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.

[Osteomyelitis in cat scratch disease: A case report and literature review]. / À propos d'un cas d'ostéomyélite de la maladie des griffes du chat.

INTRODUCTION: Cat scratch disease is an infection caused by Bartonella henselae. The main clinical form is a lymphadenopathy with fever. However, uncommon bone involvement has been described. CASE REPORT: In this paper, we report a case of osteomyelitis in a 13-year-old teenager infected with B. henselae. The diagnosis was made based on PCR only because the serology was negative. A literature review reports 65 cases of osteomyelitis due to cat scratch disease. For each case, serology and PCR were notified. CONCLUSION: Osteomyelitis caused by B. henselae is a rare clinical manifestation. The diagnosis can be difficult, but the medical history must be accurate to search for contact with a cat and a cat scratch.

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.

Evaluation of BMPA, MWY, GVPC and BCYE media for the isolation of Legionella species from respiratory samples.

Culture media performance is a critical factor in the isolation of Legionellae from respiratory samples. We showed that BMPA and MWY media yielded significantly higher isolation rates than GVPC and BCYE media in regard to performance with samples that harbored low Legionella inocula and high contamination levels.

Legionellosis and lung abscesses: contribution of legionella quantitative real-time PCR to an adapted followup.

We report a case of severe Legionnaires' disease (LD) complicated by a lung abscess in an immunocompetent patient who required ECMO therapy and thoracic surgery. The results of repeated Legionella quantitative real-time PCR performed on both sera and respiratory samples correlated with the LD severity and the poor clinical outcome. Moreover, the PCR allowed for the detection of Legionella DNA in the lung abscess specimen, which was negative when cultured for Legionella. This case report provides a logical basis for further investigations to examine whether the Legionella quantitative PCR could improve the assessment of LD severity and constitute a prognostic marker.

[Primary meningococcal B osteomyelitis and arthritis with multifocal pyomyositis in a child: a case report]. / Ostéoarthrite de hanche primitive et myosite multifocale à méningocoque B chez un enfant de 7 ans.

Neisseria meningitidis is associated with severe invasive infections such as meningitis and fulminant septicemia. Septic arthritis due to N. meningitidis is rare and bone infections have been reported exceptionally. We report the case of a 7-year-old boy who presented with septic arthritis of the right hip associated with a septic location on the pelvis and pyomyositis of the adjacent muscle. Culture of the joint fluid was sterile but universal 16S polymerase chain reaction (PCR) of this fluid revealed group B N. meningitidis. Our patient had never presented any symptoms of meningitis or septicemia and blood cultures were all sterile. Despite appropriate antibiotic treatment, the course of the disease was unusually long and his status did not improve until surgical lavage of the hip was performed. Moreover, MRI imaging showed bilateral hypersignals of the adjacent muscles and revealed an abscess formation in the left gluteus maximus muscle. Presumptive diagnosis bacterial myositis was confirmed by an elevation of creatine phosphokinase in the sera up to 21-fold the normal value but the culture of the abscess, performed 10 days after initiation of antibiotics, was sterile. Despite an initially unfavorable course, this patient's status improved after surgical drainage and he fully recovered 1 month later. This observation illustrates an unusual presentation of invasive meningococcal infection. The respective roles of infection and an inflammatory phenomenon during the course of the disease are discussed. Moreover, this case emphasizes the value of PCR for bacteriological diagnosis of bone and joint infections.

Contribution of amoebic coculture to recovery of Legionella isolates from respiratory samples: prospective analysis over a period of 32 months.

We evaluated the contribution of amoebic coculture to the recovery of Legionella spp. from 379 respiratory samples. The sensitivity of axenic culture was 42.1%. The combination of axenic culture with amoebic coculture increased the Legionella isolation rate to 47.1%. Amoebic coculture was particularly efficient in isolating Legionella spp. from respiratory samples contaminated with oropharyngeal flora.