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Incorporation of rapid detection systems to identify mutations in M. tuberculosis complex that confer resistance to isoniazid and rifampicin has potentiated the knowledge of their distribution, given the geographical variability. We performed antibiograms of the 2,993 strains isolated in Galicia, Spain (2008-2013). In the strains resistant to isoniazid, a concentration of 0.4 mg/mL and MTBDRplus Genotype test (Hain Lifescience, Germany) were used. We found that 3.64 % of strains were resistant to isoniazid, while 0.43 % were resistant to isoniazid and rifampicin (multidrug resistant, MDR). The MTBDRplus test showed an overall sensitivity of 72.48 %, with 62.5 % sensitivity for non MDR isoniazid-resistant strains and 100 % sensitivity for MDR strains. The katG gene mutation was detected at codon 315 in 38.53 % of strains. The S315T mutation appeared in 61.54 % of MDR strains and 34.38 % of non-MDR strains. The 28.44 % had mutations in inhA, (93.55 % in C15T), and 38.46 % of MDR strains were mutated. In non-MDR strains, 37.50 % were wild-type, 35.42 % and 27.08 % had mutations in katG and inhA, respectively. The most frequent mutation in rpoβ was S531L (46.15 %). The 38.71 % and 41.9 % of strains with resistance to isoniazid and streptomycin had mutations in katG and inhA, respectively (2 strains with mutations in T8C and T8A). The distribution pattern of resistance among strains with high and low concentrations of isoniazid showed statistically significant differences in relation to the mutation in katG and wild-type. The sensitivity of the Genotype MTBDRplus test for non-MDR strains in our area was at the lower threshold described.

Objective: The objective of this study was to evaluate the efficacy of two commercial nucleic acid amplification techniques to identify Mycobacterium tuberculosis in saliva., Subjects and Methods: Fifty-two participants were recruited, 32 patients with a clinical and microbiological diagnosis of pulmonary tuberculosis and 20 healthy volunteers as controls. Three sputum samples were collected from each participant and were examined by direct bacilloscopy, cultured in liquid and solid media, and processed using the Mycobacterium tuberculosis direct (MTD) test for rRNA detection. One saliva sample was collected from each participant using conventional methods and was examined by direct bacilloscopy, cultured, and processed using the MTD test for rRNA detection and the FluoroType Mycobacterium tuberculosis assay for DNA detection., Results: In saliva samples, the sensitivity, specificity, and positive and negative predictive values of the MTD test were 71.8%, 95%, 95.8%, and 67.8%, respectively. The values obtained with the FluoroType assay were 56.2%, 90%, 90%, and 56.2%, respectively., Conclusions: Our results indicate that when a sufficient volume of sputum cannot be obtained, saliva could be an alternative biological sample for the rapid diagnosis of pulmonary tuberculosis using commercial nucleic acid amplification techniques., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Ligase chain reaction amplification (LCx Abbott Laboratories) was used to detect the presence of M. tuberculosis in 101 adenopathy specimens obtained from 98 patients. A total of 30 cases of lymph node tuberculosis were diagnosed, and the data were compared with results obtained using conventional techniques. The sensitivity of auramine staining and culture were 50.0% and 66.7%, respectively. The sensitivity, specificity, positive predictive value and negative predictive value of the LCx assay were 80.0, 98.6, 96.0, and 92.1% respectively. The results confirm the reliability of ligase chain reaction amplification for the detection of lymph node tuberculosis.