Table 2.

Classification of anti-tuberculosis (anti-TB) drugs according to the site of action and its respective mechanism of resistance.

Drug classification	Groups	Anti-TB drugs	Mechanism of action	Target TB	Efficacy	Mechanism of resistance	References
Cell envelope synthesis inhibitor	Peptidoglycan	Cycloserine	Inhibit 2 enzymes forming D-alanine residues	MDR, XDR	High	Mutations in alrA	Patel et al., 2012
		Terizidone	Cycloserine derivative	MDR, XDR	High	Non	Galietti et al., 1991
	Arabinogalactan	Ethambutol	Inhibiting arabinosyltransferase, arabinose acceptor	Active	Low	embCAB operon	Telenti et al., 1997; Wolucka, 2008
	Mycolic acid	Isoniazid	Activation katG enzyme and inhibits inhA gene	Active, latent	High	Mutations in katG and inhA genes	Vilche‘ze and Jacobs, 2007; Riccardi et al., 2009
		Triclosan	Inhibits the inhA enzyme without activation katG	MDR	Low	–	Wang et al., 2004; Freundlich et al., 2009
		Pyridomycin	Inhibits the inhA enzyme	MDR, XDR	High	Mutations in inha	Hartkoorn et al., 2012
		Ethionamide	Inhibits InhA by enzyme ethA	MDR, XDR	High	Mutations in inha, etha	Wolff and Nguyen, 2012
		Prothionamide	Inhibits InhA by enzyme ethA	MDR, XDR	High	Mutations in etha	Wang et al., 2007
		Thiocarlide	Inhibiting synthesis of oleic acid	MDR, XDR	High	Mutations in ethA	Phetsuksiri et al., 2003
		Delamanid	Releasing Nitric oxide by Ddn enzyme	Active, latent, MDR, XDR	High	Non	Gler et al., 2012; Zhang et al., 2013
		SQ109	Membrane transporter MmpL3	Active, latent	High	Non	Owens et al., 2013
Protein synthesis inhibitor	Aminoglycosides	Streptomycin	Bind to 30S subunit of ribosome	MDR, XDR	High	Mutation in rpsl	Honort and Cole, 1994
		Amikacin	Bind to 30S subunit of ribosome	MDR, XDR	High	Mutation in rrs	Sowajassatakul et al., 2014
		Kanamycin	Bind to 30S subunit of ribosome	MDR, XDR	High	Mutation in rrs	Sowajassatakul et al., 2014
	Oxazolidone	Linezolid	Bind to 50S subunit of ribosome	MDR, XDR	High	Mutation in G2576T(23S)	Scheetz et al., 2008
		Sutezolid	Bind to 50S subunit of ribosome	MDR, XDR	High	Non	Zumla et al., 2015
	Peptidoglycan	Capreomycin	Peptidoglycan Breakdown	MDR, XDR	High	Mutation in tlyA	Chen et al., 2003
Nucleic acid inhibitor	Rifamycins	Rifampicin	RNA polymerase inhibitor	Active, latent	Low	Mutations in rpoB gene	Sensi, 1983; Telenti et al., 1993
		Rifapentine	RNA polymerase inhibitor (b-subunit)	Active, latent/HIV	High	Mutations in rpoB gene	Chan et al., 2014
		Rifabutin	RNA polymerase inhibitor (b-subunit)	Active, latent/HIV	High	Mutations in rpoB gene	Yan et al., 2015
		Rifalazil	RNA polymerase inhibitor (b-subunit)	Active, latent/HIV	High	Mutations in rpoB gene	Saribaş et al., 2003
	PAS	PAS	Folic acid synth inhibitor	MDR, XDR	High	Mutations in thyA	Patel et al., 2012
	Quinolones	Levofloxacin	DNA gyrase inhibitor	MDR, XDR	High	Mutations in gyrA	Pranger et al., 2011
		Moxifloxacin	DNA gyrase inhibitor	MDR, XDR	High	Mutations in gyrA	Pranger et al., 2011
New drugs		Bedaquiline	Inhibiting ATP synthase enzyme	Active, MDR, dorment,XDR	High	Mutations in atpE gene	Chan et al., 2013; Chahine et al., 2014
		Pyrazinamide	Interferes with binding to mRNA	Active,MDR	High	Mutations in RpsA, pncA	Zhang et al., 2003; Shi et al., 2011
		Clofazimine	Inhibits DNA replication	MDR, XDR/HIV	High	Mutations in rv0678	Arbiser and Moschella, 1995

PAS:para-aminosalicylic acid.