References of "Boreux, Raphaël"
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See detailDISTRIBUTION OF CAPSULAR POLYSACCHARIDES OF STREPTOCOCCUS AGALACTIAE STRAINS FROM URUGUAY. MULTIPLEX PCR VERSUS CONVENTIONAL CAPSULAR SEROTYPING
Rodriguez Cuns, Grisel ULg; BOREUX, Raphaël ULg; ADAMS, Pauline et al

in XIX Lancefield International Symposium on Streptococci and Streptococcal Diseases, Program and Abstract book (2014, November 11)

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See detailPrevalence of Campylobacter among goats and retail goat meat in Congo
Kabwang a Mpalang, Rosette; BOREUX, Raphaël ULg; Melin, Pierrette ULg et al

in Journal of Infection in Developing Countries [=JIDC] (2014), 8

Background: The prevalence of Campylobacter jejuni and Campylobacter coli was determined in goat and goat meat sold at retail outlets in Lubumbashi, Democratic Republic of Congo (DR Congo). Methodology: A ... [more ▼]

Background: The prevalence of Campylobacter jejuni and Campylobacter coli was determined in goat and goat meat sold at retail outlets in Lubumbashi, Democratic Republic of Congo (DR Congo). Methodology: A total of 644 samples, including 177 goat meat, 86 goat stomachs, 139 ready to eat (RTE) goat skewers, and 242 goat faecal samples were examined for the presence of Campylobacter jejuni and Campylobacter coli using polymerase chain reaction. Results: Overall, Campylobacter spp. were found in 34.6% of the examined samples. C. jejuni was isolated in 10.1% and C. coli in 26.7% of samples. Only 2.2% of all samples were positive for both species. There was a significant association between the prevalence of C. coli and the type of sample (p < 0.05). The overall prevalence of Campylobacter in different sample groups was 41.2%, 37.2%, 23.7%, and 35.1% for goat meat, goat stomachs, RTE goat skewers, and goat faecal samples, respectively. There was no significant difference (p > 0.05) between the prevalence observed in the rainy season (16.7%) and the dry season (20.0%). Moreover, the overall prevalence of Campylobacter in slaughter sites, open-air markets, warehouses, and semi-open-air markets was 28.2%, 34.2%, 35.4%, and 42.9%, respectively. Statistically, there was no influence of the sample collection site on the frequency of isolation of Campylobacter (p > 0.05). Conclusion: This study shows that, considering the relatively high prevalence of this [less ▲]

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See detailAssessment of pfcrt 72-76 haplotypes eight years after chloroquine withdrawal in Kinshasa, Democratic Republic of Congo
Mvumbi, Dieudonné; BOREUX, Raphaël ULg; SACHELI, Rosalie ULg et al

in Malaria Journal (2013), 12

BACKGROUND: In 2001, the World Health Organization (WHO) has recommended the use of artemisinin-based combination therapy (ACT) as the first-line treatment of uncomplicated malaria cases, as monotherapies ... [more ▼]

BACKGROUND: In 2001, the World Health Organization (WHO) has recommended the use of artemisinin-based combination therapy (ACT) as the first-line treatment of uncomplicated malaria cases, as monotherapies had become ineffective in many parts of the world. As a result, the Democratic Republic of Congo (DRC) withdrew chloroquine (CQ) from its malaria treatment policy in 2002 and an artesunate (AS)-amodiaquine (AQ) combination became the ACT of choice in DRC in 2005. AQ-resistance (AQR) has been reported in several parts of the world and mutations in codons 72-76 of the Plasmodium falciparum chloroquine-resistance transporter (pfcrt) gene have been strongly correlated with resistance, especially mutations encoding the SVMNT haplotype. This haplotype was first identified in Southeast Asia and South America but was recently reported in two African countries neighbouring DRC. These facts raised two questions: the first about the evolution of CQ resistance (CQR) in DRC and the second about the presence of the SVMNT haplotype, which would compromise the use of AQ as a partner drug for ACT. METHODS: A total of 213 thick blood films were randomly collected in 2010 from a paediatric clinic in Kinshasa, DRC. Microscopy controls and real-time polymerase chain reaction (RT-PCR) were performed for Plasmodium species identification. Haplotypes of the pfcrt gene were determined by sequencing. RESULTS: The K76T mutation was detected in 145 out of 198 P. falciparum-positive samples (73.2%).In these 145 resistant strains, only the CVIET haplotype was detected. CONCLUSIONS: This study is the first to assess the molecular markers of resistance to CQ and AQ after the introduction of ACT in DRC. The results suggest first that CQR is decreasing, as wild-type pfcrt haplotypes were found in only 26.8% of the samples and secondly that the SVMNT haplotype is not yet present in Kinshasa, suggesting that AQ remains valid as a partner drug for ACT in this region. [less ▲]

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See detailMolecular epidemiology of norovirus infections in symptomatic and and asymptomatic children from Bobo Dioulasso, Burkina Faso
HUYNEN, Pascale ULg; Mauroy, Axel ULg; Martin, Caroline et al

in Journal of Clinical Virology (2013), 58

Background: Noroviruses (NoV) are a leading cause of gastroenteritis worldwide. Few epidemiologicaldata regarding the NoV strains circulating in African countries are available.Objectives: To determine ... [more ▼]

Background: Noroviruses (NoV) are a leading cause of gastroenteritis worldwide. Few epidemiologicaldata regarding the NoV strains circulating in African countries are available.Objectives: To determine the prevalence of NoV in Bobo Dioulasso (Burkina Faso) in both symptomaticand asymptomatic gastroenteritis patients.Study design: Patients both with and without gastro-intestinal disorders were selected. Clinical andepidemiological data, as well as stool samples, were collected through March to April 2011.NoV molecular detection (genogrouping and genotyping) and viral load quantification were also per-formed for all samples.Results: NoV were detected in 22.2% of the 418 collected stool samples (21.2% and 24.8% from the 293symptomatic patients (SP) and the 125 asymptomatic patients (ASP) respectively).Genogroup (G) distribution was 7.5%, 10.2% and 3.4% for GI, GII and both GI/GII respectively among SPand 12.0%, 11.2% and 1.6% for GI, GII and both GI/GII, respectively, among ASP.Average viral load values were higher in SP than in ASP for GI (p = 0.03) but not for GII.Phylogenic analysis showed a high degree of genotype diversity in SP and ASP. One recombinantGII.7/GII.6 sequence was, to the best of our knowledge, detected for the first time.Conclusions: This study enabled identification of the specific molecular epidemiology of NoV strains cir-culating in a representative country in Eastern Africa, and additionally showed that ASP could play animportant “reservoir” role. A high strain diversity was detected with a surprisingly high proportion ofNoV GI compared to the common genotypes usually reported in comparable epidemiological studies. [less ▲]

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See detailEvaluation of a new rapid test for the detection of norovirus antigen in comparison with Real Time RT-PCR
HUYNEN, Pascale ULg; Mauroy, Axel ULg; Gérard, Catherine ULg et al

Poster (2013, September)

Diagnosis of NoV infection mainly relies on molecular methods. A detection of viral antigens can also be performed by immunochromatographic assays, and may be useful in outbreak settings. The aim of this ... [more ▼]

Diagnosis of NoV infection mainly relies on molecular methods. A detection of viral antigens can also be performed by immunochromatographic assays, and may be useful in outbreak settings. The aim of this study was to compare the performances of the new RDT ImmunoCardSTAT!®Norovirus (Meridian Bioscience®, Europe) with a real time RT-PCR. [less ▲]

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See detailPrevalence and spread of extended-spectrum β-lactamase-producing
Magoue Lonchel, Carine ULg; MELIN, Pierrette ULg; Gangoué-Piéboji, J et al

in Clinical Microbiology & Infection (2013), 19(9), 416-20

During April 2010 and June 2010, 334 Enterobacteriaceae isolates from 590 participants (outpatients, inpatients, inpatient carers, hospital workers and members of their households) were collected from ... [more ▼]

During April 2010 and June 2010, 334 Enterobacteriaceae isolates from 590 participants (outpatients, inpatients, inpatient carers, hospital workers and members of their households) were collected from faecal samples. Based on b-lactamase pattern, origin of strains and the relationship between participants, 44 isolates of extended-spectrum b-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae were selected from 44 participants (in Ngaoundere Protestant Hospital and Ngaoundere Regional Hospital, Cameroon). To determine the relatedness of bacterial strains, these isolates were fingerprinted using the automated, repetitive-sequenced-based PCR-based DiversiLab system. Subsequently, E. coli isolates that had undergone DiversiLab analysis were examined with respect to their phylogenetic group and detection of the ST131 clone to shed light on the epidemiology of these isolates in the Ngaoundere hospitals. The prevalence of faecal carriage of ESBL-producing Enterobacteriaceae among the study participants was 54.06%. According to participant groups, the prevalence of faecal carriage was also high (outpatients 45%; inpatients 67%; inpatient carers 57%; hospital workers 44%; and members of their households 46%). Analysis of the molecular epidemiology of ESBL-producing E. coli and K. pneumoniae showed a close relationship of the isolates between related and nonrelated individuals. In addition, DiversiLab results of E. coli identified four related isolates (4/22) from cluster III belonging to the epidemiologically important clone ST131. Our results highlight the importance of outpatients, inpatients, their carers, hospital workers and their families as reservoirs of ESBLproducing Enterobacteriaceae. [less ▲]

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See detailComparison of Real-Time Aspergillus PCR with Platelia™AspergillusEIA in broncho-alveolar lavage fluids for the diagnosis of invasive aspergillosis in neutropenic and non-neutropenic patients
RUZICKA, NADIA; BOREUX, Raphaël ULg; LEVAUX, Laetitia ULg et al

Poster (2013, April 27)

Objectives. Because of low sensitivity of fungal cultures and lack of standardization of Aspergillus PCR, laboratory diagnosis of invasive aspergillosis still relies on galactomannan (GM) detection in ... [more ▼]

Objectives. Because of low sensitivity of fungal cultures and lack of standardization of Aspergillus PCR, laboratory diagnosis of invasive aspergillosis still relies on galactomannan (GM) detection in broncho-alveolar lavage (BAL) fluids and serum. The aim of this study was double: first, to assess the place of a 18S rRNA Aspergillus real-time PCR test performed in BAL fluid for the diagnosis of invasive aspergillosis (IA) in neutro- and non-neutropenic patients in comparison with GM detection; secondly, to evaluate the use of three different GM cut-off values. Materials and methods. A total of 111 neutropenic and non-neutropenic patients hospitalized at the University hospital of Liège from March to October 2012 with suspicion of IA were included in the study. A total of 138 broncho-alveolar lavage fluids were evaluated by three laboratory diagnostic methods: 1/ culture on Sabouraud agar slants with antibiotics (bioMérieux, France) incubated at 28°C for 28 days; 2/ GM detection (Platelia ™Aspergillus EIA, Biorad) using GM index cut-off values at 0.5, 0.8 and 1, performed three times a week; 3/ a real-time Aspergillus PCR assay performed daily and targeting the 18S rRNA genes by using an in-house method. Clinical, radiological and microbiological data were reviewed for classification of patients. Results. Nine patients developed probable or possible IA. The sensitivity/specificity/positive (VPP) and negative (NPV) predictive values (%) for culture, PCR, and GM using 0,5 as cut-off value were respectively 41/100/100/94, 58/97/70/96, and 91/83/34/99. The use of 0,8 and 1 as GM index cut-off values increased the specificity to 89 and 92% respectively, and the VPP to 44 and 54%. PCR had a better turn-around time and allowed the detection of Aspergillus colonisation. Conclusion: GM detection in BAL fluids using a cut-off value of 1 was the most efficient laboratory test for the diagnosis of IA in neutropenic and non-neutropenic patients. Despite a lower sensitivity, PCR had a better VPP, and allowed the detection of culture-negative Aspergillus colonisations. A shorter turnaround time (TAT) due to daily practice of PCR tests may reduce the time-to-treatment up to 24 hours. [less ▲]

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See detailExtended-spectrum β-lactamase-producing Enterobacteriaceae in Cameroonian hospitals
Lonchel, Carine Magoué; MELIN, Pierrette ULg; Gangoué-Piéboji, Joseph et al

in European Journal of Clinical Microbiology & Infectious Diseases : Official Publication of the European Society of Clinical Microbiology (2013), 32(1), 79-87

Abstract Extended-spectrum β-lactamase (ESBL)-produc- ing Enterobacteriaceae have been described worldwide, but there are few reports on the carriage of these bacteria in Cameroon. In order to investigate ... [more ▼]

Abstract Extended-spectrum β-lactamase (ESBL)-produc- ing Enterobacteriaceae have been described worldwide, but there are few reports on the carriage of these bacteria in Cameroon. In order to investigate the types of ESBLs and to analyse some risk factors associated with ESBL carriage, faecal samples were collected between 3 January and 3 April 2009 from hospitalised patients at Yaounde Central Hospital and at two hospitals in Ngaoundere, Cameroon. Enterobacterial isolates resistant to third-generation cepha- losporins were screened for ESBL production using the double-disk synergy test. Polymerase chain reaction (PCR) and DNA sequencing were performed in order to find out the different types of ESBL genes in presumptive ESBL- positive isolates. During the study period, a total of 121 different patients were screened for ESBL carriage. The prevalence among these patients whose faecal samples were found to contain ESBL-producers was 55.3 % (67/121). According to a univariate analysis, hospitalisation during the previous year was found to be associated with ESBL carriage. Of the 71 bacteria isolated, Escherichia coli was predominant and represented 48 % of all isolates. ESBL characterisation revealed two types of ESBLs, CTX-M-15 (96 %) and SHV-12 (4 %). The present study emphasises the importance of screening for ESBLs in laboratories in Afri- can countries. The monitoring and detection of ESBL- producing bacteria are important in the setting up of appro- priate treatment of patients and to ensure effective infection control efforts. [less ▲]

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See detailBacteriological assessment of smoked game meat in Lubumbashi, D.R.C.
Kabwang a Mpalang, Rosette; Kakubu a Mpalang, Mireille; Mukeng Kaut, Clarence et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17

The bacteriological quality of smoked game meat in Lubumbashi has not been studied much to date. The present study focused on the analysis of 182 samples of smoked game meat from three species, Syncerus ... [more ▼]

The bacteriological quality of smoked game meat in Lubumbashi has not been studied much to date. The present study focused on the analysis of 182 samples of smoked game meat from three species, Syncerus caffer (n = 63), Phacochoerus aethiopicus (n = 60) and Sylvicapra grimmia (n = 59), sold at retail outlets in Lubumbashi. The isolation of Escherichia coli from 81.3% of samples (mean 4.87 ± 0.6 log10 CFU.g-1 of sample) confirms significant faecal contamination of smoked game meat. The study has determined by culture prevalences of 0.0%, 4.3% [CI95% 1.4-7.4], 3.8% [CI95% 1.1-6.6] and 14.2% [CI95% 9.2-19.4] respectively for Shiga toxigenic Escherichia coli (STEC), Salmonella spp., Campylobacter jejuni and Campylobacter coli. Using Polymerase Chain Reaction, these prevalences were of 2.2% [IC95% 0.1-4.3], 6.0% [IC95% 2.6-9.5], 3.8% [IC95% 1.1-6.6] and 15.9% [IC95% 10.6-21.3] respectively for STEC, Salmonella spp., C. jejuni and C. coli. Syncerus caffer was established as a potential vehicle of STEC carrying stx1 gene (3.2%), stx2 gene (1.6%) and the combination of stx2 and eae genes (1.6%). On the basis of these data, we suggested the need for developing monitoring plans of the production, preparation, handling and distribution of smoked game meat in Lubumbashi. [less ▲]

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See detailPhenotypical and Genotypical Surveillance of Macrolide and Lincosamide Resistance in Group B Streptococcus in Belgium
DESCY, Julie ULg; Ackermans, Yannick; BOREUX, Raphaël ULg et al

Poster (2012, September)

Background: Constant increase of erythromycin (E) and clindamycin (C) resistance (R) has been observed worldwide among isolates of group B streptococci (GBS). In Belgium, through the 2000s, E R increased ... [more ▼]

Background: Constant increase of erythromycin (E) and clindamycin (C) resistance (R) has been observed worldwide among isolates of group B streptococci (GBS). In Belgium, through the 2000s, E R increased rapidly from 10% to up to 30%. Therefore phenotypical and molecular surveillance of E and C R has to be conducted. Methods: 275 clinical isolates (N1) were obtained from a Belgian surveillance for invasive GBS disease in newborns (59 isolates with 32 early- and 27 late-onset diseases) and adults (216 strains) during 2008 to 2011 and 53 isolates (N2) from vagino-rectal colonization in pregnant women in 2010. E and C MICs were determined by using Etest® (EUCAST interpretive criteria). Furthermore, for the E R isolates, the inducible (iMLS), constitutive (cMLS) and M phenotypes were assessed by a double disk diffusion test; the distribution of genes encoding RNA methylases and efflux pumps was investigated by PCR. Results: Of the N1 and N2 isolates, 92 (33.5%) and 15 (28.3%) were respectively R to E, with a higher rate among serotype V (p <0.001) and serotype IV (p <0.05). Among these 107 E-R isolates, 100 (93.5%) exhibited the MLS phenotype (R to E and CC): 73 were cMLS with E MIC50 >256 mg/L and 27 iMLS with E MIC50/MIC90 12/>256 mg/L. The M phenotype (R to E and S to C) was expressed by 7 (6.5%) of E R isolates with E MIC50/MIC90 4/12 mg/L. One colonizing strain presented a newly described resistance mechanism in GBS: the L phenotype (S to E and R to C) with a C MIC at 8 mg/L. For cMLS, the most common E R genotype was ermB (66%) (p <0.05) followed by ermTR (29%) and ermB+ermTR (5%). All iMLS isolates harbored an ermTR gene except 3 (2 with ermB, 1 with both ermB and ermTR); and all M phenotype were positive for mefA/B gene. Conclusions:1) In Belgium, by year 2010, prevalence of macrolides R in GBS exceeded 30%, 2) MLS R phenotypes (target-site modification) were the majority mechanism; M phenotype (efflux R mechanism) was also prevalent. 3) E and C susceptibility testing and surveillance are mandatory to guide prophylaxis and treatment of serious GBS infections in penicillin-allergic patients (at high risk for anaphylaxis) but also to identify emergence of newly acquired resistance mechanisms such as the L phenotype. [less ▲]

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See detailPhenotypical and genotypical surveillance of macrolide and lincosamide resistance in group B streptococcus in Belgium
DESCY, Julie ULg; ACKERMANS, Yanick; BOREUX, Raphaël ULg et al

in Program and Abstract of the 52nd Intersciences Conference on Antimicrobial Agents and Chemotherapy (2012, September)

Background: Constant increase of erythromycin (E) and clindamycin (C) resistance (R) has been observed worldwide among isolates of group B streptococci (GBS). In Belgium, through the 2000s, E R increased ... [more ▼]

Background: Constant increase of erythromycin (E) and clindamycin (C) resistance (R) has been observed worldwide among isolates of group B streptococci (GBS). In Belgium, through the 2000s, E R increased rapidly from 10% to up to 30%. Therefore phenotypical and molecular surveillance of E and C R has to be conducted. Methods: 275 clinical isolates (N1) were obtained from a Belgian surveillance for invasive GBS disease in newborns (59 isolates with 32 early- and 27 late-onset diseases) and adults (216 strains) during 2008 to 2011 and 53 isolates (N2) from vagino-rectal colonization in pregnant women in 2010. E and C MICs were determined by using Etest® (EUCAST interpretive criteria). Furthermore, for the E R isolates, the inducible (iMLS), constitutive (cMLS) and M phenotypes were assessed by a double disk diffusion test; the distribution of genes encoding RNA methylases and efflux pumps was investigated by PCR. Results: Of the N1 and N2 isolates, 92 (33.5%) and 15 (28.3%) were respectively R to E, with a higher rate among serotype V (p <0.001) and serotype IV (p <0.05). Among these 107 E-R isolates, 100 (93.5%) exhibited the MLS phenotype (R to E and CC): 73 were cMLS with E MIC50 >256 mg/L and 27 iMLS with E MIC50/MIC90 12/>256 mg/L. The M phenotype (R to E and S to C) was expressed by 7 (6.5%) of E R isolates with E MIC50/MIC90 4/12 mg/L. One colonizing strain presented a newly described resistance mechanism in GBS: the L phenotype (S to E and R to C) with a C MIC at 8 mg/L. For cMLS, the most common E R genotype was ermB (66%) (p <0.05) followed by ermTR (29%) and ermB+ermTR (5%). All iMLS isolates harbored an ermTR gene except 3 (2 with ermB, 1 with both ermB and ermTR); and all M phenotype were positive for mefA/B gene. Conclusions:1) In Belgium, by year 2010, prevalence of macrolides R in GBS exceeded 30%, 2) MLS R phenotypes (target-site modification) were the majority mechanism; M phenotype (efflux R mechanism) was also prevalent. 3) E and C susceptibility testing and surveillance are mandatory to guide prophylaxis and treatment of serious GBS infections in penicillin-allergic patients (at high risk for anaphylaxis) but also to identify emergence of newly acquired resistance mechanisms such as the L phenotype. [less ▲]

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See detailProportion of extended-spectrum ß-lactamase-producing Enterobacteriaceae in community setting in Ngaoundere, Cameroon
LONCHEL, Carine Magoué; MEEX, Cécile ULg; Gangoué-Piéboji, Joseph et al

in BMC Infectious Diseases (2012), 12

BACKGROUND: There is no information regarding the resistance mechanisms of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae in community setting in Cameroon. The current study aimed to ... [more ▼]

BACKGROUND: There is no information regarding the resistance mechanisms of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae in community setting in Cameroon. The current study aimed to determine the proportion of ESBLs in Enterobacteriaceae isolated in the community and to analyse some risk factors associated with ESBL carriage. METHODS: Faecal samples were collected from 208 different outpatients and 150 healthy student volunteers between 3 January and 3 April 2009. Enterobacterial isolates resistant to third-generation cephalosporins were screened for ESBL production by the double-disk synergy test. Presumptive ESBL-producing isolates with positive synergy test were identified by Mass Spectrometry using the BioTyper MALDI-TOF. For such ESBL positive isolates, antibiotic susceptibility was determined by the Vitek 2 system. PCR and sequencing were performed for the detection of different types of ESBL genes in presumptive ESBL-producing isolates. Statistical methods were used for the univariate calculation of risk factors. RESULTS: During the study period, a total of 358 faecal samples were analysed; 58 of such samples (16%) showed an ESBL phenotype and were confirmed by PCR. The proportion of ESBL producers in faecal carriage was statistically different between outpatients and student volunteers (23.1% vs. 6.7%: p < 0.000). According to a univariate analysis, previous use of antibiotics (ciprofloxacin) appeared to be a risk factor for ESBL carriage (p < 0.05).Escherichia coli was the species most frequently isolated among the ESBL producers in outpatients (66.7%) and student volunteers (90%). Isolates showed additional resistance to gentamicin, ciprofloxacin and trimethoprim/sulfamethoxazole but none of them was resistant to temocillin, amikacin or meropenem. Most of the strains (97%) produced a CTX-M group 1 enzymes [CTX-M-15 (98%) or CTX-M-1 (2%)] and the remaining strains produced SHV-12 enzyme (3%). CONCLUSIONS: The use of drugs such as amoxicillin, ciprofloxacin and trimethoprim/sulfamethoxazole does not seem appropriate for empirical treatment because of emerging resistance. The implementation in Cameroon or in other African countries of methods of screening ESBL-producing organisms in routine laboratories is of great importance in order for us to offer patients appropriate treatment and for infection control efforts to succeed. [less ▲]

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See detailTypage des souches de Norovirus circulant dans les populations symptomatiques et asymptomatiques au Burkina Faso
HUYNEN, Pascale ULg; Mauroy, Axel ULg; MARTIN, Caroline et al

Poster (2012)

Appartenant à la famille des Caliciviridae, genre Norovirus, les norovirus (NoV) sont des virus non enveloppés dont le génome est composé d’un ARN monocaténaire de polarité positive ... [more ▼]

Appartenant à la famille des Caliciviridae, genre Norovirus, les norovirus (NoV) sont des virus non enveloppés dont le génome est composé d’un ARN monocaténaire de polarité positive d’approximativement 7,5 kb. Les NoV infectent l’homme chez qui ils représentent au niveaumondial un agent majeur de gastroentérites épidémiques, d’origine souvent alimentaire mais aussi sporadique, et ce, toutes classes d'âges confondues. Les souches humaines sont classées génétiquement dans différents génotypes au sein de trois des cinq génogroupes, nommés (G) I, II et IV, composant le genre Norovirus. La voie de transmission des NoV est féco-orale. Les NoV sont très résistants dans l’environnement et la dose infectieuse est faible. Dans la population humaine, une grande diversité de souches appartenant principalement aux G I et II co-circulent. Parmi ces souches, le génotype Lordsdale (GII-4) est prédominant dans les épidémies actuelles, notamment lorsqu'une transmission de personne à personne est incriminée, alors que les souches du G I semblent plus fréquemment rapportées au cours des épidémies d’origine environnementale, comme celles liées à la consommation de fruits de mer. Si de nombreuses études d'épidémiologie moléculaire concernant ces virus ont été réalisées dans les pays industrialisés, les données sont par contre manquantes ou ténues pour bien des pays non industrialisés, et en particulier africains. Au cours d'une étude épidémiologique réalisée à Bobo Dioulasso au Burkina Faso et portant sur la prévalence des NoV dans les échantillons de selles de patients présentant ou non des symptômes de gastro-entérite, les souches détectées ont été quantifiées, leur génogroupe a été déterminé et pour certaines d'entre elles le génotype a été précisé. Quatre cent cinquante trois patients ont été prélevés, dont 319 présentant des symptômes diarrhéiques et 134 sujets témoins ne présentant pas de symptomatologie digestive. La détection des NoV et la quantification des charges virales excrétées ont été effectuées sur tous les échantillons par RT-PCR en temps réel permettant de discriminer les souches appartenant aux G I ou II. Une RT-PCR conventionnelle visant les régions de la polymérase (ORF1 du virus) ou de la capside (ORF2) a ensuite été réalisée sur une partie des échantillons détectés positifs en vue du séquençage de ces régions. Les relations phylogénétiques des souches circulant dans la population du Burkina Faso aux souches de référence ont aussi été inférées. Les résultats de RT-PCR en temps réel ont permis de mettre en évidence que les prévalences apparentes de l'infection par les NoV sont similaires dans les populations symptomatique et asymptomatique : une détection moléculaire de NoV chez 67 patients présentant de la diarrhée (21,0 %) et chez 31 des sujets témoins (23,1 %) a pu être observée. Les génotypes circulant détectés sont très variés dans les deux génogroupes, avec une proportion assez surprenante de NoV appartenant au G I. Université polytechnique de Bobo-Dioulasso, Institut supérieur des Sciences de la Santé (INSSA), Bobo-Dioulasso, Burkina Faso. Cette étude a permis de préciser l'épidémiologie moléculaire des souches de NoV circulant dans un pays représentatif de l'Afrique de l'Ouest. Elle a également montré que des individus asymptomatiques pourraient jouer un rôle assez important de réservoir du virus. Elle souligne enfin que, malgré le fait que les souches GII, et en particulier celles de génotype GII.4, soient à l'heure actuelle rapportées majoritairement au niveau mondial, les souches G I doivent être excrétées en égale proportion dans l'environnement. L'origine épidémiologique de la différence entre les prévalences apparentes des infections par les souches de GI et de GII, bien que partiellement expliquée par les différences de sensibilité génétique et d'immunité de population, reste donc à élucider. Remerciements: à la fondation A. Seghers, au Centre de Coopération au Développement de l'Université de Liège, à R. Boreux (assistance technique), aux membres du laboratoire du CMA de Dô et aux agents de santé de Bobo-Dioulasso (Burkina-Faso). [less ▲]

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See detailEvaluation of a new commercial real time PCR for the detection of Aspergillus spp. in serum and respiratory samples
Hayette, Marie-Pierre ULg; Meex, Cécile ULg; Boreux, Raphaël ULg et al

Poster (2007, April)

Objectives. Diagnosis of invasive aspergillosis is still disappointing and often delayed because of the lack of sensitivity of diagnostic tools. DNA detection based-methods have been developed, but differ ... [more ▼]

Objectives. Diagnosis of invasive aspergillosis is still disappointing and often delayed because of the lack of sensitivity of diagnostic tools. DNA detection based-methods have been developed, but differ widely and comparisons are difficult to assess. The objective of the study is to compare a new commercial real-time PCR kit, affigene® Aspergillus tracer assay, with an in house nested PCR targeting 18S rRNA Aspergillus sp. gene. Methods. Twelve patients at risk for invasive aspergillosis were included in the study. They were classified to have possible (5 cases), probable (1 case) or proven (6 cases) invasive aspergillosis following E.O.R.T.C. criteria. Fifteen serum and respiratory paired samples were collected. The DNA extraction was performed by using the QIAmp DNA mini kit® (Qiagen, Germany). All samples were tested by both PCR assays and respiratory samples were cultured. Results. Respiratory samples. A. fumigatus, A. niger and A. flavus were isolated from 10/15 samples; both PCR methods were positive for these samples except one that was positive for affigene® and equivocal for the nested PCR. The real-time PCR assay reported cycle thresholds ranging from 25 to 38. Three of the five culture-negative samples were negative by both PCR methods; one of three was negative in affigene® assay and equivocal by nested PCR; the last sample was positive in affigene® assay and negative by nested PCR. Serum. Thirteen of fifteen blood samples were negative by both PCR methods. One sample was equivocal by nested PCR and was inhibited in affigene® assay despite a culture-positive paired respiratory sample. The last case was inhibited by the real-time PCR assay and negative by nested PCR. Nor the nested PCR, nor affigene® assay could detect any Aspergillus DNA in serum. In total, there was 93% of agreement between the two PCR assays. Conclusion. Both methods are in good agreement and can detect at least three different species of Aspergillus. However, the sensitivity of both assays does not permit the detection of Aspergillus DNA in serum. affigene® assay can easy replace the “in house” assay: it allows a fast and standardized detection of Aspergillus sp. DNA in respiratory samples without inconvenient due to the handling of PCR products. [less ▲]

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See detailUse of a serum-free medium to produce in vitro Neospora caninum and Toxoplasma gondii tachyzoites on Vero cells
De Meerschman, F.; Rettigner, C.; Focant, Charles ULg et al

in Veterinary Research (2002), 33(2, Mar-Apr), 159-168

Neospora caninum and Toxoplasma gondii are cyst-forming coccidian parasites of human and veterinary clinical relevance. In vitro cultivation of the protozoans using Vero cells is usually performed in ... [more ▼]

Neospora caninum and Toxoplasma gondii are cyst-forming coccidian parasites of human and veterinary clinical relevance. In vitro cultivation of the protozoans using Vero cells is usually performed in order to produce antigenic materials. Quantitative and qualitative comparisons of Vero cells grown in RPMI medium supplemented either with foetal calf serum (FCS), horse serum (HS) or a specific serum-free additive (DefCell) were performed. A serum-free cell culture system used to propagate N. caninum (NC-1 isolate) and T. gondii tachyzoites (Rh stain) were compared with the other two cell culture systems. FCS supplemented media was found to be more effective than the others in promoting Vero cells and N. caninum tachyzoites. However, it was found unable to support adequate T. gondii tachyzoite proliferation. Vero cells, T. gondii and N. caninum tachyzoite production gave similar growth patterns with either HS or DefCell supplemented media. Defcell was considered as a good alternative to supplement culture medium. [less ▲]

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