Diagnostic performance of the AID line probe assay in the detection of Mycobacterium tuberculosis and drug resistance in Romanian patients with presumed TB.

BACKGROUND: The AID line probe assay has shown promising evaluation data on the detection of Mycobacterium tuberculosis as well as 1st- and 2nd-line drug resistance, using isolates and selected clinical samples in previous studies. METHODS: The diagnostic performance of three AID-modules (AID INH/RIF, AID FQ/EMB and AID AG) was analyzed in sputum samples from patients with presumed tuberculosis against culture methods and phenotypic drug resistance as reference standards. RESULTS: 59 patients had culture-confirmed tuberculosis. All AID modules showed moderate sensitivity (46/59, 78.0%, 65.3-87.7) and very good specificity (100%, 95.5%, 93.7%). There was a high proportion of invalid tests, resulting in 32.6%, 78.3% and 19.6% of 46 AID-positive tuberculosis cases, who could not be assessed for drug resistance by the AID INH/RIF-, AID FQ/EM- and AID AG-module, respectively. A small number of patients showed drug resistance by reference standards: Three MDR-TB cases plus three, one and one patients with resistance to streptomycin, fluoroquinolones and aminoglycosides, respectively. The AID-assay detected all MDR-TB cases, two of three streptomycin-resistant TB cases, one of one of fluoroquinolone-resistant and missed one aminoglycoside-resistant TB case. DISCUSSION: The high proportion of invalid results precludes the use of the AID-assay from direct sputum-based tuberculosis and drug-resistance testing.

The TB Portals: an Open-Access, Web-Based Platform for Global Drug-Resistant-Tuberculosis Data Sharing and Analysis.

The TB Portals program is an international consortium of physicians, radiologists, and microbiologists from countries with a heavy burden of drug-resistant tuberculosis working with data scientists and information technology professionals. Together, we have built the TB Portals, a repository of socioeconomic/geographic, clinical, laboratory, radiological, and genomic data from patient cases of drug-resistant tuberculosis backed by shareable, physical samples. Currently, there are 1,299 total cases from five country sites (Azerbaijan, Belarus, Moldova, Georgia, and Romania), 976 (75.1%) of which are multidrug or extensively drug resistant and 38.2%, 51.9%, and 36.3% of which contain X-ray, computed tomography (CT) scan, and genomic data, respectively. The top Mycobacterium tuberculosis lineages represented among collected samples are Beijing, T1, and H3, and single nucleotide polymorphisms (SNPs) that confer resistance to isoniazid, rifampin, ofloxacin, and moxifloxacin occur the most frequently. These data and samples have promoted drug discovery efforts and research into genomics and quantitative image analysis to improve diagnostics while also serving as a valuable resource for researchers and clinical providers. The TB Portals database and associated projects are continually growing, and we invite new partners and collaborations to our initiative. The TB Portals data and their associated analytical and statistical tools are freely available at https://tbportals.niaid.nih.gov/.

LPA or GeneXpert in the diagnosis of multidrug-resistant tuberculosis.

Facing a constant increase of multidrug-resistant tuberculosis (MDR-TB), there is large need for routine use of new diagnostic tests, based on molecular techniques that allow both a rapid diagnosis for TB complex and rapid identification of resistance mutations. The resistances are due to genetic factors: accumulation of changes within the genome structure, acquisition or loss of genes, spontaneous mutations in chromosomal genes, and changes that induce selection of resistant strains during a suboptimal treatment. The bacteriology laboratory plays a crucial role in the making of the diagnosis, monitoring and preventing TB transmission. World Health Organization offers consistent recommendations in favour of use of Xpert MTB/RIF, GeneXpert platform, as initial diagnostic test in adults and children suspected of TB, because it can simultaneously determine the presence of Mycobacterium tuberculosis and the Rifampicin resistance, which is a surrogate marker of MDR strains. The very high sensibility and specificity, also in the smear negative samples, as well as the short time needed for the results, make Xpert MTB/RIF a valuable tool in the fight against TB. Other recommended tests are: LPA, which identifies M. Tuberculosis complex, the Rifancim and Isoniazid resistance; MTBDR plus or, for second line anti-TB drugs, the MTBDRsl.

[Conventional and molecular diagnosis in a group of patients with drug-resistant tuberculosis]. / Diagnostic conventional si molecular la un esantion de paciensi cu TB-DR.

Worldwide, although the incidence of the sensitive/susceptible tuberculosis diminished, the number of drug resistant tuberculosis is growing. The bacteriological diagnosis, genetic and phenotypic, becomes essential for the epidemic control. The resistance appears as a phenotypic expression of mutations from M. tuberculosis genome. The mutations that appear for Rifampicin are in region rpoB, for Isoniazid in region katG and inhA, for Ethambutol-embB, Quinolone-gyrA, Aminoglicozid and Cyclical Peptides-rrs. To follow the concordance of results of drug sensitivity test (DST) through phenotypic and genetic method, we analyzed a group of 40 patients with TB-DR. We performed drug susceptibility testing on Lowenstein-Jensen medium according to the instructions of the manufacturer. The strains were tested indirect genetic too, Genotype MTBDR plus forl INH and RIF and Genotype MTBDRsl for the second line drugs. The concordance between genetic method and the phenotypic method is 95%, 5% from the patients have different sensitivity to INH and RIF, butphenotypical they are resistant, meaning that they have other mutations undetected by the strip. The most common mutation in region rpoB is MUT3 (52%) associating the absence of band W8. Mutations in the region rpoB MUT1 and MUT2A are 12.5%, and 15% respectively. For high resistance to INH, the mostcommon isMUT1 forkatG 95% and forlow resistance to INHMUTI from region inhA-30%. For the second line drugs, the most frequent concordance between genetic method andphenotypic method is for EMB, of 30%, geneticallyspeaking the strains display no mutation in region embB, but are resistantin phenotypic method. For FQ, KAN, AMKand CAP the concordance between the two methods is of 100% to all tested strains. In conclusion, genetic methods have high sensitivity, they are fast and shorten significantly the diagnosis time.