Characterization of a Novel Rapidly Growing Mycobacterium Species Associated with Sepsis

A rapidly growing mycobacterium was isolated five times from blood cultures from a 6-year-old female patient with relapsed pre-B-cell acute lymphocytic leukemia. All five isolates had identical nucleotide sequences for the first 500 bp of the 16S rRNA gene, indicative of a single species. High-performance liquid chromatography analysis of mycolic acids indicated that the species was similar to Mycobacterium smegmatis. Sequence analysis of the 16S rRNA gene (1,455 bp) for one isolate demonstrated that the species was closely related to Mycobacterium diernhoferi. Based on the phenotypic features and phylogenetic analysis, it was concluded that the isolates represented a novel rapidly growing Mycobacterium species. The name “Mycobacterium hackensackense” is proposed for this unique strain, 147-0552(T), which was deposited in the American Type Culture Collection as ATCC BAA-823(T)

First Isolations of Segniliparus rugosus from Patients with Cystic Fibrosis▿

We report three cases of the new genus Segniliparus isolated from patients with cystic fibrosis. All isolates were unambiguously identified by 16S rRNA gene sequencing as Segniliparus rugosus (GenBank accession no. AY 60892). Drug susceptibility results that may enhance treatment for cystic fibrosis patients with this opportunistic pathogen are presented

Assessment of the QuantiFERON-TB Gold In-Tube test for the detection of <i>Mycobacterium tuberculosis</i> infection in United States Navy recruits

<div><p>Background</p><p>Immunologic tests such as the tuberculin skin test (TST) and QuantiFERON^®-TB Gold In-Tube test (QFT-GIT) are designed to detect M<i>ycobacterium tuberculosis</i> infection, both latent <i>M</i>. <i>tuberculosis</i> infection (LTBI) and infection manifesting as active tuberculosis disease (TB). These tests need high specificity to minimize unnecessary treatment and high sensitivity to allow maximum detection and prevention of TB.</p><p>Methods</p><p>Estimate QFT-GIT specificity, compare QFT-GIT and TST results, and assess factor associations with test discordance among U.S. Navy recruits.</p><p>Results</p><p>Among 792 subjects with completed TST and QFT-GIT, 42(5.3%) had TST indurations ≥10mm, 23(2.9%) had indurations ≥15mm, 14(1.8%) had positive QFT-GIT results, and 5(0.6%) had indeterminate QFT-GITs. Of 787 subjects with completed TST and determinate QFT-GIT, 510(64.8%) were at low-risk for infection, 277(35.2%) were at increased risk, and none had TB. Among 510 subjects at low-risk (presumed not infected), estimated TST specificity using a 15mm cutoff, 99.0% (95%CI: 98.2–99.9%), and QFT-GIT specificity, 98.8% (95%CI: 97.9–99.8%), were not significantly different (p>0.99). Most discordance was among recruits at increased risk of infection, and most was TST-positive but QFT-GIT-negative discordance. Of 18 recruits with TST ≥15mm but QFT-GIT negative discordance, 14(78%) were at increased risk. TB prevalence in country of birth was the strongest predictor of positive TST results, positive QFT-GIT results, and TST-positive but QFT-GIT-negative discordance. Reactivity to <i>M</i>. <i>avium</i> purified protein derivative (PPD) was associated with positive TST results and with TST-positive but QFT-GIT-negative discordance using a 10 mm cutoff, but not using a 15 mm cutoff or with QFT-GIT results.</p><p>Conclusions</p><p><i>M</i>. <i>tuberculosis</i> infection prevalence was low, with the vast majority of infection occurring in recruits with recognizable risks. QFT-GIT and TST specificities were high and not significantly different. Negative QFT-GIT results among subjects with TST induration ≥15 mm who were born in countries with high TB prevalence, raise concerns.</p></div

Test agreement.

<p>Test agreement.</p

Results for various cohort subsets.

<p>Results for various cohort subsets.</p

Associations between selected subject characteristics and tuberculin skin test or QuantiFERON^®-TB Gold In-Tube test results.

<p>Associations between selected subject characteristics and tuberculin skin test or QuantiFERON^®-TB Gold In-Tube test results.</p

Outcomes of the QuantiFERON^®-TB Gold In-Tube test versus the tuberculin skin test among 856 U.S. Navy recruits who had blood collected and skin test placed.

<p>Outcomes of the QuantiFERON^®-TB Gold In-Tube test versus the tuberculin skin test among 856 U.S. Navy recruits who had blood collected and skin test placed.</p

Diagram of study participants and testing.

<p>QFT = QuantiFERON^®-TB test; QFT-G = QuantiFERON^®-TB Gold test; QFT-GIT = QuantiFERON^®-TB Gold In-Tube test; TST = tuberculin skin test.</p