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Background While Lynch syndrome (LS) is a highly penetrant colorectal cancer (CRC) syndrome, there is considerable variation in penetrance, few studies have investigated the association between microbiome and CRC risk in LS. We analyzed the microbiome composition among individuals with LS with and without personal history of colorectal neoplasia (CRN) and non-LS controls. Methods We sequenced the V4 region of the 16S rRNA gene from the stool of 46 individuals with LS and 53 individuals without LS. We characterized within community and in between community microbiome variation, compared taxon abundance and built machine learning models to investigate differences in microbiome. Results There was no difference within or between community variation among LS groups, but there was a statistically significant difference in both within and between community variation comparing LS to non-LS. Streptococcus and Actinomyces were differentially enriched in LS-CRC compared to LS-without CRN. There were numerous differences in taxa abundance comparing LS to non-LS notably Veillonella was enriched and Facaelibacterium and Romboustia were depleted in LS. Finally, machine learning models classifying LS from non-LS controls and LS-CRC from LS-without CRN performed moderately well. Conclusions Differences in microbiome composition between LS and non-LS may suggest a microbiome pattern unique to LS formed by underlying differences in epithelial biology and immunology. We found specific taxa differences among LS groups, which may be due to underlying anatomy. Larger prospective studies following for CRN diagnosis and microbiome composition changes are needed to determine if microbiome composition contributes to CRN development in patients with LS.

Background The protective effect of hormonal contraception may offer a potential intervention against bacterial vaginosis (BV). Study Design Three hundred thirty reproductive-age women enrolled in a contraceptive program from April 2005 to October 2006 at two sexually transmitted diseases clinics in Baltimore, MD. Participants were supplied with hormonal contraceptives of their choice and followed prospectively. BV was diagnosed by Amsel's criteria. Results from population-level analysis were compared to a case-crossover analysis. Results BV was diagnosed in 189 (13.0%) of the visits among 133 (40.3%) women. In the population-level analysis, the use of progestin-only and combined contraception was associated with a decreased risk of BV compared to intervals of no hormonal contraceptive use [adjusted odds ratio (AOR): 0.42 (95% CI: 0.20–0.88) and AOR: 0.66 (95% CI: 0.39–1.10), respectively]. The case-crossover analysis demonstrated a similar trend in findings. Conclusion Hormonal contraception was associated with a decreased risk of BV in an STD clinic cohort.

Objective: Identify factors associated with false-positive rapid HIV antibody tests. Design: This retrospective cohort study with nested case–controls involved patients tested for HIV by Boston Medical Center (BMC) affiliates. Methods: Cases had a reactive fingerstick OraQuick ADVANCE rapid HIV 1/2 antibody test and a negative Western blot. Controls had nonreactive rapid tests. We compared the prevalence of HIV risk factors between cases and the total nonreactive population and the prevalence of other clinical factors between cases and controls. Results: Of the 15 094 tests, 14 937 (98.9%) were negative and 11 (0.07%) were false positives (specificity of 99.9%). Cases were more likely to have had an HIV-infected sex partner and to be tested at certain sites compared to true negatives. More cases than controls had O-negative blood type. Conclusion: O-negative blood type and sex with an HIV-infected person may increase false-positive HIV fingerstick results. More targeted studies should examine these risk factors.