Clinical utility of the Gen-Probe amplified Mycobacterium tuberculosis direct test compared with smear and culture for the diagnosis of pulmonary tuberculosis

ObjectiveTo evaluate the clinical efficacy of the Gen-Probe amplified Mycobacterium tuberculosis direct test (AMTD), a recently developed amplification test for the detection of M. tuberculosis complex directly from clinical specimens, for the diagnosis of pulmonary tuberculosis and its suitability for use in a routine microbiology laboratory.MethodsSequential respiratory specimens were tested with AMTD and results were compared with those of acid-fast stain and culture. Performance of AMTD was tested over a 13-month period, using 278 respiratory specimens, from 219 patients, submitted to the microbiology laboratory of our hospital. AMTD's sensitivity, specificity and positive and negative predictive values were determined, with the combination of culture and clinical diagnosis being taken as the standard.ResultsThirty-three specimens were collected from 23 patients with a conclusive diagnosis of pulmonary tuberculosis. Of these specimens, 13 were smear positive, 22 culture positive and 30 AMTD positive. AMTD was more sensitive in detecting pulmonary tuberculosis in patients partially treated but with undiagnosed disease (100%), and in smear-positive disease (100%). The overall sensitivities, specificities and positive and negative predictive values were: 39.4%, 100%, 100%, and 92.4% for staining; 66.7%, 100%, 100% and 95.7% for culture; and 90.9%, 100%, 100%, and 98.8% for AMTD.ConclusionsAMTD is a rapid, reliable and accurate test for the detection of M. tuberculosis complex in respiratory specimens. Repeat testing of those samples whose results fall between 30 000 and 300 000 relative light units, increases test specificity by preventing the majority of false positives

Mycobacterium celatum Pulmonary Infection in the Immunocompetent: Case Report and Review

Mycobacterium celatum has been shown to cause disease in immunocompromised patients. We report a case of serious pulmonary infection caused by M. celatum in an apparently immunocompetent patient and review the characteristics of two other reported cases. Clinical and radiologic symptoms and signs included cough, malaise, and weight loss associated with cavitary lesions and pulmonary infiltrates. Although M. celatum is easy to detect in clinical specimens by liquid and solid media, it may be misidentified as a member of the M. tuberculosis complex or as M. xenopi. M. celatum pulmonary infection appears to respond to antimycobacterial chemotherapy, particularly with clarithromycin

Multicenter evaluation of mycobacteria growth indicator tube (MGIT) compared with the BACTEC radiometric method, BBL biphasic growth medium and Löwenstein—Jensen medium

ObjectiveTo evaluate the new BBL mycobacteria growth indicator tube (MGIT) in comparison with other media.MethodsMGIT was evaluated in 10 Italian centers on 433 clinical samples, mainly of respiratory origin and mainly smear positive, in comparison with Löwenstein—Jensen and with one or more other methods represented, according to participating centers, by the BACTEC radiometric method or by the biphasic BBL Septi-Chek AFB system. While MGIT and Löwenstein—Jensen were used for all the samples, 285 of them were also inoculated in BACTEC vials and 274 in biphasic bottles. Of these samples, 132 were investigated with all the four methods.ResultsAlthough less rapid and sensitive than the radiometric method, the results of MGIT were equal when compared with the other two media with respect to overall isolation yield; furthermore, it allowed the detection of growth in significantly shorter times.ConclusionsThe results of this study indicate the value of MGIT for the detection of mycobacteria and, thanks to its extreme simplicity of use, its suitability for small and large laboratories. Its combined use with a solid medium can substantially improve the diagnosis of mycobacterial infection

Mycobacterium triplex Pulmonary Disease in Immunocompetent Host

Mycobacterium triplex, a recently described, potentially pathogenic species, caused disease primarily in immunocompromised patients. We report a case of pulmonary infection due to this mycobacterium in an immunocompetent patient and review the characteristics of two other cases. In our experience, Mycobacterium triplex pulmonary infection is unresponsive to antimycobacterial chemotherapy

Tuberculosis in Kindergarten and Primary School, Italy, 2008–2009

An outbreak of tuberculosis (TB) in Italy involved 19 schoolchildren with active TB and 43 with latent infection. The source of the outbreak was a school assistant born in Italy who had a family history of TB. This outbreak highlights the need for maintaining clinical and public health expertise in countries with low TB incidence

Extrapulmonary Infections Associated with Nontuberculous Mycobacteria in Immunocompetent Persons

Incidence data are lacking, and diagnosis remains difficult

First Community-Wide, Comparative Cross-Linking Mass Spectrometry Study

The number of publications in the field of chemical cross-linking combined with mass spectrometry (XL-MS) to derive constraints for protein three-dimensional structure modeling and to probe protein-protein interactions has increased during the last years. As the technique is now becoming routine for in vitro and in vivo applications in proteomics and structural biology there is a pressing need to define protocols as well as data analysis and reporting formats. Such consensus formats should become accepted in the field and be shown to lead to reproducible results. This first, community-based harmonization study on XL-MS is based on the results of 32 groups participating worldwide. The aim of this paper is to summarize the status quo of XL-MS and to compare and evaluate existing cross-linking strategies. Our study therefore builds the framework for establishing best practice guidelines to conduct cross-linking experiments, perform data analysis, and define reporting formats with the ultimate goal of assisting scientists to generate accurate and reproducible XL-MS results