Reduced rates of HIV acquisition during unprotected sex by Kenyan female sex workers predating population declines in HIV prevalence

Kimani, Joshua; Kaul, Rupert; Nagelkerke, Nico; Luo, Ma; MacDonald, Kelly S.; Ngugi, Elizabeth; Fowke, Keith R.; Ball, Blake; Kariri, Anthony; Ndinya‐Achola, Jeckoniah; Plummer, Francis A.

doi:10.1097/qad.0b013e3282f27035

Cited by 56 publications

(60 citation statements)

References 30 publications

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“…Older FSW were also more likely to be HIV infected at baseline and therefore excluded from the HIV-negative cohort. The HIV prevalence in Kenya has also declined, following HIV incidence declines in FSW cohorts [24]. These factors together could imply that FSW have less exposure to HIV in their sexual networks, thus lowering their risk.…”

Section: Discussionmentioning

confidence: 99%

Risk Factors for HIV Acquisition in a Prospective Nairobi-Based Female Sex Worker Cohort

et al. 2015

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With two million new HIV infections annually, ongoing investigations of risk factors for HIV acquisition is critical to guide ongoing HIV prevention efforts. We conducted a prospective cohort analysis of HIV uninfected female sex workers enrolled at an HIV prevention clinic in Nairobi (n = 1640). In the initially HIV uninfected cohort (70 %), we observed 34 HIV infections during 1514 person-years of follow-up, i.e. an annual incidence of 2.2 % (95 % CI 1.6-3.1 %). In multivariable Cox Proportional Hazard analysis, HIV acquisition was associated with a shorter baseline duration of sex work (aHR 0.76, 95 % CI 0.63-0.91), minimum charge/sex act (aHR 2.74, 0.82-9.15, for low vs. intermediate; aHR 5.70, 1.96-16.59, for high vs. intermediate), N. gonorrhoeae infection (aAHR 5.89, 95 % CI 2.03-17.08), sex with casual clients during menses (aHR 6.19, 95 % CI 2.58-14.84), Depo Provera use (aHR 5.12, 95 % CI 1.98-13.22), and estimated number of annual unprotected regular partner contacts (aHR 1.004, 95 % CI 1.001-1.006). Risk profiling based on baseline predictors suggested that substantial heterogeneity in HIV risk is evident, even within a key population. These data highlight several risk factors for HIV acquisition that could help to re-focus HIV prevention messages.

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Section: Discussionmentioning

confidence: 99%

Risk Factors for HIV Acquisition in a Prospective Nairobi-Based Female Sex Worker Cohort

et al. 2015

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“…Vaginal samples were collected as part of a larger study in a cohort of commercial sex workers in Nairobi, Kenya (18). Midvaginal swabs were collected by a single physician during 6-month follow-up examinations.…”

Section: Methodsmentioning

confidence: 99%

Pyrosequencing of the Chaperonin-60 Universal Target as a Tool for Determining Microbial Community Composition

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et al. 2009

Appl Environ Microbiol

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We compared dideoxy sequencing of cloned chaperonin-60 universal target (cpn60 UT) amplicons to pyrosequencing of amplicons derived from vaginal microbial communities. In samples pooled from a number of individuals, the pyrosequencing method produced a data set that included virtually all of the sequences that were found within the clone library and revealed an additional level of taxonomic richness. However, the relative abundances of the sequences were different in the two datasets. These observations were expanded and confirmed by the analysis of paired clone library and pyrosequencing datasets from vaginal swabs taken from four individuals. Both for individuals with a normal vaginal microbiota and for those with bacterial vaginosis, the pyrosequencing method revealed a large number of low-abundance taxa that were missed by the clone library approach. In addition, we showed that the pyrosequencing method generates a reproducible profile of microbial community structure in replicate amplifications from the same community. We also compared the taxonomic composition of a vaginal microbial community determined by pyrosequencing of 16S rRNA amplicons to that obtained using cpn60 universal primers. We found that the profiles generated by the two molecular targets were highly similar, with slight differences in the proportional representation of the taxa detected. However, the number of operational taxonomic units was significantly higher in the cpn60 data set, suggesting that the protein-encoding gene provides improved species resolution over the 16S rRNA target. These observations demonstrate that pyrosequencing of cpn60 UT amplicons provides a robust, reliable method for deep sequencing of microbial communities.

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“…Samples were collected from African women as part of a larger study, ongoing since the 1980s, examining the factors associated with resistance to human immunodeficiency virus infection in a cohort of commercial sex workers in Nairobi, Kenya (22). Other samples were collected from young women from North America within the scope of a research program aimed at developing methodologies for studying the vaginal microbiota (36).…”

Section: Methodsmentioning

confidence: 99%

Multiplex Detection of Bacteria Associated with Normal Microbiota and with Bacterial Vaginosis in Vaginal Swabs by Use of Oligonucleotide-Coupled Fluorescent Microspheres

et al. 2009

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Bacterial vaginosis (BV) is a recurrent condition that is associated with a range of negative outcomes, including the acquisition of human immunodeficiency virus and other sexually transmitted diseases, preterm births, and pelvic inflammatory disease. In contrast to the Lactobacillus-dominated normal vaginal microbiota, BV is characterized by a lack of lactobacilli and an abundance of anaerobic and gram-negative organisms, including Gardnerella vaginalis and Atopobium vaginae. To date, the laboratory diagnosis of BV has relied upon the fulfillment of criteria determined by microscopic observation of Gram-stained vaginal swabs. We describe a molecular-based method for the easy determination of the species profile within the vaginal microbiota based on the amplification of the chaperonin-60 genes of all bacteria present in the swab and hybridization of the amplicon to species-specific oligonucleotide-coupled fluorescent beads that are identified by flow cytometry with a Luminex instrument. We designed a nineplex Luminex array for characterization of the vaginal microbiota and applied it to the analysis of vaginal swabs from individuals from Africa and North America. Using the presence of A. vaginae or G. vaginalis, or both, as the defining criterion for BV, we found that the method was highly specific and sensitive for the diagnosis of BV using microscopy as a gold standard.Bacterial vaginosis (BV), which is defined by a reduction in the vaginal Lactobacillus populations and an increase in the number of microbial species present, including Gardnerella spp., Atopobium spp., and others, is increasingly recognized as an important risk factor for adverse reproductive health outcomes, such as miscarriage and premature birth, and sexually transmitted diseases, including human immunodeficiency virus infection (25). Despite intense investigation, the etiology and clinical course of BV have not been well defined, probably because the normal variation of the vaginal microbial communities between individuals and their dynamics over time are complex and poorly understood. Consequently, the accurate diagnosis of BV, as well as the elaboration of effective prevention and treatment strategies, remains a major challenge (26, 44).The current "gold standard" for the diagnosis of BV in the laboratory setting relies on microscopic profiling of microbial types in Gram-stained vaginal swab smears by using the criteria of Nugent et al. (29) or Ison and Hay (20). These scoring systems are based on the relative abundance of Lactobacillus morphotypes (large gram-positive rods) compared to the abundance of the bacterial morphotypes suggestive of BV (gramnegative or gram-variable coccobacilli and curved rods and gram-positive cocci). Although this method provides reliable information and is particularly well suited for use in resourcepoor settings, it requires well-trained, highly experienced individuals to interpret the results and is simplistic in its reflection of the variety of organisms present in the microbial communities present in he...

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Reduced rates of HIV acquisition during unprotected sex by Kenyan female sex workers predating population declines in HIV prevalence

Cited by 56 publications

References 30 publications

Risk Factors for HIV Acquisition in a Prospective Nairobi-Based Female Sex Worker Cohort

Risk Factors for HIV Acquisition in a Prospective Nairobi-Based Female Sex Worker Cohort

Pyrosequencing of the Chaperonin-60 Universal Target as a Tool for Determining Microbial Community Composition

Multiplex Detection of Bacteria Associated with Normal Microbiota and with Bacterial Vaginosis in Vaginal Swabs by Use of Oligonucleotide-Coupled Fluorescent Microspheres

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