Comparison of GeneXpert and line probe assay for detection of Mycobacterium tuberculosis and rifampicin-mono resistance at the National Tuberculosis Reference Laboratory, Kenya

Aricha, S. A.; Kingwara, Leonard; Mwirigi, Nkirote; Chaba, Linda; Kiptai, T.; Wahogo, Josephine; Otwabe, J.S; Onyango, Patrick; Karanja, Muthoni; Ayieko, Cyrus; Matu, S.W.

doi:10.1186/s12879-019-4470-9

Cited by 25 publications

(17 citation statements)

References 30 publications

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“…Such difference between the two findings might be due to the difference in number of drug resistant isolates. Further, the agreement between Culture MGIT and LPA in detecting katG , inhA and both ( katG and inhA ) resistance was almost perfect and agrees with a study from Kenya [ 17 ].…”

Section: Discussionsupporting

confidence: 89%

“…In the case of freezed live Mycobacterium , its survival could be interrupted through time until it was sub-cultured using the MGIT instrument. The higher sensitivity result 94.2% of LPA and its lower specificity value 30.2% is comparable with similar settings done in Kenya where its sensitivity and specificity was 99.2 and 26.9%, respectively [ 17 ]. This showed that LPA has a good performance in detecting the true positivity of Mycobacterium and in a fair agreement (Kappa = 0.276; P < 0.001) with the BACTEC MGIT 960 performance.…”

Section: Discussionsupporting

confidence: 79%

“…The translated sensitivity, specificity, positive predictive value and negative predictive value were 94.2, 30.2, 68.4 and 76.5%, respectively. There was a fair agreement (Kappa = 0.276; P < 0.001) between the two methods (MGIT and LPA) in detecting the Mycobacterium (Table 1 ) when MGIT was used as the reference standard in the analysis [ 17 ].…”

Section: Resultsmentioning

confidence: 99%

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Phenotypic and genotypic drug sensitivity profiles of Mycobacterium tuberculosis infection and associated factors in northeastern Ethiopia

et al. 2021

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Background Tuberculosis is a devastating and a deadly disease despite the novel advances in its diagnostic tools and drug therapy. Drug resistant Mycobacterium contributes a great share to tuberculosis mortality. Status of drug resistance and patients’ awareness toward the disease is unknown in northeastern Ethiopia. Thus, the aim of this study was to determine the phenotypic and genotypic drug sensitivity patterns and associated factors in Oromia Special Zone and Dessie Town, northeastern Ethiopia. Methods In a cross-sectional study, 384 smear positive tuberculosis cases were recruited and Löwenstein-Jensen culture was done. The performance of GenoTypic MTBDRplus assay using the conventional BACTEC MGIT 960 as a “gold standard” was determined. Drug resistant strains were identified using spoligotyping. Pearson Chi-square test was used to determine the association of drug sensitivity test and tuberculosis type, lineages, dominant strains and clustering of the isolates. Results The 384 smear positive Mycobacterium samples were cultured on LJ media of which 29.2% (112/384) as culture positive. A fair agreement was found between MTBDRplus assay and the conventional MGIT test in detecting the Mycobacterium tuberculosis with sensitivity, specificity, positive and negative predictive value of 94.2, 30.2, 68.4 and 76.5%, respectively. Among LJ culture positive samples 95 of them gave valid result for MTBDRplus assay and 16.8% (16/95) as drug resistant. Similarly, MGIT subculture was made for the 112 isolates and 69 of them gave positive result with 15.9% (11/69) as drug resistant. Cohen’s kappa value showed almost a perfect agreement between the two testing methods in detecting rifampicin (sensitivity 100% and specificity 98.3%) and multi-drug resistance (sensitivity 83.3% and specificity 100%). Spoligotyping identified 76.5% (13/17) of the drug resistant isolates as Euro-American and family 33 as the predominant family. Significant association was observed between drug resistant isolates and the dominant strains (χ2: 34.861; p = 0.040) of the Mycobacterium. Conclusion Higher magnitude of drug resistance was found in the study area. The GenoTypic MDRTBplus assay had an acceptable drug sensitivity testing performance.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

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Phenotypic and genotypic drug sensitivity profiles of Mycobacterium tuberculosis infection and associated factors in northeastern Ethiopia

et al. 2021

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“…The performance characteristics of this assay were, however, higher than the study performed in Ethiopia [ 32 ]. Geographical locations of sample collection, variances in sampling technique, MDR-TB and mutations within the rpoB gene might be the responsible factors for variations in diagnostic performance characteristics [ 33 ]. Both Xpert MTB/RIF and LPA assays are associated with less biological hazards and short turnaround time, in comparison to the conventional DST.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Xpert MTB/RIF Assay, MTB Culture and Line Probe Assay for the Detection of MDR Tuberculosis in AFB Smear Negative Specimens

et al. 2022

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The global burden of tuberculosis (TB), particularly with multidrug resistance (MDR), is escalating and has become a major health challenge. It is well known that acid-fast bacilli (AFB) smear-negative TB patients are the major source of spreading TB to healthy individuals when left untreated. Early diagnosis of TB and rapid detection of drug resistance are important for the proper management of drug-resistant TB (DR-TB). Therefore, a laboratory based cross-sectional study was conducted from July to December 2019 at the National Tuberculosis Centre, Thimi, Nepal, with the objective of evaluating the diagnostic performance of Xpert MTB/RIF assay, Mycobacterium tuberculosis (MTB) culture and line probe assay (LPA) for the detection of MDR-TB in AFB smear-negative sputum samples. We evaluated a total of 222 AFB smear-negative sputum specimens, of which 21.6% (n = 48) showed MTB positive with Xpert MTB/RIF assay and, while culturing on Lowenstein–Jensen (LJ) media, 21.2% (n = 47) were MTB culture positive. The sensitivity, specificity, PPV and NPV at 95% confidence interval of Xpert MTB/RIF assay on diagnosing M. tuberculosis from smear-negative specimens were 73% (57–84), 92% (87–96), 71% (59–81) and 93% (89–95), respectively. In addition, the sensitivity of Xpert MTB/RIF assay and LPA in detecting rifampicin resistance was 75% (42–94, 95% CI) and 91.67% (62–99, 95% CI), respectively. The current study also assessed a significant association between the occurrence of pulmonary tuberculosis with different age group, TB history and alcohol consumption. These findings indicate that Xpert MTB/RIF assay and LPA are appropriate methods for early detection and accurate diagnosis of TB and RIF mono-resistant cases.

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“…The challenges of smear microscopy are well documented and include low sensitivity, especially in all patients with extrapulmonary tuberculosis, resulting in missed cases and delays in initiation of treatment [ 7 ]. In Tanzania, drug susceptibility testing is frequently carried out on Lowenstein–Jensen solid media using the proportion method [ 8 , 9 ]. This test method takes weeks before results can be obtained, delaying patient management, hence the need for more rapid and reliable methods with shorter turnaround times.…”

Section: Introductionmentioning

confidence: 99%

Comparative Performance of Line Probe Assay and GeneXpert in the Detection of Rifampicin Monoresistance in a TB-Endemic African Country

et al. 2022

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Rapid, accurate and reliable assays are required for timely detection of drug-resistant tuberculosis and early initiation of second-line TB treatment as well as to minimize transmission of resistant strains. This study assessed diagnostic performance characteristics of two rapid molecular assays, line probe assay (LPA) and GeneXpert (MTB/RIF), in the detection rifampicin monoresistance using the phenotypic proportion method on Lowenstein–Jensen media as the gold standard. This study involved a total of 357 isolates, 74 rifampicin-resistant and 283 rifampicin-susceptible, collected at the Central Tuberculosis Reference Laboratory (CTRL) in Dar es Salaam, Tanzania, between 2016 and 2019. Sensitivity, specificity and positive and negative predictive values were used to assess the performance characteristics of the two assays while kappa coefficient was used to determine agreement of test results. The receiver operating curve (ROC) was used to determine the discriminatory ability of the test in distinguishing resistant and susceptible TB isolates. Our results showed that GeneXpert had sensitivity, specificity and positive and negative predictive values of 93.2, 82.7, 58.5 and 97.9%, respectively; the corresponding performance for LPA was 86.5, 97.5, 90.1 and 96.5%, respectively. Compared with conventional phenotypic DST results, GeneXpert had a moderate agreement (kappa 0.621, p < 0.001), while LPA had high agreement (0.853, p < 0.001). LPA showed an accuracy of 95.2% compared to GeneXpert’s 84.9%. ROC curve depicted the ability of the tests to distinguish rifampicin-sensitive and rifampicin-resistant strains to be 87.9% for GeneXpert and 92.0% for LPA. Our results indicate the superiority of LPA over GeneXpert regarding detection of rifampicin monoresistance. However, logistic challenges such as longer turnaround time and need for skilled laboratory personnel may limit its use.

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Comparison of GeneXpert and line probe assay for detection of Mycobacterium tuberculosis and rifampicin-mono resistance at the National Tuberculosis Reference Laboratory, Kenya

Cited by 25 publications

References 30 publications

Phenotypic and genotypic drug sensitivity profiles of Mycobacterium tuberculosis infection and associated factors in northeastern Ethiopia

Phenotypic and genotypic drug sensitivity profiles of Mycobacterium tuberculosis infection and associated factors in northeastern Ethiopia

Evaluation of Xpert MTB/RIF Assay, MTB Culture and Line Probe Assay for the Detection of MDR Tuberculosis in AFB Smear Negative Specimens

Comparative Performance of Line Probe Assay and GeneXpert in the Detection of Rifampicin Monoresistance in a TB-Endemic African Country

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