Rita Verhelst - Academia.edu (original) (raw)

Papers by Rita Verhelst

<b>Copyright information:</b>Taken from "Comparison between Gram stain and cultu... more <b>Copyright information:</b>Taken from "Comparison between Gram stain and culture for the characterization of vaginal microflora: Definition of a distinct grade that resembles grade I microflora and revised categorization of grade I microflora"BMC Microbiology 2005;5():61-61.Published online 14 Oct 2005PMCID:PMC1266370.Copyright © 2005 Verhelst et al; licensee BioMed Central Ltd.ll types. g, h: grade I-like, i.e. irregular-shaped Gram positive rods. i, j: grade II, i.e. mixture of cell types and bacterial vaginosis-associated bacteria (, and cell types). k, l: grade III, i.e. bacterial vaginosis.

Background. Improved knowledge on the relationships between the cervicovaginal microbiome and adv... more Background. Improved knowledge on the relationships between the cervicovaginal microbiome and adverse reproductive health outcomes could lead to low cost interventions directed at maintaining and restoring a healthy microbiome. Methods. Cervical samples of 174 female sex workers in Kigali, Rwanda, were analysed cross-sectionally using a phylogenetic microarray specifically designed for the cervicovaginal microbiome. Women with sexually transmitted infections (STIs) were purposefully oversampled. Two hundred fifty one probes were used for co-regularised spectral clustering analysis and 123 probes (specific at species or genus level) to describe the cervicovaginal microbiome clusters. Demographic, behavioral, and clinical correlates of the clusters were also determined. Results. Six cervicovaginal microbiome clusters were identified. Clusters R-I and R-II were dominated by Lactobacillus crispatus and L. iners, respectively, were associated with a Nugent score of 0-3, and had a low (se...

OBJECTIVE: The purpose of this study was to assess concentrations of soluble triggering receptor ... more OBJECTIVE: The purpose of this study was to assess concentrations of soluble triggering receptor expressed on myeloid cells (sTREM)-1 in maternal serum during term and preterm labor (PTL). MATERIALS AND METHODS: This cross-sectional study included 176 singleton pregnancies in the following groups: (1) preterm birth, delivered before 34 weeks gestation (PTB) (n=52); (2) preterm (PT) not in labor, matched for gestational age (GA) with the PTB group (n=52); (3) women with an episode of PTL who delivered at term (n=10); (4) AT in labor (n=40) and (5) AT not in labor (n=32). Serum concentrations of sTREM-1 were determined by enzyme-linked immunoassay. RESULTS: sTREM-1 was detected in all serum samples. Median sTREM-1 concentrations were significantly higher in women with PTB vs. PT not in labor (367.3 pg/ml, interquartile range (IQR) 303.9-483.1 vs. 272.7 pg/ml, IQR 207.7-334.1; P<0.001) and in women AT in labor vs. AT not in labor (300.0 pg/ml, IQR 239.1-353.0 vs. 227.6 pg/ml, IQR 17...

OBJECTIVE: MMPs may play a role in initiating labour and rupture of membranes. Therefore, we meas... more OBJECTIVE: MMPs may play a role in initiating labour and rupture of membranes. Therefore, we measured serum concentrations of MMP-3 and MMP-9 in women in preterm labour (group 1) as compared to women in term labour (group 2) and gestational age matched controls between 24-33 weeks not in labour (group 3). METHODS: Case-control study in singleton pregnancies. MMP-9 levels were measured in 27 women in group 1 and 3, and 26 women in group 2. MMP-3 levels were determined in 15 women in each group. Maternal serum MMP-3 and MMP-9 were measured by Luminex multianalyte profiling technology. A spike and recovery experiment was performed to validate the immunoassay for serum. RESULTS: Mean MMP-9 serum levels were significantly higher in preterm labour compared to term labour (3588.9 pg/ml vs. 1791.6 pg/ml; P < 0.001). MMP-9 levels were also higher in the preterm labour group as compared to gestational age matched controls (3588.9 pg/ml vs. 1628.4 pg/ml; P < 0.001). MMP-3 levels were not...

Clinical Microbiology and Infection, 2010

Blood, 1998

Human umbilical cord blood (UCB) hematopoietic stem cells (HSC) receive increased attention as a ... more Human umbilical cord blood (UCB) hematopoietic stem cells (HSC) receive increased attention as a possible target for gene-transfer in gene therapy trials. Diseases affecting the lymphoid lineage, as adenosine deaminase (ADA) deficiency and acquired immunodeficiency syndrome (AIDS) could be cured by gene therapy. However, the T-cell progenitor potential of these HSC after gene-transfer is largely unknown and was up to now not testable in vitro. We show here that highly purified CD34++ Lineage marker-negative (CD34++Lin−) UCB cells generate T, natural killer (NK), and dendritic cells in a severe combined immunodeficient mouse fetal thymus organ culture (FTOC). CD34++Lin− and CD34++CD38−Lin− UCB cells express the retroviral encoded marker gene Green Fluorescent Protein (GFP) after in vitro transduction with MFG-GFP retroviral supernatant. Transduced cells were still capable of generating T, NK, and dendritic cells in the FTOC, all expressing high levels of GFP under control of the Molo...

PeerJ, 2016

Background.It is widely assumed that the uterine cavity in non-pregnant women is physiologically ... more Background.It is widely assumed that the uterine cavity in non-pregnant women is physiologically sterile, also as a premise to the long-held view that human infants develop in a sterile uterine environment, though likely reflecting under-appraisal of the extent of the human bacterial metacommunity. In an exploratory study, we aimed to investigate the putative presence of a uterine microbiome in a selected series of non-pregnant women through deep sequencing of the V1-2 hypervariable region of the 16S ribosomal RNA (rRNA) gene.Methods.Nineteen women with various reproductive conditions, including subfertility, scheduled for hysteroscopy and not showing uterine anomalies were recruited. Subjects were highly diverse with regard to demographic and medical history and included nulliparous and parous women. Endometrial tissue and mucus harvesting was performed by use of a transcervical device designed to obtain endometrial biopsy, while avoiding cervicovaginal contamination. Bacteria were...

AFRICAN JOURNAL OF BIOTECHNOLOGY

Lactobacilli predominate normal vaginal microflora and are important in maintenance of vaginal he... more Lactobacilli predominate normal vaginal microflora and are important in maintenance of vaginal health. The current study set out to identify and compare culture isolates of vaginal microflora of human immunodeficiency virus (HIV) positive (HIV +) and HIV negative (HIV-) women at different phases during menstrual cycle from a suburban population of Kenya. Seventy four (74) women, 41 HIV + and 33 HIV-, followed up two consecutive menstrual cycles, had high vaginal swabs taken to prepare Gram stains for six visits and anaerobic cultures for four. All 751 isolates identified by t-DNA polymerase chain reaction (PCR) belong to 51 species. Species cultured more frequently in HIV + participants were: Lactobacillus jensenii (p=0.01), Lactobacillus iners (p=0.02), Gardnerella vaginalis (p=0.01) and Peptoniphilus lacrimalis (p=0.01). Species cultured more frequently in HIVwomen were Dialister micraerophilus (p=0.02) and Streptococcus agalactiae (p=0.04). Lactobacillus predominating both groups were Lactobacilli crispatus, L. jensenii, L. iners and Lactobacilli vaginalis. Bacterial vaginosis (BV) was equally high in HIV + and HIVwomen. Lactobacillus and BV-associated species were cultured more frequently in HIV + women. Minor species differences were found. Predominant Lactobacillus in culture were L. crispatus, L. iners, L. jensenii and L. vaginalis. These women had lower concentrations of lactobacilli in vaginal microflora than observed in previous studies of Caucasian women.

Background: The ideal microbicide should reduce the risk of HIV-infection while preserving the in... more Background: The ideal microbicide should reduce the risk of HIV-infection while preserving the integrity of the cervicovaginal epithelium. RTI could hamper the protective effect of microbicides. Methods: The Microbicide Safety Biomarkers Study is a prospective cohort study in Kenya (adult, adolescent and pregnant women), South-Africa (adult, adolescent, pregnant and women engaging in vaginal practices) and Rwanda (high-risk and HIV-positive women). Biomarkers of the cervico-vaginal microbiome and inflammation, HIV target cells and reproductive tract infections (RTI) were studied. RTI data at screening are presented. Results: There was a significant difference (p=<0.001) in the prevalence of Candida albicans, Chlamydia trachomatis (CT), Neisseria gonorrhoea (NG), syphilis and herpes simplex-2 (HSV-2) between different study groups. Pregnant women have the highest prevalence of Candida (56.7% South-Africa, 23.3% Kenya), followed by the South-African adolescents (36.7%) and vaginal practices group (32.3%). HIV-positive women in Rwanda have the highest prevalence of NG (13.3%), syphilis (20%) and HSV-2 (82.2%), and women engaging in vaginal practices have the highest prevalence of CT (25.8%). When stratifying according to sexual risk taking, no significant difference was seen for Candida or Trichomonas vaginalis (TV). But NG, syphilis and HSV-2 were associated with sexual risk taking (p=<0.001); for example HSV-2 was detected almost twice as frequent in the high risk-takers (51.5%) compared to the low risk-takers (28.6%). Further, CT was associated (p=<0.001) with BV, women who didn’t suffer from BV had a lower risk (1.5%) at acquiring CT than women with BV (9%). For CT, NG, syphilis and HSV-2, the same trend was seen, but for Candida, the prevalence was comparable for women with (22.3%) and without BV (24.2%). Conclusion: Among African women targeted for microbicide trials, RTI are common and vary by multiple factors. It is therefore essential to evaluate the effects of RTI on the efficacy and safety of microbicides.

B-ENT, 2009

To assess the presence of middle ear pathogens in nasopharynx (NP), middle ear fluid (MEF), and m... more To assess the presence of middle ear pathogens in nasopharynx (NP), middle ear fluid (MEF), and middle ear mucosal swabs (MES) of 14 patients undergoing middle ear surgery. Bacteria were assessed by culture and species specific PCR. Biofilm was investigated by confocal laser scanning microscopy (CLSM) of middle ear biopsies (MEBs). Bacteria were absent in CLSM of MEBs in three of the four closed and healthy middle ears. Bacteria occurred in the ear with a foreign body (middle ear prosthesis), which showed localized living and dead bacteria, indicating biofilm. Bacterial growth was present in ten patient ears, but biofilm occurred in only one patient. CLSM indicated biofilm in the middle ear of two patients for whom PCR detected Haemophilus influenzae in the MEF. The three classical pathogens could frequently be found in the nasopharynx, by culture and PCR, but not from the middle ear. Alloiococcus otitidis was detected in the MEF of all five patients with open inflamed ears, though ...

BMC Infectious Diseases, 2015

Background: Women in sub-Saharan Africa are vulnerable to acquiring HIV infection and reproductiv... more Background: Women in sub-Saharan Africa are vulnerable to acquiring HIV infection and reproductive tract infections. Bacterial vaginosis (BV), a disruption of the vaginal microbiota, has been shown to be strongly associated with HIV infection. Risk factors related to potentially protective or harmful microbiota species are not known. Methods: We present cross-sectional quantitative polymerase chain reaction data of the Lactobacillus genus, five Lactobacillus species, and three BV-related bacteria (Gardnerella vaginalis, Atopobium vaginae, and Prevotella bivia) together with Escherichia coli and Candida albicans in 426 African women across different groups at risk for HIV. We selected a reference group of adult HIV-negative women at average risk for HIV acquisition and compared species variations in subgroups of adolescents, HIV-negative pregnant women, women engaging in traditional vaginal practices, sex workers and a group of HIV-positive women on combination antiretroviral therapy. We explored the associations between presence and quantity of the bacteria with BV by Nugent score, in relation to several factors of known or theoretical importance. Results: The presence of species across Kenyan, South African and Rwandan women was remarkably similar and few differences were seen between the two groups of reference women in Kenya and South Africa. The Rwandan sex workers and HIV-positive women had the highest G. vaginalis presence (p = 0.006). Pregnant women had a higher Lactobacillus genus mean log (7.01 genome equivalents (geq)/ml) compared to the reference women (6.08 geq/ml). L. vaginalis (43%) was second to L. iners (81.9%) highly present in women with a normal Nugent score. Recent sexual exposure negatively affected the presence of L. crispatus (<0.001), L. vaginalis (p = 0.001), and Lactobacillus genus (p < 0.001). Having more than one sexual partner in the last three months was associated with an increased prevalence of G. vaginalis (p = 0.044) and L. iners (p = 0.001). Conclusions: Although the composition of species across the studied African countries was similar, the presence of protective species i.e. L. crispatus and L. vaginalis in women with a normal Nugent score appeared lower compared to non-African studies. Furthermore, Lactobacillus species were negatively affected by sexual behavioural. Strategies to support protective Lactobacillus species are urgently needed.

BMC Infectious Diseases, 2015

Background: Sociodemographic, behavioral and clinical correlates of the vaginal microbiome (VMB) ... more Background: Sociodemographic, behavioral and clinical correlates of the vaginal microbiome (VMB) as characterized by molecular methods have not been adequately studied. VMB dominated by bacteria other than lactobacilli may cause inflammation, which may facilitate HIV acquisition and other adverse reproductive health outcomes. Methods: We characterized the VMB of women in Kenya, Rwanda, South Africa and Tanzania (KRST) using a 16S rDNA phylogenetic microarray. Cytokines were quantified in cervicovaginal lavages. Potential sociodemographic, behavioral, and clinical correlates were also evaluated. Results: Three hundred thirteen samples from 230 women were available for analysis. Five VMB clusters were identified: one cluster each dominated by Lactobacillus crispatus (KRST-I) and L. iners (KRST-II), and three clusters not dominated by a single species but containing multiple (facultative) anaerobes (KRST-III/IV/V). Women in clusters KRST-I and II had lower mean concentrations of interleukin (IL)-1α (p < 0.001) and Granulocyte Colony Stimulating Factor (G-CSF) (p = 0.01), but higher concentrations of interferon-γ-induced protein (IP-10) (p < 0.01) than women in clusters KRST-III/IV/V. A lower proportion of women in cluster KRST-I tested positive for bacterial sexually transmitted infections (STIs; p trend = 0.07) and urinary tract infection (UTI; p = 0.06), and a higher proportion of women in clusters KRST-I and II had vaginal candidiasis (p trend = 0.09), but these associations did not reach statistical significance. Women who reported unusual vaginal discharge were more likely to belong to clusters KRST-III/IV/V (p = 0.05). Conclusion: Vaginal dysbiosis in African women was significantly associated with vaginal inflammation; the associations with increased prevalence of STIs and UTI, and decreased prevalence of vaginal candidiasis, should be confirmed in larger studies.

Sexually Transmitted Diseases, 2015

Lecture Notes in Computer Science, 2013

In many unsupervised learning problems data can be available in different representations, often ... more In many unsupervised learning problems data can be available in different representations, often referred to as views. By leveraging information from multiple views we can obtain clustering that is more robust and accurate compared to the one obtained via the individual views. We propose a novel algorithm that is based on neighborhood co-regularization of the clustering hypotheses and that searches for the solution which is consistent across different views. In our empirical evaluation on publicly available datasets, the proposed method outperforms several state-of-the-art clustering algorithms. Furthermore, application of our method to recently collected biomedical data leads to new insights, critical for future research on determinants of the cervicovaginal microbiome and the cervicovaginal microbiome as a risk factor for the transmission of HIV. These insights could have an influence on the interpretation of clinical presentation of women with bacterial vaginosis and treatment decisions. 1 Introduction The multi-view paradigm [1-3] is particularly suitable for learning on datasets having more than a single data representation. A classic example is a web document classification task [1], where documents are represented via two different These authors contributed equally to this work.. Note that the left-hand side matrix is positive definite and therefore invertible.

BMC infectious diseases, Jan 14, 2005

Mycoplasmas are present worldwide in a large number of animal hosts. Due to their small genome an... more Mycoplasmas are present worldwide in a large number of animal hosts. Due to their small genome and parasitic lifestyle, Mycoplasma spp. require complex isolation media. Nevertheless, already over 100 different species have been identified and characterized and their number increases as more hosts are sampled. We studied the applicability of amplified rDNA restriction analysis (ARDRA) for the identification of all 116 acknowledged Mycoplasma species and subspecies. Based upon available 16S rDNA sequences, we calculated and compared theoretical ARDRA profiles. To check the validity of these theoretically calculated profiles, we performed ARDRA on 60 strains of 27 different species and subspecies of the genus Mycoplasma. In silico digestion with the restriction endonuclease AluI (AG--CT) was found to be most discriminative and generated from 3 to 13 fragments depending on the Mycoplasma species. Although 73 Mycoplasma species could be differentiated using AluI, other species gave undis...

The Journal of Infection in Developing Countries, 2012

Introduction: Chlamydia antibody testing (CAT) in serum has been introduced as a screening method... more Introduction: Chlamydia antibody testing (CAT) in serum has been introduced as a screening method in the infertility workup. We evaluated the test characteristics of two ELISA tests compared to micro-immunofluorescence tests (MIFs). MIFs are considered the gold standard in the C. trachomatis IgG antibodies detection. We also compared the accuracy of all CAT tests in predicting tubal subfertility, using laparoscopy as a reference. Methodology: Four commercial serological methods were used to analyse 101 serum samples for the presence of C. trachomatis IgG antibodies from patients at the Infertility Clinic of Ghent University Hospital. The diagnostic utility for prediction of tubal infertility of serological methods was evaluated based on patients' medical records. Results: A comparison of the serological assays showed little difference in the major performance characteristics: the sensitivities of all MIFs and ELISAs were 100% for all assays (except the ELISA Vircell, with a s...

<b>Copyright information:</b>Taken from "Comparison between Gram stain and cultu... more <b>Copyright information:</b>Taken from "Comparison between Gram stain and culture for the characterization of vaginal microflora: Definition of a distinct grade that resembles grade I microflora and revised categorization of grade I microflora"BMC Microbiology 2005;5():61-61.Published online 14 Oct 2005PMCID:PMC1266370.Copyright © 2005 Verhelst et al; licensee BioMed Central Ltd.ll types. g, h: grade I-like, i.e. irregular-shaped Gram positive rods. i, j: grade II, i.e. mixture of cell types and bacterial vaginosis-associated bacteria (, and cell types). k, l: grade III, i.e. bacterial vaginosis.

Background. Improved knowledge on the relationships between the cervicovaginal microbiome and adv... more Background. Improved knowledge on the relationships between the cervicovaginal microbiome and adverse reproductive health outcomes could lead to low cost interventions directed at maintaining and restoring a healthy microbiome. Methods. Cervical samples of 174 female sex workers in Kigali, Rwanda, were analysed cross-sectionally using a phylogenetic microarray specifically designed for the cervicovaginal microbiome. Women with sexually transmitted infections (STIs) were purposefully oversampled. Two hundred fifty one probes were used for co-regularised spectral clustering analysis and 123 probes (specific at species or genus level) to describe the cervicovaginal microbiome clusters. Demographic, behavioral, and clinical correlates of the clusters were also determined. Results. Six cervicovaginal microbiome clusters were identified. Clusters R-I and R-II were dominated by Lactobacillus crispatus and L. iners, respectively, were associated with a Nugent score of 0-3, and had a low (se...

OBJECTIVE: The purpose of this study was to assess concentrations of soluble triggering receptor ... more OBJECTIVE: The purpose of this study was to assess concentrations of soluble triggering receptor expressed on myeloid cells (sTREM)-1 in maternal serum during term and preterm labor (PTL). MATERIALS AND METHODS: This cross-sectional study included 176 singleton pregnancies in the following groups: (1) preterm birth, delivered before 34 weeks gestation (PTB) (n=52); (2) preterm (PT) not in labor, matched for gestational age (GA) with the PTB group (n=52); (3) women with an episode of PTL who delivered at term (n=10); (4) AT in labor (n=40) and (5) AT not in labor (n=32). Serum concentrations of sTREM-1 were determined by enzyme-linked immunoassay. RESULTS: sTREM-1 was detected in all serum samples. Median sTREM-1 concentrations were significantly higher in women with PTB vs. PT not in labor (367.3 pg/ml, interquartile range (IQR) 303.9-483.1 vs. 272.7 pg/ml, IQR 207.7-334.1; P<0.001) and in women AT in labor vs. AT not in labor (300.0 pg/ml, IQR 239.1-353.0 vs. 227.6 pg/ml, IQR 17...

OBJECTIVE: MMPs may play a role in initiating labour and rupture of membranes. Therefore, we meas... more OBJECTIVE: MMPs may play a role in initiating labour and rupture of membranes. Therefore, we measured serum concentrations of MMP-3 and MMP-9 in women in preterm labour (group 1) as compared to women in term labour (group 2) and gestational age matched controls between 24-33 weeks not in labour (group 3). METHODS: Case-control study in singleton pregnancies. MMP-9 levels were measured in 27 women in group 1 and 3, and 26 women in group 2. MMP-3 levels were determined in 15 women in each group. Maternal serum MMP-3 and MMP-9 were measured by Luminex multianalyte profiling technology. A spike and recovery experiment was performed to validate the immunoassay for serum. RESULTS: Mean MMP-9 serum levels were significantly higher in preterm labour compared to term labour (3588.9 pg/ml vs. 1791.6 pg/ml; P < 0.001). MMP-9 levels were also higher in the preterm labour group as compared to gestational age matched controls (3588.9 pg/ml vs. 1628.4 pg/ml; P < 0.001). MMP-3 levels were not...

Clinical Microbiology and Infection, 2010

Blood, 1998

Human umbilical cord blood (UCB) hematopoietic stem cells (HSC) receive increased attention as a ... more Human umbilical cord blood (UCB) hematopoietic stem cells (HSC) receive increased attention as a possible target for gene-transfer in gene therapy trials. Diseases affecting the lymphoid lineage, as adenosine deaminase (ADA) deficiency and acquired immunodeficiency syndrome (AIDS) could be cured by gene therapy. However, the T-cell progenitor potential of these HSC after gene-transfer is largely unknown and was up to now not testable in vitro. We show here that highly purified CD34++ Lineage marker-negative (CD34++Lin−) UCB cells generate T, natural killer (NK), and dendritic cells in a severe combined immunodeficient mouse fetal thymus organ culture (FTOC). CD34++Lin− and CD34++CD38−Lin− UCB cells express the retroviral encoded marker gene Green Fluorescent Protein (GFP) after in vitro transduction with MFG-GFP retroviral supernatant. Transduced cells were still capable of generating T, NK, and dendritic cells in the FTOC, all expressing high levels of GFP under control of the Molo...

PeerJ, 2016

Background.It is widely assumed that the uterine cavity in non-pregnant women is physiologically ... more Background.It is widely assumed that the uterine cavity in non-pregnant women is physiologically sterile, also as a premise to the long-held view that human infants develop in a sterile uterine environment, though likely reflecting under-appraisal of the extent of the human bacterial metacommunity. In an exploratory study, we aimed to investigate the putative presence of a uterine microbiome in a selected series of non-pregnant women through deep sequencing of the V1-2 hypervariable region of the 16S ribosomal RNA (rRNA) gene.Methods.Nineteen women with various reproductive conditions, including subfertility, scheduled for hysteroscopy and not showing uterine anomalies were recruited. Subjects were highly diverse with regard to demographic and medical history and included nulliparous and parous women. Endometrial tissue and mucus harvesting was performed by use of a transcervical device designed to obtain endometrial biopsy, while avoiding cervicovaginal contamination. Bacteria were...

AFRICAN JOURNAL OF BIOTECHNOLOGY

Lactobacilli predominate normal vaginal microflora and are important in maintenance of vaginal he... more Lactobacilli predominate normal vaginal microflora and are important in maintenance of vaginal health. The current study set out to identify and compare culture isolates of vaginal microflora of human immunodeficiency virus (HIV) positive (HIV +) and HIV negative (HIV-) women at different phases during menstrual cycle from a suburban population of Kenya. Seventy four (74) women, 41 HIV + and 33 HIV-, followed up two consecutive menstrual cycles, had high vaginal swabs taken to prepare Gram stains for six visits and anaerobic cultures for four. All 751 isolates identified by t-DNA polymerase chain reaction (PCR) belong to 51 species. Species cultured more frequently in HIV + participants were: Lactobacillus jensenii (p=0.01), Lactobacillus iners (p=0.02), Gardnerella vaginalis (p=0.01) and Peptoniphilus lacrimalis (p=0.01). Species cultured more frequently in HIVwomen were Dialister micraerophilus (p=0.02) and Streptococcus agalactiae (p=0.04). Lactobacillus predominating both groups were Lactobacilli crispatus, L. jensenii, L. iners and Lactobacilli vaginalis. Bacterial vaginosis (BV) was equally high in HIV + and HIVwomen. Lactobacillus and BV-associated species were cultured more frequently in HIV + women. Minor species differences were found. Predominant Lactobacillus in culture were L. crispatus, L. iners, L. jensenii and L. vaginalis. These women had lower concentrations of lactobacilli in vaginal microflora than observed in previous studies of Caucasian women.

Background: The ideal microbicide should reduce the risk of HIV-infection while preserving the in... more Background: The ideal microbicide should reduce the risk of HIV-infection while preserving the integrity of the cervicovaginal epithelium. RTI could hamper the protective effect of microbicides. Methods: The Microbicide Safety Biomarkers Study is a prospective cohort study in Kenya (adult, adolescent and pregnant women), South-Africa (adult, adolescent, pregnant and women engaging in vaginal practices) and Rwanda (high-risk and HIV-positive women). Biomarkers of the cervico-vaginal microbiome and inflammation, HIV target cells and reproductive tract infections (RTI) were studied. RTI data at screening are presented. Results: There was a significant difference (p=<0.001) in the prevalence of Candida albicans, Chlamydia trachomatis (CT), Neisseria gonorrhoea (NG), syphilis and herpes simplex-2 (HSV-2) between different study groups. Pregnant women have the highest prevalence of Candida (56.7% South-Africa, 23.3% Kenya), followed by the South-African adolescents (36.7%) and vaginal practices group (32.3%). HIV-positive women in Rwanda have the highest prevalence of NG (13.3%), syphilis (20%) and HSV-2 (82.2%), and women engaging in vaginal practices have the highest prevalence of CT (25.8%). When stratifying according to sexual risk taking, no significant difference was seen for Candida or Trichomonas vaginalis (TV). But NG, syphilis and HSV-2 were associated with sexual risk taking (p=<0.001); for example HSV-2 was detected almost twice as frequent in the high risk-takers (51.5%) compared to the low risk-takers (28.6%). Further, CT was associated (p=<0.001) with BV, women who didn’t suffer from BV had a lower risk (1.5%) at acquiring CT than women with BV (9%). For CT, NG, syphilis and HSV-2, the same trend was seen, but for Candida, the prevalence was comparable for women with (22.3%) and without BV (24.2%). Conclusion: Among African women targeted for microbicide trials, RTI are common and vary by multiple factors. It is therefore essential to evaluate the effects of RTI on the efficacy and safety of microbicides.

B-ENT, 2009

To assess the presence of middle ear pathogens in nasopharynx (NP), middle ear fluid (MEF), and m... more To assess the presence of middle ear pathogens in nasopharynx (NP), middle ear fluid (MEF), and middle ear mucosal swabs (MES) of 14 patients undergoing middle ear surgery. Bacteria were assessed by culture and species specific PCR. Biofilm was investigated by confocal laser scanning microscopy (CLSM) of middle ear biopsies (MEBs). Bacteria were absent in CLSM of MEBs in three of the four closed and healthy middle ears. Bacteria occurred in the ear with a foreign body (middle ear prosthesis), which showed localized living and dead bacteria, indicating biofilm. Bacterial growth was present in ten patient ears, but biofilm occurred in only one patient. CLSM indicated biofilm in the middle ear of two patients for whom PCR detected Haemophilus influenzae in the MEF. The three classical pathogens could frequently be found in the nasopharynx, by culture and PCR, but not from the middle ear. Alloiococcus otitidis was detected in the MEF of all five patients with open inflamed ears, though ...

BMC Infectious Diseases, 2015

Background: Women in sub-Saharan Africa are vulnerable to acquiring HIV infection and reproductiv... more Background: Women in sub-Saharan Africa are vulnerable to acquiring HIV infection and reproductive tract infections. Bacterial vaginosis (BV), a disruption of the vaginal microbiota, has been shown to be strongly associated with HIV infection. Risk factors related to potentially protective or harmful microbiota species are not known. Methods: We present cross-sectional quantitative polymerase chain reaction data of the Lactobacillus genus, five Lactobacillus species, and three BV-related bacteria (Gardnerella vaginalis, Atopobium vaginae, and Prevotella bivia) together with Escherichia coli and Candida albicans in 426 African women across different groups at risk for HIV. We selected a reference group of adult HIV-negative women at average risk for HIV acquisition and compared species variations in subgroups of adolescents, HIV-negative pregnant women, women engaging in traditional vaginal practices, sex workers and a group of HIV-positive women on combination antiretroviral therapy. We explored the associations between presence and quantity of the bacteria with BV by Nugent score, in relation to several factors of known or theoretical importance. Results: The presence of species across Kenyan, South African and Rwandan women was remarkably similar and few differences were seen between the two groups of reference women in Kenya and South Africa. The Rwandan sex workers and HIV-positive women had the highest G. vaginalis presence (p = 0.006). Pregnant women had a higher Lactobacillus genus mean log (7.01 genome equivalents (geq)/ml) compared to the reference women (6.08 geq/ml). L. vaginalis (43%) was second to L. iners (81.9%) highly present in women with a normal Nugent score. Recent sexual exposure negatively affected the presence of L. crispatus (<0.001), L. vaginalis (p = 0.001), and Lactobacillus genus (p < 0.001). Having more than one sexual partner in the last three months was associated with an increased prevalence of G. vaginalis (p = 0.044) and L. iners (p = 0.001). Conclusions: Although the composition of species across the studied African countries was similar, the presence of protective species i.e. L. crispatus and L. vaginalis in women with a normal Nugent score appeared lower compared to non-African studies. Furthermore, Lactobacillus species were negatively affected by sexual behavioural. Strategies to support protective Lactobacillus species are urgently needed.

BMC Infectious Diseases, 2015

Background: Sociodemographic, behavioral and clinical correlates of the vaginal microbiome (VMB) ... more Background: Sociodemographic, behavioral and clinical correlates of the vaginal microbiome (VMB) as characterized by molecular methods have not been adequately studied. VMB dominated by bacteria other than lactobacilli may cause inflammation, which may facilitate HIV acquisition and other adverse reproductive health outcomes. Methods: We characterized the VMB of women in Kenya, Rwanda, South Africa and Tanzania (KRST) using a 16S rDNA phylogenetic microarray. Cytokines were quantified in cervicovaginal lavages. Potential sociodemographic, behavioral, and clinical correlates were also evaluated. Results: Three hundred thirteen samples from 230 women were available for analysis. Five VMB clusters were identified: one cluster each dominated by Lactobacillus crispatus (KRST-I) and L. iners (KRST-II), and three clusters not dominated by a single species but containing multiple (facultative) anaerobes (KRST-III/IV/V). Women in clusters KRST-I and II had lower mean concentrations of interleukin (IL)-1α (p < 0.001) and Granulocyte Colony Stimulating Factor (G-CSF) (p = 0.01), but higher concentrations of interferon-γ-induced protein (IP-10) (p < 0.01) than women in clusters KRST-III/IV/V. A lower proportion of women in cluster KRST-I tested positive for bacterial sexually transmitted infections (STIs; p trend = 0.07) and urinary tract infection (UTI; p = 0.06), and a higher proportion of women in clusters KRST-I and II had vaginal candidiasis (p trend = 0.09), but these associations did not reach statistical significance. Women who reported unusual vaginal discharge were more likely to belong to clusters KRST-III/IV/V (p = 0.05). Conclusion: Vaginal dysbiosis in African women was significantly associated with vaginal inflammation; the associations with increased prevalence of STIs and UTI, and decreased prevalence of vaginal candidiasis, should be confirmed in larger studies.

Sexually Transmitted Diseases, 2015

Lecture Notes in Computer Science, 2013

In many unsupervised learning problems data can be available in different representations, often ... more In many unsupervised learning problems data can be available in different representations, often referred to as views. By leveraging information from multiple views we can obtain clustering that is more robust and accurate compared to the one obtained via the individual views. We propose a novel algorithm that is based on neighborhood co-regularization of the clustering hypotheses and that searches for the solution which is consistent across different views. In our empirical evaluation on publicly available datasets, the proposed method outperforms several state-of-the-art clustering algorithms. Furthermore, application of our method to recently collected biomedical data leads to new insights, critical for future research on determinants of the cervicovaginal microbiome and the cervicovaginal microbiome as a risk factor for the transmission of HIV. These insights could have an influence on the interpretation of clinical presentation of women with bacterial vaginosis and treatment decisions. 1 Introduction The multi-view paradigm [1-3] is particularly suitable for learning on datasets having more than a single data representation. A classic example is a web document classification task [1], where documents are represented via two different These authors contributed equally to this work.. Note that the left-hand side matrix is positive definite and therefore invertible.

BMC infectious diseases, Jan 14, 2005

Mycoplasmas are present worldwide in a large number of animal hosts. Due to their small genome an... more Mycoplasmas are present worldwide in a large number of animal hosts. Due to their small genome and parasitic lifestyle, Mycoplasma spp. require complex isolation media. Nevertheless, already over 100 different species have been identified and characterized and their number increases as more hosts are sampled. We studied the applicability of amplified rDNA restriction analysis (ARDRA) for the identification of all 116 acknowledged Mycoplasma species and subspecies. Based upon available 16S rDNA sequences, we calculated and compared theoretical ARDRA profiles. To check the validity of these theoretically calculated profiles, we performed ARDRA on 60 strains of 27 different species and subspecies of the genus Mycoplasma. In silico digestion with the restriction endonuclease AluI (AG--CT) was found to be most discriminative and generated from 3 to 13 fragments depending on the Mycoplasma species. Although 73 Mycoplasma species could be differentiated using AluI, other species gave undis...

The Journal of Infection in Developing Countries, 2012

Introduction: Chlamydia antibody testing (CAT) in serum has been introduced as a screening method... more Introduction: Chlamydia antibody testing (CAT) in serum has been introduced as a screening method in the infertility workup. We evaluated the test characteristics of two ELISA tests compared to micro-immunofluorescence tests (MIFs). MIFs are considered the gold standard in the C. trachomatis IgG antibodies detection. We also compared the accuracy of all CAT tests in predicting tubal subfertility, using laparoscopy as a reference. Methodology: Four commercial serological methods were used to analyse 101 serum samples for the presence of C. trachomatis IgG antibodies from patients at the Infertility Clinic of Ghent University Hospital. The diagnostic utility for prediction of tubal infertility of serological methods was evaluated based on patients' medical records. Results: A comparison of the serological assays showed little difference in the major performance characteristics: the sensitivities of all MIFs and ELISAs were 100% for all assays (except the ELISA Vircell, with a s...