THIORIDAZINE CURES MDR/XDR TB INFECTIONS .

THIORIDAZINE CURES MDR/XDR TB INFECTIONS.

Targetting the human macrophage for enhanced killing of intracellular mdr/xdr mtb: a new concept for therapy of MDR/XDR TB.

Leonard Amaral (Portugal)

Eduardo Abbate (Argentina) Martin J Boeree (Netherlands) Noton Dutta (USA) Paulo Ferrinho (Portugal)Stephen H Gillespie (UK) Eduardo Gotuzzo (Peru) Jette E Kristiansen (Denmark) Marta S Martins (Ireland) Chuck Sohaskey (USA) Rubin Thanacoody (UK) Zarir F Udwadia (India) Jakko van Ingen (Netherlands) Dick van Soolingen (Netherlands) Miguel Viveiros (Portugal)

ISN

• Causative agent of Tuberculosis (TB)

Emergence of Multi-Drug Resistant strains (MDR-TB)

Resistance to at least isoniazid (INH) + rifampicin

(RIF)

Emergence of Extensively-Drug Resistance strains

(XDR-TB)

WHO; Weekly Epidemiol Record; 2008

Mycobacterium tuberculosis

Progression of Resistance

TOTALLY DRUG RESISTANT Mtb

Remains to be defined

Multi-Drug Resistant M. tuberculosis

Macrophage model

In vitro, ex vivo and in vivo studies

Purpose of the studies

New approaches - Phenothiazines

Role of efflux pumps

L Amaral, June 2012

PULMONARY TUBERCULOSIS IS CAUSED BY THE STEADFAST HUMAN PATHOGEN MYCOBATERIUM tuberculosis.IT IS AN INTRACELLULAR INFECTION OF THE PULMONARYMACROPHAGE (ALVEOLAR II CELL)

L Amaral, June 2012

WHEREAS AN INFECTION BYMtb IS INTRACELLULAR, ACTIVE TUBERCULOSIS IS WHEN THE BACTERIUM BREAKS OUT OF ITSMACROPHAGE PRISON AND IS EXPELLED TO THE OUTSIDE INMICRODROPLETS OF SPUTUM.

ACTIVE TB IS INFECTIOUS!

L Amaral, June 2012

ANTIBIOTIC SUSCEPTIBLE Mtb SUSCEPTIBLE TO ISONIAZID (INH) AND RIFAMPIN (RF).

MULTIDRUG RESISTANT Mtb (MDR-TB) RESISTANT TO INH AND RF.

EXTENSIVELY DRUG RESISTANT Mtb(XDR TB) RESISTANT TO INH, RF, STREPTOMYCIN, ANY FLUOROQUINOLONE, AND TO INJECTAB LE ANTI-TB DRUGS (AMIKACIN, KANAMYCIN AND CAPREOMYCIN).

DEFINITION OF ANTIBIOTIC RESISTANCE

TDR-TB

5 CASES OF TDR-TB IN ONE MUMBAI HOSPITAL 2012. IS THERE A PROBLEM?

Udwadia ZF. Totally drug resistant tuberculosis in India: who let the djinn out? Respirology. 2012. [Epub ahead of print] PubMed PMID: 22564108.

L Amaral, June 2012

W.H.O 2009 SHORT GLOBAL REPORT

L Amaral, June 2012

PROBLEM: WHAT IS MEANT BY NEW CASES OF TUBERCULOSIS?

ANSWER: NEW CASES OF ACTIVE TB

L Amaral, June 2012

GLOBAL TUBERCULOSIS: FACTS 2007 (W.H.O. 2009 Report).

2 TO 3 BILLION INFECTED WITH Mtb.

10.5 MILLION NEW CASES.

OVER 2 MILLION DEATHS.

511,000 NEW CASES OF MDR TB.

XDR TB ?????

TDR-TB ?????

L Amaral, June 2012

MORTALITY PRODUCED BY:

MDR-TB 20 TO 80 % within 2 years.

MDR-TB co-infected with HIV/presenting w/AIDS 80 to 100 % within 1 year depending on area where therapy is given.

XDR-TB > 80% within 6 months or sooner if co-infected with HIV/presenting with AIDS.

TDR-TB ?????

L Amaral, June 2012

THERE ARE NO SAFE AND EFFECTIVE DRUGS AGAINST MDR/XDR/TDR-TB, EXCEPT FOR ----------.

L Amaral, June 2012

ESSENTIAL CHARACTERISTICS FOR A PERFECT ANTI-MDR/XDR/TDR-TB DRUG!

1. HAVE ACTIVITY AGAINST ALL FORMS OF ANTIBIOTIC RESISTANT STRAINS.

2. HAVE ACTIVITY WHERE THE MDR/XDR TB STRAIN RESIDES: THE HUMAN PULMONARY MACROPHAGE!

3. HAVE NO TOXICITY.4. NO RESISTANCE TO THE DRUG CAN BE MADE

BY MUTATION OF MDR/XDR/TDR Mtb.

L Amaral, June 2012

HISTORY OF PHENOTHIAZINES

1890 MB inhibits mobiliby of bacteria; kills malaria and syphilis causing organisms (Guttmann & Ehrlich).1890’s Makes cats and humans lethargic (Bodini).1957 Methylene blue (MB) dye. Chlorpromazine (CPZ)

derived from MB by Rhone-Polenc: first neuroleptic.1975 CPZ In Vitro activity against Mtb (Molnar). 1966 Thioridazine (TZ) derived from CPZ. 1996 In vitro activity of TZ against all forms of antibiotic resistant strains of Mtb (Amaral et al).

1891 1953 1964

TZ DERIVATIVES

2004-2008

Guttman& Erhlich

Charpentier

Schnetzler & Carrel

Amaral et al; others

• Serious side-effects (toxicity)• Gradually replaced by TZ

(TZ)

(CPZ)

• Mellaril®

• less toxic than CPZ• Drowsiness (most common)

• Wide gamut of in vitro antimicrobial activity.

Develop new anti-TB drugs effective against intracellular MDR/XDR-TB.Phenothiazines

L Amaral, June 2012

PHENOTHIAZINES

Chlorpromazine (CPZ)

Thioridazine (TZ)

The antimycobacterial activity of thioridazine derivatives against drug resistant Mycobacterium tuberculosis:

in vitro, ex vivo and in vivo studies

Unidade de Micobactérias and UPMMInstituto de Higiene e Medicina Tropical

Universidade Nova de LisboaLisbon, 4th November 2008

TZ

K+

H+

Ca2+

H+K+

ATP

K+

ATP

Ca2+ Ca2+

ATP

Na+

K+

Ca2+ Ca2+

ATP

H+ K+

ATP

Ca2+

Ca2+Ca2+

Ca2+

Ca2+

Ca2+

Na+AA

BB

K+

K+

ATP

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

K+

Ca2+

H+ATP

H+

K+

K+

ATP

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

K+

Ca2+

K+

K+

ATP

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

K+

Ca2+

K+

K+

ATP

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

K+

Ca2+

H+ATP

H+ H+ATP

H+

EE

GG

H+

H+

H+H+

H+K+

ATP

Ca2+

Ca2+

H+K+

Ca2+

H+H+

H+

H+H+

H+

H+H+

H+

H+H+

H+K+

ATP

Ca2+

Ca2+

H+K+

Ca2+

H+H+

H+K+

ATP

Ca2+

Ca2+

H+K+

Ca2+

H+H+

K+

ATP

Ca2+

Ca2+

H+K+

Ca2+

H+

K+

H+H+

Ca2+

K+

Ca2+

Ca2+

Ca2+ Ca2+

ATPATP

K+

Ca2+

K+

H+H+

Ca2+

K+

Ca2+

Ca2+

Ca2+ Ca2+

ATPATP

K+

Ca2+

K+

H+H+

Ca2+

K+

Ca2+

Ca2+

Ca2+ Ca2+

ATPATP

K+

Ca2+

H+H+

Ca2+

K+

Ca2+

Ca2+

Ca2+ Ca2+

ATPATP

K+

Ca2+

H+

Ca2+

K+

Ca2+

Ca2+

Ca2+ Ca2+

ATPATP

K+

Ca2+

Ca2+

K+

Ca2+

Ca2+

Ca2+ Ca2+

ATPATP

K+

Ca2+

Ca2+

K+H+

Ca2+

ATP

Ca2+

K+H+

Ca2+

ATP

Ca2+

K+H+

Ca2+

ATP

Ca2+

K+H+

Ca2+

ATP

K+

H+ATP

CC

DD

H+

ATP

K+ H+

Ca2+

H+

Ca2+

Ca2+

Ca2+

K+H+

ATP

K+ H+

Ca2+

H+

Ca2+

Ca2+

Ca2+

H+

ATP

K+ H+

Ca2+

H+

Ca2+

Ca2+

Ca2+

H+

ATP

K+ H+

Ca2+

H+

Ca2+

Ca2+

Ca2+

H+

ATP

K+ H+

Ca2+

H+

Ca2+

Ca2+

Ca2+

H+

ATP

K+ H+

Ca2+

H+

Ca2+

Ca2+

Ca2+

H+

ATP

K+ H+

Ca2+

H+

Ca2+

Ca2+

Ca2+

H+

ATP

K+ H+

Ca2+

H+

Ca2+

Ca2+

Ca2+

H+

ATP

K+ H+

Ca2+

H+

Ca2+

H+

ATP

K+ H+

Ca2+

H+

ATP

K+ H+H+H+H+H+

ATP

K+ H+

ATP

K+ H+K+ H+

Ca2+

H+

Ca2+

H+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

K+K+

FATP

K+H+

Ca2+

Ca2+

FATP

K+H+

Ca2+

Ca2+

ATP

K+H+

Ca2+

Ca2+

K+H+

Ca2+

Ca2+

Ca2+Ca2+Ca2+

Ca2+Ca2+

L Amaral, June 2012Amaral L et al..Journal of Antimicrobial Chemotherapy (1996) 38, 1049-1053

L Amaral, June 2012

HOWEVER, IN VITRO CONCENTRATIONS ARE CLINICALLY IRRELEVANT SINCE THEMAXIMUM CONCENTRATION OF THESE COMPOUNDS THAT CAN BE ACHIEVED IN THE PATIENT IS 0.5 mg/L OF PLASMA!

M. tuberculosis / MDR-TBMIC and MBC – BACTEC 460TM

Minimum Inhibitory Concentration (MIC)

Minimum Bactericidal Concentration (MBC)

Studies

In vitro

Screening of TZ derivatives (22)

Toxicity in lymphocytes(Trypan blue exclusion method)

Infection studies in macrophages(phagocytosis assay)

Toxicity assays (Balb/C) – TZ and derivatives

Non-toxic and non-mutagenic

derivatives

Mutagenicity Assay

(Ames test)

Infection studies – TZ and derivatives

Ex vivo

In vivo

S. aureus / MRSA (model)MIC and MBC – microdilution method

Experimental outline

• Synthesis: Prof. György

Hajós (Chemistry Institute

of Budapest, Hungary);

Chemical manipulation of

the parent compound (TZ)

Amaral L, Martins M and Viveiros M. (2007). Infect. Disord. Drug Targets 7(3):257.

TZ+

TZ derivatives

L Amaral, June 2012

In Vitro Growth inhibition of Mycobacterium tuberculosis by Thioridazine derivatives.

Compounds MIC 50 (mg/L).

Thioridazine 10Isoniazid 0.08#1550 >20#1686 20#1687 20#1532 20#1688 20#1689 20#1819 >20#1820 >20#1821 >20#1867 5#1868 20#1869 >20#1870 10#1871 >20#1872 20#1873 >20#1874 >20#1875 5#1929 >20

L Amaral, June 2012

ENHANCED KILLING OF MYCOBACTERIUM tuberculosisby 0.1 mg/L of DERIVATIVES OF THIORIDAZINE.

Martins M, Schelz Z, Martins A, Molnar J, Hajös G, Riedl Z, Viveiros M, Yalcin I, Aki-Sener E, Amaral L.. In vitro and ex vivo activity of thioridazine derivatives against Mycobacterium tuberculosis. Int J Antimicrob Agents. 2007;;29:338-40.

L Amaral, June 2012

INTRACELLULAR ACTIVTY OF NON-PHENOTHIAZINES

L Amaral, June 2012

ENHANCED KILLING ACTIVITY OF XDR-TB BY SILA 421

Martins M, Viveiros M, Ramos J, Couto I, Molnar J, Boeree M, Amaral L. SILA 421, an inhibitor of efflux pumps of cancer cells, enhances the killing of intracellular extensively drug-resistant tuberculosis (XDR-TB). Int J Antimicrob Agents. 2009;33:479-82

L Amaral, June 2012

IN VIVO STUDIES

E F

25 50 100 200 400 1200

mg TZ/kg/day

• daily inoculations• daily weighing

√ In all the concentrations tested no toxicity was obtained

√ Concentrations selected for treatment: 100, 400 and 1200 mg TZ/Kg/day

• Animal model: Balb/C females (25 gms)

Toxicity assays - TZ

100Control 400 1200

mg TZ/kg/day

Day 0I.P. injection

Day 30Treatment (TZ)

Infection with TB (1×106 CFU/mL)

Except the Control group

• Organs removal (lungs, liver and spleen) – plating – CFU

NO TZ

Infection studies with M. tuberculosis

1,00E-02

1,00E+00

1,00E+02

1,00E+04

1,00E+06

1,00E+08

1,00E+10

0 30 60 90 120 150 180 210 240 270 300

Time (days)

CFU

/mg

Control

1200mg TZ

Spleen

1,00E-02

1,00E+00

1,00E+02

1,00E+04

1,00E+06

1,00E+08

1,00E+10

0 30 60 90 120 150 180 210 240 270 300

Time (days)

CFU

/mg

Control

1200mg TZ

Liver

Amaral L, Martins M, Viveiros M. (2007). J. Antimicrob. Chemother. 59:1237.

Mice treated with TZ (equivalent in the human to

1200 mg/Kg/day)

• colony forming units (CFU) reduction – lungs

Results - In vivo studies

Lungs

CONFIRMATION OF MOUSE WORK

van Soolingen D, Pando RH, Orozco H, Aguilar D, Magis C, van Ingen J, Amaral L, Boeree M.

Thioridazine shows promising activity in a murine model of multi-drug resistant

tuberculosis. PloS One 2010;5. pii: e12640.

Thioridazine in combination with INH, Rifampin and PZA.

L Amaral June 2012

Effect of combined treatment with standard anti-tuberculosis treatment and TZ on lung bacillary load in

mice infected with M. Tuberculosis H37Rv

Grey bars: Animals treated 60 days with conventional therapy: Isoniazid, Rifampicin and PyrazinamideBlack bars: Animals treated 60 days with conventional therapy in combination with TZ 32mg dailyWhite bars: untreated control mice.

H37Rv Control infection

H37RvInfectionPlus Thioridazine

MDRControlInfection

MDR InfectionPlus Thioridazine

(A) Extensive lungconsolidation (arrows) is visible in control animals after 120 days of infection by drug-sensitive control Strain H37Rv.

(B) In contrast, less pneumonia (arrow) is seen in the lung of Mice treated with Thioridazine 32 mg/kg

daily by intragastric cannula.

(C) Controlmice after 120 days of infection with MDR strain show extensive pneumonic areas (arrow)

In comparison, less lung consolidation (arrow) is seen in the lung of mice infected by the MDR-TB strain and treated daily during two months with 70 mg/kg of thioridazine

L Amaral June 2012

Thioridazine cures XDR TB

L Amaral June 2012

L Amaral June 2012

CURE OF XDR-TB (SECOND STUDY)

Abbate E, Vescovo M, Natiello M, Cufré M, García A, Gonzalez Montaner P,Ambroggi M, Ritacco V, van Soolingen D. Successful alternative treatment of extensively drug-resistant tuberculosis in Argentina with a combination of linezolid, moxifloxacin and thioridazine. J Antimicrob Chemother. 2011 Dec 1.[Epub ahead of print] PubMed PMID: 22134348.

MECHANISM OF ACTION

L Amaral June 2012

Inhibition of macrophage

intracellular pumps?

Concentration of the compound inside the

macrophage?

• macrophage can concentrate 100 times the phenothiazines inside lysosomes / phagosomes

• MIC TZ (TB/MDR-TB) = 20 mg/L• MBC TZ (TB/MDR-TB) = 30 mg/L

• Ca2+ / K+ pumps inhibitors

• Inhibitors of Ca2+ transport (calmodulin) and influx/efflux processes dependent on cellular energy

0.1 mg/L10 mg/L

• Clinical concentrations

However…

Questions raised…

Mechanism of action of TZ and its derivatives inside the macrophage?

• Dependent upon transport processes affected by agents that inhibit Ca2+-activated K+ pumps

• Killing activity of phagocytic cells (Neutrophils)

• Correlated with K+ availability

• Rise of Ca2+ and K+ associated with the killing activity of phagocytic cells

Other studies… Jump to main content

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Advanced search J ourna l home > Archive > Article > Abs tract Article Nature 416, 291-297 (21 March 2002) | do i: 10.1038/416291a; Recei ved 12 D ecember 2001; Ac cepted 23 J anuary 2002

Killing activ ity of neutrophils is mediated through activation of pr oteases by K+ flux Emer P. Reeves1,2, Hui Lu1,2, Hugue s Lortat Jacobs3, Carlo G. M. Me ssina1, Steve Bolsove r4, Giorgio Gabella5, Er ic O. Potma6, Al ice Warley7, Jürgen Roes8 and Anthony W. S egal1

1. Centre for Molecular Medicine, Uni versity Co llege L ondon, 5 University Street , L ondon WC1E 6J J , U K 2. Centre for Molecular Medicine, Department o f Physiology , Universi ty College London, 5 University

Street, London WC1E 6J J , UK 3. Centre for Molecular Medicine, Department o f Anatomy , University Coll ege London, 5 Universi ty

Street, London WC1E 6J J , UK 4. Windeyer I nstitute o f Medical Sci enc es, University Col lege L ondon, 5 University Street, London WC1E

6J J, UK 5. Institut de Biologie Struc tura le, 41 rue H orowitz, 38027 Grenoble, France 6. Ultrafast Laser and Spectroscopy Laboratory, Materia ls S cience Centre , Univers ity of Groningen,

Nij enborgh 4, 9747 AG Groningen, The Netherl ands 7. Rayne I nstitute , St Thomas' Hospital, Lambeth Pa lac e Road, London SE1 7EH, UK 8. These authors c ontributed equa lly to this w ork.

Correspondence to : Anthony W. Sega l1 Correspondence and requests for materia ls should be address ed to A.W. S. (e-mail: Emai l: rmhaase@ucl. ac.uk).

Top of pag e Abs trac t

• Inhibition of efflux pumps of bacteria and eukaryotic cells

• indirect effects on the K+ pumps of mammalian cells

• direct effects on the K+ pumps of mammalian cells

• Ca2+ channel blocker; inhibits plasma membrane mediated transport of K+

into the macrophage preventing access to Ca2+

Verapamil Reserpine Ouabain

Ca2+/K+ pump inhibitors

Other Ca2+/K+ pump inhibitors

1,00E+00

1,00E+01

1,00E+02

1,00E+03

1,00E+04

1,00E+05

1,00E+06

1,00E+07

1,00E+08

1,00E+09

1,00E+10

0 2 4 6

Hours post-infection

Bac

teria

l con

cent

ratio

n (b

acte

ria/m

L)

Control

TZ 0.1 mg/L

Reserpine 80 mg/L

Ouabain 80 mg/L

Verapamil 80mg/L

• Enhancement of the macrophage killing activity

• Reduction of CFU with all the inhibitors tested

Martins M & Amaral L (2006). Res. J. Microbiol. 1(3): 203.

In phagocytosed MRSA:

In phagocytosed M. tuberculosis:

• Enhancement of the macrophage killing activity

• Reduction of CFU

• Verapamil: more active than TZ (higher concentrations)

• MACROPHAGE MODEL

MRSA

Results – Ex vivo studies with the other Ca2+/K+ pump inhibitors

1,00E+00

1,00E+01

1,00E+02

1,00E+03

1,00E+04

1,00E+05

1,00E+06

1,00E+07

0 1 2 3

Days post-infection

Bac

teria

l con

cent

ratio

n (b

acte

ria/m

L)

Control

TZ 0.1 mg/L

Reserpine 80 mg/L

Ouabain 80 mg/L

Verapamil 80 mg/L

Martins M, Viveiros M, Amaral L. (2008). In Vivo 22(1): 69.

M. tuberculosis

K+

H+

Ca2+

H+K+

ATP

K+

ATP

Ca2+ Ca2+

ATP

Na+

K+

Ca2+ Ca2+

ATP

H+ K+

ATP

Ca2+

Ca2+Ca2+

Ca2+

Ca2+

Ca2+

Na+

B

K+

K+

ATP

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

K+

Ca2+

H+ATPH+

E

G

K+

H+H+

Ca2+

K+

Ca2+

Ca2+

Ca2+ Ca2+

ATPATP

K+

Ca2+

Ca2+

K+H+

Ca2+

ATP

K+

H+ATP

C

D

H+

ATP

K+ H+

Ca2+

H+

Ca2+

Ca2+

Ca2+

K+

FATP

K+H+

Ca2+

Ca2+

Amaral L, Martins M, Viveiros M. (2007). J. Antimicrob. Chemother. 59:1237.

H+H+

H+

ATPK+

Ca2+

Ca2+

K+

Ca2+

H+

H+

H+

H+

H+H+

H+

A

L Amaral, May 2011

The Role of efflux pumps in MDR-Mtb

L Amaral, June 2012

Laboratory demonstrations of induced efflux activity

by bacteria.

L Amaral, June 2012

Time course of induced INH resistance and reversion of the H37Rv (ATCC 27294) reference strain.

Viveiros M, Portugal I, Bettencourt R, Victor TC, Jordaan AM, Leandro C, Ordway D, Amaral L. Isoniazid-induced transient high-level resistance in Mycobacterium tuberculosis. Antimicrob Agents Chemother. 2002 Sep;46(9):2804-10.

RE

Thioridazine added @ IL 7 immediately reduces resistance to INH (arrow)

Ethidium Bromide (EB)

Viveiros M et al, Int J Antimicrob Agents. 31(5):458-62, 2008.Spengler G et al, Anticancer Research 29: 2173-2177, 2009.

transport of fluorescent substrates (EB) through the

cell envelope of living bacterial cells

common substrate of bacterial efflux pumps

emits weak fluorescence in aqueous solution (outside cells)

and becomes strongly fluorescent when concentrated in periplasm

Automated EB method for bacteria

Detection of Efflux Activity by Real-time Fluorometry

Detection of efflux activity on a real-time basis

Separate detection of accumulation and efflux of ethidium bromide (EtBr)

Identification of compounds with efflux pump inhibitory activity – efflux pump inhibitors (EPIs)

Ethidium bromide (EtBr)

LED light source(rotates for each channel)

rotor spins tubes at 500 rpm

lens

filter set(rotates for

each channel) sensitive PMT (photomultiplier)

detector

Rotor-Gene 3000TM (Corbett Research)

PKI

Effect of chlorpromazine (CPZ), thioridazine (TZ) andverapamil (VP) on the efflux of ethidium bromide in M.

smegmatismc2155 (A) and M. avium ATCC25291T (B)

Rodrigues L, Aínsa JA, Amaral L and Viveiros M. Inhibition of Drug Efflux in Mycobacteria with Phenothiazines and Other Putative Efflux Inhibitors. Recent Patents on Anti-Infective Drug Discovery, 2011; 6:118-127.

Strains

Relative expression level ± SD

mmpl7 Rv1258c p55 efpA mmr Rv2459

H37Rv INH (R) 0.44 1.99 0.82 0.34 0.44 0.50

H37Rv INH (I) 10.56 15.26 6.96 8.00 9.95 22.63

401/06 INH (C) 34.30 22.63 18.38 16.00 24.25 9.19

401/07 INH (C) 17.15 14.93 9.85 6.96 9.19 27.86

401/08 INH (C) 4.16 7.80 11.31 8.57 2.29 2.64

Average quantification of the relative expression level, by RT-qPCR, of the genes that code for efflux pumps in M. tuberculosis.

Machado D, Couto I, Perdigão J, Rodrigues L, Portugal I, Baptista P, Veigas B, Viveiros M. and Amaral L . Contribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis. PLoS One 2012; 7(4): e34538. doi:10.1371/journal.pone.0034538

CONCLUSIONS• THIORIDAZINE HAS IN VITRO ACTIVITY AGAINST ALL STRAINS OF Mtb.• THIORIDAZINE ENHANCES INTRACELLULAR KILLING OF MDR/XDR Mtb.• THIORIDAZINE CURES THE MOUSE OF AN MDR Mtb INFECTION.• THIORIDAZINE CURES THE HUMAN OF AN XDR-TB INFECTION.• DUAL MECHANISM OF ACTION: A) INHIBITION OF K+ EFFLUX OF MACROPHAGE PERMITTING

ACIDIFICATION OF PHAGOLYSOSOME. B) INHIBITION OF EFFLUX PUMPS OF Mtb THAT BESTOW MDR

PHENOTYPE.• BY-PASSES ANY MUTATIONAL RESPONSE MADE BY Mtb THAT WOULD

LEAD TO RESISTANCE.• THIORIDAZINE IS CHEAP, RELATIVELY SAFE WHEN PATIENT IS

MONITORED FOR CARDIA FUNCTION, AND SHOULD BE CONSIDERED FOR THERAPY OF XDR/TDR Mtb INFECTIONS.

May 2011 Special Issue of PRI: Thioridazine MDR/XDR TB

ADDITIONAL BENEFITS OF THIORIDAZINE

INHIBITS ESSENTIAL GENES OF Mtb (Dutta NK, Mazumdar K, Dastidar SG, Karakousis PC, Amaral L. New patentable use of an old neuroleptic compound thioridazine to combat tuberculosis: a gene regulation perspective. Recent Pat Antiinfect Drug Discov 2011;6:128-138.)

IMPROVES QUALITY OF LIFE OF THE XDR-TB PATIENT (Udwadia ZF, Sen T, Pinto LM. Safety and efficacy of thioridazine as salvagetherapy in Indian patients with XDR-TB. Recent Pat Antiinfect Drug Discov. 2011;6:88-91.

KILLS DORMANT Mtb (Sohaskey C. Latent tuberculosis: is there a role for thioridazine? Recent Pat Antiinfect Drug Discov. 2011;6:139-46. Review. ).

ANTICIPATED SHORT TERM USAGE FOR MDR/XDR/TDR-TB INFECTIONS WILL DO NO HARM (Thanacoody RH. Thioridazine: the good and the bad. Recent Pat Antiinfect Drug Discov 2011;6:92-98. Review.).

RESEARCH TEAM

L Amaral, May 2011

ISN