Browsing by Author "Rice, Peter A."

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    Desialylation of Neisseria gonorrhoeae Lipooligosaccharide by Cervicovaginal Microbiome Sialidases: The Potential for Enhancing Infectivity in Men
    (Oxford University Press, 2016-12-01) Ketterer, Margaret R.; Rice, Peter A.; Gulati, Sunita; Kiel, Steven; Byerly, Luke; Fortenberry, J. Dennis; Soper, David E.; Apicella, Michael A.; Pediatrics, School of Medicine
    Previous studies have demonstrated that Neisseria gonorrhoeae sialylates the terminal N-acetyllactosamine present on its lipooligosaccharide (LOS) by acquiring CMP-N-acetyl-5-neuraminic acid upon entering human cells during infection. This renders the organism resistant to killing by complement in normal human serum. N-acetyllactosamine residues on LOS must be free of N-acetyl-5-neuraminc acid (Neu5Ac; also known as "sialic acid") in order for organisms to bind to and enter urethral epithelial cells during infection in men. This raises the question of how the gonococcus infects men if N-acetyllactosamine residues are substituted by Neu5Ac during infection in women. Here, we demonstrate that women with gonococcal infections have levels of sialidases present in cervicovaginal secretions that can result in desialylation of (sialylated) gonococcal LOS. The principle sialidases responsible for this desialylation appear to be bacterial in origin. These studies suggest that members of the cervicovaginal microbiome can modify N. gonorrhoeae, which will enhance successful transmission to men.
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    Genotype-specific Concordance of Chlamydia trachomatis Genital Infection within Heterosexual Partnerships
    (Lippincott, Williams & Wilkins, 2016-12) Schillinger, Julia A.; Katz, Barry P.; Markowitz, Lauri E.; Braslins, Phillip G.; Shrier, Lydia A.; Madico, Guillermo; Van Der Pol, Barbara; Orr, Donald P.; Rice, Peter A.; Batteiger, Byron E.; Biostatistics, School of Public Health
    Background Sexual transmission rates of Chlamydia trachomatis (Ct) cannot be measured directly; however, the study of concordance of Ct infection in sexual partnerships (dyads) can help to illuminate factors influencing Ct transmission. Methods Heterosexual men and women with Ct infection and their sex partners were enrolled and partner-specific coital and behavioral data collected for the prior 30 days. Microbiological data included Ct culture, nucleic acid amplification testing (NAAT), quantitative Ct polymerase chain reaction (qPCR), and ompA genotyping. We measured Ct concordance in dyads, and factors (correlates) associated with concordance. Results 121 women and 125 men formed 128 dyads. Overall, 72.9% of male partners of NAAT-positive women and 68.6% of female partners of NAAT-positive men were Ct-infected. Concordance was more common in dyads with culture-positive members (78.6% of male partners, 77% of female partners). Partners of women and men who were NAAT-positive only had lower concordance (33.3%, 46.4%, respectively). Women in concordant dyads had significantly higher median endocervical qPCR values (3,032) compared with CT-infected women in discordant dyads (1,013 IFU DNA equivalents per ml), p<0.01. Among 54 Ct-concordant dyads with ompA genotype data for both members, 96.2% had identical genotypes. Conclusions Higher organism load appears associated with concordance among women. Same-genotype chlamydial concordance was high in sexual partnerships. No behavioral factors were sufficiently discriminating to guide partner services activities. Findings may help model coitus-specific transmission probabilities.