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Additional file 1: Figure S1. (A) Metagenomic sequencing of the negative blood culture from the patient with a growth signal in the BacT/ALERT system (363′851 classified reads), (B) of an inoculated blood culture without a growth signal in the BacT/ALERT system (12′500 classified reads) and (C) of the non-inoculated blood culture growth medium (16′047 classified reads).

Treatment of multidrug-resistant Mycobacterium tuberculosis is a challenge. This letter describes the emergence of resistance to new therapies, bedaquiline and delamanid.

Whole genome sequencing allows rapid detection of drug-resistant isolates. However, the availability of high-quality data linking quantitative phenotypic drug susceptibility testing (DST) and genomic data has thus far been limited.We determined drug resistance profiles of 176 genetically diverse clinical isolates from Democratic Republic of the Congo, Ivory Coast, Peru, Thailand and Switzerland by quantitative phenotypic DST for 11 antituberculous drugs using the BD BACTEC MGIT 960 system and 7H10 agar dilution to generate a cross-validated phenotypic DST readout. We compared DST results with predicted drug resistance profiles inferred by whole genome sequencing.Classification of strains by the two phenotypic DST methods into resistotype/wild type populations was concordant in 73-99 % of cases, depending on the drug. Our data suggests that the established critical concentration (5 mg/L) for ethambutol resistance (MGIT 960 system) is too high and may misclassify strains as susceptible, compared to 7H10 agar dilution. Increased minimal inhibitory concentrations were explained by mutations identified by whole genome sequencing. Using whole genome sequences, we were able to predict quantitative drug resistance levels for the majority of drug resistance mutations. Predicting quantitative levels of drug resistance by whole genome sequencing was partially limited due to incompletely understood drug resistance mechanisms. The overall sensitivity and specificity of whole genome-based DST were 86.8 % and 94.5 %, respectively.Despite some limitations, whole genome sequencing has the potential to infer resistance profiles without the need for time-consuming phenotypic methods.

Mutations in the genes of the F420 signaling pathway, including dnn, fgd1, fbiA, fbiB, fbiC, and fbiD, of Mycobacterium tuberculosis (Mtb) complex can lead to delamanid resistance. We searched for such mutations among 129 Mtb strains from Asia, South-America, and Africa using whole-genome sequencing; 70 (54%) strains had at least one mutation in one of the genes. For ten strains with mutations, we determined the minimum inhibitory concentration (MIC) of delamanid. We found one strain from a delamanid-naïve patient carrying the natural polymorphism Tyr29del (ddn) that was associated with a critical MIC to delamanid.

BACKGROUND Drug resistance is a challenge for the global control of tuberculosis. We examined mortality in patients with tuberculosis from high-burden countries, according to concordance or discordance of results from drug susceptibility testing done locally and in a reference laboratory. METHODS This multicentre cohort study was done in Côte d'Ivoire, Democratic Republic of the Congo, Kenya, Nigeria, South Africa, Peru, and Thailand. We collected Mycobacterium tuberculosis isolates and clinical data from adult patients aged 16 years or older. Patients were stratified by HIV status and tuberculosis drug resistance. Molecular or phenotypic drug susceptibility testing was done locally and at the Swiss National Center for Mycobacteria, Zurich, Switzerland. We examined mortality during treatment according to drug susceptibility test results and treatment adequacy in multivariable logistic regression models adjusting for sex, age, sputum microscopy, and HIV status. FINDINGS We obtained M tuberculosis isolates from 871 patients diagnosed between 2013 and 2016. After exclusion of 237 patients, 634 patients with tuberculosis were included in this analysis; the median age was 33·2 years (IQR 26·9-42·5), 239 (38%) were women, 272 (43%) were HIV-positive, and 69 (11%) patients died. Based on the reference laboratory drug susceptibility test, 394 (62%) strains were pan-susceptible, 45 (7%) monoresistant, 163 (26%) multidrug-resistant (MDR), and 30 (5%) had pre-extensively or extensively drug resistant (pre-XDR or XDR) tuberculosis. Results of reference and local laboratories were concordant for 513 (81%) of 634 patients and discordant for 121 (19%) of 634. Overall, sensitivity to detect any resistance was 90·8% (95% CI 86·5-94·2) and specificity 84·3% (80·3-87·7). Mortality ranged from 6% (20 of 336) in patients with pan-susceptible tuberculosis treated according to WHO guidelines to 57% (eight of 14) in patients with resistant strains who were under-treated. In logistic regression models, compared with concordant drug susceptibility test results, the adjusted odds ratio of death was 7·33 (95% CI 2·70-19·95) for patients with discordant results potentially leading to under-treatment. INTERPRETATION Inaccurate drug susceptibility testing by comparison with a reference standard leads to under-treatment of drug-resistant tuberculosis and increased mortality. Rapid molecular drug susceptibility test of first-line and second-line drugs at diagnosis is required to improve outcomes in patients with MDR tuberculosis and pre-XDR or XDR tuberculosis. FUNDING National Institutes of Allergy and Infectious Diseases, Swiss National Science Foundation, Swiss National Center for Mycobacteria.