This study proposes new HI based on different allowable limits, and can therefore serve as a starting point for future harmonization of hemolysis interference evaluation needed in routine laboratory practice.

Objectives: Mycobacterium chimaera is a recently described nontuberculous mycobacterium belonging to the Mycobacterium avium complex (MAC). Because this species is implicated in a worldwide outbreak due to contaminated heaterecooler unit water tanks during open-heart surgery, it has become mandatory for clinical microbiology laboratories to be able to differentiate M. chimaera from the other MAC species, especially M. intracellulare. Such identification has so far been restricted to specialized laboratories because it required the analysis of several gene sequences. The aim of this study was to evaluate commercial methods for identifying M. chimaera with regard to the reference gene sequencing ITS, the internal transcribed spacer 16e23S. Methods: Forty-seven clinical and environmental isolates including 41 MAC were identified by (a) PCR sequencing of the ITS and hsp65 genes, (b) three molecular biology kits (INNO-LiPA Mycobacteria, GenoType Mycobacterium CM and GenoType NTM-DR) and (c) matrix-assisted desorption ionizatione time of flight mass spectrometry (MALDI-TOF MS) using Microflex LT. Results: There was a high concordance for species determination between the reference ITS sequencing and the GenoType NTM-DR test (39/41, 95%), the INNO-LiPA Mycobacteria test (38/41, 93%) and the hsp65 sequencing (38/41, 93%). The GenoType Mycobacterium CM test did not distinguish M. chimaera from M. intracellulare. MALDI-TOF MS distinguished two M. chimaeraeM. intracellulare groups separated from M. avium and from the other mycobacterial species on a score-oriented dendrogram, but it also failed to differentiate the two species. Conclusions: INNO-LiPA Mycobacteria and GenoType NTM-DR are efficient assays for M. chimaera identification in clinical microbiology laboratories.

The GeneLEAD VIII (Diagenode, Belgium) is a new, fully automated, sample-to-result precision instrument for the extraction of DNA and PCR detection of Mycobacterium tuberculosis complex (MTBC) directly from clinical samples. The Deeplex Myc-TB® assay (Genoscreen, France) is a diagnostic kit based on the deep sequencing of a 24-plexed amplicon mix allowing simultaneously the detection of resistance to 13 antituberculous (antiTB) drugs and the determination of spoligotype. We evaluated the performance of a strategy combining the both mentioned tools to detect directly from clinical samples, in 8 days, MTBC and its resistance to 13 antiTB drugs, and identify potential transmission of strains from patient-to-patient. Using this approach, we screened 112 clinical samples (65 smear-negative) and 94 MTBC cultured strains. The sensitivity and the specificity of the GeneLEAD/Deeplex Myc-TB approach for MTBC detection were 79.3% and 100%, respectively. One hundred forty successful Deeplex Myc-TB results were obtained for 46 clinical samples and 94 strains, a total of 85.4% of which had a Deeplex Myc-TB susceptibility and resistance prediction consistent with phenotypic drug susceptibility testing (DST). Importantly, the Deeplex Myc-TB assay was able to detect 100% of the multidrug-resistant (MDR) MTBC tested. The lowest concordance rates were for pyrazinamide, ethambutol, streptomycin, and ethionamide (84.5%, 81.5%, 73%, and 55%, respectively) for which the determination of susceptibility or resistance is generally difficult with current tools. One of the main difficulties of Deeplex Myc-TB is to interpret the non-synonymous uncharacterized variants that can represent up to 30% of the detected single nucleotide variants. We observed a good level of concordance between Deeplex Myc-TB-spoligotyping and MIRU-VNTR despite a lower discriminatory power for spoligotyping. The median time to obtain complete results from clinical samples was 8 days (IQR 7–13) provided a high-throughput NGS sequencing platform was available. Our results highlight that the GeneLEAD/Deeplex Myc-TB approach could be a breakthrough in rapid diagnosis of MDR TB in routine practice.