Interpretation of the Elecsys Toxo IgG avidity results for very low and very high index: study on 741 sera with a determined date of toxoplasmosis.

Initial results with the Elecsys Toxo IgG Avidity assay showed some potential for interpretation of a very low or very high index result. We aimed to examine these new insights into interpretation using a large panel of serum samples and to define the optimal thresholds. A total of 741 patient serum samples with known date of infection (from a few weeks to more than 9 months after infection), were analysed with the Elecsys Toxo IgG Avidity assay. Values ≥80% (threshold defined by the manufacturer) were reported in 289 sera; 288 sera were sampled more than 4 months after infection. Thus, avidity values ≥80% excluded an infection less than 4 months. Avidity values ≥90% were reported in 112 sera sampled more than 9 months after infection. Thus, avidity values ≥90% excluded infection less than 9 months. Moreover avidity values ≤15% were reported in the 62 sera sampled less than 3 months after infection. Thus avidity values ≤15% excluded infection more than 3 months.

Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis.

Toxoplasmosis, a benign infection, is asymptomatic or paucisymptomatic in over 80% of cases, except in immunocompetent patients suffering from ocular toxoplasmosis or in immunocompromised patients with opportunistic or congenital toxoplasmosis. Diagnosis is based mainly on serology testing. Thus, we compared the performance of the nine most commonly used commercial automated or semiautomated immunoassays for IgG and IgM Toxoplasma gondii antibody detection, that is, the Advia Centaur, Architect, AxSYM, Elecsys, Enzygnost, Liaison, Platelia, VIDAS, and VIDIA assays. The assays were conducted on four panels of serum samples derived during routine testing from patients with an interfering disease and who exhibited a low IgG antibody level in one of two clinical settings, namely, acute or chronic toxoplasmosis. As a result, IgG sensitivities ranged from 97.1% to 100%, and IgG specificities ranged from 99.5% to 100%. For IgG quantification, strong differences in IgG titers (expressed in IU/ml) were noted depending on the assay used. IgM sensitivities ranged from 65% to 97.9%, and IgM specificities ranged from 92.6% to 100%. For defining the best serological strategies to be implemented, it appears crucial to compare the diagnostic performance of the different tests with respect to their specificity and sensitivity in detecting the presence of IgG and IgM antibodies.

Fast and accurate identification of dermatophytes by matrix-assisted laser desorption ionization-time of flight mass spectrometry: validation in the clinical laboratory.

The performance of a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) workflow using an extensive reference database for dermatophyte identification was evaluated on 176 clinical strains. Using a direct-deposit procedure after 3 incubation days yielded 40% correct identification. Both increasing incubation time and using an extraction procedure resulted in 100% correct identification.

Toxoplasma seroconversion with negative or transient immunoglobulin M in pregnant women: myth or reality? A French multicenter retrospective study.

Classically, Toxoplasma infection is associated with high levels of specific IgM antibody and a rise in specific IgG levels 1 to 3 weeks later. Atypical IgG seroconversion, without IgM detection or with transient IgM levels, has been described during serologic follow-up of seronegative pregnant women and raises difficulties in interpreting the results. To evaluate the frequency and the characteristics of these atypical cases of seroconversion, an investigation was conducted within the French National Reference Center for Toxoplasmosis, from which 26 cases collected from 12 laboratories belonging to the network were identified. The aim of this work was to retrospectively analyze the results of serologic testing, the treatments administered, and the results of prenatal and postnatal follow-up for these women. In each case, IgG antibodies were detected using both screening and confirmatory tests. IgM antibodies were not detected in 15 cases, and the levels were equivocal or low-positive in 11 cases. The IgG avidity results were low in 16 cases and high in one case. Most of the pregnant women (22/26) were treated with spiramycin from the time that IgG antibodies appeared until delivery. Amniotic fluid was analyzed for Toxoplasma gondii DNA by PCR in 11/26 cases, and the results were negative in all cases. Congenital toxoplasmosis was ruled out in 12/26 newborns. There was no abnormality observed at birth for 10 newborns and no information available for 4 newborns. In conclusion, when the interpretation of serological results is so difficult, it seems cautious to initiate treatment by spiramycin and to follow the pregnant women and their newborns.

Histological and molecular biology diagnosis of neurocysticercosis in a patient without history of travel to endemic areas: case report.

BACKGROUND: in endemic areas, neurocysticercosis appears mainly as a single, large, spherical and non-enhancing intracranial cyst. CASE PRESENTATION: an atypical case of neurocysticercosis (NCC) in a French Caucasian, without history of travel to endemic areas, was confirmed by histology and molecular speciation. Imaging was atypical, showing several hook-bearing scolices visible in the cyst, while the serology employed was non-contributary. CONCLUSIONS: NCC should be considered when multiple taeniid scolices are observed within the same cystic lesion.

[Management of ocular toxoplasmosis in France: Results of a modified Delphi study]. / Prise en charge de la toxoplasmose oculaire en France : résultats d'une étude Delphi modifiée.

OBJECTIVE: To evaluate diagnostic and therapeutic practices and then establish a consensus on the management of ocular toxoplasmosis in France through a Delphi study. MATERIALS AND METHODS: Twenty-three French experts in ocular toxoplasmosis were invited to respond to a modified Delphi study conducted online, in the form of two questionnaires, in an attempt to establish a consensus on the diagnosis and management of this pathology. The threshold for identical responses to reach consensus was set at 70 %. RESULTS: The responses of 19 experts out of the 23 selected were obtained on the first questionnaire and 16 experts on the second. The main elements agreed upon by the experts were to treat patients with a decrease in visual acuity or an infectious focus within the posterior pole, to treat peripheral lesions only in the presence of significant inflammation, the prescription of first-line treatment with pyrimethamine-azithromycin, the use of corticosteroid therapy after a period of 24 to 48hours, the prophylaxis of frequent recurrences (more than 2 episodes per year) with trimethoprim-sulfamethoxazole as well as the implementation of prophylactic treatment of recurrences in immunocompromised patients. On the other hand, no consensus emerged with regard to the examinations to be carried out for the etiological diagnosis (anterior chamber paracentesis, fluorescein angiography, serology, etc.), second-line treatment (in the case of failure of first-line treatment), or treatment of peripheral foci. CONCLUSION: This study lays the foundations for possible randomized scientific studies to be conducted to clarify the management of ocular toxoplasmosis, on the one hand to confirm consensual clinical practices and on the other hand to guide practices for which no formal consensus has been demonstrated.

[Toxoplasmosis in pregnancy: Practical Management]. / Toxoplasmose pendant la grossesse : proposition actuelle de prise en charge pratique.

The burden of congenital toxoplasmosis has become small in France today, in particular as a result of timely therapy for pregnant women, fetuses and newborns. Thus, the French screening and prevention program has been evaluated and recently confirmed despite a decline over time in the incidence of toxoplasmosis. Serological diagnosis of maternal seroconversion is usually simple but can be difficult when the first trimester test shows the presence of IgM, requiring referral to an expert laboratory. Woman with confirmed seroconversion should be referred quickly to an expert center, which will decide with her on treatment and antenatal diagnosis. Although the level of proof is moderate, there is a body of evidence in favor of active prophylactic prenatal treatment started as early as possible (ideally within 3 weeks of seroconversion) to reduce the risk of maternal-fetal transmission, as well as symptoms in children. The recommended therapies to prevent maternal-fetal transmission are: (1) spiramycin in case of maternal infection before 14 gestational weeks; (2) pyrimethamine and sulfadiazine (P-S) with folinic acid in case of maternal infection at 14 WG or more. Amniocentesis is recommended to guide prenatal and neonatal care. If fetal infection is diagnosed by PCR on amniotic fluid, therapy with P-S should be initiated as early as possible or continued in order reduce the risk of damage to the brain or eyes. Further research is required to validate new approaches to preventing congenital toxoplasmosis.

Reduced fungal contamination of the indoor environment with the Plasmair system (Airinspace).

Aspergillus spp. and other moulds cause life-threatening opportunistic infections in immunocompromised patients. Indoor contamination and construction work that liberate fungal spores are a major source of nosocomial aspergillosis. Dijon hospital is a tertiary care institution in northeast France undergoing construction work beside high-risk clinical units. To determine the impact of this activity, a surveillance programme was implemented one year before building work began in order to establish baseline levels of contamination. Air and surface fungal contamination in adult and paediatric haematology units were prospectively examined following use, or not, of a new air-treatment system with mobile Plasmair units (Airinspace). There were significant reductions in overall fungal contamination for the Plasmair treated rooms for air and surface samples in both clinical units. Plasmair treatment also significantly reduced A. fumigatus in the air. These data suggest that Plasmair units may provide an efficient method of reducing indoor fungal contamination in hospitals.

Prospective survey of indoor fungal contamination in hospital during a period of building construction.

An 18-month survey of indoor fungal contamination was conducted in one haematology unit during a period of construction work. Air was sampled with a portable Air System Impactor and surfaces with contact Sabouraud plates. During this survey the mean concentration of viable fungi in air was 4.2 cfu/m(3) and that for surfaces was 1.7 cfu/plate. At the beginning of construction work, there were increases in airborne fungal spores (from 3.0 to 9.8 cfu/m(3)) in the unit, but concentrations did not exceed 10 cfu/m(3) during the 18-month period. The most frequently recovered airborne fungi were Penicillium spp. (27-38%), Aspergillus spp. (25%) and Bjerkandera adusta, a basidiomycete identified with molecular tools (7-12%). Blastomycetes accounted for more than 50% of the fungal flora on surfaces. Investigating the impact of a new air-treatment system (mobile Plasmair units), there were significant reductions in fungal contamination for the Plasmer -treated rooms, and in these rooms we observed the same level of fungal load whether construction work was in progress or not.

[Targeting abattoirs to control cystic echinococcosis in Algeria]. / Le ciblage des abattoirs dans la lutte contre l'échinococcose kystique en Algérie.

Cystic echinococcosis (CE) is an important anthropozoonotic parasitic common in Algeria. The predominant life cycle of E. granulosus is a synanthropic cycle with domestic dogs as definitive hosts and livestock animals as intermediate hosts. Slaughter activity represents a potential source for dogs to access infected offal. The aim of the present study was to determine if the contact between dogs and potentially infected offal was possible in licensed abattoirs. Eighty-one private and public abattoirs located in eastern Algeria were assessed with respect to their level of protection against the intrusion of dogs.We have demonstrated that in 42 % of these abattoirs, dogs could easily come in contact with potentially parasitized offal. The most common incorrect practices were the dumping of offal freely into the environment, the feeding of dogs with offal, and the leaving of unattended offal in an unsealed chamber. Overall, some hazardous practices remained common customs of workers, and enough abattoirs remain non-compliant that the cattledog domestic cycle of CE is unlikely to be broken. Hence, some recommended measures to interrupt parasite transmission include the following: recognition of the importance of abattoirs in the maintenance of canine echinococcosis, the controlled and proper disposal of offal, the abolishment of the custom of feeding dogs with infected offal and improvements in the level of health education of abattoir staff.

Serological diagnosis of Toxoplasma gondii infection: Recommendations from the French National Reference Center for Toxoplasmosis.

Toxoplasmosis manifests no clinical signs in 80% of cases in immunocompetent patient, causing immunization characterized by the persistence of cysts, particularly in brain, muscles, and retina. Assessing the serological status, based on testing for serum toxoplasma IgG and IgM antibodies, is essential in cases that are increasingly at risk for the more severe disease forms, such as congenital or ocular toxoplasmosis. This disease also exposes immunosuppressed patients to reactivation, which can lead to more widespread forms and increased mortality. By interpreting the serological results, we can estimate the risk of contamination or reactivation and define appropriate prophylactic and preventive measures, such as hygienic and dietetic, therapeutic, biological, and clinical follow-up, according to the clinical context. We hereby propose practical approaches based on serological data, resulting from a consensus of a group of experts from the French National Reference Center Network for Toxoplasmosis, according to both routine and specific clinical situations.

[A case of free-living Amoebae keratitis in a non contact lens wearer]. / Une kératite à amibes libres chez un non porteur de lentilles de contact.

Free living amoebae keratitis is a rare but severe infection due to ubiquitous protozoa of the genus Acanthamoeba. Most cases occur in contact lens wearers. In the present paper, we report a case of Acanthamoeba keratitis secondary to a vegetal injury of the cornea in a patient who did not wear contact lens. This case emphasizes the fact that the visual outcome is dependent on early treatment and outlines the need for a rapid diagnosis of amoebic keratitis. The diagnosis is based essentially on culture of trophozoïtes and cysts of the parasite from a corneal scrape or a biopsy specimen. The treatment is long, difficult and often a failure. Successful management of amoebic keratitis infection thus requires constant dialogue between the physician and the clinical microbiologist, a quality sample and efficient laboratory tests.

Comparison of MALDI-TOF mass spectra with microsatellite length polymorphisms in Candida albicans.

Candida albicans is the most frequent yeast involved in human infections. Its population structure can be divided into several genetic clades, some of which have been associated with antifungal susceptibility. Therefore, detecting and monitoring fungal clones in a routine laboratory setting would be a major epidemiological advance. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra results are now widely used as bar codes to identify microorganisms in clinical microbiology laboratories. This study aimed at testing MALDI-TOF mass spectra bar codes to identify clades among a set of C. albicans isolates. Accordingly, 102 clinical strains were genotyped using 10 microsatellite markers and analyzed via MALDI-TOF mass spectrometry. The mass spectra were compared with a reference spectral library including 33 well-characterized collection strains, using a Microflex(TM) system and Biotyper(TM) software, to test the capacity of the spectrum of a given isolate to match with the reference mass spectrum of an isolate from the same genetic clade. Despite high confidence species identification, the spectra failed to significantly match with the corresponding clade (p = 0.74). This was confirmed with the MALDI-TOF spectra similarity dendrogram, in which the strains were dispersed irrespective of their genetic clade. Various attempts to improve intra-clade spectra recognition were unsuccessful. In conclusion, MALDI-TOF mass spectra bar code analysis failed to reliably recognize genetically related C. albicans isolates. Further studies are warranted to develop alternative MALDI-TOF mass spectra analytical approaches to identify and monitor C. albicans clades in the routine clinical laboratory.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry: revolutionizing clinical laboratory diagnosis of mould infections.

The clinical diagnosis of mould infections currently involves complex species identification based on morphological criteria, which is often prone to error. Employing an extensive mould species reference spectral library (up to 2832 reference spectra, corresponding to 708 strains from 347 species), we assessed the extent to which matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) enhanced the accuracy of species identification. MALDI-TOF MS data were validated against morphology-based and DNA sequence-based results with 262 clinical isolates collected over a 4-month period in 2013. The implementation of MALDI-TOF MS resulted in a dramatic improvement in mould identification at the species level (from 78.2% to 98.1%) and a marked reduction in the misidentification rate (from 9.8% to 1.2%). We then compared the mould identification results obtained before (i.e. 2011) and after (i.e. 2013) the implementation of MALDI-TOF MS in routine identification procedures, which showed an improvement from 64.57% to 100%. Reassessment of a set of isolates from 2011 with this procedure, including MALDI-TOF MS, yielded an increase in species diversity from 16 to 42 species. Finally, application of this procedure during a 16-month period (2012-2013) enabled the identification of 1094 of 1107 (98.8%) clinical mould isolates corresponding to 107 distinct species. MALDI-TOF MS-based mould species identification may soon challenge traditional techniques in the clinical laboratory, as patient prognosis is largely contingent on rapid and accurate diagnosis.

Comparison of real-time PCR with conventional methods to detect dermatophytes in samples from patients with suspected dermatophytosis.

A PCR detecting dermatophytes within a short turnaround time would significantly enhance the management of patients with suspected dermatophytosis. This study aimed at comparing the results of a real-time PCR assay with those of the conventional diagnostic (direct microscopy and culture) performed by a dermatologist working in a medical mycology laboratory for the detection of dermatophytes in nail and skin samples. A total of 112 specimens (54 nail and 58 skin) were collected from 52 patients with one to four suspected dermatophytosis lesions. The PCR diagnostic indices were calculated for either sample- or patient-based dermatophytosis diagnosis. The sample-based diagnostic efficacy yielded 79% sensitivity and 73% specificity. The patient-based diagnostic efficacy was higher with 100% sensitivity and 82% specificity. Interestingly, PCR yielded significantly (p < 0.004) lesser false negative results and performed overall better (diagnostic odds ratio = 24.0 vs. 5.5) in nail than in skin samples. In conclusion, this real-time PCR assay performance was consistent with those of the conventional methods in the hands of a skilled expert and particularly efficacious in diagnosing dermatophyte onychomycosis. This PCR is suited to high throughput batch processing; if used instead of direct microscopy, it could reduce hands-on time in the routine clinical laboratory workflow.

Long-term ocular outcome in congenital toxoplasmosis: a prospective cohort of treated children.

OBJECTIVES: Congenital toxoplasmosis remains a public health problem throughout the world. Long-term longitudinal studies are still needed to argument controversial screening and treatment strategies and to enable to accurately counsel parents. METHODS: We conducted a prospective cohort study over 16 years in Marseilles, France. Seronegative pregnant women underwent monthly serological testing. Children were treated antenatally with rovamycine as soon as maternal infection was detected and with pyrimethamine and sulfadoxine in case of positive Toxoplasma PCR on amniotic fluid. Postnatal treatment with pyrimethamine and sulfadoxine was systematically prescribed for one year and possibly continued at the physician discretion. RESULTS: 127 children were included. 24 children (18.9%) presented ocular lesions causing visual impairment in eight cases. Eleven children (8.7%) presented with ocular lesions at birth, mostly macular. Sixteen children (12.6%) developed ocular lesions during follow-up, mostly peripheral. The first ocular lesion could occur as late as 12 years after birth. No significant risk factor of chorioretinitis was identified including gestational age at infection, type of antenatal treatment and shorter postnatal treatment. CONCLUSIONS: These results confirm the overall good prognosis of congenital toxoplasmosis in Europe but highlight though a low risk of late ocular manifestation. Chorioretinitis affected 18.9% of children suffering from congenital toxoplasmosis despite antenatal and neonatal screening associated with early treatment. Long-standing follow-up is needed because first lesion can occur as late as 12 years after birth. Late lesions were less often macular but nevertheless caused sometimes visual impairment.

Dynamics of fungal colonization in a new medical mycology laboratory.

OBJECTIVE OF THE STUDY: Study of the spatio-temporal fungal colonization in a new medical mycology laboratory. METHODS: A 17-month survey of airborne fungal contamination was conducted in a new medical mycology laboratory at a tertiary care university hospital. This survey was implemented at three different periods: before the new premises were occupied (period A), during the move into the new laboratory (period B) and after resumption of the mycological activities in these new premises (period C). RESULTS: During period A, the airborne fungal load ranged from 2.3 to 6 cfu/m(3). The most frequently recovered airborne fungi were Penicillium spp. (75 to 100%). During period B, a dramatic increase in Penicillium chrysogenum conidia was observed in the air of the new laboratory (40 to 160 cfu/m(3)). During period C, the fungal load ranged from 4.5 to 8.4 cfu/m(3). Penicillium was the most common genus identified in rooms of the laboratory where no filamentous fungi were handled, while Aspergillus was clearly the predominant genus (78%) in the room dedicated to the culture of filamentous fungi. CONCLUSIONS: We suggest that the specific fungal ecology in air of the room dedicated to the culture of filamentous fungi is due to the handling of a large number of medical strains of A. fumigatus.