Exponential-phase cells of Neisseria gonorrhaeae 2686 were examined for phospholipid composition and for membrane-associated phospholipase A activity. When cells were harvested by centrifugation, washed, and lyophilized before extraction, approximately 74% of the total phospholipid was phosphatidylethanolamine, 18% was phosphatidylglycerol, 2% was cardiolipin, and 10% was lysophosphatidylethanolamine. However, when cells still suspended in growth medium were extracted, the amount of lysophosphatidylethanolamine decreased to approximately 1% of the phospholipid composition. This suggests that a gonococcal phospholipase A may be activated by conditions encountered during centrifugation and/or lyophilization of cells preceding extraction. Phospholipase A activity associated with cell membranes was assayed by measuring the conversion of tritiated phosphatidylethanolamine to lysophosphatidylethanolamine. Optimal activity was demonstrated in 10% methanol at pH 8.0 to 8.5, in the presence of calcium ions. The activity was both detergent sensitive and thermolabile. Comparisons of gonococcal colony types 1 and 4 showed no significant differences between the two types with respect to either phospholipid content or phospholipase A activity.
Gonococcal (GC) infections are very common and are sustained by a core group of persons who often have repeated GC infections. Identifying individual risk factors for repeated GC infection is essential so that infection control programs can develop better strategies for decreasing the incidence of GC infection. A case-control study among high-risk persons found that being African American, having previous chlamydia infection, and having less than a high-school education were associated with repeated GC infections. Remarkably, measures of sexual behavior and access to health care were not associated with repeated GC infections. These findings suggest that among high-risk persons, the community prevalence of GC infection is more important in predicting risk for repeated GC infections than individual behavior. Interventions should include continued use of resources in high-prevalence communities and better understanding of the roles social and economic discrimination play in the risk for GC infections.
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