Get Permission Mumena, Kwenda, Ngugi, and Nyerere: Drug-target genes and their spontaneous mutations associated with resistance to first-line, second-line, third-line, novel and repurposed anti-tuberculosis drugs in Mycobacterium tuberculosis resistant strains


Introduction

Tuberculosis (TB) is a global public health emergency.1, 2 It causes high mortality and morbidity rates, it kills one person every 21 seconds.3, 4 TB is caused by species of the Mycobacterium tuberculosis complex (MTBC), some of which are adapted to humans (Mycobacterium tuberculosis [MTB] and Mycobacterium africanum), while others to animals (Mycobacterium bovis, Mycobacterium microti, Mycobacterium pinnipedii, Mycobacterium mungi, and Mycobacterium caprae), and others are smooth bacilli (Mycobacterium canettii).5, 6, 7 MTB is the major causative pathogen for human TB among the species of MTBC, as it causes 97-99% of all TB cases globally.3

TB is the second leading cause of death from a single infectious agent, after coronavirus disease 2019 (COVID-19), a highly infectious disease caused by a virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).8, 9 The current TB morality is severely impacted by COVID-19 and not HIV/AIDS. COVID-19 has reversed years of progress made in the fight against TB. Globally TB targets have gone off-track and many years of progress reversed.9 The burden of TB is driven by the emergence and spreading of drug-resistant MTB strains.2, 4, 10 TB-HIV co-infection has led to an increase in different types of drug-resistant TB.11

The latest World Health Organization Global TB Report of 2021 revealed that 132,222 cases of multidrug-resistant/rifampicin resistant tuberculosis (MDR/RR-TB) and 25,681 of pre-extensively drug-resistant/extensively drug-resistant tuberculosis (pre-XDR/XDR-TB) were detected in 2020.9 The global prevalence of MDR/RR-TB stood at 3.5% and 18% among the new TB cases and previously treated cases respectively. 9 In 2019, 206,030 cases of MDR/RR-TB were detected and notified globally.12 This meant the global prevalence of MDR/RR-TB was 3.3% among the new TB cases and 17.7% among the previously treated cases.12, 13 In 2018, 186,772 cases of MDR/RR-TB were detected and notified globally.14 The global prevalence of MDR/RR-TB was 3.4% and 18% among the new TB cases and previously treated TB cases respectively.14 In 2017, 160,684 cases of MDR/RR-TB were detected and notified globally.15 The global prevalence of MDR/RR-TB was 3.5% among the new TB cases and 18% among the previously treated TB cases, in 2017.15 An estimated 8.5% of MDR-TB cases were estimated to have XDR-TB in 2017. In 2016, 153,119 cases of MDR/RR-TB were detected and notified globally.16 The global prevalence of MDR/RR-TB was 4.1% and 19% among the new TB cases and previously treated TB cases respectively, in 2016.16

Drug-resistant tuberculosis (DR-TB) is jeopardizing efforts in the control and prevention of TB.2 DR-TB can be transmitted through the air from one person to another or can develop when MTB strains become resistant to anti-TB drugs due to a number of factors which include: poor adherence, poor compliance, poor selection of regimens, low efficacy anti-TB drugs, late diagnosis, interrupted supply, stock-outs, spontaneous mutations, and chromosomal replication errors.3, 10, 17, 18, 19, 20, 21 Different categories of DR-TB have been defined and they include; multidrug-resistant tuberculosis (MDR-TB), pre-extensively drug-resistant tuberculosis (Pre-XDR-TB), extensively drug-resistant tuberculosis (XDR-TB), extremely drug-resistant tuberculosis (XXDR-TB), and totally drug-resistant tuberculosis (TDR-TB).4, 5, 22

MDR-TB is TB resistant to at least rifampicin (RIF) and isoniazid (INH).23, 24 Pre-XDR TB is TB resistant to RIF, INH, plus any one fluoroquinolone (FLQ) (levofloxacin, moxifloxacin, ofloxacin, or gatifloxacin), or any one of the second-line injectable drugs (SLIDs) (kanamycin, capreomycin, or amikacin).3 XDR-TB is TB resistant to RIF, INH, plus any FLQs, plus any SLIDs.10 XXDR-TB is a type of TB characterized by the presence of MTB isolates that show in-vitro resistance to all first- and second-line anti-TB drugs tested.4, 25, 26 TDR-TB is TB characterized by MTB isolates that show resistance to all tested antibiotics plus some that are currently in the discovery pipeline.4, 27

Mutations in target genes or their promoter regions of genes are associated with resistance to anti-TB drugs.22 Resistance to first-line anti-TB drugs is mainly caused by mutations in the following genes: rpoB gene for resistance to rifampicin; inhA, kasA, ahpC, katG and ndh genes for resistance to isoniazid; embB gene for resistance to ethambutol; and finally, the pncA, panD, rpsA, clpC1, and Rv2783c genes for resistance to pyrazinamide.28, 29 While resistance to second-line anti-TB drugs is mainly caused by mutations in the following genes: rpsL, rrs and gidB genes for resistance to streptomycin; gyrA and gyrB genes for resistance to the fluoroquinolones; rrs, eis and tlyA genes for resistance to the aminoglycosides and cyclic polypeptide antibiotics.29, 30

The aim of this comprehensive mini-review was to highlight molecular targets and their mutations associated with drug-resistance to first-line, second-line, novel and repurposed anti-tuberculosis drugs in resistant MTB clinical isolates. The identification of drug-target genes with their spontaneous mutations helps in designing new drugs or improving the efficacy of the available drugs as well as help in providing vital information for designing new molecular diagnostic assays for rapid detection of DR-TB.

Mechanisms for Drug-Resistance to First-Line Anti-Tuberculosis Drugs

First-line anti-TB drugs used are rifampicin, isoniazid, pyrazinamide and ethambutol.31 MTB resistance to each one of the first-line anti-TB drugs has been detected in TB patients. MTB resistance is attributed to a number of factors some of which include: the mycolic acid, lipid layer of the cell wall, presence of β-lactamase enzymes, presence of efflux pumps, and the development of mutations in the target genes of MTB. 32 The mycolic acid, lipid layer of MTB makes the cell wall to become less permeable to a number of anti-TB drugs. 33 The efflux pumps play a role of pumping several antimicrobial agents out of the cells of MTB. 33, 34 The β-lactamase enzyme of MTB inactivates the β-lactam antibiotics thus causes resistance to this class of antibiotics. 33 The development of mutations in the target genes of MTB is a major mechanism through which resistance to anti-TB drugs occurs. 35, 36

Drug Target Genes and Mutations Conferring Resistance to Isoniazid

Isoniazid resistance is brought about by mutations in several genes of M. tuberculosis such as the katG, inhA, ahpC, kasA, oxyR, furA, fabG1-inhA, and ndh genes. 3, 34, 37 However, Current research has shown that resistance to isoniazid can also be caused by an upregulation of efflux pumps or isoniazid inactivators.38, 39 Mutations in the katG, inhA and its promoter, and the oxyR-ahpC intergenic region frequently confer resistance to INH. 3, 22, 29 While mutations in the following genes oxyR, furA, ndh, ahpC, kasA, and fabG1-inhA infrequently confer resistance to INH. 3, 34 Recent studies have also found that mutations in the dfrA gene cause resistance to isoniazid. 29 Mutations in the inhA gene cause resistance to both isoniazid and ethionamide which share the same binding site on the promoter region. 40 The most frequently identified mutation in the katG gene is the Ser315Thr1, which confer a high-level resistance to INH. 3, 23, 29 While that in the inhA gene is the C-15T, which confer low-level resistance to INH. 3 The two mutations katG MUT (Ser315Thr1) and inhA MUT (C-15T) account for 80% of resistance to INH. 34, 41 The four most frequently identified mutations in the inhA gene that are associated with resistance to INH are Cys15Thr, Thr8Cys, Thr8Ala, and Ala16Gly. 3, 42 Isoniazid resistance that is associated with mutations in the katG gene occurs before rifampicin resistance. 29 Mutations in the katG gene can therefore, serve as a key marker for pre-MDR TB. 43

Drug Target Genes and Mutations Conferring Resistance to Rifampicin

Mutations within a hypervariable region of the rpoB gene, which codes for the β-subunit RNA polymerase confer resistance to RIF in 95% of MTB clinical isolates. 22, 44, 45, 46, 47 About 96% of RIF- resistance occurs within the rifampicin resistance determining region (RRDR) which is also called the “hot-spot region” (HSR-rpoB), covering codons 507-533 of the rpoB gene. 22 Mutations at codons 531, 526, and 516 in the rpoB gene are the most commonly identified in RIF-resistant MTB isolates. 22 Mutations at codons 529, 526, 518, and 516 confer low-level resistance to RIF, whereas mutations at codons 526-531 show the highest frequency and are associated with a high-level resistance to RIF. 22, 23 Mutations at codon 531 is associated with cross-resistance to rifabutin. 22 The most frequent mutations associated with resistance to RIF in the rpoB gene are Ser531Leu, His526Asp, His526Tyr, and Asp516Val. 23, 42 These point mutations involve changes in the positions of amino acids, and can be an insertion, deletion, or missense. 45, 48

Drug Target Genes and Mutations Conferring Resistance to Ethambutol

Mutations in genes that confer resistance to ethambutol (EMB), occur in specific regions known as ethambutol resistance-determining regions (ERDR) or “hot-spot regions” (HSR). 49 EMB resistance in M. tuberculosis is caused by mutations in the following genes: embA, embB, embC, embR, UbiA, aftA, and iniA genes. 5, 22, 29, 50 The most common mechanism for resistance to ethambutol is mutation in the embB gene, occurring at codon 306. 29 Mutations at codon 406 and 497 within the embB gene have also been detected. 51 For example the mutations Met306Leu and Met306Val at codon 306 in the embB gene are associated with resistance to EMB. 22 Novel mutations embB Gly43Cys, embB Gly554Asn, and embB Ser412Pro in the embB gene also confer resistance to EMB. 5 Mutations in the ubiA gene in-conjunction with mutations in the embB gene have been found to cause a high-level resistance to ethambutol. 22, 52 Studies have also shown that the high-level resistance to ethambutol develop via a stepwise acquisition of mutations in the embB, ubiA, and embC genes. 53 From the total of 98% of mutations that occur in the embB CAB locus of the embB gene in resistant MTB isolates, 70% are found in codon 306, 406, or 497, while 13% of the mutations are found out side of the three regions between condons 296 and 426, and 15% are in the embC-embA intergenic region. 22 The embCAB operon comprises of three genes embA, embB, and embC. Therefore, mutations in this operon are associated with resistance to EMB. 51

Drug Target Genes and Mutations Conferring Resistance to Pyrazinamide

Mutations in the pncA, panD, rpsA, clpC1(Rv3596c), and Rv2783c genes of MTB confer resistance to pyranamide (PZA). 22, 29, 40, 54 However, mutations in the pncA and its promoter region are the most frequently identified as they account for 72-99% of resistance to PZA. 22, 54 The most frequent mutations in the pncA gene are: Asp49Asn, Tyr64Ser, Trp68Gly, and Phe94Ala. 54 Studies have also shown that PZA resistance is strongly associated with rifampicin resistance. This finding confirms that the burden of PZA resistance is in patients who have rifampicin resistance. 29

Drug Target Genes and Mutations Conferring Resistance to Second-Line Anti-Tuberculosis Drugs

The second-line drugs are key in the management of drug-resistant TB, and they include: fluoroquinolones, aminoglycosides, streptomycin, cycloserine, ethionamide, prothionamide, para-amino salicylic acid, and cyclic poly-peptides. 29, 37 Drug-resistance to all anti-TB drugs has been reported in some countries. 55 MTB resistance is mainly caused by mutations in the target genes. 56 Mutations in the rpsL, rrs and gid genes cause resistance to streptomycin, while mutations in the gyrA and gyrB genes cause resistance to the fluoroquinolones. Mutations in the rrs, eis and tlyA genes cause resistance to the aminoglycosides and cyclic polypeptide antibiotics. 30

Drug Target Genes and Mutations Conferring Resistance to Streptomycin

Streptomycin (STR) resistance by M. tuberculosis is caused by mutations in the rpsL, rrs, and gidB genes. 22, 23, 40 The following mutations confer resistance to STR, rpsL (Lys43Arg, Lys88Gln, Lys88Arg, Cys117Thr), rrs (Cys517Thr, Ala514Cys, Ala906Gly, Ala907Cys), gidB (Ala183Val, Gly71Arg, Tyr22His, Gly37Arg, Pro75Ser, Gly76Asp, Ile81Thr, Phe100Leu, Val124Gly, Ala134Gly, Ala138Pro, Ser149Arg, Leu152Ser, and Gly157Arg). 57 Mutations in the rpsL and rrs genes are the major mechanisms that confer resistance to STR in M. tuberculosis, they account for 60-70% of resistance to STR. 29 Recent studies have revealed that mutations in the gidB gene cause low-level resistance and accounts for 33% of resistance to STR in clinical M. tuberculosis isolates. 29, 37, 40 The most frequently identified mutation in the rpsL gene is the replacement of lysine with arginine at position 43 and 88. 22 While in the rrs gene is the mutation Ala80Pro. 22 MTB strains that are resistant to STR confer cross-resistance to amikacin and kanamycin. 22

Drug Target Genes and Mutations Conferring Resistance to Aminoglycosides and Cyclic Poly-Peptide Antibiotics

Aminoglycosides and the cyclic polypeptide antibiotics are second-line drugs that are used in the treatment of drug-resistant TB. 29 The two key aminoglycosides are kanamycin (KAN) and amikacin (AMK), while capreomycin (CAP) and viomycin (VIO) are key cyclic polypeptide antibiotics.37 The three drugs kanamycin, amikacin, and capreomycin are called second-line injectable drugs. 29

Mutations in the rrs, eis, tlyA genes result in resistance to the second-line injectable drugs 37 Mutations in the rrs gene cause resistance to all the three second-line injectable drugs, and is the most common molecular mechanism for resistance to this class of anti-TB drugs. 29 Mutations in the rrs gene, specifically at positions 1400, 1401, and 1483 base pair (bp) are associated with a high-level resistance to both AMK and KAN in KAN-resistant MTB strains. 22 The mutation Ala1401Gly in the rrs gene confer a high-level resistance to AMK and KAN along with cross-resistance to CAP. While the mutation Cys1402Thr or Gly1484Thr is associated with resistance to CAP and a cross-resistance to KAN or VIO. 22 Mutations in the rrs gene are also associated with resistance to CAP and VIO. 34 Mutations in the eis gene confer low-level resistance to KAN. 22 Mutations in the rrs gene accounts for about 70-80% resistance to CAP and AMK as well as 60% resistance to KAN in resistant M. tuberculosis isolates worldwide. 29 Mutations in the eis gene cause about 80% low-level resistance to KAN but not to AMK. 29 While mutations in the tlyA gene cause about 3% resistance to CAP. 29, 37Cross-resistance to streptomycin and KAN occur due to mutations in the whiB7 gene of M. tuberculosis. 58 Mutations in the tlyA gene also results in resistance in both CAP and VIO. 37

Drug Target Genes and Mutations Conferring Resistance to Fluoroquinolones

Fluoroquinolones (FLQs) are second-line anti-TB drugs, examples of those used in the treatment of drug-resistant TB include; levofloxacin, ofloxacin, gatifloxacin and moxifloxacin. 59, 60, 61

Mutations in the quinolone resistance determining region (QRDR) of both gyrA and gyrB genes of MTB cause resistance to FLQs. 3, 22, 29, 34, 40 Mutations in the gyrA gene cause a high-level resistance to FLQs, while mutations in the gyrB gene cause a low-level resistance to FLQs. However, combined mutations in both the gyrA and gyrB genes result in a high-level resistance to FLQs. 58 The most common mutations in the gyrA gene are: Gly88Cys, Gly88Ala, Ala90Val, Ser91Pro, Asp94Gly, Asp94Ala, Asp94His, Asp94Asn and Asp94Tyr. While those in the gyrB gene are: Glu540Val, and Asn538Asp. 3, 22 Mutations in the gyrB gene are not frequently found among MTB clinical isolates. 22 Mutations in both gyrA and gyrB genes, such as Asn538Ile (gyrB)-Asp94Ala (gyrA) and Ala543Val (gyrB)- Asp94Asn/Asp94Gly(gyrA) cause very high-resistance to FLQs. 22, 58 Cross-resistance among the FLQs occurs. 37 Resistance to ofloxacin causes resistance to other FLQs. 61 FLQ resistance is one of the most important criteria that is used for defining extensively drug-resistant TB. 62

The second mechanism through which M. tuberculosis develops resistance to FLQs is the use of efflux pumps. 34, 59 These biological pumps remove the fluoroquinolone drugs out of the mycobacterial cells. 59

Drug Target Genes and Mutations Conferring Resistance to Cycloserine

D-cycloserine (DCS) is a second-line drug used in the treatment of MDR-TB and XDR-TB. 22, 63

Resistance to cycloserine by MTB is due to mutations in the alr, ddlA, ald (Rv2780) and cycA genes. 22, 64, 65 Mutations in the alr gene are the main cause for resistance to cycloserine and involve three major mutations: alr mtb Y364D, alr mtb R373L, and alr mtb M319T. 63 The point mutation in the cycA gene of M. bovis confer resistance to DCS. 22 While the over expression of alrA cause resistance to DCS in recombinant mutant of M. smegmatis. 22

Drug Target Genes and Mutations Conferring Resistance to Ethionamide

Ethionamide (ETH) is a second-line drug used in the treatment of MDR-TB. 66 Mutations in the ethR, inhA, ndh, mshA, and etaA/ethA genes of MTB result in resistance to ethionamide. 22, 29, 66 Mutations in the inhA gene result in co-resistance to ETH and INH, because the two drugs are structural analogues of each other, share the same target and mechanism of action. 29, 66 Mutations in the ethA and ethR genes confer resistance to ETH and prothionamide. 22 Mutations in ethA/ethR genes, coupled with mutations in the inhA or its promoter region confer resistance to both ETH and INH. 22 The mutation C-15T confer a low-level resistance to INH and a cross-resistance to ETH. 67, 68 The mutations Ala95Thr and Phe110Leu in the ethR gene confer resistance to ETH. 69 While the mutations Ile95Pro, Ser94Ala, and Ile21Thr in the inhA gene confer resistance to both INH and ETH in MTB resistant clinical isolates. 70

Drug Target Genes and Mutations Conferring Resistance to Prothionamide

Prothionamide (PTH) is a second-line drug used in the treatment of drug-susceptible TB meningitis, miliary TB and MDR-TB. 71 PTH is a structural analogue of INH. The two drugs have a common target, which is inhA gene. 69 Mutations in the ethA, ethR, mshA, ndh, katG, inhA and/or its promoter region result in resistance to PTH. 69, 71, 72 PTH resistance is most commonly caused by mutations in the ethA gene of MTB. 71 Mutations in the inhA and ndh genes result in cross-resistance to PTH, ETH, and INH. 29, 66, 71, 72 Mutations in both the ethA and mshA genes result in cross-resistance to PTH and ETH. 66, 71, 72 The mutations Val152Met and Arg216Cys in the ethR gene confer resistance to PTH. 69 Mutations in the katG and ethA confer resistance to both PTH and INH, for instance katG (Ser315Th, Ala264Val, Thr275Ala), and ethA (Cys137Arg, Ser266Arg, Pro334Ala). 69

Drug Target Genes and Mutations Conferring Resistance to Para-Amino Salicylic Acid

Para-amino salicylic acid (PAS) is a structural analogue of para-amino benzoic acid (PABA), it is a second-line drug used in the treatment of MDR-TB. 29, 73 PAS improves the cure rate and reduces the emergence of drug-resistant TB. 74 Mutations in the thyA, dfrA, folC, folP1, folP2, and ribD genes of M. tuberculosis confer resistance to PAS.22, 29, 75, 76 The following mutations in the thyA gene confer resistance to PAS Arg127Leu, Leu143Pro, Leu172Pro, Cys146Arg, Ala182Pro, and Val261Gly. 76 A study done at the Central Laboratory, Public Health Medical Centre, Chongqing, in South-western China found that resistance to PAS in MTB was mainly caused by mutations in the thyA, ribD and folC genes, with mutations in the folC gene being the most frequent. 73

Drug Target Genes and Mutations Conferring Resistance to Novel and Repurposed Anti-Tuberculosis Drugs

The emergence of new resistant mechanisms by M. tuberculosis has led to the development of new anti-TB drugs by different pharmaceutical companies to treat drug-resistant TB cases. 77 Examples of new anti-TB drugs that have recently been developed include: bedaquiline (BDQ), linezolid (LZD), delamanid (DLM), pretomanid (PTM), and clofazimine (CFZ). However, drug-resistance has already been reported even to some of these newly developed drugs. 29

Drug Target Genes and Mutations Conferring Resistance to Bedaquiline

Bedaquiline (BDQ) is used in combination with other anti-TB drugs for the treatment of MDR-TB. 78 Mutations in the atpE (Rv1305), pepQ (Rv2535c), and mmpR (Rv0678), Rv1979c genes of MTB confer resistance to BDQ. 29, 79 Mutations in the atpE gene cause a high-level resistance to BDQ with the most frequently identified mutations being Ala63Pro and Ile66Met. 22, 29, 34, 80 The other mutations occurring in atpE include Asp28Ala, Ala63Val, and Ile66Val. 81 Mutations in the Rv0678 gene include Gly66Glu, Met1Ala, Trp42Arg, Ser53Leu, Ser63Arg, and Ser63Gly. 82 Mutations in the Rv0678 gene cause an upregulation of MmpL5, a multi-substrate efflux pump, resulting to resistance not only to BDQ but also to clofazimine (CFZ). 22 Mutations in the Rv0678 gene cause a low-level cross resistance between BDQ and CFZ. 79 Similarly, mutations in the Rv2535c cause a low-level resistance to BDQ and CFZ. 79 Mutations in the pepQ gene confer cross-resistance between CLO and BDQ. 22

Drug Target Genes and Mutations Conferring Resistance to Pretomanid and Delamanid

Mutations in the ddn, fgd1, fbiA, fbiB, fbiC, fbiD, and MmpS5-MmpL5genes genes result in resistance to pretomanid (PTM) or delamanid (DLM). 22, 29, 81, 83, 84 Mutations in the fbiA and fgd1 genes of M. tuberculosis result in resistance to DLM. 29 Mutations in the fgd1 occur between codons 43 and 230, for Pro43Arg example. 81 Cross-resistance between the drugs, PTM and DLM has been reported. This cross-resistance is inevitable because the two drugs have a similar chemical structure. 80 The following mutations ddn (Asp113Asn, Arg72Trp, Gly34Arg, Gly81Ser, Pro131Leu, Pro45Leu, Met1Thr, Trp88Arg, Tyr65Ser, Leu49Pro, Leu107Pro, Gly81Asp, and Gly53Asp), fgd1 (Thr960Cys, Arg64Ser, Gln88Glu, Lys270Met, Lys296Glu, Lys296Arg, Arg247Trp, and Met93Ile), fbiA (Lys2Glu, Ile280Val, Ile209Val, Ser126Pro, Arg304Gln, Arg175His, Asp49Tyr, Gly139Arg, Ala178Thr, and Asp49Thr), fbiB (Lys448Arg, Ala31Thr, Asp90Asn, Arg265Gln, Val348Ile, Gly325Ser, Pro182Leu, Pro361Ala, and Leu326Phe), fbiC (Val318Ile, Cys105Arg, Leu228Phe, Leu377Pro, Ala856Pro, Ala835Val, Ser762Asn, Ala416Val, Trp678Gly, Thr273Ala, Trp678Gly, Ile128Val, Gly655Ser, and Thr455Ala) confer resistance to DLM or PTM.81, 84, 85 The three non-synonymous single nucleotide polymorphisms (SNPs), Gly84Val, Ala175Thr, and Met221Arg in the ndh gene of Mycobacterium smegmatis confer resistance to DLM, but not in M. tuberculosis. 84

Drug Target Genes and Mutations Conferring Resistance to Linezolid

Linezolid (LZD) is used in combination with other anti-TB drugs for the treatment of complicated cases of MDR-TB and XDR-TB. 86 Mutations in the rrl and rplC genes of M. tuberculosis confer resistance to both LZD and sutezolid (SZD). 22, 29, 87 The following mutations rrl (Ala2810Cys, Gly2299Thr, Gly2814Thr, Gly2270Thr, Gly2270Cys, and Gly2746Ala), and rplC (Cys154Arg, Thr460Cys, Ala328Gly, and Cys154Arg) confer resistance to LZD. 22, 81, 88, 89 Mutations in the rplC gene are associated with higher minimum inhibitory concentration (MIC) values to LZD, while those in rrl gene are associated with lower MIC values. 89 Mutations in the rrl gene cause a high-level resistance to LZD. 29, 87

Drug Target Genes and Mutations Conferring Resistance to Clofazimine

Clofazimine (CFZ) is used in combination with other anti-TB drugs for the treatment of drug-resistant TB. 90 Resistance to CFZ by M. tuberculosis is attributed to mutations in the Rv0678, Rv1979c, Rv2535c, ndh and pepQ genes. 29, 88 The following mutations Rv0678 (Val85Phe, Arg31Ser, Gly65Ala, Ala86Val, Arg109Pro, Gln131His, Val20Phe, Cys46Tyr, Ala36Val, Thr33Asn, Leu43Arg, Gln51Arg, Ser68Gly, Ala59Val, Ser53Leu, Gly65Glu, Ser63Asn, Ala84Glu, Glu66Val, Arg90Pro, Arg89Leu, Ala102Val, Leu114Pro, Ala102Thr, Leu122Pro, and Val351Ala), pepQ (Leu145Ile), Rv1979c (Val351Ala), and Rv2535 (Glu89*- a stop codon mutation) confer resistance to CFZ. 56, 91 The major mechanism for resistance to CFZ is due to mutations in the Rv0678 gene. 91 Cross-resistance between the drugs CFZ and bedaquiline has been reported and is actually due to mutations in the Rv0678 and pepQ genes as well as to an up regulation in the MmpL5 efflux pump in M. tuberculosis. 29, 92

Drug Target Genes and Mutations Conferring Resistance to Ethylenediamine

The drug 1,2-ethylenediamine (SQ-109) is derived from ethambutol pharmacophore. SQ-109 inhibits cell wall biosynthesis by blocking MmpL3 (Mycobacterial membrane proteins large 3). 93 It is effective against MTB clinical isolates that are resistant to ethambutol. 93 MmpL3 performs a vital role in cell wall biosynthesis in MTB, as it helps in transporting trehalose mono-mycolates (TMMs) across the cell envelop/inner membrane for subsequent incorporation into trehalose di-mycolates (TDMs) or arabinogalactan during cell wall biosynthesis in MTB. 82, 94 Mutations in the MmpL3 gene of resistant MTB clinical isolates cause resistance SQ-109. While an up-regulation of the ahpC gene causes resistance to SQ-109, EMB, and INH. 22 Mutations in the MmpL3 gene include Val285Ala, Leu567Pro, Val646Met, Met649Thr, Ala700Thr, Leu567Pro, and Gln40Arg. 82, 94

Conclusion

Drug-resistant TB (MDR-TB, pre-XDR-TB, XDR-TB, XXDR-TB, and TDR-TB) is one of the major public health crises, causing high mortality rates globally, and is hampering efforts in the control of TB. DR-TB has worsened due to the COVID-19 pandemic, which has reversed years of progress made in the fight against TB. DR-TB is mainly caused by spontaneous mutations in genes that code for drug converting enzymes or drug-targets. Identification of drug-target genes with their spontaneous mutations helps in designing new drugs or improving the efficacy of the available drugs as well as help in providing vital information for designing new molecular diagnostic assays for rapid detection of DR-TB. Indeed, drug-target genes with their mutations offer therapeutic and diagnostic value.

Conflict of Interest

The authors declare no conflict of interest with regards to the publication of this research review article.

Source of Funding

None.

References

1 

K Zong C Luo H Zhou Y Jiang S Li Xpert MTB/RIF assay for the diagnosis of rifampicin resistance in different regions: a meta-analysisBMC Microbiol J20191917712110.1186/s12866-019-1516-5

2 

LN Welekidan E Skjerve TA Dejene MW Gebremichael O Brynildsrud Characteristics of pulmonary multidrug- resistant tuberculosis patients in Tigray Region, Ethiopia: A cross-sectional studyPLoS ONE202015812010.1371/journal.pone.0236362

3 

D K Mumena G Kwenda C W Ngugi A K Nyerere Molecular Detection of Drug-Resistant Mycobacterium tuberculosis in Sputum Specimens from the New and Previously Treated Tuberculosis Cases at the National Reference Chest Diseases Laboratory in Lusaka, ZambiaJ Biomed Res Environ Sci2021242324310.37871/jbres1218

4 

A Allué-Guardia J I García J B Torrelles Evolution of Drug-Resistant Mycobacterium tuberculosis strains and their adaptation to the Human lung environmentFront Microbiol20211261267510.3389/fmicb.2021.612675

5 

M Al-Saeedi S Al-Hajoj Diversity and evolution of drug-resistance mechanisms in Mycobacterium tuberculosisJ Infect Drug Resist2017103334210.2147/IDR.S144446

6 

M Senghore B Diarra F Gehre J Out A Worwui A K Muhammad Evolution of Mycobacterium tuberculosis complex lineages and their role in an emerging threat of multidrug- resistant tuberculosis in Bamako, MaliNat Scientific Rep2020103271910.1038/s41598-019-56001-0

7 

S Khoshnood E Taki N Sadeghifard V H Kaviar Mechanism of Action, Resistance, Synergism, and Clinical Implications of Delamanid Against Multidrug-Resistant Mycobacterium tuberculosis Structure of DrugFront Microbiol20211271704510.3389/fmicb.2021.717045

8 

F P Polack S J Thomas N Kitchin J Absalon A Gurtman S Lockhart J L Perez P G Marc E D Moreira C Zerbin Safety and Efficacy of the BNT162b2 mRNA Covid-19 VaccineThe New England Journal of Medicine20203832726032615

9 

World Health Organization (WHO). Global Tuberculosis Report 2021. World Health Organization. Geneva, Switzerland: World Health Organization 2021120https://apps.who.int/iris

10 

NK Chisompola EM Streicher C Miriam K Muchemwa RM Warren SL Sampson Molecular epidemiology of drug-resistant Mycobacterium tuberculosis in Africa: a systematic reviewBMC Infect Dis20202034410.1186/s12879-020-05031-5

11 

SS Swain D Sharma T Hussain S Pati Molecular mechanisms of underlying genetic factors and associated mutations for drug resistance in Mycobacterium tuberculosisEmerg Microbes Infect20209116526310.1080/22221751.2020.1785334

12 

World Health Organization (WHO). Global Tuberculosis Report 2020. Geneva, Switzerland: World Health Organization 2020138https://apps.who.int/iris

13 

FLD Santos Lll Souza ATI Bruce JDA Crispim LH Arroyo ACV Ramos Patients’ perceptions regarding multidrug- resistant tuberculosis and barriers to seeking care in a priority city in Brazil during COVID-19 pandemic: A qualitative studyPLoS ONE202116411910.1371/journal.pone.0249822

14 

World Health Organization (WHO). Global Tuberculosis Report 2019. Geneva, Switzerland: World Health Organization 201917https://apps.who.int/iris

15 

World Health Organization (WHO). Global Tuberculosis Report 2018. Geneva, Switzerland: World Health Organization201814

16 

World Health Organization (WHO). Global Tuberculosis Report 2017. Geneva, Switzerland: World Health Organization2017544https://apps.who.int/iris

17 

B Seyoum M Demissie A Worku S Bekele A Aseffa Prevalence and Drug-resistance patterns of Mycobacterium tuberculosis among new smear positive pulmonary tuberculosis patients in Eastern EthiopiaJ Tuberc Res Treat201475349210.1155/2014/753492

18 

M Seifert D Catanzaro A Catanzaro T C Rodwell Genetic mutations associated with isoniazid resistance in Mycobacterium tuberculosis: a systematic reviewPLoS One2015103e011962810.1371/journal.pone.0119628

19 

D Okethwangu D Birungi C Biribawa B Kwesiga S Turyahabwe A R Ario Multidrug-resistant tuberculosis outbreak associated with poor treatment adherence and delayed treatmentBMC Infect Dis J201919111010.1186/s12879-019-4014-3

20 

A Iacobino L Fattorini F Giannoni Drug-Resistant Tuberculosis 2020: Where We StandAppl Sci2020106 215310.3390/app10062153

21 

B N Simbwa A Katamba E B Katana Eao Laker S Nabatanzi E Sendaula The burden of drug resistant tuberculosis in a predominantly nomadic population in Uganda: a mixed methods studyBMC Infect Dis20212195010.1186/s12879-021-06675-7

22 

HMA Hameed M Islam C Chhotaray WW Yew J Liu T Zhang Molecular Targets Related Drug Resistance Mechanisms in MDR- , XDR- , and TDR- Mycobacterium tuberculosis StrainsFront Cell Infect Microbiol2018811410.3389/fcimb.2018.00114

23 

TNA Nguyen BV Anton-Le A L Bañuls TVA Nguyen Molecular Diagnosis of Drug-Resistant Tuberculosis; A Literature ReviewFront Microbiol20191079410.3389/fmicb.2019.00794

24 

R Charoenpak W Santimaleeworagun G Suwanpimolkul W Manosuthi P Kongsanan S Petsong Association Between the Phenotype and Genotype of Isoniazid Resistance Among Mycobacterium tuberculosis Isolates in ThailandJ Infect Drug Resist2020136273410.2147/IDR.S242261

25 

P Farnia MR Masjedi MA Merza P Tabarsi GKS Zhavnerko TA Ibrahim Growth and cell-division in extensive (XDR) and extremely drug resistant (XXDR) tuberculosis strains: transmission and atomic force observationInt J Clin Exp Med20103430814

26 

A A Velayati P Farnia M R Masjedi Totally drug-resistant tuberculosis (TDR-TB): A debate on global health communitiesInt J Mycobacteriol20132271210.1016/j.ijmyco.2013.04.005

27 

S K Parida R Axelsson-Robertson M V Rao N Singh I Master A Lutckii Totally drug-resistant tuberculosis and adjunct therapiesJ Intern Med2015277438840510.1111/joim.12264

28 

D Damtie D Woldeyohannes B Mathewos Review on Molecular mechanism of first-line antibiotic resistance in Mycobacterium tuberculosisMycobact Dis2014461410.4172/2161-1068.1000174

29 

N Dookie S Rambaran N Padayatchi S Mahomed K Naidoo Evolution of drug resistance in Mycobacterium tuberculosis: A review on the molecular determinants of resistance and implications for personalized careJ Antimicrob Chemother201873511385110.1093/jac/dkx506

30 

CY Chen JY Weng HH Huang WC Yen YH Tsai TC Cheng A new oligonucleotide array for the detection of multidrug and extensively drug-resistance tuberculosisSci Rep201991442510.1038/s41598-019-39339-3

31 

J Briffotaux S Liu B Gicquel Genome-wide transcriptional responses of Mycobacterium to AntibioticsFront Microbiol20191024910.3389/fmicb.2019.00249

32 

PDAS Eduardo JC Palomino Molecular basis and mechanisms of drug-resistance in Mycobacterium tuberculosis: Classical and new drugsJ Antimicrob Chemother201166714173010.1093/jac/dkr173

33 

K Gokulan K I Varughese Drug-resistance in Mycobacterium tuberculosis and targeting the L, D-transpeptidase enzymeJ Drug Dev Res201880111810.1002/ddr.21455

34 

MJ Nasiri M Haeili M Ghazi H Goudarzi A Pormohammad AAI Fooladi New Insights in to the Intrinsic and Acquired Drug Resistance Mechanisms in MycobacteriaFront Microbiol2017868110.3389/fmicb.2017.00681

35 

S M Gygli S Borrell A Trauner S Gagneux Antimicrobial resistance in Mycobacterium tuberculosis: Mechanistic and evolutionary perspectivesFEMS Microbiol Rev20174133547310.1093/femsre/fux011

36 

H Ghajavand M K Kamakoli S Khanipour SP Dizaji M Masoumi FR Jamnani Scrutinizing the drug-resistance mechanism of multi- and extensively-drug resistant Mycobacterium tuberculosis: Mutations versus efflux pumpsAntimicrob Resist Infect Control201987010.1186/s13756-019-0516-4

37 

JC Palomino A Martin Drug-resistance mechanisms in Mycobacterium tuberculosisAntibiotics (Basel)2014333174010.3390/antibiotics3030317

38 

L Y Hsu L Y Lai P F Hsieh T L Lin W H Lin H Y Tasi Two Novel katG Mutations Conferring Isoniazid Resistance in Mycobacterium tuberculosisFront Microbiol164411164410.3389/fmicb.2020.01644

39 

J Havumaki D Hillemann N Ismail SV Omar SB Georghiou SG Schumacher Comparative accuracy of the REBA MTB MDR and Hain MTBDRplus line probe assays for the detection of multidrug-resistant tuberculosis: A multi-centre, non-inferiority studyPLoS ONE 201712311210.1371/journal. pone.0173804

40 

P U Katia C T Fabiola S R Beatriz Bdl Mario Drug-resistance in Mycobacterium tuberculosisIntech Open Assess J2018131182910.5772/intech open.69656

41 

P Torres-Gonzalez Cervera-Hernandez Me A Martinez-Gamboa L Garcia-Garcia Cruz-Hervert Lp M B Valle Human tuberculosis caused by Mycobacterium bovis: a retrospective comparison with Mycobacterium tuberculosis in a Mexican tertiary care centreBMC Infect Dis20001665710.1186/s12879-016-2001-5

42 

E I Namburete I Tivane M Lisboa M Passeri R Pocente J J Ferro Drug-resistant tuberculosis in Central Mozambique: the role of a rapid genotypic susceptibility testingBMC Infect Dis20161642310.1186/s12879-016-1766-x

43 

A L Manson K A Cohen T Abeel C A Desjardins D T Armstrong J Brand Genomic analysis of globally diverse Mycobacterium tuberculosis strains provides insight into emergence and spread of multidrug-resistanceNat Genet201749339540210.1038/ng.3767

44 

GE Louw RM Warren NCG van Pittius R Leon A Jimenez R Hernandez-Pando Rifampicin reduces susceptibility to ofloxacin in rifampicin-resistant Mycobacterium tuberculosis through effluxAm J Respir Crit Care Med201118422697610.1164/rccm.201011-1924OC

45 

M Muthaiah S S Shivekar Kvr Cuppusamy C Alagappan A Sakkaravarthy U Brammachary Prevalence of mutations in genes associated with rifampicin and isoniazid resistance in Mycobacterium tuberculosis clinical isolatesJ Clin Tuberc Other Mycobact Dis20178192510.1016/j.jctube.2017.06.001

46 

NM Almutairi S Ahmad E Mokaddas HS Eldeen S Joseph Occurrence of disputed rpoB mutations among Mycobacterium tuberculosis isolates phenotypically susceptible to rifampicin in a country with a low incidence of multidrug-resistant tuberculosisBMC Infect Dis J2019191310.1186/s12879-018-3638-z

47 

R Singh S P Dwivedi U S Gaharwar R Meena P Rajamani T Prasad Recent updates on drug- resistance in Mycobacterium tuberculosisJ Appl Microbiol2019128615476710.1111/jam.14478

48 

M T Zaw N A Emran Z Lin Mutations inside rifampicin-resistance determining region of rpoB gene associated with rifampicin-resistance in Mycobacterium tuberculosisJ Infect Public Health20181156051010.1016/j.jiph.2018.04.005

49 

R Ramazanzadeh B Mohammadi Mutations in embB gene associated with resistance to ethambutol in Mycobacterium tuberculosis strains isolated from TB patients in the west of IranInt J Mycobacteriol201651S14010.1016/j.ijmyco.2016.11.013

50 

Y Xu H Jia H Huang Z Sun Z Zhang Mutations Found in embCAB, embR, and ubiA Genes of Ethambutol-Sensitive and -Resistant Mycobacterium tuberculosis Clinical Isolates from ChinaJ Biomed Res Int2015

51 

A D Khosravi M Sirous M Abdi N Ahmadkhosravi Characterization of the most common embCAB gene mutations associated with ethambutol resistance in Mycobacterium tuberculosis isolates from IranJ Infect Drug Resist2019125798410.2147/IDR.S196800

52 

O Tulyaprawat A Chaiprasert P Chongtrakool K Suwannakarn P Ngam-Skulrungroj Association of ubiA mutations and high-level of ethambutol resistance among Mycobacterium tuberculosis Thai clinical isolatesJ Tuberc2019114942610.1016/j.tube.2018.11.006

53 

S Lingaraju L Rigouts A Gupta J Lee A N Umubyeyi A L Davidow Geographic differences in the contribution of ubiA mutations to high-level Ethambutol resistance in Mycobacterium tuberculosisJ Antimicrob Agents Chemother20166074101510.1128 /AAC.03002-15

54 

A S Nangraj A Khan S Umbreen S Sahar Insights into Mutations Induced Conformational Changes and Rearrangement of Fe2+ Ion in pncA Gene of Mycobacterium tuberculosis to Decipher the Mechanism of Resistance to PyrazinamideFront Mol Biosci2021863336510.3389/fmolb.2021.633365

55 

YEA Oppong J Phelan J Perdigão D Machado A Miranda M Viveiros Genome-wide analysis of Mycobacterium tuberculosis polymorphisms reveals lineage-specific associations with drug resistanceBMC Genomics20192025210.1186/s12864-019-5615-3

56 

Y Liu J Gao J Du W Shu L Wang Y Wang Acquisition of clofazimine resistance following bedaquiline treatment for multidrug-resistant tuberculosisInt J Infect Dis2020102392610.1016/j.ijid.2020.10.081

57 

P Bwalya T Yamaguchi ES Solo JY Chizimu G Mbulo C Nakajima Characterization of Mutations associated with Streptomycin Resistance in Multidrug-Resistant Mycobacterium tuberculosis in ZambiaAntibiotics (Basel)1169101011690.3390/antibiotics10101169

58 

S Zhang J Chen P Cui W Shi W Zhang Y Zhang Identification of novel mutations associated with clofazimine resistance in Mycobacterium tuberculosisJ Antimicrob Chemother201570925071010.1093/jac/dkv150

59 

K Jabeen S Shakoor R Hasan Fluoroquinolone-resistant tuberculosis: Implications in settings with weak healthcare systemsInt J Infect Dis2015321182310.1016/j.ijid.2015.01.006

60 

S Tiberi A Scardigli R Centis L D'Ambrosio M Muñoz-Torrico MÁ Salazar-Lezama Classifying new anti-tuberculosis drugs: rationale and future perspectivesInt J Infect Dis201756181410.1016/j.ijid.2016.10.026

61 

H G Mamatha V Shanthi Baseline resistance and cross-resistance among fluoroquinolones in multidrug-resistant Mycobacterium tuberculosis isolates at a National reference laboratory in IndiaJ Glob Antimicrob Resist20181251010.1016/j.jgar.2017.08.014

62 

S Malik M Willby D Sikes OV Tsodikov JE Posey New insights into fluoroquinolone-resistance in Mycobacterium tuberculosis: Functional genetic analysis of gyrA and gyrB mutationsPLoS One201276e3975410.1371/journal.pone.0039754

63 

MJ Catalão SR Filipe M Pimentel Revisiting anti-tuberculosis therapeutic Strategies that target the peptidoglycan structure and synthesisFront Microbiol20191019010.3389/fmicb.2019.00190

64 

CA Desjardins KA Cohen V Munsamy T Abeel K Maharaj BJ Walker Genomic and functional analyses of Mycobacterium tuberculosis strains implicate ald in D-cycloserine resistanceNat Genet20164855445110.1038/ng.3548

65 

Y Nakatani Hko Reading M Merker D Machado S Andres S S Kumar Role of Alanine Racemase Mutations in Mycobacterium tuberculosis d-Cycloserine ResistanceAntimicrob Agents Chemother20176112e01575-1710.1128/AAC.01575-17

66 

J Rueda T Realpe I Mejia E Zapata C Rozo E Ferro Genotypic analysis of genes associated with independent resistance and cross-resistance to isoniazid and ethionamide in Mycobacterium tuberculosis clinical isolatesAntimicrob Agents Chemother2015591278051010.1128/AAC.01028-15

67 

D Machado J Perdigao J Ramos I Couto I Portugal C Ritter High-level resistance to isoniazid and ethionamide in multidrug-resistant Mycobacterium tuberculosis of the Lisboa family is associated with inhA double mutationsJ Antimicrob Chemother201368817283210.1093/jac/dkt090

68 

G Mugumbate B Nyathi A Zindoga G Munyuki Application of Computational Methods in Understanding Mutations in Mycobacterium tuberculosis Drug ResistanceFront Mol Biosci2021864384910.3389/fmolb.2021.643849

69 

MM Islam Y Tan HMA Hameed Z Liu C Chhotaray Y Liu Detection of novel mutations associated with independent resistance and cross-resistance to isoniazid and prothionamide in Mycobacterium tuberculosis clinical isolatesClin Microbiol Infect20182581041.e1e710.1016/j.cmi.2018.12.008

70 

C Vilcheze WR Jacobs Resistance to Isoniazid and Ethionamide in Mycobacterium tuberculosis: Genes, Mutations, and CausalitiesMicrobiol Spectr201924MGM2-0014-201310.1128/microbiolspec.MGM2-0014-2013

71 

Y Tan B Su H Zheng Y Song Y Wang Y Pang Molecular Characterization of Mycobacterium tuberculosis Isolates in Southern ChinaFront Microbiol20178235810.3389/fmicb.2017.02358

72 

X Chen G He S Wang S Lin J Chen W Zhang Evaluation of whole-genome sequence method to diagnose resistance of 13 anti-tuberculosis drugs and Characterize resistance genes in clinical multi-drug resistance Mycobacterium tuberculosis isolates from ChinaFront Microbiol174110174110.3389/fmicb.2019.01741

73 

M Luo K Li H Zhang X Yan J Gu Z Zhang Molecular characterization of para-aminosalicylic acid resistant Mycobacterium tuberculosis clinical isolates in South-Western ChinaJ Infect Drug Resist20191222697510.2147/IDR.S207259

74 

W Wei H Yan J Zhao H Li Z Li H Guo Multi-omics comparisons of p-aminosalicylic acid (PAS) resistance in folC mutated and un-mutated Mycobacterium tuberculosis strainsEmerg Microbes Infect2019812486110.1080/22221751.2019.1568179

75 

G Li J Zhang Y Jiang L Zhao H Liu M Li Cross-resistance of isoniazid, para-aminosalicylic acid and pasiniazid against isoniazid-resistant Mycobacterium tuberculosis isolates in ChinaJ Glob Antimicrob Resist2019202758110.1016/j.jgar.2019.08.005

76 

B Pandey S Grover J Kaur A Grover Analysis of mutations leading to para-aminosalicylic acid resistance in Mycobacterium tuberculosisSci Rep2019913617 10.1038/s41598-019-48940-5

77 

L Peyclit S A Baron J M Rolain Drug repurposing to fight colistin and carbapenem-resistant bacteriaFront Cell Infect Microbiol2019919310.3389/fcimb.2019.00193

78 

M Karmakar CHM Rodrigues KE Holt SJ Dunstan J Denholm DB Ascher Empirical ways to identify novel Bedaquiline-resistance mutations in the AtpE genePLoS ONE 2019145e021716910.1371/journal.pone.0217169

79 

S Wu H Chan H Hsiao R Jou L B Adams Primary Bedaquiline Resistance Among Cases of Drug-Resistant Tuberculosis in TaiwanFront Microbiol20211275424910.3389/fmicb.2021.754249

80 

ID Olaru GBF Von J Heyckendorf WW Yew C Lange KC Chang Novel drugs against tuberculosis: A clinician’s perspectiveEur Respir J201445411193110.1183/09031936.00162314

81 

S Kadura N King M Nakhoul H Zhu G Theron CU Köser Systematic review of mutations associated with resistance to the new and repurposed Mycobacterium tuberculosis drugs bedaquiline, clofazimine, linezolid, delamanid and pretomanidJ Antimicrob Chemother202075820314310.1093/jac/dkaa136

82 

K T Angula L J Legoabe R M Beteck Chemical Classes Presenting Novel Antituberculosis Agents Currently in Different Phases of Drug Development: A 2010 - 2020 ReviewPharmaceuticals (Basel)202114546110.3390/ph14050461

83 

Y Shimokawa K Sasahara N Yoda K Mizuno K Umehara Delamanid does not inhibit or induce cytochrome P450 enzymes in VitroBiol Pharm Bull2014371117273510.1248/bpb.b14-00311

84 

PJG González J Perdigao P Gomes Z M Puyen D S Lazaro G Napier Genetic diversity of candidate loci linked to Mycobacterium tuberculosis resistance to bedaquiline, delamanid and pretomanidSci Rep20211111943110.1038/s41598-021-98862-4

85 

M L Reichmuth R Hömke K Zürcher P Sander A Avihingsanon J Collantes Natural Polymorphisms in Mycobacterium tuberculosis Conferring Resistance to Delamanid in Drug-Naive PatientsAntimicrob Agents Chemother20206411e00513-2010.1128/AAC.00513-20

86 

D Sharma Y K Dhuriya N Deo D Bisht Repurposing and revival of the drugs: A new approach to combat the drug-resistant tuberculosisFront Microbiol 2017845210.3389/fmicb.2017.02452

87 

S Wasserman G Louw L Ramangoaela G Barber C Hayes SV Omar Linezolid resistance in patients with drug-resistant TB and treatment failure in South AfricaJ Antimicrob Chemother201974823778410.1093/jac/dkz206

88 

S Zhang J Chen P Cui W Shi X Shi H Niu Mycobacterium tuberculosis Mutations Associated with Reduced Susceptibility to LinezolidAntimicrob Agents Chemother20166042542410.1128/AAC.02941-15

89 

R Bharadwaj Linezolid-resistant Mycobacterium tuberculosis: Will it impact the tuberculosis elimination programme?Indian J Med Respir2021154116810.4103/ijmr.IJMR_3537_20

90 

H Duan X Chen Z Li Y Pang W Jing P Liu Clofazimine improves clinical outcomes in multidrug-resistant tuberculosis: a randomized controlled trialJ Clin Microbiol Infect20192521283010.1016/j.cmi.2018.07.012

91 

S Zhang J Chen P Cui W Shi W Zhang Y Zhang Identification of novel mutations associated with clofazimine resistance in Mycobacterium tuberculosisJ Antimicrob Chemother201570925071010.1093/jac/dkv150

92 

RC Hartkoorn S Uplekar ST Cole Cross-resistance between clofazimine and bedaquiline through upregulation of MmpL5 in Mycobacterium tuberculosisAntimicrob Agents Chemother201458529798110.1128/AAC.00037-14

93 

S Chetty M Ramesh A S Pillay MES Soliman Recent advancements in the development of anti-tuberculosis drugsBioorg Med Chem Lett20172733708610.1016/j.bmcl.2016.11.084

94 

M B Mcneil T O'Malley D Dennison CD Shelton B Sunde T Parish Multiple Mutations in Mycobacterium tuberculosis MmpL3 Increase Resistance to MmpL3 InhibitorsmSphere202055e00985-2010.1128/mSphere.00985-20



jats-html.xsl


This is an Open Access (OA) journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms.

  • Article highlights
  • Article tables
  • Article images

Article History

Received : 15-06-2022

Accepted : 18-07-2022


View Article

PDF File   Full Text Article


Copyright permission

Get article permission for commercial use

Downlaod

PDF File   XML File   ePub File


Digital Object Identifier (DOI)

Article DOI

https://doi.org/10.18231/j.ijmmtd.2022.040


Article Metrics






Article Access statistics

Viewed: 736

PDF Downloaded: 193



Medical Abbreviation List