STI testing, particularly for people living outside of urban centres. Some noted that an internet approach would also have the potential to allay embarrassment that can arise when seeking STI testing in a face-to-face clinical setting. There was strong interest in assuring anonymity for those using the proposed internet testing service. Participants also emphasised the importance of providing information related to HIV diagnosis and referrals to peer support and counselling for those waiting for and receiving test results. Conclusions Internet testing was deemed to be acceptable and desirable and appears to hold promise as a means to complement to existing clinic-based STI testing services in Vancouver, Canada.
O5-S2.04 Table 1 Sexually transmitted infections provider knowledge, beliefs and attitudes in Gauteng, South Africa, 2008e2009
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