FromFrom microbialmicrobial pathogenesispathogenesis toto thethe discoverydiscovery ofof antivirulenceantivirulence drugsdrugs
Efflux pump inhibitors to restore antibiotic efficacy
Françoise Van Bambeke Unité de Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain
www.facm.ucl.ac.be
07-10-2009 ESCMID 1 WhyWhy activeactive effluxefflux ??
Manneken Pis, who saved Brussels from fire
07-10-2009 ESCMID 2 Chemotherapeutic agents exert toxic effects on specific targets
enzymes
nucleic acids
ribosomes
How can these drugs reach their target inside the cells ?
07-10-2009 ESCMID 3 Reaching an intracellular target …
polar drug
lipophilic drug
physico-chemical properties are inadequate for reaching an intracellular target !
Van Bambeke et al., Biochem. Pharmacol (2000) 60:457-70 07-10-2009 ESCMID 4 Reaching an intracellular target …
amphipathic drug
most drugs are amphipathic by design, to be able to cross membrane barriers !
Van Bambeke et al., Biochem. Pharmacol (2000) 60:457-70 07-10-2009 ESCMID 5 Intracellular chemotherapeutic agents
But a diffusible compound may have potentially harmful effects !
Van Bambeke et al., Biochem. Pharmacol (2000) 60:457-70 07-10-2009 ESCMID 6 Why efflux transporters ?
Extrusion by efflux pumps
Van Bambeke et al., Biochem. Pharmacol (2000) 60:457-70 07-10-2009 ESCMID 7 Why efflux transporters ?
Extrusion by efflux pumps
general mean of protection against cell invasion by diffusible molecules
Van Bambeke et al., Biochem. Pharmacol (2000) 60:457-70 07-10-2009 ESCMID 8 Typical ‘toxic’ diffusible substances as substrates for efflux pumps
antibiotics antifungals
anticancer agents
07-10-2009 ESCMID 9 Most antibiotics do act on intracellular targets
(lipo- and glycopeptides) (β-lactams)
sulfamides quinolones tetracyclines
Efflux as a mechanism of resistance by reducing antibiotic concentration inside the bacteria
07-10-2009 ESCMID 10 Most antibiotics are amphiphilic !
cationic amphiphiles + + + fluoroquinolone
+
+ +
sulfamide
rifampicin lincosamide
Van Bambeke et al., Biochem. Pharmacol (2000) 60:457-70 07-10-2009 ESCMID 11 Most antibiotics are amphiphilic !
anionic amphiphiles
-
-
β-lactam -
fluoroquinolone
Van Bambeke et al., Biochem. Pharmacol (2000) 60:457-70 07-10-2009 ESCMID 12 Antibiotic efflux transporters are ubiquitous
distribution spectrum prokaryotes eukaryotes Gram (+) Gram (-) narrow MATE SMR
MFS
ABC
RND
broad Mesaros et al., Louvain médical (2005) 124:308-20 07-10-2009 ESCMID 13 General structure of efflux pumps in bacteria
Gram(-)
Gram(+)
Mesaros et al., Louvain médical (2005) 124:308-20 07-10-2009 ESCMID 14 Efflux and resistance in pathogenic bacteria
NO YES bacteria efflux pump super β -lactams FA AG Tet OX ML LM CP Rif Q SM TM family penams cephems penems mbact. inhib NA FQ β-ase
S.aureus NorA MFS TetK-L MFS S. pneumoniae PatA/B ABC MefE MFS pmrA MFS TetK-L MFS S. pyogenes MefA MFS
E. coli EmrE SMR SetA MFS EmrB MFS TetA-E MFS Bcr MFS MdfA MFS AcrAB RND AcrD RND P. aeruginosa CmlA MFS TetA,C,E MFS MexAB OprM RND MexCD OprJ RND MexEF OprN RND MexXY RND
Van Bambeke et al., J. Antimicrob. Chemother (2003) 51:1055-65 Efflux and resistance in pathogenic bacteria
1 bacteria several pumps multi-resistance
1 pump several classes cross-resistance of antibiotics
1 class several pumps efficacy of of antibiotics inhibitors ?
07-10-2009 ESCMID 16 RoleRole ofof effluxefflux inin pathogenicitypathogenicity
Belgian beer
07-10-2009 ESCMID 17 Colonization
Efflux pumps contribute to invasion in enteric pathogens
Disruption of efflux pump expression reduces adhesion and invasion of Salmonella in cultured cells and in vivo
• export of quorum sensing molecules ? • export of bile salts ? • export of virulence factors ? • expression of virulence factors ? •…
Blair et al, JAC (2009) Epub [PMID: 19744979]; Buckley et al, Cell Microbiol (2006) 8:847-56 07-10-2009 ESCMID 18 Colonization
Gene expression alterations in efflux deficient strains
Disruption of efflux pump expression reduces the expression of genes involved in motility and anaerobic metabolism
Webber et al, J. Bacteriol. (2009) 191:4276-85 07-10-2009 ESCMID 19 Biofilm formation
Efflux pumps expression in biofilms
Higher expression of MexAB-OprM in P. aeruginosa growing in biofilms
De Kievit et al, Antimicrob Agents Chemother. (2001) 45:1761-70 07-10-2009 ESCMID 20 Biofilm formation
Efflux pumps expression in biofilms
Reduced susceptibility to antibiotics in P. aeruginosa growing in biofilms
reduced role of MexAB-OprM susceptibility in biofilm resistance to AB De Kievit et al, Antimicrob Agents Chemother. (2001) 45:1761-70 in bioflims 07-10-2009 ESCMID 21 RoleRole ofof effluxefflux inin resistanceresistance
Niagara Falls 07-10-2009 ESCMID 22 Antibiotic exposure can induce efflux pump expression
FQ, whether substrates or not, induce the expression of patA/patB in S. pneumoniae
patA patB 175 175 175 175 CIP CIP MXF MXF 150 150 150 150
125 125 125 125
100 100 100 100
75 75 75 75
50 50 50 50
expression ratio (% value at 4 h) 25 25 25 25
0 0 0 0 0 1 2 3 4 5 6 0 1 2 3 4 5 0 1 2 3 4 5 6 0 1 2 3 4 5 time (h) time (h)
4 h with ½ MIC; up to 5 h without FQ El Garch et al, ECCMID (2009) O495 07-10-2009 ESCMID 23 Efflux and selection of resistance to FQ
Exposure to subMIC concentrations favors the selection of target mutations !
Gyrase/ Topoisomerase
07-10-2009 ESCMID 24 Efflux and selection of resistance to FQ
Frequency of Levofloxacin-resistant mutants in Pseudomonas aeruginosa with deletions of the efflux pump operons
Pump status LVX MIC Frequency of LVX- resistant mutants
WT 0.25 2 × 107 -4 ×107 Δ mexAB-oprM 0.015 2 × 107 -4 ×107 Δ mexCD-oprJ 0.25 2 × 107 -4 ×107 Δ mexEF-oprN 0.25 2 × 107 -4 ×107 Δ mexAB-oprM;Δ mexEF-oprN 0.015 2 × 107 -107 Δ mexCD-oprJ; Δ mexEF-oprN 0.25 2 × 106 Δ mexAB-oprM; Δ mexCD-oprJ 0.015 1 × 109 Δ mexAB-oprM; Δ mexCD-oprJ; 0.015 <1 × 1011 Δ mexEF-oprN
Selection of mutants in FQ target Lomovskaya et al, undetectable if ALL pumps are disrupted AAC (1999) 43:1340-1346
07-10-2009 ESCMID 25 Efflux cooperates with other mechanisms of resistance R
physical CN chemical O clearance clearance COOH
R R β-lactamase
CN CHN O O OH COOH COOH
07-10-2009 ESCMID 26 Efflux cooperates with other mechanisms of resistance
Contributions of the AmpC β-lactamase and the AcrAB Multidrug Efflux System in intrinsic resistance of E. coli to β -lactams
Efflux β-lactamase MIC carbenicillin MIC ofloxacin
-- 0.20.05 WT: + - 12.5 0.2 intrinsic resistance ! +++ - 50 1.56 - + 100 0.05 + + 200 0.39 +++ + 400 1.56
Mazzariol et al, AAC (2000) 44:1387-1390 07-10-2009 ESCMID 27 Efflux selection during treatment
Prevalence of MexA and MexX overexpressers in 62 phylogentically-related pairs of P. aeruginosa isolated from ICU patients (VAP)
DAY x (%) DAY 0 (%) 9.68% 17.74%
11.29% MexA-/MexX- 38.71% MexA+/MexX- MexX+/MexA- 20.97% 12.90% MexA+/MexX+ 66.13%
22.58%
Riou, Avrain, Van Bambeke, Tulkens, et al; unpublished data 07-10-2009 ESCMID 28 Efflux and therapeutic failure
Rabbit Endocarditis – P. aeruginosa; mimicking human dosages
(MexAB++) (WT)
Boutouille et al, Int J Antimicrob Agents (2009) 33:417-20 07-10-2009 ESCMID 29 HowHow toto preventprevent resistanceresistance byby effluxefflux ??
J.M. Folon, La Hulpe, Belgium 07-10-2009 ESCMID 30 How to prevent resistance by efflux ? general strategies
Pages & Amaral, Biochim. Biophys. Acta (2009) 1794:826-33 07-10-2009 ESCMID 31 What is the way to go ?
07-10-2009 ESCMID 32 How to prevent resistance by efflux ? general strategies
Pages & Amaral, Biochim. Biophys. Acta (2009) 1794:826-33 07-10-2009 ESCMID 33 Altering the expression of pump components
inhibitors of MarA
T. E. Bowser et al, Bioorg. Med. Chem. Lett. (2007) 17: 5652–5655 Randall and Woodward, Res Vet Sci. (2002) 72:87-93 07-10-2009 ESCMID 34 Altering the expression of pump components
genetic strategies
A first strategy to inhibit efflux pump activity could consist of repressing the expression of corresponding genes. This approach may employ antisense oligonucleotides or small interfering RNA (which selectively prevent the transcription of the gene coding for the pump), or other non-traditional antisense molecules, which can interfere with the transcription or the translation of that gene of that RNA. This patented* strategy was exemplified for the inhibition of the AcrAB efflux pump in E. coli
* Oethinger & Levy (2004) US6677133 07-10-2009 ESCMID 35 How to prevent resistance by efflux ? general strategies
Pages & Amaral, Biochim. Biophys. Acta (2009) 1794:826-33 07-10-2009 ESCMID 36 Inhibiting functional assembly
Alteration of addressing of OM proteins
WT +/- CCCP
efflux strain + CCCP
efflux strain + PABN
efflux strain + globomycin
efflux strain X
active only on growing cells !
Malléa et al, Biochem. Biophys. Res. Comm. (2002) 293:1370–1373 Tokudaa & Matsuyama, Biochim. Biophys. Acta (2004) 1693:5 – 13 07-10-2009 ESCMID 37 How to prevent resistance by efflux ? general strategies
Pages & Amaral, Biochim. Biophys. Acta (2009) 1794:826-33 07-10-2009 ESCMID 38 Blocking outer membrane channel
blocking of the channel activity
of TolC by Co(NH3)6
Higgins et al, J Mol Biol. (2004) 342:697-702 07-10-2009 ESCMID 39 How to prevent resistance by efflux ? general strategies
Pages & Amaral, Biochim. Biophys. Acta (2009) 1794:826-33 07-10-2009 ESCMID 40 Collapsing energy source
proton ionophore uncoupler of mitochondrial respiration
energy source for most efflux pumps
very useful in vitro!
07-10-2009 ESCMID 41 How to prevent resistance by efflux ? general strategies
Pages & Amaral, Biochim. Biophys. Acta (2009) 1794:826-33 07-10-2009 ESCMID 42 ciprofloxacin vs levofloxacin
MIC distribution in S. pneumoniae isolated from CAP patients
O O 100
F 90 OH 80
70 N N CIP 60 HN 50
ciprofloxacin 40 O O 30 LVX
cumulative percentage (%) percentage cumulative 20 F OH 10
0 5 .5 1 2 4 8 N N 0 0.25 0.12 MIC values N O
levofloxacin adapted from Lismond et al, ECCMID 2009-P1068 07-10-2009 ESCMID 43 ciprofloxacin vs levofloxacin
MIC distribution in S. pneumoniae isolated from CAP patients
O O 100
F 90 OH 80
70 N N CIP 60 CIP+R HN 50
ciprofloxacin 40 O O 30 LVX LVX+R cumulative percentage (%) percentage cumulative 20 F OH 10
0 5 1 2 4 8 N N 25 .25 0. 1 0 0. MIC values N O
levofloxacin adapted from Lismond et al, ECCMID 2009-P1068 07-10-2009 ESCMID 44 erythromycin vs telithromycin
N N O O N H3C CH3 CH OH OH 3 CH3
O OCH H3C OH CH3 3
(H3C)2N H3C CH3 N CH3 HO H3CH2C O O N(CH3)2 O CH3 CH3 O OH CH2CH3 O O O CH3 O O H3CO CH3 CH3 O O O erythromycin CH3 telithromycin H3C OH
Species Erythromycin Telithromycin
S. pyogenes (WT) 0.03 0.08 (mef) 8 0.5 S. pneumoniae (WT) 0.03 0.008 (mef) 2 0.125
07-10-2009 ESCMID 45 minocycline vs tigecycline
minocycline
H3C CH3 H3C CH3 NH NH glycyl- HO O H C N CH3 O C N tigecycline OH H CH3 [tertbutyl-glycyl-minocycline] NH2 O OH O OH CH3
Influx of tetracycline (left) and glycylcycline (right) in inverted vesicles
Someya et al, AAC (1995) 39:247-249 07-10-2009 ESCMID 46 How to prevent resistance by efflux ? general strategies
Pages & Amaral, Biochim. Biophys. Acta (2009) 1794:826-33 07-10-2009 ESCMID 47 Characteristics of the ideal EPI
« to do » list for a winning molecule :
9 Enhance activity of AB in efflux pumps overproducers by inhibiting efflux
9 Not affect AB activity in strains lacking efflux pumps 9 Not potentiate activity of AB that are not effluxed 9 Not affect proton gradients across the inner membrane (Gram-negative bacteria)
9 Not affect eucaryotic efflux pumps
Lomovskaya et al. AAC (2001) 45:105-116 07-10-2009 ESCMID 48 Different types of EPI
¾ Pharmacological agents fortuitously found to inhibit efflux BUT active at supra-therapeutic concentrations ! unusable in vivo because of toxicity !
¾ Analogs of antibiotic substrates narrow spectrum efflux pumps ?
¾ Natural molecules and semi-synthetic derivatives thereof standardisation
¾ New chemical entities often partial characterization against a small number of bacteria and for a few antibiotics potential interest under-estimated ?
Van Bambeke et al. Rec. Patents Antiinf. Drug Discov. (2006) 1:157-175 07-10-2009 ESCMID 49 Different types of EPI
¾ Pharmacological agents fortuitously found to inhibit efflux BUT active at supra-therapeutic concentrations ! unusable in vivo because of toxicity !
¾ Analogs of antibiotic substrates narrow spectrum efflux pumps ?
¾ Natural molecules and semi-synthetic derivatives thereof standardisation
¾ New chemical entities often partial characterization against a small number of bacteria and for a few antibiotics potential interest under-estimated ?
Van Bambeke et al. Rec. Patents Antiinf. Drug Discov. (2006) 1:157-175 07-10-2009 ESCMID 50 Pharmacological agents Type of inhibitor structure activity
ABs bacteria µg/ml
H CO N 3 O OCH alkaloids N 3 FQ S. pneumo 20 H O OCH3 S. aureus (reserpine) H3CO OCH OCH3 O 3 phenothiazines (H3C)2N TET E. coli 45
(chlorpromazine) N
S selective serotonin F TET E. coli 120 O reuptake inhibitors O isoniazid M. smegmatis 25
(paroxetine) O
N H 2+ OCH3 OCH3 Ca antagonists H3CO OCH3 FQ S. aureus 20
(verapamil) N E. coli CH(CH3)2 TET CN CH3
proton pump OCH3 FQ S. aureus 100 H3C CH3 inhibitors O S N OCH3 N (omeprazole) HN
07-10-2009 ESCMID 51 Different types of EPI
¾ Pharmacological agents fortuitously found to inhibit efflux BUT active at supra-therapeutic concentrations ! unusable in vivo because of toxicity !
¾ Analogs of antibiotic substrates narrow spectrum efflux pumps ?
¾ Natural molecules and semi-synthetic derivatives thereof standardisation
¾ New chemical entities often partial characterization against a small number of bacteria and for a few antibiotics potential interest under-estimated ?
Van Bambeke et al. Rec. Patents Antiinf. Drug Discov. (2006) 1:157-175 07-10-2009 ESCMID 52 Analogs of antibiotic substrates
antibiotic inhibitors
H3C CH3 H3C CH3 HO CH3 N R1 R2 N OH OH H H TET N N H A OH OH OH O OH O O tetracycline OH O OH O O (1-16 µg/ml) R OH 2 OH OH R O HN O HO H R O H N HO N 3 HO 2 NH O NH HO NH O 2 NH2O 2 HO O OH R NH2 HO O R OH R O AGs HN OH HO O OH O H2N O OH O OHNHR1 O HO NH HO O NH2 HO NH HO 2 R O OR4 paromomycin OH NH2
O R5 R4 F COOH R4a R6 R2
FQ N N R X N HN 7 ciprofloxacin R1 Y (4-20 µg/ml)
07-10-2009 ESCMID 53 Different types of EPI
¾ Pharmacological agents fortuitously found to inhibit efflux BUT active at supra-therapeutic concentrations ! unusable in vivo because of toxicity !
¾ Analogs of antibiotic substrates narrow spectrum efflux pumps ?
¾ Natural molecules and semi-synthetic derivatives thereof standardisation
¾ New chemical entities often partial characterization against a small number of bacteria and for a few antibiotics potential interest under-estimated ?
Van Bambeke et al. Rec. Patents Antiinf. Drug Discov. (2006) 1:157-175 07-10-2009 ESCMID 54 Natural products
Type of inhibitor structure activity
ABs bacteria µg/ml
flavonolignans OH FQ S. aureus 10 OCH3 O OCH3 HO O O OH
OH O phenolic ML S. aureus 1 OH diterpenes FQ TET
piperine O FQ S. aureus 6.25 analogues R N
O H3CO
O H3CO
07-10-2009 ESCMID 55 Different types of EPI
¾ Pharmacological agents fortuitously found to inhibit efflux BUT active at supra-therapeutic concentrations ! unusable in vivo because of toxicity !
¾ Analogs of antibiotic substrates narrow spectrum efflux pumps ?
¾ Natural molecules and semi-synthetic derivatives thereof standardisation
¾ New chemical entities often partial characterization against a small number of bacteria and for a few antibiotics potential interest under-estimated ?
Van Bambeke et al. Rec. Patents Antiinf. Drug Discov. (2006) 1:157-175 07-10-2009 ESCMID 56 New chemical entities ~ Gram(+) efflux pumps
O N O OH CH3 N C2H5 HC
H3C CH3 indoles CH O CH3 3
N H indans O TET aromatic amides O
N N H H CHO O CH3 ureas O S R NR1R2 thiophenes 9-formyl-5-methyl- deca-2,8-dienoic acid ML, FQ amides FQ O
07-10-2009 ESCMID 57 New chemical entities ~ Gram(+) efflux pumps
N piperidines-carboxylic acid also inhibitors derivatives Cl of human P-gp N H C 3 N O O O N N
H3CO OCH3 (VX-853) N OCH3 O N O O O (VX-710) acridine carboxamides O
H3CO OCH3 OCH3 OCH3 N N OCH H 3 OCH 3 O N H (GF120918)
07-10-2009 ESCMID 58 New chemical entities ~ Gram(-) efflux pumps
N N HN N O HN N O S
N CH3 O2N N O2N N CH CH 3 N CH3 3 alkylaminoquinolines alkoxy- and thioalkoxy-quinolines
NH N O H specific of MexAB-OprM N H2N N H in P. aeruginosa O arylpiperazines NH
N NH2 H N peptidomimetics S O N N N broad spectrum N O Nh → do not bind to the « substrate » site! pyridopyrimidines N
07-10-2009 ESCMID 59 New chemical entities : hybrids (AB+inhibitor)
Ball et al, ACS Chem Biol. (2006) 1:594-600 07-10-2009 ESCMID 60 AnAn exampleexample ofof developmentdevelopment :: peptidomimeticspeptidomimetics fromfrom MpexMpex PharmaceuticalsPharmaceuticals……..
07-10-2009 ESCMID 61 An example of development : peptidomimetics from Mpex Pharmaceuticals….
librairy of 200,000 synthetic and natural compounds
in vitro screening in combination with levofloxacin against P. aeruginosa overexpressing Mex pumps
Renau et al. J. Med. Chem. (1999) 42: 4928-31; Lomovskaya et al. JMMB (2001) 3: 225-36 07-10-2009 ESCMID 62 Demonstration of in vitro activity
EPI are as effective as disruption of pump genes to restore antibiotic efficacy !
MIC ratio
antibiotic WT strain / Δ MexAB-OprM AB / AB + MC-207,110
levofloxacin 64 32 sparfloxacin 32 128 erythromycin 32 32 chloramphenicol 512 128
Lomovskaya et al, AAC (2001) 45:105-116 07-10-2009 ESCMID 63 Demonstration of the mode of action
Concentration-dependent inhibition of N-phenyl-1-naphtylamine efflux
Ocaktan et al. JBC (1997) 272: 21964-69; Lomovskaya et al. AAC (2001) 45:105-116 07-10-2009 ESCMID 64 EPI does not affect proton gradients across the IM
NMR spectra of 31 P to detect pH gradients
CCCP EPI
carbonyl cyanide m-chlorophenylhydrazone
other mode of action ? Lomovskaya et al. AAC (2001) 45:105-116 07-10-2009 ESCMID 65 EPI as permeabilizing agents in strains lacking efflux pumps ?
Testing the hydrolysis rate of a non permeant β-lactam
nitrocefin
periplasm β-lactamase
cytosol
Lomovskaya et al. AAC (2001) 45:105-116 07-10-2009 ESCMID 66 EPI as permeabilizing agents in strains lacking efflux pumps ?
Δ MexAB-OprM
EPI increases OM permeability when MexAB-OprM not functional
MexAB-OprM overproducer
EPI as substrates of efflux pumps ?
Lomovskaya et al. AAC (2001) 45:105-116 07-10-2009 ESCMID 67 On the way to a « drug-able » molecule ….
L-Phe-L-Arg-β-naphthylamide
O H N H2N N H 4-aminomethyl- O 2-pyrrolidinecarboxamide NH -D-hPhe-6-aminoquinoline
N NH2 H
• switching amino-acids position keeps activity O • using D-series amino-acids confers stability H H N N • conformationally restricted analogues N H avoid toxicity O N
H2N Renau et al. Bioorg. Med. Chem Lett. (2001) 11:663-7; (2003) 13:2755-58
07-10-2009 ESCMID 68 EPI increases susceptibility of clinical isolates
MIC distribution for levofloxacin in clinical isolates of P. aeruginosa
all strains below the EUCAST bkpt
MIC 50 MIC 90 (µg/ml) (µg/ml)
LVX 0.5 8 LVX + 0.03 0.5 MC-207,110
Lomovskaya et al. JMMB (2001) 3: 225-36 07-10-2009 ESCMID 69 EPI as adjuvant therapy
EPI (MC-04,124) potentiates levofloxacin activity in P. aeruginosa mouse thigh model
effective max regimen LVX MIC (mg/L) regrowth Δ log time (h) CFU
LVX (30 mg/kg) 2 3 0.1
LVX (30 mg/kg) + 0.125 13 3.6 MC-04,124 (25 mg/kg)
Griffith et al. ICAAC (2001) F-340 07-10-2009 ESCMID 70 The story is not yet finished …..
07-10-2009 ESCMID 71 PotentialPotential interestsinterests ofof effluxefflux pumpspumps inhibitorsinhibitors
Old Faithful Geyser 07-10-2009 ESCMID 72 Prevention of colonization
Efflux pumps contribute to resistance to bile salts in enteric pathogens
EPI prevent colonization of chicken by Campylobacter by increasing susceptibility to bile salts
Lin & Martinez, JAC (2006) 58:966-72 07-10-2009 ESCMID 73 Inhibition of biofilm formation
Efflux pumps contribute to biofilm formation
EPI decrease biofilm formation
Kvist et al, Appl Environ Microbiol. (2008) 74:7376-82 07-10-2009 ESCMID 74 Increased activity against intracellular bacteria
L. monocytogenes in broth
MIC of Listeria strains andMIC effect (mg/L) of reserpine
EGD CLIP quinolone Res. (-) Res. (+) Res. (-) Res. (+)
CIP 1.2 1.0 5.0 1.0
MXF 0.6 0.6 0.5 0.25
Lismond et al., Antimicrob. Ag. Chemother. (2008) 52:3040-46 07-10-2009 ESCMID 75 Increased activity against intracellular bacteria
Ciprofloxacin and Listeria inside macrophages
Wild-type cells and bacteria
Lismond et al., Antimicrob. Ag. Chemother. (2008) 52:3040-46 07-10-2009 ESCMID 76 Increased activity against intracellular bacteria
Ciprofloxacin and Listeria inside « resistant » macrophages cells and overproducing efflux pumps for ciprofloxacin
Lismond et al., Antimicrob. Ag. Chemother. (2008) 52:3040-46 07-10-2009 ESCMID 77 Increased activity against intracellular bacteria
Ciprofloxacin and resistant Listeria inside macrophages
bacteria overproducing bacteria and cells overproducing efflux pumps for ciprofloxacin efflux pumps for ciprofloxacin
Lismond et al., Antimicrob. Ag. Chemother. (2008) 52:3040-46 07-10-2009 ESCMID 78 Increased activity against intracellular bacteria
Moxifloxacin and Listeria inside macrophages
cells and bacteria overproducing Wild-type cells and bacteria efflux pumps for ciprofloxacin
Lismond et al., Antimicrob. Ag. Chemother. (2008) 52:3040-46 07-10-2009 ESCMID 79 Reduction of selection of resistance
In vitro PD model (mimicking human treatment), WT S. pneumoniae
Selection of mutants growing at 2-3 X MIC if : • low AB dosage • no efflux pump inhibitor
Louie et al, AAC (2007) 51: 3988–4000 07-10-2009 ESCMID 80 Reduction of selection of resistance
In vitro PD model (mimicking human treatment), efflux (+) S. pneumoniae
Much more rapid selection of mutants growing at 2-3 X MIC if : • low AB dosage • no efflux pump inhibitor
Louie et al, AAC (2007) 51: 3988–4000 07-10-2009 ESCMID 81 Increased efficacy of antibiotic treatments
model of P. aeruginosa pneumonia in the rat
D13-9001 MexAB-OprM inhibitor
improves efficacy of aztreonam (and levofloxacin)
Yoshida et al., Bioorg Med Chem. (2007) 15:7087-97. 07-10-2009 ESCMID 82 Efflux pump inhibitors as diagnostic tools
would require a universal inhibitor !
Frempong-Manso et al, Int J Antimicrob Agents (2009) 33:360-3 07-10-2009 ESCMID 83 Efflux pump inhibitors as diagnostic tools
or need to be combined with genotypic approaches !
Mesaros et al, J. Antimicrob. Chemother. (2007) 59:378-386 07-10-2009 ESCMID 84 AA stillstill uncertainuncertain futurefuture forfor EPIEPI ……..
Magritte, Belgian surrealist
07-10-2009 ESCMID 85 Lack of published clinical data ….. • lack of in vivo relevance of efflux ?
Efflux-positive strains easier to treat !
Craig, ICAAC 2004 07-10-2009 ESCMID 86 Lack of published clinical data ….. • toxicity ?
« At least one class of broad-spectrum bacterial efflux pump inhibitors (EPIs) has been previously reported and extensively characterized both in vitro and in vivo.
While these efforts demonstrated a significant potential for developing small molecule inhibitors of efflux pumps with acceptable serum pharmacokinetics and efficacy and no mechanism-based toxicities, they could not overcome unfavorable tissue accumulation and concomitant local organ toxicity of these compounds.
We have initiated an EPI discovery program and conceived of the approach to avoid the tissue accumulation toxicity. This resulted in synthesis of MP-01,003, which demonstrated a persistent serum level but due to specific enzymatic instability, rapidly degraded in tissues, thus avoiding tissue accumulation and concomitant local toxicity.»
O. Lomovskaya, Mpex Pharmaceuticals, in OPTIMIZING POSITIVE “HITS” FOR POTENCY AND SAFETY, National Institute for Allergy and Infectious Diseases February 7-8, 2007 07-10-2009 ESCMID 87 Lack of published clinical data ….. • resistance ?
Mutation (Val to Leu) in Bmr pump of B. subtilis confers resistance to reserpine
Reserpine no more capable of reverting resistance to EtBr
Ahmed et al, JBC (1993) 268:11086-9 07-10-2009 ESCMID 88 Lack of published clinical data ….. • resistance ? Reserpine induces PatA/PatB expression in S. pneumoniae
strain description MIC (µg/ml) CIP + RES + O-vanadate RES R6 WT 1 0.5 1 64 M169 R6 resR mutant >4 22256
CIP accumulation PatA/PatB expression
Garvey & Piddock, AAC (2008) 52:1677-85 07-10-2009 ESCMID 89 Conclusions
9 efflux mechanisms largely spread and contributing to • increased pathogenesis • reduced susceptibility to antibiotics 9 strategies of potential interest : • selection of « poor substrates » antibiotics • co-administration of EPI
9 EPI usefulness demonstrated for : • reducing pathogenesis • reducing MICs and selection of resistance • increasing efficacy in vitro / in vivo
¾ human data critically lacking so far !
07-10-2009 ESCMID 90 StillStill aa lotlot ofof workwork aheadahead ……..
07-10-2009 ESCMID 91 ThankThank youyou forfor youryour attentionattention andand havehave aa safesafe triptrip backback home!home!
07-10-2009 ESCMID 92