Biomedical subjects

Françoise Dromer

Publications and source records attributed to Françoise Dromer.

At least 19 recordsLinked to original sources

PubMed2006

Long-term outcome of AIDS-associated cryptococcosis in the era of combination antiretroviral therapy.

BACKGROUND: Immune restoration following combination antiretroviral therapy (cART) questions the maintenance of prophylaxis among HIV-infected patients with cryptococcosis. OBJECTIVE: To describe the long-term outcome after the diagnosis of cryptococcosis at the cART era. DESIGN: Multicentre cohort of patients with a diagnosis of cryptococcosis between 1996 and 2000, follow-up until December 2002. Comparison with a historical cohort (1990-1994) for survival. SETTING: Eighty-four French AIDS clinical centres. PATIENTS: Two-hundred and forty HIV-infected adult patients at the cART era and 149 at the pre-cART era experiencing a first episode of culture-confirmed cryptococcosis. RESULTS: In the cART era, 82/189 patients surviving more than 3 months after initiation of antifungal therapy had their maintenance therapy interrupted with a subsequent median follow-up of 19 months. Their relapse rate per 100 person-years was 0.9 [95% confidence interval (CI),0.0-2.0]. When considering the whole cART cohort, probability of reaching negative serum cryptococcal antigen was 71% after 48 months of follow-up. A CD4 cell count < 100/microl [relative risk (RR), 5.5; 95% CI, 1.3-22.2], antifungal therapy < 3 months over the past 6 months [RR, 5.0; 95% CI, 1.1-22.3] and serum cryptococcal antigen titre > or = 1/512 [RR, 3.5; 95% CI, 1.1-10.8] were associated with a higher rate of cryptococcosis relapse. The mortality rate per 100 person-years was 15.3 [95% CI,12.2-18.4] in the cART era versus 63.8 [95% CI,53.0-74.9] in the pre-cART era although early mortality did not differ between the two periods. CONCLUSION: Overall survival after cryptococcosis has dramatically improved at the cART era. Immune restoration and low serum cryptococcal antigen titres are associated with lower cryptococcosis relapse rates.

AIDS-Related Opportunistic Infections↗

PubMed2006

Combination of amphotericin B with flucytosine is active in vitro against flucytosine-resistant isolates of Cryptococcus neoformans.

The combination of flucytosine and amphotericin B was tested against 10 flucytosine-resistant isolates of Cryptococcus neoformans by checkerboard, killing curves, and Etest. Although differences were observed depending on the technique used, antagonism was never observed. The synergistic interaction was related to the mechanism of flucytosine resistance of the isolates.

Amphotericin B↗

PubMed2006

Immune reconstitution inflammatory syndrome in HIV-infected patients with disseminated histoplasmosis.

Four HIV-1-infected patients presented with unusual clinical manifestations in the course of disseminated histoplasmosis, including liver abscesses, compressive lymphadenitis, intestinal obstruction, uveitis and arthritis within a median of 45 days after initiation of highly active antiretroviral therapy (HAART). They had a median increase of 106 CD4 cells/mul and granulomas with caseation in three. Partial immune reconstitution induced by HAART during disseminated histoplasmosis either related to the variety capsulatum or duboisii may be associated with immune reconstitution inflammatory syndrome.

AIDS-Related Opportunistic Infections↗

PubMed2006

Unique hybrids between the fungal pathogens Cryptococcus neoformans and Cryptococcus gattii.

Cryptococcus neoformans and Cryptococcus gattii are yeasts that cause meningoencephalitis, but that differ in host range and geographical distribution. Cryptococcus neoformans occurs world-wide and mostly infects immunocompromised patients, whereas C. gattii occurs mainly in (sub)tropical regions and infects healthy individuals. Anomalous C. neoformans strains were isolated from patients. These strains were found to be monokaryotic, and diploid or aneuploid. Amplified Fragment Length Polymorphism (AFLP) and sequence analyses indicated that AFLP genotypes 2 (C. neoformans) and 4 (C. gattii) were present. The strains were serologically BD. Mating- and serotype-specific PCR reactions showed that the strains were MATa-serotype D/MATalpha-serotype B. This study is the first to describe naturally occurring hybrids between C. neoformans and C. gattii.

Adult↗

PubMed2006

Efficacy of amphotericin B in combination with flucytosine against flucytosine-susceptible or flucytosine-resistant isolates of Cryptococcus neoformans during disseminated murine cryptococcosis.

Whether or not flucytosine should be administered to patients infected with Cryptococcus neoformans isolates found to be resistant to flucytosine in vitro remains a controversial issue. Thus, the efficacy of amphotericin B and flucytosine in combination was investigated by mortality and fungal burden studies in a murine model of disseminated cryptococcosis using two clinical isolates of Cryptococcus neoformans, one susceptible and one resistant (i.e., 64 microg/ml) to flucytosine. Amphotericin B was given intraperitoneally at 0.25 or 0.5 mg/kg/day, while flucytosine was given at 100 or 250 mg/kg/day orally. Treatment was started 24 h or day 6 after inoculation and continued for 5 days in fungal burden and mortality studies, respectively. The combination of amphotericin B at 0.5 mg/kg/day and flucytosine at 250 mg/kg/day was significantly more effective than monotherapies for reducing fungal burden in brain, spleen, and lungs after infection by the flucytosine-susceptible isolate and in brain and spleen for the flucytosine-resistant isolate. For the flucytosine-resistant isolate, the combination of amphotericin B at 0.5 mg/kg/day with flucytosine at 100 mg/kg/day was significantly better than monotherapies for reducing the fungal burden in the brain. Survival obtained after the combination of amphotericin B at 0.5 mg/kg/day and flucytosine at 250 mg/kg/day increased compared to that obtained with monotherapies for both isolates, but the difference was statistically significant only for the flucytosine-susceptible isolate. Antagonism was never observed. This study demonstrates the beneficial effect of the addition of flucytosine to amphotericin B against experimental disseminated cryptococcal infection even when the C. neoformans isolate is resistant to flucytosine.

Amphotericin B↗

PubMed2006

Molecular identification of black-grain mycetoma agents.

Black-grain mycetomas are subcutaneous devastating chronic infections due to several dematiaceous fungi. They are diagnosed mostly in tropical countries. Identification of these fungi with standard mycological procedures is difficult because of their poor or delayed sporulation. The aim of this study was thus to assess the accuracy of molecular identification of these fungi. A total of 54 strains, mostly of clinical origin, were used, including 15 Madurella mycetomatis, 6 Madurella grisea, 12 Leptosphaeria senegalensis, 4 Leptosphaeria tompkinsii, 6 Pyrenochaeta spp., 4 Curvularia lunata, and 7 Exophiala jeanselmei strains. The internal transcribed spacer 1 (ITS1)-5.8S-ITS2 DNA region was amplified by using universal fungal primers and sequenced. Both intra- and interspecies sequence similarities were assessed. Madurella mycetomatis appeared to be a homogeneous species. More intraspecies variations were found for C. lunata and E. jeanselmei, leading, in some instances, to changes in the initial identification. L. senegalensis and L. tompkinsii showed intraspecies similarities of >99%, but similarity between the two species was <88%. Intergenera and interspecies variations were important, with sequence homologies of <81% between genera. In contrast, Pyrenochaeta romeroi and M. grisea appeared to be heterogeneous, with intraspecies similarities of 40 to 100% and 53 to 100%, respectively, which suggest either erroneous identification or the need for taxonomic revision. Epidemiological and therapeutic studies could benefit from a precise identification of the fungi responsible for black-grain mycetoma based not only on phenotypical characteristics but also on ITS sequencing.

DNA, Fungal↗

PubMed2006

Molecular identification of zygomycetes from culture and experimentally infected tissues.

Mucormycosis is an emerging infection associated with a high mortality rate. Identification of the causative agents remains difficult and time-consuming by standard mycological procedures. In this study, internal transcribed spacer (ITS) sequencing was validated as a reliable technique for identification of Zygomycetes to the species level. Furthermore, species identification directly from infected tissues was evaluated in experimentally infected mice. Fifty-four Zygomycetes strains belonging to 16 species, including the most common pathogenic species of Rhizopus spp., Absidia spp., Mucor spp., and Rhizomucor spp., were used to assess intra- and interspecies variability. Ribosomal DNA including the complete ITS1-5.8S-ITS2 region was amplified with fungal universal primers, sequenced, and compared. Overall, for a given species, sequence similarities between isolates were >98%. In contrast, ITS sequences were very different between species, allowing an accurate identification of Zygomycetes to the species level in most cases. Six species (Rhizopus oryzae, Rhizopus microsporus, Rhizomucor pusillus, Mucor circinelloides, and Mucor indicus) were also used to induce disseminated mucormycosis in mice and to demonstrate that DNA extraction, amplification of fungal DNA, sequencing, and molecular identification were possible directly from frozen tissues.

Amino Acid Sequence↗

PubMed2005

Incidence and risk factors of immune reconstitution inflammatory syndrome complicating HIV-associated cryptococcosis in France.

BACKGROUND: Immune reconstitution inflammatory syndrome (IRIS) in association with cryptococcosis has been anecdotically reported following administration of highly active antiretroviral therapy (HAART). OBJECTIVE: To analyse the incidence and risk factors for IRIS-associated cryptococcosis among HIV-infected patients. DESIGN: Retrospective multicentre study between 1996 and 2000 through the French Cryptococcosis Database. METHODS: Subsequent occurrence of IRIS examined in 120 HIV-infected adult patients treated with HAART and experiencing a first episode of culture-confirmed cryptococcosis. RESULTS: Ten patients developed IRIS during the study period, giving an incidence of 10/239, or 4.2/100 person-years [95% confidence interval (CI), 2.2-7.8]. IRIS consisted of acute symptoms consistent with inflammation occurring within a median of 8 months (range, 2-37) after the diagnosis of cryptococcosis in the context of negative cultures and immunological and/or virological response to HAART. Radiology and histopathology detected features compatible with inflammation. Symptom severity required transfer into intensive care units for three patients and use of anti-inflammatory drugs for four. Three patients with evolutive IRIS died. Compared with patients without IRIS for whom complete clinical and microbiological information were available at baseline, previously unknown HIV infection [odds ratio (OR), 4.8; 95% CI, 1.0-21.7], CD4 cell count < 7 x 10 cells/l (OR, 4.0; 95% CI, 0.9-17.2), fungaemia (OR, 6.1; 95% CI, 1.1-35.2) and HAART initiation within 2 months of cryptococcosis diagnosis (OR, 5.50; 95% CI, 1.0-29.6) were independently associated with the risk of subsequent IRIS. CONCLUSIONS: IRIS-related cryptococcosis was observed more frequently in severely immunocompromised patients with disseminated infection and HAART initiation soon after the diagnosis.

AIDS-Related Opportunistic Infections↗

PubMed2005

Capsule structure changes associated with Cryptococcus neoformans crossing of the blood-brain barrier.

Cryptococcus neoformans is a yeast responsible for disseminated meningoencephalitis in patients with cellular immune defects. The major virulence factor is the polysaccharide capsule. We took advantage of a relevant murine model of disseminated meningoencephalitis to study the early events associated with blood-brain barrier (BBB) crossing. Mice were sacrificed at 1, 6, 24, and 48 hours post-intravenous inoculation, and classical histology, electron microscopy, and double immunofluorescence were used to study tissues and yeasts. Crossing of the BBB occurred early after inoculation, did not involve the choroid plexus but instead occurred at the level of the cortical capillaries, and caused early and severe damage to the structure of the microvessels. Seeding of the leptomeninges was not the primary event but occurred secondary to leakage of cortical pseudocysts. Organ invasion was associated with changes in cryptococcal capsule structure and cell size, which differed in terms of magnitude and kinetics, depending on both the organs involved, and potentially, on the bed structure of the local capillary. The rapid changes in capsule structure could contribute to inability of the host immune response to control cryptococcal infection in extrapulmonary spaces.

Animals↗

PubMed2005

The Yak1p kinase controls expression of adhesins and biofilm formation in Candida glabrata in a Sir4p-dependent pathway.

Biofilm is the predominant type of microbial development in natural environments, and potentially represents a major form of resistance or source of recurrence during host infection. Although a large number of studies have focussed on the genetics of bacterial biofilm formation, very little is known about the genes involved in this type of growth in fungi. A genetic screen for Candida glabrata Biofilm mutants was performed using a 96-well plate model of biofilm formation. Study of the isolated mutant strains allowed the identification of four genes involved in biofilm formation (RIF1, SIR4, EPA6 and YAK1). Epa6p is a newly identified adhesin required for biofilm formation in this pathogenic yeast. EPA6 and its close paralogue EPA7 are located in subtelomeric regions and their transcription is regulated by Sir4p and Rif1p, two proteins involved in subtelomeric silencing. Biofilm growth conditions induce the transcription of EPA6 and EPA7: this is dependent on the presence of an intact subtelomeric silencing machinery and is independent of the Mpk1p signalling pathway. Finally, the kinase Yak1p is required for expression of both adhesin genes and acts through a subtelomeric silencing machinery-dependent pathway.

Biofilms↗

PubMed2005

Deletions of endocytic components VPS28 and VPS32 affect growth at alkaline pH and virulence through both RIM101-dependent and RIM101-independent pathways in Candida albicans.

Ambient pH signaling involves a cascade of conserved Rim or Pal products in ascomycetous yeasts or filamentous fungi, respectively. Recent evidences in the fungi Aspergillus nidulans, Saccharomyces cerevisiae, Yarrowia lipolytica, and Candida albicans suggested that components of endosomal sorting complexes required for transport (ESCRT) involved in endocytic trafficking were needed for signal transduction along the Rim pathway. In this study, we confirm these findings with C. albicans and show that Vps28p (ESCRT-I) and Vps32p/Snf7p (ESCRT-III) are required for the transcriptional regulation of known targets of the Rim pathway, such as the PHR1 and PHR2 genes encoding cell surface proteins, which are expressed at alkaline and acidic pH, respectively. We additionally show that deletion of these two VPS genes, particularly VPS32, has a more drastic effect than a RIM101 deletion on growth at alkaline pH and that this effect is only partially suppressed by expression of a constitutively active form of Rim101p. Finally, in an in vivo mouse model, both vps null mutants were significantly less virulent than a rim101 mutant, suggesting that VPS28 and VPS32 gene products affect virulence both through Rim-dependent and Rim-independent pathways.

Alkalies↗

PubMed2005

Cryptococcus neoformans Galactoxylomannan contains an epitope(s) that is cross-reactive with Aspergillus Galactomannan.

We report a case of cryptococcosis in which a serum enzyme-linked immunosorbent assay (ELISA) for Aspergillus galactomannan was positive, with no evidence of aspergillosis. Soluble antigens from 19 Cryptococcus neoformans strains and purified carbohydrates of C. neoformans capsule were thus assayed in the Aspergillus galactomannan ELISA. Antigens from all C. neoformans strains, and purified galactoxylomannan, gave a positive reaction, suggesting that C. neoformans galactoxylomannan contains an epitope(s) that is cross-reactive with Aspergillus galactomannan.

Adult↗

PubMed2005

Breakthrough disseminated Aspergillus ustus infection in allogeneic hematopoietic stem cell transplant recipients receiving voriconazole or caspofungin prophylaxis.

Aspergillus ustus is an uncommon clinical species which is poorly susceptible to antifungals. We report two cases of A. ustus infections that occurred in allogeneic stem cell transplant recipients while they were receiving either voriconazole or caspofungin. Prolonged use of these new antifungal agents may increase the risk of the emergence of resistant organisms.

Adolescent↗

PubMed2004

Epidemiology of HIV-associated cryptococcosis in France (1985-2001): comparison of the pre- and post-HAART eras.

OBJECTIVE: To analyse the epidemiological evolution of cryptococcosis in France after the introduction of highly active antiretroviral therapy (HAART). DESIGN: Retrospective study of cryptococcosis cases recorded at the National Reference Center for Mycoses in France since 1985. METHODS: Using the national surveillance data, we reviewed 1644 cases of HIV-associated cryptococcosis diagnosed in France (population, 59 million) between 1985 and 2001 and compared them to 335 cases recorded in HIV-negative patients. RESULTS: The total number of cryptococcosis cases evolved in parallel to that recorded for HIV-infected patients. Changes occurring after HAART introduction were analysed. A negative binomial regression model established a 46% decrease of the incidence of cryptococcosis during the post-HAART era (1997-2001, n = 292) compared to the pre-HAART era (1985-1996, n = 1352). According to multivariate analysis, African origin, older age, heterosexual HIV contamination, no previous AIDS-defining illness, and no previous HIV infection diagnosis were variables independently associated with an increased risk of cryptococcosis during the post-HAART era. During the same period, the characteristics of the HIV-negative population did not change. CONCLUSIONS: Our analysis of the national surveillance identified demographic factors associated with an increased risk of cryptococcosis in the post-HAART era suggesting that failure to consult and considering oneself not at risk were determinant in the current epidemiology of HIV-related cryptococcosis in France.

AIDS-Related Opportunistic Infections↗

PubMed2004

Pulmonary cryptococcosis.

Pulmonary cryptococcosis is the consequence of the inhalation of Cryptococcus neoformans, an encapsulated yeast, from various environmental sources. It is commonly accepted that the acquisition of the disease occurs early in life and that the disease is mostly related to a reactivation from a pulmonary site in immunocompromised hosts such as patients infected with human immunodeficiency virus. Clinical and radiological presentations of the disease are nonspecific and are more severe in immunocompromised hosts with acquired immunodeficiency syndrome (AIDS). However, fulminant forms have also been reported in apparently immunocompetent hosts. C. neoformans has rarely been responsible for colonization of the respiratory tract; this usually occurs in immunocompetent hosts with preexisting pulmonary disease. Diagnosis of pneumonia is obtained by either analysis of bronchoalveolar lavage in AIDS patients or by the histology/mycological analysis of a pulmonary nodule. In any case, a careful work-up for diagnosing dissemination should always be performed. Antifungal treatment has to be given in most of the immunocompetent hosts and always in those with any kind of immunodeficiency with isolated pulmonary cryptococcosis.

Journal Article↗

PubMed2004

In vitro evaluation of double and triple combinations of antifungal drugs against Aspergillus fumigatus and Aspergillus terreus.

Microdilution broth checkerboard techniques based on the National Committee for Clinical Laboratory Standards methodology were used to study double and triple antifungal combinations against clinical isolates of Aspergillus fumigatus and A. terreus. The influences of the end-point definition (partial or complete inhibition) and the mode of reading (visually or spectrophotometrically) were determined. Interactions between antifungal drugs were also evaluated by agar diffusion tests. Combinations of caspofungin with either amphotericin B or voriconazole were additive for all the isolates, and antagonism was not observed. The interaction between caspofungin and flucytosine was synergistic for 62% of the isolates. In contrast, the interaction between voriconazole and flucytosine was never synergistic and antagonism was noted for 93% of the isolates. The triple combination of caspofungin with flucytosine and amphotericin B was synergistic for all the isolates tested. The triple combination of caspofungin with flucytosine and voriconazole was also mostly synergistic; but complex interactions were obtained for some isolates, with synergy or antagonism depending on the concentrations of caspofungin and voriconazole. Analysis of the influence of the reading technique on the results showed that spectrophotometric reading was a good alternative to the recommended visual reading. The results of these in vitro tests suggest that the activity of flucytosine as part of a double combination with caspofungin and as part of a triple combination with caspofungin and amphotericin B against Aspergillus spp. warrants further investigations. Animal studies are needed to evaluate the in vivo efficacies of these combinations.

Antifungal Agents↗

PubMed2004

Cryptococcus neoformans capsule structure evolution in vitro and during murine infection.

Cryptococcus neoformans capsule structure modifications after prolonged in vitro growth or in vivo passaging have been reported previously. However, nothing is known about the dynamics of these modifications or about their environmental specificities. In this study, capsule structure modifications after mouse passaging and prolonged in vitro culturing were analyzed by flow cytometry using the glucuronoxylomannan-specific monoclonal antibody E1. The capsule structures of strains recovered after 0, 1, 8, and 35 days were compared by using the level of E1-specific epitope expression and its cell-to-cell heterogeneity within a given cell population. In vitro, according to these parameters, the diversity of the strains was higher on day 35 than it was initially, suggesting the absence of selection during in vitro culturing. In contrast, the diversity of the strains recovered from the brain tended to decrease over time, suggesting that selection of more adapted strains had occurred. The strains recovered on day 35 from the spleen and the lungs had different phenotypes than the strains isolated from the brain of the same mouse on the same day, thus strongly suggesting that there is organ specificity for C. neoformans strain selection. Fingerprinting of the strains recovered in vitro and in vivo over time confirmed that genotypes evolved very differently in vitro and in vivo, depending on the environment. Overall, our results suggest that organ-specific selection can occur during cryptococcosis.

Animals↗

PubMed2003

Primary cutaneous cryptococcosis: a distinct clinical entity.

Cryptococcus neoformans is an encapsulated yeast responsible for disseminated meningitis in immunocompromised hosts. Controversies persist on the existence of primary cutaneous cryptococcosis (PCC) versus cutaneous cryptococcosis being only secondary to hematogenous dissemination. Thus, we reviewed cryptococcosis cases associated with skin lesions reported in the French National Registry. Patients with PCC (n=28) differed significantly from those with secondary cutaneous cryptococcosis (n=80) or other forms of the disease (n=1866) by living area (mostly rural), age (older), ratio of men to women (approximately 1:1), and the lack of underlying disease. Evidence of PCC included the absence of dissemination and, predominantly, a solitary skin lesion on unclothed areas presenting as a whitlow or phlegmon, a history of skin injury, participation in outdoor activities, or exposure to bird droppings, and isolation of C. neoformans serotype D. Therefore, PCC is a distinct epidemiological and clinical entity with a favorable prognosis even for immunocompromised hosts.

Adult↗