Clinical Evaluation of the Luminex NxTAG Respiratory Pathogen Panel.

An evaluation of the Luminex NxTAG Respiratory Pathogen Panel was performed on 404 clinical respiratory specimens. Clinical sensitivities and specificities of the assay compared to those of the reference methods were 80.0% to 100.0% and 98.9% to 100.0%, respectively. Correct genotyping information was provided for 95.5% of influenza virus A specimens. The closed-tube format of the assay simplified the workflow and minimized carryover contamination.

Fusobacterium nucleatum subspecies identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

We explored the use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for identification of Fusobacterium nucleatum subspecies. MALDI-TOF MS spectra of five F. nucleatum subspecies (animalis, fusiforme, nucleatum, polymorphum, and vincentii) were analyzed and divided into four distinct clusters, including subsp. animalis, nucleatum, polymorphum, and fusiforme/vincentii. MALDI-TOF MS with the modified SARAMIS database further correctly identified 28 of 34 F. nucleatum clinical isolates to the subspecies level.

Performance characteristics of the Cepheid Xpert vanA assay for rapid identification of patients at high risk for carriage of vancomycin-resistant Enterococci.

We compared the performance characteristics of culture and the Cepheid Xpert vanA assay for routine surveillance of vancomycin-resistant enterococci (VRE) from rectal swabs in patients at high risk for VRE carriage. The Cepheid Xpert vanA assay had a limit of detection of 100 CFU/ml and correctly detected 101 well-characterized clinical VRE isolates with no cross-reactivity in 27 non-VRE and related culture isolates. The clinical sensitivity, specificity, positive predictive value, and negative predictive value of the Xpert vanA PCR assay were 100%, 96.9%, 91.3%, and 100%, respectively, when tested on 300 consecutively collected rectal swabs. This assay provides excellent predictive values for prompt identification of VRE-colonized patients in hospitals with relatively high rates of VRE carriage.

Evaluation of Luminex xTAG fungal analyte-specific reagents for rapid identification of clinically relevant fungi.

Invasive fungal infections (IFI) remain a serious threat to immunocompromised hosts. Current diagnostic methods, including fungal culture and antigen detection, are slow and often lack specificity. Rapid diagnostic tools with increased sensitivity and specificity could improve the care of patients with IFI. Recently, Luminex Molecular Diagnostics (Toronto, Canada) developed 23 analyte-specific reagents (ASRs) for the detection of the most common clinically relevant fungi. This study's objective was to evaluate the sensitivity and specificity of a subset of these ASRs for fungal isolates and clinical specimens. Previously characterized fungal and bacterial isolates (n = 110), blood culture specimens (n = 34), and respiratory specimens (n = 44) were tested using either a Candida 7-plex panel (Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, Candida lusitaniae, Candida guilliermondii, and Candida krusei) or a mold 11-plex panel (Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Aspergillus terreus, Scedosporium prolificans, Scedosporium apiospermum, Fusarium oxysporum/Fusarium solani, Rhizopus arrhizus, Rhizopus microsporus, Mucor indicus, and Cunninghamella bertholletiae). The Candida 7-plex panel correctly identified all Candida isolates as confirmed by fungal culture and biochemical tests, for a sensitivity and specificity of 100%. The mold 11-plex panel correctly identified all mold isolates tested except for A. niger. Fungal isolates of Rhizopus and Mucor species were not detected, either, although they could represent species other than those targeted by the ASRs. Further evaluation will be necessary to confirm the sensitivities of some of the mold ASRs. Implementation of these ASRs will allow same-day detection of fungal DNA in clinical specimens.

Atypical presentation of Legionella pneumonia among patients with underlying cancer: A fifteen-year review.

BACKGROUND: Immunocompromised patients, especially those receiving treatment with corticosteroids and cytotoxic chemotherapy are at increased risk for developing Legionella pneumonia. OBJECTIVE: The aim of this study was to determine clinical and radiographic characteristics of pulmonary infection due to Legionella in persons undergoing treatment for cancer and stem cell transplant (SCT) recipients. METHODS: Retrospective review of Legionella cases at MSKCC over a fifteen-year study period from January 1999 and December 2013. Cases were identified by review of microbiology records. RESULTS: During the study period, 40 cases of Legionella infection were identified; nine among these were due to non-pneumophila species. Most cases occurred during the summer. The majority [8/9, (89%)] of patients with non-pneumophila infection had underlying hematologic malignancy, compared to 18/31 (58%) with Legionella pneumophila infections. Radiographic findings were varied-nodular infiltrates mimicking invasive fungal infection were seen only among patients with hematologic malignancy and hematopoietic stem cell transplant (SCT) recipients and were frequently associated with non-pneumophila infections (50% vs 16%; P = 0.0594). All cases of nodular Legionella pneumonia were found incidentally or had an indolent clinical course. CONCLUSIONS: Legionella should be considered in the differential diagnosis of nodular lung lesions in immunocompromised patients, especially those with hematologic malignancy and SCT recipients. Most cases of nodular disease due to Legionella are associated with non-pneumophila infections.

Prosthetic-Joint-Associated Bordetella holmesii Infection.

Bordetella holmesii is a globally distributed pathogen that is increasingly recognized as a cause of both pertussis-like respiratory infections and invasive disease. In this study, we describe a case of an immunocompetent man who developed B holmesii infection of his femoral prosthesis-the fifth B holmesii orthopedic infection reported in literature to date. This article highlights the potentially underrecognized role of B holmesii in orthopedic infections by reviewing these previously reported cases in the context of the current literature.

Emergence of daptomycin-resistant VRE: experience of a single institution.

Recent surveillance from US hospitals shows that more than 99.5% of vancomycin-resistant enterococci (VRE) isolates remain susceptible to daptomycin. This report describes emergence of daptomycin-resistant VRE at a major cancer center. The percentage of patients with daptomycin-resistant VRE bacteremia increased from 3.4% in 2007 to 15.2% in 2009 ([Formula: see text]). Without susceptibility data, empiric daptomycin therapy for VRE infections should be used with caution.