Adaptation of Amoeba Plate Test To Recover Legionella Strains from Clinical Samples.

The isolation of Legionella from respiratory samples is the gold standard for diagnosis of Legionnaires' disease (LD) and enables epidemiological studies and outbreak investigations. The purpose of this work was to adapt and to evaluate the performance of an amoebic coculture procedure (the amoeba plate test [APT]) for the recovery of Legionella strains from respiratory samples, in comparison with axenic culture and liquid-based amoebic coculture (LAC). Axenic culture, LAC, and APT were prospectively performed with 133 respiratory samples from patients with LD. The sensitivities and times to results for the three techniques were compared. Using the three techniques, Legionella strains were isolated in 46.6% (n = 62) of the 133 respiratory samples. The sensitivity of axenic culture was 42.9% (n = 57), that of LAC was 30.1% (n = 40), and that of APT was 36.1% (n = 48). Seven samples were positive by axenic culture only; for those samples, there were <10 colonies in total. Five samples, all sputum samples, were positive by an amoebic procedure only (5/5 samples by APT and 2/5 samples by LAC); all had overgrowth by oropharyngeal flora with axenic culture. The combination of axenic culture with APT yielded a maximal isolation rate (i.e., 46.6%). Overall, the APT significantly reduced the median time for Legionella identification to 4 days, compared with 7 days for LAC (P < 0.0001). The results of this study support the substitution of LAC by APT, which could be implemented as a second-line technique for culture-negative samples and samples with microbial overgrowth, especially sputum samples. The findings provide a logical basis for further studies in both clinical and environmental settings.

Community-acquired Legionnaires' disease in a renal transplant recipient with unclear incubation period: the importance of molecular typing.

Transplant recipients are at risk of developing Legionnaires' disease (LD) because of impaired cellular immunity. Here, we describe a renal transplant recipient who developed LD at least 10 days after hospital admission and transplantation. The hospital water network was initially suspected, but further testing determined that the probable source was the patient's domestic water supply. Our report also suggests that the patient's immunosuppressed state may have switched potential colonization to pneumonia.

Comparison of Sofia Legionella FIA and BinaxNOW® Legionella urinary antigen card in two national reference centers.

The Sofia Legionella Fluorescence Immunoassay (FIA; Quidel) is a recently introduced rapid immunochromatographic diagnostic test for Legionnaires' disease using immunofluorescence technology designed to enhance its sensitivity. The aim of this study was to evaluate its performance for the detection of urinary antigens for Legionella pneumophila serogroup 1 in two National Reference Centers for Legionella. The sensitivity and specificity of the Sofia Legionella FIA test were determined in concentrated and nonconcentrated urine samples, before and after boiling, in comparison with the BinaxNOW® Legionella Urinary Antigen Card (UAC; Alere). Compared with BinaxNOW® Legionella UAC, the sensitivity of the Sofia Legionella test was slightly higher in nonconcentrated urine samples and was identical in concentrated urine samples. The specificity of the Sofia Legionella FIA test was highly reduced by the concentration of urine samples. In nonconcentrated samples, a lack of specificity was observed in 2.3 % of samples, all of them resolved by heat treatment. The Sofia Legionella FIA is a sensitive test for detecting Legionella urinary antigens with no previous urine concentration. However, all positive samples have to be re-tested after boiling to reach a high specificity. The reading is automatized on the Sofia analyzer, which can be connected to laboratory information systems, facilitating accurate and rapid reporting of results.

Legionnaires' disease in France.

The aim of this review was to describe the current knowledge of Legionnaires' disease (LD) illustrated by the epidemiological situation in France in 2013. LD is a severe pneumonia commonly caused by Legionella pneumophila serogroup 1. The diagnosis is usually based on the urinary antigen test. This rapid method reduces the delay between clinical suspicion and initiation of an appropriate treatment. However, the availability of a clinical strain is important to improve knowledge of circulating bacteria, to document case clusters, and to identify the sources of contamination. The source of contamination is unknown in most cases. The main contamination sources generating aerosols are water network systems and cooling towers. Thanks to the strengthening of clinical and environmental monitoring and to several guidelines, no epidemic has been reported in France since 2006. Despite these efforts, the number of LD cases has not decreased in recent years. It is essential that applied research continue to better understand the spatial and temporal dynamics of the disease and its characteristics (impact of environmental factors, sources of exposure, strains, host, etc.). Fundamental knowledge has been greatly improved (pathogenesis, immune mechanisms, etc.). The results of this research should help define new strategies for the diagnosis, prevention, and control to decrease the number of LD cases diagnosed every year.

[Congenital toxoplasmosis: long-term ophthalmologic follow-up praised by patients]. / Toxoplasmose congénitale; le suivi ophtalmologique à long terme plébiscité par les patients.

INTRODUCTION: Ocular lesions of congenital toxoplasmosis may occur and relapse unpredictably even a long time after birth. There is no consensus concerning the necessity or timing of ophthalmologic follow-up for these patients. We surveyed adults with congenital toxoplasmosis followed regularly since birth, in order to learn their perceptions of this follow-up. The goal of this study was to provide doctors with patient-reported information on how they perceived the long-term monitoring of their disease. METHODS: Enrolled patients were given a two-question questionnaire addressing the way they perceived the long-term follow-up and their attitudes toward continuing it. Eligible patients had to be 18 years or older and to have undergone ophthalmologic follow-ups, including funduscopy, every year since birth. The last ophthalmologic examination had to be within one year of the patient's inclusion in the study. RESULTS: Of the 102 patients finally included in the study, 98% stated that the follow-up was useful and 92% reassuring. Among the 11% of patients who found the follow-ups frightening, the proportion of patients with low visual acuity and low score on the visual function test was significantly higher than among the others. All patients except two wished to continue with regular follow-up. CONCLUSION: Without general agreement or guidelines on how patients with congenital toxoplasmosis should be monitored, the patient's wishes are important in making a decision. Our study brought out a clear fact; the majority of patients found long-term follow-up useful and reassuring and wished to continue.

Qualitative and quantitative study of the antigens and antibodies of the HL-A system-automatic fluorochrome method.

It was possible to obtain a successful evaluation of the quantity of HL-A antigens on lymphocytes using a fluorochromatic test with double marking by fluorescine diacetate and ethidium bromide. It was also possible to detect anti-HL-A antibodies, to study their cross-reactions and to perform tissue typing using this automatic, sensitive and repeatable method.