Rita Verhelst | Ghent University (original) (raw)

Papers by Rita Verhelst

Research paper thumbnail of Terminal restriction fragment length polymorphism analysis of the microflora in necrotic teeth of patients irradiated in the head and neck region

Journal of Endodontics, Jan 9, 2008

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Otitis media microbes: culture, PCR, and confocal laser scanning microscopy

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 virtually absent from the nasopharynx. Pseudomonas aeruginosa was present in seven. It was the only pathogen found on several occasions in all three locations in one patient. This study confirms the association of H. influenzae with middle ear biofilm, and indicates a potential role of P. aeruginosa in middle ear inflammation and biofilm formation. Biofilm does not seem to cause inflammation. It is unclear whether the predominance of A. otitidis in chronically inflamed open middle ears indicates a pathogenic or contaminant role for this organism.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Inflammatory response in maternal serum during preterm labour

Wetenschapsdag Posters, 2012

ABSTRACT Preterm birth (PTB), defined as a delivery before 37 weeks of gestation, is the leading ... more ABSTRACT Preterm birth (PTB), defined as a delivery before 37 weeks of gestation, is the leading cause of perinatal morbidity and mortality worldwide. Diagnosis of preterm labour as well as accurate prediction of PTB is notoriously difficult. Preterm birth is initiated by multiple mechanisms including infection or inflammation which is the only pathological process for which a firm causal link with PTB has been established. Intrauterine infection evokes an immune response that involves the release of cytokines and chemokines, prostaglandins and matrix-degrading enzymes. These substances trigger uterine contractions, membrane rupture and cervical ripening. Most intra-uterine infections are chronic and subclinical in nature and consequently hard to diagnose before labour or rupture of the membranes. The best studied site of infection is amniotic fluid, but this requires an invasive procedure. A non-invasive approach seems to be more relevant to clinical practice. However, few studies have investigated the maternal inflammatory response during preterm labour. Therefore, the overall objective of this study was to determine several inflammatory markers in maternal serum from pregnant women in labour (either term or preterm) vs. non-labouring controls. We completed a nested case control study in which singleton pregnancies were recruited at Ghent University Hospital and divided into groups according to gestational age and labour status. Multiple proteins were evaluated in maternal serum using enzyme-linked or multiplex bead immunoassays including soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), matrix metalloproteinases (MMP)-9 and MMP-3, tissue inhibitor of metalloproteinases (TIMP)-1, TIMP-2, TIMP-3 and TIMP-4 and a panel of 30 cytokines, chemokines and growth factors.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Prevalence reproductive tract infections (RTI) in women targeted for microbicide trials: the Microbicide Safety Biomarkers Study in Kenya, Rwanda, and South Africa

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Characterisation of the human uterine microbiome in non-pregnant women through deep sequencing of the V1-2 region of the 16S rRNA gene

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 targeted by use of a barcoded Illumina MiSeq paired-end sequencing method targeting the 16S rRNA gene V1-2 region, yielding an average of 41,194 reads per sample after quality filtering. Taxonomic annotation was pursued by comparison with sequences available through the Ribosomal Database Project and the NCBI database. Results. Out of 183 unique 16S rRNA gene amplicon sequences, 15 phylotypes were present in all samples. In some 90% of the women included, community architecture was fairly similar inasmuch B. xylanisolvens, B. thetaiotaomicron, B. fragilis and an undetermined Pelomonas taxon constituted over one third of the endometrial bacterial community. On the singular phylotype level, six women showed predominance of L. crispatus or L. iners in the presence of the Bacteroides core. Two endometrial communities were highly dissimilar, largely lacking the Bacteroides core, one dominated by L. crispatus and another consisting of a highly diverse community, including Prevotella spp., Atopobium vaginae, and Mobiluncus curtisii.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Characterisation of the vaginal microflora of human immunodeficiency virus (HIV) positive and negative women in a sub-urban population of Kenya

AFRICAN JOURNAL OF BIOTECHNOLOGY

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Otitis media microbes: culture, PCR, and confocal laser scanning microscopy

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 ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The significance of Lactobacillus crispatus and L. vaginalis for vaginal health and the negative effect of recent sex: a cross-sectional descriptive study across groups of African women

BMC Infectious Diseases, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Vaginal Microbiota: What Have We Learned after a Decade of Molecular Characterization?

PLoS ONE, 2014

Bookmarks Related papers MentionsView impact

Research paper thumbnail of P1.032 Bacterial Species in the Vaginal Microbiome Correlated by Nugent Score: Cross-Sectional Data from the Microbicide Safety Biomarkers Study in Kenya, Rwanda, and South Africa

Sexually Transmitted Infections, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Bacterial vaginosis: an update on diagnosis and treatment

Expert Review of Anti-infective Therapy, 2009

Bacterial vaginosis is the most common cause of vaginal complaints. Bacterial vaginosis is furthe... more Bacterial vaginosis is the most common cause of vaginal complaints. Bacterial vaginosis is further associated with a sizeable burden of infectious complications. Diagnosis relies on standardized clinical criteria or on scoring bacterial cell morphotypes on a Gram-stained vaginal smear. A few point-of-care tests have not gained footage in clinical practice, but molecular diagnosis is now pending. Treatment remains cumbersome and clinicians are currently rather poorly armed to treat bacterial vaginosis in the long run. As an adjuvant to standard treatment with antibiotics, alternative treatments with antiseptics and disinfectants, vaginal-acidifying and -buffering agents, and probiotics hold some promise for long-term prevention.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of In vivo evaluation of the vaginal distribution and retention of a multi-particulate pellet formulation

European Journal of Pharmaceutics and Biopharmaceutics, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A pilot study evaluating the safety of vaginal administration of a multi-particulate pellet formulation

European Journal of Pharmaceutics and Biopharmaceutics, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Evaluation of a new multiplex polymerase chain reaction assay STDFinder for the simultaneous detection of 7 sexually transmitted disease pathogens

Diagnostic Microbiology and Infectious Disease, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Microflora of the penile skin-lined neovagina of transsexual women

BMC Microbiology, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Longitudinal analysis of the vaginal microflora in pregnancy suggests that L. crispatus promotes the stability of the normal vaginal microflora and that L. gasseri and/or L. iners are more conducive to the occurrence of abnormal vaginal microflora

BMC Microbiology, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Comparison of different sampling techniques and of different culture methods for detection of group B streptococcus carriage in pregnant women

BMC Infectious Diseases, 2010

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The development of a 16S rRNA gene based PCR for the identification of Streptococcus pneumoniae and comparison with four other species specific PCR assays

BMC Infectious Diseases, 2010

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Group A streptococcal vaginitis: an unrecognized cause of vaginal symptoms in adult women

Archives of Gynecology and Obstetrics, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Terminal Restriction Fragment Length Polymorphism for Identification of Cryptosporidium Species in Human Feces

Applied and Environmental Microbiology, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Terminal restriction fragment length polymorphism analysis of the microflora in necrotic teeth of patients irradiated in the head and neck region

Journal of Endodontics, Jan 9, 2008

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Otitis media microbes: culture, PCR, and confocal laser scanning microscopy

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 virtually absent from the nasopharynx. Pseudomonas aeruginosa was present in seven. It was the only pathogen found on several occasions in all three locations in one patient. This study confirms the association of H. influenzae with middle ear biofilm, and indicates a potential role of P. aeruginosa in middle ear inflammation and biofilm formation. Biofilm does not seem to cause inflammation. It is unclear whether the predominance of A. otitidis in chronically inflamed open middle ears indicates a pathogenic or contaminant role for this organism.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Inflammatory response in maternal serum during preterm labour

Wetenschapsdag Posters, 2012

ABSTRACT Preterm birth (PTB), defined as a delivery before 37 weeks of gestation, is the leading ... more ABSTRACT Preterm birth (PTB), defined as a delivery before 37 weeks of gestation, is the leading cause of perinatal morbidity and mortality worldwide. Diagnosis of preterm labour as well as accurate prediction of PTB is notoriously difficult. Preterm birth is initiated by multiple mechanisms including infection or inflammation which is the only pathological process for which a firm causal link with PTB has been established. Intrauterine infection evokes an immune response that involves the release of cytokines and chemokines, prostaglandins and matrix-degrading enzymes. These substances trigger uterine contractions, membrane rupture and cervical ripening. Most intra-uterine infections are chronic and subclinical in nature and consequently hard to diagnose before labour or rupture of the membranes. The best studied site of infection is amniotic fluid, but this requires an invasive procedure. A non-invasive approach seems to be more relevant to clinical practice. However, few studies have investigated the maternal inflammatory response during preterm labour. Therefore, the overall objective of this study was to determine several inflammatory markers in maternal serum from pregnant women in labour (either term or preterm) vs. non-labouring controls. We completed a nested case control study in which singleton pregnancies were recruited at Ghent University Hospital and divided into groups according to gestational age and labour status. Multiple proteins were evaluated in maternal serum using enzyme-linked or multiplex bead immunoassays including soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), matrix metalloproteinases (MMP)-9 and MMP-3, tissue inhibitor of metalloproteinases (TIMP)-1, TIMP-2, TIMP-3 and TIMP-4 and a panel of 30 cytokines, chemokines and growth factors.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Prevalence reproductive tract infections (RTI) in women targeted for microbicide trials: the Microbicide Safety Biomarkers Study in Kenya, Rwanda, and South Africa

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Characterisation of the human uterine microbiome in non-pregnant women through deep sequencing of the V1-2 region of the 16S rRNA gene

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 targeted by use of a barcoded Illumina MiSeq paired-end sequencing method targeting the 16S rRNA gene V1-2 region, yielding an average of 41,194 reads per sample after quality filtering. Taxonomic annotation was pursued by comparison with sequences available through the Ribosomal Database Project and the NCBI database. Results. Out of 183 unique 16S rRNA gene amplicon sequences, 15 phylotypes were present in all samples. In some 90% of the women included, community architecture was fairly similar inasmuch B. xylanisolvens, B. thetaiotaomicron, B. fragilis and an undetermined Pelomonas taxon constituted over one third of the endometrial bacterial community. On the singular phylotype level, six women showed predominance of L. crispatus or L. iners in the presence of the Bacteroides core. Two endometrial communities were highly dissimilar, largely lacking the Bacteroides core, one dominated by L. crispatus and another consisting of a highly diverse community, including Prevotella spp., Atopobium vaginae, and Mobiluncus curtisii.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Characterisation of the vaginal microflora of human immunodeficiency virus (HIV) positive and negative women in a sub-urban population of Kenya

AFRICAN JOURNAL OF BIOTECHNOLOGY

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Otitis media microbes: culture, PCR, and confocal laser scanning microscopy

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 ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The significance of Lactobacillus crispatus and L. vaginalis for vaginal health and the negative effect of recent sex: a cross-sectional descriptive study across groups of African women

BMC Infectious Diseases, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Vaginal Microbiota: What Have We Learned after a Decade of Molecular Characterization?

PLoS ONE, 2014

Bookmarks Related papers MentionsView impact

Research paper thumbnail of P1.032 Bacterial Species in the Vaginal Microbiome Correlated by Nugent Score: Cross-Sectional Data from the Microbicide Safety Biomarkers Study in Kenya, Rwanda, and South Africa

Sexually Transmitted Infections, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Bacterial vaginosis: an update on diagnosis and treatment

Expert Review of Anti-infective Therapy, 2009

Bacterial vaginosis is the most common cause of vaginal complaints. Bacterial vaginosis is furthe... more Bacterial vaginosis is the most common cause of vaginal complaints. Bacterial vaginosis is further associated with a sizeable burden of infectious complications. Diagnosis relies on standardized clinical criteria or on scoring bacterial cell morphotypes on a Gram-stained vaginal smear. A few point-of-care tests have not gained footage in clinical practice, but molecular diagnosis is now pending. Treatment remains cumbersome and clinicians are currently rather poorly armed to treat bacterial vaginosis in the long run. As an adjuvant to standard treatment with antibiotics, alternative treatments with antiseptics and disinfectants, vaginal-acidifying and -buffering agents, and probiotics hold some promise for long-term prevention.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of In vivo evaluation of the vaginal distribution and retention of a multi-particulate pellet formulation

European Journal of Pharmaceutics and Biopharmaceutics, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A pilot study evaluating the safety of vaginal administration of a multi-particulate pellet formulation

European Journal of Pharmaceutics and Biopharmaceutics, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Evaluation of a new multiplex polymerase chain reaction assay STDFinder for the simultaneous detection of 7 sexually transmitted disease pathogens

Diagnostic Microbiology and Infectious Disease, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Microflora of the penile skin-lined neovagina of transsexual women

BMC Microbiology, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Longitudinal analysis of the vaginal microflora in pregnancy suggests that L. crispatus promotes the stability of the normal vaginal microflora and that L. gasseri and/or L. iners are more conducive to the occurrence of abnormal vaginal microflora

BMC Microbiology, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Comparison of different sampling techniques and of different culture methods for detection of group B streptococcus carriage in pregnant women

BMC Infectious Diseases, 2010

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The development of a 16S rRNA gene based PCR for the identification of Streptococcus pneumoniae and comparison with four other species specific PCR assays

BMC Infectious Diseases, 2010

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Group A streptococcal vaginitis: an unrecognized cause of vaginal symptoms in adult women

Archives of Gynecology and Obstetrics, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Terminal Restriction Fragment Length Polymorphism for Identification of Cryptosporidium Species in Human Feces

Applied and Environmental Microbiology, 2009

Bookmarks Related papers MentionsView impact