PubMed Health⌕ Search

Biomedical subjects

Françoise Portaels

Publications and source records attributed to Françoise Portaels.

54 records · Page 3Linked to original sources
PubMed2004

Potential role for fish in transmission of Mycobacterium ulcerans disease (Buruli ulcer): an environmental study.

This study reports a potential role that fish may play in the transmission of Mycobacterium ulcerans disease (Buruli ulcer). Fish found positive for M. ulcerans DNA all appear to feed on insects or plankton and are believed to concentrate M. ulcerans from this usual food source. These observations provide additional data supporting our previous hypothesis on sources of M. ulcerans and modes of transmission.

Animals↗
PubMed2004

PCR-based genotyping of Mycobacterium tuberculosis with new GC-rich repeated sequences and IS6110 inverted repeats used as primers.

In the present study we attempted to develop a PCR-based epidemiological tool for the differentiation of Mycobacterium tuberculosis isolates. Use of the designed primers Mtb1 (5'-CCG-GCG-GGG-CCG-GCG-G) and Mtb2 (5'-CGG-CGG-CAA-CGG-CGG-C) targeting frequently repeated 16-bp sequences in combination with primers sited at the inverted repeats flanking IS6110 allowed differentiation of M. tuberculosis isolates.

DNA Fingerprinting↗
PubMed2004

Genotypic and phenotypic heterogeneity among Mycobacterium tuberculosis isolates from pulmonary tuberculosis patients.

Although the heterogeneity of Mycobacterium tuberculosis populations and the existence of mixed infections are now generally accepted, systematic studies on their relative importance are rare. In the present study, 10 individual colonies of each M. tuberculosis isolate (primary isolate) from 97 tuberculosis patients in a primarily human immunodeficiency virus-negative population were screened for heterogeneity and detectable mixed infections by spoligotyping, IS6110-based restriction fragment length polymorphism analysis, and mycobacterial interspersed repetitive unit-variable number of tandem repeat typing. The MICs of antituberculosis drugs for colonies with divergent fingerprints were determined. Infections with different bacterial subpopulations were detected in the samples from eight patients (8.2%), and the frequency of detectable mixed infections in the study population was estimated to be 2.1%. Genotypic variations were found to be independent of the drug susceptibilities, and the various molecular markers evolved independently in most cases. The predominant strains and the primary isolates always had concordant drug susceptibility and MIC testing results. These findings have implications on the interpretation of molecular epidemiology results for patient follow-up and in transmission studies.

Adolescent↗
PubMed2004

Mycobacterium ulcerans disease (Buruli ulcer) in rural hospital, Southern Benin, 1997-2001.

Data from 1,700 patients living in southern Benin were collected at the Centre Sanitaire et Nutritionnel Gbemoten, Zagnanado, Benin, from 1997 through 2001. In the Zou region in 1999, Buruli ulcer (BU) had a higher detection rate (21.5/100,000) than leprosy (13.4/100,000) and tuberculosis (20.0/100,000). More than 13% of the patients had osteomyelitis. Delay in seeking treatment declined from 4 months in 1989 to 1 month in 2001, and median hospitalization time decreased from 9 months in 1989 to 1 month in 2001. This reduction is attributed, in part, to implementing an international cooperation program, creating a national BU program, and making advances in patient care.

Benin↗
PubMed2004

Buruli ulcer disease in Cameroon rediscovered.

To assess the magnitude of the Buruli ulcer (BU) problem in Cameroon, we conducted a cross-sectional survey in the Nyong River basin and identified on clinical grounds a total of 436 cases of active or inactive BU (202 and 234, respectively). Swab specimens were taken from 162 active cases with ulcerative lesions and in 135 of these (83.3%) the clinical diagnosis was confirmed by the IS2404 polymerase chain reaction. Most lesions (93%) were located on the extremities, with lower limbs being twice as commonly involved as upper limbs. The age of patients with active BU ranged from 2 to 90 years with a median age of 14.5 years. Vaccination with bacilli Calmette-Guérin appeared to protect children against more severe forms of BU with multiple lesions. We conclude that in Cameroon BU is endemic, at least in the study area, and that a comprehensive control program for BU in Cameroon is urgently needed.

Adolescent↗
PubMed2003

Buruli ulcer: a systemic disease.

We studied a 4-year-old boy from Angola who presented with 2 cutaneous ulcerations of the right hip and osteomyelitis of the left knee and right ankle. Mycobacterium ulcerans disease was confirmed by direct smear examination and by polymerase chain reaction. The patient was treated with antimycobacterial drugs, repeated surgical debridement, skin grafting, and daily hyperbaric oxygenation. Despite significant improvement of the local lesions in response to hyperbaric oxygenation, swelling of the right knee, without associated skin lesions, was noted. Radiological evaluation and open biopsy revealed extensive metaphyseal osteomyelitis of the right distal femur. A 99technetium bone scan revealed an additional focus in the diaphysis of the left humerus, without soft-tissue involvement. This case documents, for the first time (to our knowledge), the systemic spread of M. ulcerans, with subsequent multifocal osteomyelitis and secondary involvement of soft tissues and supports the hypothesis that low tissue oxygen levels promote hematogenous spread of M. ulcerans. Sickle cell anemia, with associated microthrombosis and microinfarction, may have contributed to tissue hypoxia.

Antitubercular Agents↗
PubMed2003

First case of Mycobacterium ulcerans disease (Buruli ulcer) following a human bite.

Mycobacterium ulcerans disease (MUD) is rapidly reemerging in many countries, especially in West African countries. Antecedent trauma has often been related to the lesions that characterize this frequently crippling disease. We report here the first case of MUD that followed a human bite at the site where the lesion later occurred.

Adolescent↗
PubMed2003

Psychosocial aspects of health seeking behaviours of patients with Buruli ulcer in southern Benin.

We investigated cultural beliefs and psychosocial factors associated with Buruli ulcer in southern Benin in order to elaborate and deliver appropriate health education messages. We conducted a qualitative study among 130 adults and 30 children in Zou province, a highly endemic region. Focus group interviews of inhabitants, patients and their assistants, health care professionals and traditional healers took place in Dasso, Ouinhi, Sagon and Zagnanado. Drawing sessions followed by individual interviews were organized among school children in Dasso and Sagon. We found that although Buruli ulcer is well known and recognized - even at a very early stage of the disease - and perceived as threatening, most people are reluctant to seek treatment at the health care centre. They are unclear about the origin of the disease (environmental factors or sorcery) and treatment is considered devastating, expensive and ineffective in some cases.

Adolescent↗
PubMed2003

Molecular diagnosis of nontuberculous mycobacteria.

PURPOSE OF REVIEW: Diagnosis of infection due to nontuberculous mycobacteria is not easy, as it must be distinguished from colonization or contamination by other nontuberculous mycobacteria. Molecular methods offer many advantages over conventional methods of identification. The results are obtained rapidly, are reliable and reproducible, and even mixed or contaminated cultures can be examined. This review highlights the recent advances in molecular techniques for identification of nontuberculous mycobacteria. RECENT FINDINGS: Nontuberculous mycobacteria are ubiquitous towards the environment and have the potential to colonize and cause serious infection. An increasing number of species and clinical presentations are being described, and progress has been made towards the understanding of the underlying predisposing factors. Disease caused by nontuberculous mycobacteria is often associated with various forms of immunosuppression, particularly HIV infection, whereas mild forms of immune defects have been observed in some patients who, apart from their nontuberculous mycobacterial disease, seem to be healthy on initial examination. Molecular techniques have shown their usefulness for the identification of most mycobacteria. Probes are widely used in clinical laboratories for the identification of the most common mycobacterial species. Because automated DNA sequencing and the programs for analysing sequence data have become technically simpler, polymerase chain reaction-based sequencing is now used in many mycobacterial reference laboratories as a routine method for species identification. SUMMARY: Significant advances have been made with molecular tools for diagnosis of mycobacteria. The DNA microarray technique holds great promise for the future because it is easy to perform, it can be readily automated, and it allows the identification of a large number of mycobacterial species in one reaction.

Bacterial Typing Techniques↗
PubMed2003

Resazurin microtiter assay plate testing of Mycobacterium tuberculosis susceptibilities to second-line drugs: rapid, simple, and inexpensive method.

The emergence of multidrug-resistant tuberculosis calls for new, rapid drug susceptibility tests. We have tested 150 Mycobacterium tuberculosis isolates against the second-line drugs ethionamide, kanamycin, capreomycin, ofloxacin, and para-aminosalicylic acid by the colorimetric resazurin microtiter assay and the proportion method. By visual reading, MICs were obtained after 8 days. A very good correlation between results by the colorimetric resazurin microtiter assay and the proportion method was obtained. The colorimetric resazurin microtiter assay is inexpensive, rapid, and simple to perform, and implementation of the assay is feasible for low-resource countries.

Antitubercular Agents↗
PubMed2003

Heterogeneity of mycolactones produced by clinical isolates of Mycobacterium ulcerans: implications for virulence.

Mycobacterium ulcerans is the causative agent of Buruli ulcer, a severe necrotizing skin disease endemic in tropical countries. Clinical evidence suggests that M. ulcerans isolates from Asia, Mexico, and Australia may be less virulent than isolates from Africa. In vivo studies suggest that mycolactone, a polyketide-derived macrolide toxin, plays a major role in the tissue destruction and immune suppression which occur in cases of Buruli ulcer. Mycolactones were extracted from 34 isolates of M. ulcerans representing strains from Africa, Malaysia, Asia, Australia, and Mexico. Thin-layer chromatography, mass spectroscopic analysis, and cytopathic assays of partially purified mycolactones from these isolates revealed that M. ulcerans produces a heterogeneous mixture of mycolactone variants. Mycolactone A/B, the most biologically active mycolactone species, was identified by mass spectroscopy as [M(+)Na](+) at m/z 765.5 in all cytotoxic isolates except for those from Mexico. Mycolactone C [M+Na](+) at m/z 726.3 was the dominant mycolactone species in eight Australian isolates, and mycolactone D [M+Na](+) m/z 781.2 was characteristic of two Asian strains. Mycolactone species are conserved within specific geographic areas, suggesting that there may be a correlation between mycolactone profile and virulence. In addition, the core lactone, [M+Na](+) m/z 447.4, was identified as a minor species, supporting the hypothesis that mycolactones are synthesized by two polyketide synthases. A cytopathic assay of the core lactone showed that this molecule is sufficient for cytotoxicity, although it is much less potent than the complete mycolactone.

Animals↗
PubMed2002

A pilot study of treatment of Buruli ulcer with rifampin and dapsone.

OBJECTIVE: Buruli ulcer disease (BU), caused by Mycobacterium ulcerans, is endemic in many regions of Africa and causes substantial physical disability. Surgical resection, currently the mainstay of clinical management of BU, is impractical in many endemic areas. Therefore, the study was undertaken to evaluate an antibiotic regimen for medical management of BU. METHODS: A randomized, placebo-controlled pilot study of dapsone plus rifampin versus placebo was conducted. RESULTS: Forty-one participants were recruited in a BU-endemic zone of Côte d'Ivoire. Thirty persons completed the 2-month trial: 15 were treated with placebo and 15 with dapsone and rifampin. On blinded evaluation of photographs of the ulcers, clinicians with experience examining BU judged that 82% of ulcers in the treatment group improved compared with 75% in the placebo group (P=0.51). The median change in ulcer size was a decrease of 14.0 cm2 in the treatment group and a decrease of 2.5 cm2 in the placebo group (P=0.02), but initial ulcer sizes were larger in the treatment group (median 26.2 cm2) compared with the placebo group (median 4.8 cm2) (P=0.04). CONCLUSIONS: Results of this study indicate that larger studies of antimycobacterial therapy of BU are warranted and can be successfully undertaken.

Adolescent↗
PubMed2002

Molecular evidence to support a proposal to reserve the designation Mycobacterium avium subsp. avium for bird-type isolates and 'M. avium subsp. hominissuis' for the human/porcine type of M. avium.

In an attempt to clarify the taxonomy of the Mycobacterium avium complex, the relationship between IS1245 RFLP, growth temperature, 16S rDNA signature sequences and the 16S-23S rDNA internally transcribed spacer (ITS) of 160 M. avium-complex isolates from different sources was investigated. All 70 isolates identified as M. avium by INNO-LiPA MYCOBACTERIA (Innogenetics, Belgium), a DNA probe test that targets the ITS, and by 16S rDNA analysis carried multiple copies of IS1245. Three isolates with multiple copies of IS1245 were identified by 16S rDNA analysis as Mycobacterium intracellulare and by LiPA as M. intracellulare (n = 1) and M. avium-intracellulare complex (n = 2). A dichotomy among the M. avium isolates was found on the basis of a C and a G signature nucleotide at position 228 of the 16S-23S rDNA spacer sequence, and this grouping was largely confirmed on the basis of similarities in IS1245 RFLPs. Strains with the characteristic three-band IS1245 'bird-type', as well as M. avium subsp. silvaticum or 'wood-pigeon' strains, invariably contained the C signature. A third characteristic that separated the M. avium bird-type isolates from M. avium isolates from humans and other mammals was growth-temperature tolerance: in contrast to bird isolates, human/porcine isolates grew at 24 and 45 degrees C. Based on differences in IS1245 RFLP, 16S-23S rDNA ITS and growth temperature, M. avium isolates originating from birds should be considered as a separate, evolutionarily conserved taxon. Because all M. avium isolates from birds are invariably of this type, the designation M. avium subsp. avium should be reserved for these bird-type strains. For clarity in the epidemiology of M. avium-related disease, isolates from humans and pigs with multibanded IS1245 RFLPs merit a separate designation. The designation 'M. avium subsp. hominissuis' is suggested for this group of bacteria.

Animals↗
PubMed2002

Resazurin microtiter assay plate: simple and inexpensive method for detection of drug resistance in Mycobacterium tuberculosis.

A method for detecting multidrug-resistant Mycobacterium tuberculosis by using a reduction of resazurin is described. Eighty clinical isolates were evaluated against isoniazid and rifampin; results at 7 days were compared with those of the proportion method. Specificity and sensitivity were excellent. The method is simple, inexpensive, and rapid and might be used with other antituberculosis drugs.

Antitubercular Agents↗
PubMed2002

IS6110 fingerprinting of sensitive and resistant strains (1991-1992) of Mycobacterium tuberculosis in Colombia.

The standardized method to study the polymorphism of IS 6110 was used to characterize 53 isolates of Mycobacterium tuberculosis obtained during 1991-1992 from 14 regions in Colombia. In Valle region cluster rate was 25% (4/16). The mean number of IS6110 band was 10 +/- 3. Similarity between strains was of 60% in 81% of strains and this tended to be correlated with geographic origin. For the first time M. tuberculosis without IS6110 bands in restriction fragment length polymorphism analysis was found in Colombia. Additional studies are necessaries in order to best characterize the situation in relation to human immunodeficiency virus epidemic and recent changes in tuberculosis control program.

Cluster Analysis↗