Successful treatment of Trichosporon asahii fungemia with isavuconazole in a patient with hematologic malignancies

International audienceTrichosporon spp. are yeast-like microorganisms responsible for skin, urinary, pulmonary, or bloodstream infections. Due to intrinsic resistance to echinocandins, poor susceptibility to polyenes, and preferred occurrence in immunocompromised patients, such infections are often of poor prognosis. Yet no consensual therapeutic guidelines are presently available. Several clinical cases of Trichosporon infections have been successfully treated with azole therapy, including voriconazole which appeared frequently effective against Trichosporon both in vitro and in vivo. However, the low efficacy associated with some Trichosporon genotypes, complex pharmacokinetics, and the side effects of voriconazole represent limitations for its use and has prompted a search for other therapeutic options. Here, we report a case of T. asahii fungemia in a patient with B-cell acute lymphoblastic leukemia which was successfully treated with isavuconazole consecutive to stopping voriconazole therapy due to severe side effects. This observation suggests that isavuconazole with a similar spectrum to voriconazole, fewer pharmacology interactions, and side effects may be considered as a valuable therapeutic option against Trichosporon infections

Comparison of three commercial multiplex PCR assays for the diagnosis of intestinal protozoa

Although microscopic examination of stool samples remains the reference method for the diagnosis of intestinal protozoal infections, these techniques are time-consuming and require operators who are experienced and well trained. Molecular biology seems to offer performances at least equivalent in terms of sensitivity and specificity for certain parasites. This study aimed to compare three multiplex PCR assays on 93 prospectively collected positive stools (prospective cohort) and a panel of 12 more Cryptosporidium-positive samples (Cryptosporidium panel). On the prospective cohort, the sensitivity was 89%, 64% and 41% for Giardia sp. detection for BD MaxTM, G-DiaParaTM and RIDA®GENE, respectively and 75%, 100% and 100% for C. parvum/hominis detection. The sensitivity of the RIDA®GENE assay for all Cryptosporidium species was 100%, and for D. fragilis 71%. All the techniques obtained the same results for E. histolytica detection, with one positive sample. All species in the Cryptosporidium panel were identified by the RIDA®GENE PCR. The BD MaxTM and G-DiaParaTM assays detected only C. parvum/hominis with the exception of one positive sample for C. meleagridis. No assay showed satisfactory results for all parasites simultaneously, and the DNA extraction seems to be the critical step. More studies are needed to standardize this procedure

Common occurrence of Cryptosporidium hominis in asymptomatic and symptomatic calves in France

International audienceSymptomatic infection by the Apicomplexan Cryptosporidium spp. is presently considered the most frequent parasitic cause of acute diarrhea in both humans (especially severe in immunocompromised individuals and infants in both developed and developing countries) and cattle (calves), while asymptomatic infections are less often documented. Cryptosporidium (C.) hominis once considered to be restricted to humans accounts for the majority of pediatric cases in several countries. C. parvum can also infect cattle as well as C. bovis, C. andersoni, and C. ryanae. Recently, cattle C. hominis cryptosporidiosis has been reported, suggesting that the presence of C. hominis in calves was previously underestimated. The aim of this work was to characterize Cryptosporidium spp. infection in both asymptomatic and symptomatic dairy and beef calves from Metropolitan France. From February to November 2015, C. parvum or C. hominis infected calves were detected in farms from 5 geographic regions of France. Surprisingly, C. hominis was present in about one fifth of Cryptosporidium spp. infected calves, and exhibited genotypes which were previously reported in human and nonhuman primate. Further investigations are aimed at documenting direct or indirect C. hominis transmissions between and among livestock and humans

Evaluation of voriconazole anti-Acanthamoeba polyphaga in vitro activity, rat cornea penetration and efficacy against experimental rat Acanthamoeba keratitis

International audienceBackground: Acanthamoeba keratitis (AK) is a sight-threatening infectious disease. Its effective and safe medical therapy remains highly debated. Recently, voriconazole, a monotriazole with noted in vitro activity against a large variety of fungi, has been successfully used both topically and systemically to treat human AK cases.Objectives: To measure anti-Acanthamoeba polyphaga in vitro activity, anti-rat AK efficiency and rat cornea penetration of eye-drop and oral voriconazole.Methods: A. polyphaga was maintained in axenic cultures. In vitro, amoebicidal and cysticidal activities of voriconazole were measured using an XTT assay. AK lesions of Sprague Dawley rats were scored from grade 0 to grade 3. For 21 days, from day 7 post-infection, voriconazole (1% solution) eye drops were instilled or voriconazole was administered by gavage (60 mg/kg/day). After killing, superficial corneal epithelium scrapings were cultured and analysed by PCR, and eye-globe histology was performed. Cornea and plasma concentrations were determined using 2D HPLC separation and tandem MS.Results: In vitro, voriconazole inhibited trophozoite proliferation with an IC50 value of 0.02 mg/L and an IC90 value of 2.86 mg/L; no cysticidal effect was found. In AK rats, eye drops reduced clinical worsening from day 7 to day 14 post-infection and oral voriconazole was not effective. Voriconazole cornea concentrations were directly dependent on the frequency of eye-drop instillations, which resulted in lower plasma concentrations, whilst oral voriconazole resulted in lower cornea concentrations.Conclusions: Present data underline the need for high-frequency eye-drop instillation regimens for efficient AK therapy

Seroprevalence of malaria in inhabitants of the urban zone of Antananarivo, Madagascar

BACKGROUND: Antananarivo, the capital of Madagascar, is located at an altitude of over 1,200 m. The environment at this altitude is not particularly favourable to malaria transmission, but malaria nonetheless remains a major public health problem. The aim of this study was to evaluate exposure to malaria in the urban population of Antananarivo, by measuring the specific seroprevalence of Plasmodium falciparum. METHODS: Serological studies specific for P. falciparum were carried out with an indirect fluorescent antibody test (IFAT). In a representative population of Antananarivo, 1,059 healthy volunteers were interviewed and serum samples were taken. RESULTS: The seroprevalence of IgG+IgA+IgM was 56.1% and that of IgM was 5.9%. The major risk factor associated with a positive IgG+IgA+IgM IFAT was travel outside Antananarivo, whether in the central highlands or on the coast. The abundance of rice fields in certain urban districts was not associated with a higher seroprevalence. CONCLUSION: Malaria transmission levels are low in Antananarivo, but seroprevalence is high. Humans come into contact with the parasite primarily when travelling outside the city. Further studies are required to identify indigenous risk factors and intra-city variations more clearly

Cytometric measurement of in vitro inhibition of Plasmodium falciparum field isolates by drugs: a new approach for re-invasion inhibition study.

International audienceBACKGROUND: A flow cytometric method is proposed to study in vitro drug sensitivity of Plasmodium falciparum. Standard [3H]-hypoxanthine incorporation assay gives only information on inhibition of maturation by drugs. This method is usable on field isolates and provides data on both inhibition of maturation and re-invasion. METHODS: The method is based on the staining of parasites with hydroethidine (HE) and thiazole orange (TO) which allow differential identification of early, trophozoite and late stage of the parasite by flow cytometry. Late stages of the parasites are obtained by incubation in culture for 24 hours. Reinvasion is followed by culturing parasitized red blood cells for 24 h more. RESULTS: Compared to the standard [3H]-hypoxanthine incorporation assay, it gave similar results as expressed by 50% inhibitory concentrations for chloroquine of laboratory strains and "field" isolates. The effect of quinine on the schizont-ring transition was also explored using this method. First data on the inhibition of re-invasion induced by quinine are presented for both P. falciparum-cultured strains and field isolates. DISCUSSION: This method is simple to use event for field isolate study. It is suitable to analyse effect of drugs on steps of the parasite life cycle different for the maturation one. Using this method quinine was found to have a inhibitory effect on re-invasion of red cells by Plasmodium

Comparaison de trois kits commerciaux de PCR multiplex pour la mise en évidence de protozoaires intestinaux.

International audienceAlthough microscopic examination of stool samples remains the reference method for the diagnosis of intestinal protozoal infections, these techniques are time-consuming and require operators who are experienced and well trained. Molecular biology seems to offer performances at least equivalent in terms of sensitivity and specificity for certain parasites. This study aimed to compare three multiplex PCR assays on 93 prospectively collected positive stools (prospective cohort) and a panel of 12 more Cryptosporidium-positive samples (Cryptosporidium panel). On the prospective cohort, the sensitivity was 89%, 64% and 41% for Giardia sp. detection for BD MaxTM, G-DiaParaTM and RIDA®GENE, respectively and 75%, 100% and 100% for C. parvum/hominis detection. The sensitivity of the RIDA®GENE assay for all Cryptosporidium species was 100%, and for D. fragilis 71%. All the techniques obtained the same results for E. histolytica detection, with one positive sample. All species in the Cryptosporidium panel were identified by the RIDA®GENE PCR. The BD MaxTM and G-DiaParaTM assays detected only C. parvum/hominis with the exception of one positive sample for C. meleagridis. No assay showed satisfactory results for all parasites simultaneously, and the DNA extraction seems to be the critical step. More studies are needed to standardize this procedure.Bien que l’examen microscopique des selles reste la méthode de référence pour le diagnostic des protozooses intestinales, ces techniques sont chronophages et demandent une grande expérience et des opérateurs entrainés. La biologie moléculaire semble offrir des performances au moins équivalentes en termes de sensibilité comme de spécificité pour certains parasites. Cette étude visait à comparer trois techniques de PCR multiplex sur une cohorte de 93 selles positives collectées prospectivement et un panel de 12 échantillons positifs à Cryptosporidium. Respectivement pour BD MaxTM, G-DiaParaTM et RIDA®GENE la sensibilité était de 89 %, 64 % et 41 % pour la détection de Giardia sp. et 75 %, 100 % et 100 % pour la détection de C. parvum/hominis. La sensibilité de la technique RIDA®GENE pour l’ensemble des espèces de Cryptosporidium était de 100 % et de 71 % pour D. fragilis. Toutes les techniques ont obtenu les mêmes résultats pour la détection d’E. histolytica (1 échantillon positif). Toutes les espèces de Cryptosporidium ont été détectées par la PCR RIDA®GENE. Les techniques BD MaxTM et G-DiaParaTM ont détecté seulement C. parvum/hominis en dehors d’un échantillon positif à C. meleagridis. Aucun essai n’a montré de résultats satisfaisants pour l’ensemble des parasites simultanément et l’extraction d’ADN semble être l’étape critique. Plus d’études sont nécessaires afin de standardiser cette procédure

“Seven shades of Cryptosporidium”

International audienc

Comparative Evaluation of Commercial Concentration Procedures for Human Intestinal Parasite Detection

International audienceBackground. Effective stool concentration is essential in microscopically based diagnosis of human intestinal parasite infections.Objective. To compare the performances of 4 concentration commercial kits and 1 homemade procedure in 96 clinical stool specimens that tested positive for the detection of 9 helminth and 8 protozoa parasites.Methods. The presence or absence of parasite forms was microscopically determined under conditions of standard practice. Also, we established the accuracies, concentration factors, and extraction yields.Results. No difference was observed between procedures for preconcentration specimens that tested positive. However, for preconcentration specimens that tested negative, we discovered that the homemade procedure was the most effective, and 2 of the 4 commercial kits were discovered to be satisfactory for routine applications.Conclusions. For all parasites, procedures with biphasic solvents exhibited higher performances than organic solvent-free procedures. For the first time, the effectiveness of commercial concentration kits has been evaluated on several common stool parasites, and the results suggest that improvement of commercial procedures is possible