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. 2019 Nov 15:12:3585-3593.
doi: 10.2147/IDR.S222905. eCollection 2019.

Efficacy Of Line Probe Assay In Detection Of Drug-Resistant Pulmonary Tuberculosis In Comparison With GeneXpert And Phenotypic Methods In Iran And Genetic Analysis Of Isolates By MIRU-VNTR

Hossein Kazemian  1 , Jalil Kardan-Yamchi  2 , Abbas Bahador  1 , Shadi Khonsari  3 , Mahshid Nasehi  4 , Gholamreza Hamzehloo  5 , Farzam Vaziri  6 , Mohammad Reza Salehi  7 , Mohammad Mehdi Feizabadi  1   8
Affiliations

Efficacy Of Line Probe Assay In Detection Of Drug-Resistant Pulmonary Tuberculosis In Comparison With GeneXpert And Phenotypic Methods In Iran And Genetic Analysis Of Isolates By MIRU-VNTR

Hossein Kazemian et al. Infect Drug Resist. .

Abstract

Background: Successful treatment of tuberculosis depends on early diagnosis and use of appropriate drug susceptibility testing in a timely manner. In the present study, LPA efficacy was assayed in detection and drug susceptibility testing of pulmonary tuberculosis in comparison to available methods in Iran and phylogenetic analyses of isolated cases carried out by MIRU-VNTR.

Methods: This study was conducted at the Tehran Regional Reference Laboratory for Tuberculosis. All sputum specimens were subjected to smear, culture, and drug susceptibility testing (DST), GeneXpert, and LPA. Finally, 15-locus-based MIRU-VNTR was used for molecular genotyping.

Results: From a total of 920 sputum specimens, 6.08% (n=56) were identified as MTBC by culture, 6.8% (n=63) by GeneXpert, and 6.5% (n=60) by LPA. Phenotype DST and LPA methods confirmed the resistance of 4 and 14 specimens to rifampin (RIF) and isoniazid (INH); two cases were considered as multidrug-resistant (MDR). Using GeneXpert, four cases were identified as RIF-resistant. Based on LPA results, inhA and katG mutations were detected in 100% and 21.4% of INH-resistant cases, respectively. All 56 culture positive Mycobacterium tuberculosis isolates were placed in 29 different clusters using MIRU-VNTR genotyping. Two MDR-TB, 2 RIF mono-resistant, and 12 INH mono-resistant cases were placed in different clusters.

Conclusion: LPA is an appropriate method for early detection and accurate diagnosis of TB and drug-resistant cases that makes it possible to distinguish INH mono-resistant cases from MDR cases in Iran.

Keywords: drug resistance; early diagnosis; line probe assay; mutation; tuberculosis.

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Conflict of interest statement

The authors report no conflicts of interest in this work.

Figures

Figure 1
Figure 1
Laboratory performance for each pulmonary sample.
Figure 2
Figure 2
Banding patterns obtained by GenoType MTBDRplus VER 2.0 test. CC; conjugate control, AC; amplification control, TUB; M. tuberculosis complex-specific control, rpoB, katG and inhA; locus control zones specific for each gene. (Sample 8 is positive control of MTB (H37Rv), sample 2 have katG WT (wild type) and katG MUT1 bands which show S315T1 mutation in codon 315 of katG gene; Samples 1, 2, 5, 7, 10, 11, and 12 have inh WT1, 2 and inhA MUT1 bands which show A–16G mutation in inhA gene. Sample 2 has both KatG (S315T1) and inhA (A–16G) mutations simultaneously.
Figure 3
Figure 3
Genetic relatedness of 53 M. tuberculosis isolates by MIRU-VNTR genotyping (0.17 cut-off). Right hand: the allele number of 15 loci in MIRU-VNTR for each isolate. Isolate 1 is M. tuberculosis H37Rv.
See this image and copyright information in PMC

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