Performance of Cepheid® Xpert MTB/RIF® and TB-Biochip® MDR in two regions of Russia with a high prevalence of drug-resistant tuberculosis

Abstract

The purpose of this study was to assess the performance of Cepheid® Xpert MTB/RIF® ("Xpert") and TB-Biochip® MDR ("TB-Biochip"). Sputum specimens from adults with presumptive tuberculosis (TB) were homogenized and split for: (1) direct Xpert and microscopy, and (2) concentration for Xpert, microscopy, culture [Lowenstein-Jensen (LJ) solid media and Mycobacteria Growth Indicator Tube® (MGIT)], indirect drug susceptibility testing (DST) using the absolute concentration method and MGIT, and TB-Biochip. In total, 109 of 238 (45.8 %) specimens were culture-positive for Mycobacterium tuberculosis complex (MTBC), and, of these, 67 isolates were rifampicin resistant (RIF-R) by phenotypic DST and 64/67 (95.5 %) were isoniazid resistant (INH-R). Compared to culture of the same specimen, a single direct Xpert was more sensitive for detecting MTBC [95.3 %, 95 % confidence interval (CI), 90.0-98.3 %] than direct (59.6 %, 95 % CI, 50.2-68.5 %) or concentrated smear (85.3 %, 95 % CI, 77.7-91.1 %) or LJ culture (80.8 %, 95 % CI, 72.4-87.5 %); the specificity was 86.0 % (95 % CI, 78.9-91.3 %). Compared with MGIT DST, Xpert correctly identified 98.2 % (95 % CI, 91.5-99.9 %) of RIF-R and 95.5 % (95 % CI, 85.8-99.2 %) of RIF-susceptible (RIF-S) specimens. In a subset of 104 specimens, the sensitivity of TB-Biochip for MTBC detection compared to culture was 97.3 % (95 % CI, 91.0-99.5 %); the specificity was 78.1 % (95 % CI, 61.5-89.9 %). TB-Biochip correctly identified 100 % (95 % CI, 94.2-100 %) of RIF-R, 94.7 % (95 % CI, 76.7-99.7 %) of RIF-S, 98.2 % (95 % CI, 91.4-99.9 %) of INH-R, and 78.6 % (95 % CI, 52.1-94.2 %) of INH-S specimens compared to MGIT DST. Xpert and Biochip were similar in accuracy for detecting MTBC and RIF resistance compared to conventional culture methods.

Systematic review, meta-analysis and economic modelling of molecular diagnostic tests for antibiotic resistance in tuberculosis

“…After the first phase of screening, 557 papers were identified as being potentially eligible for the review (Figure 1). A total of 56 studies contained sufficient information on the performance of the rapid diagnostic tests to be included in the review. These studies were divided into five categories, depending on the rapid test investigated: INNO-LiPA studies (n = 9), 33,35,[51][52][53][54][55][56][57] GeneXpert studies (n = 6), 29,38,[58][59][60][61] MTBDRplus …”

“…A total of six 29,38,[58][59][60][61] studies reporting the use of GeneXpert were eligible for inclusion and subsequently analysed ( Table 2). The reported sensitivity and specificity of the GeneXpert test varied between 81.3-100.0% and 97.4-100.0%, respectively (see Table 2).…”

“…38 Kurbatova (2013) 59 Naidoo (2010) 63 Kim (2012) 58 Boehme (2010) Concerns regarding a high risk of bias in both the 'Reference test' and 'Index test' domains were associated with the absence of, or a lack of clarity associated with, blinding within the study. The study identified as high risk in the 'Patient selection' domain did not enrol patients either consecutively or randomly, and there was a strong indication that convenience sampling had been used.…”

Diagnostic accuracy of three technologies for the diagnosis of multi-drug resistant tuberculosis

“…Se analizaron en total 28 estudios en sendos países, de los cuales 12 (42,9 %) se realizaron en países de ingreso alto (27,30,31,(35)(36)(37)(38)(39)(40)(41)(42)(43), diez (35,7 %), en países de ingreso medio alto (22,29,33,44,45), cuatro (14,3 %), en países de ingreso medio bajo (22,29,32), y dos (7,1 %), en países de ingreso bajo (29,46). Veinte estudios (71,4 %) eran prospectivos, cuatro (14,3 %) eran retrospectivos y cuatro (14,3 %) combinaban el diseño retrospectivo y el prospectivo.…”

Tb Screening in Hiv- Infected Prisoners, Released Prisoners and Homeless Persons in a Multi-Centre Cohort Study in the North-West Region of Russia

“…Кроме того, недостаточное примене-ние бактериологических методов с определением лекарственной устойчивости повышает риск раз-вития МЛУ-ТБ в период тюремного пребывания пациента и увеличивает вероятность неэффек-тивного лечения не установленного своевремен-но первичного МЛУ-ТБ. В данном исследовании МЛУ-ТБ в 2011 г. в Ленинградской области со-ставил лишь 2,3%, что значительно ниже данных в ранних исследованиях, которые варьировали в пенитенциарных учреждениях российских реги-онов до 23% [12,21,22].…”