Post on 14-Apr-2017
Molecular markers for the detection of malaria drug resistance
Presented by-
Anil kumarM.Sc PHE Ist yearVCRC(ICMR)
NEED…???
• As per 2015, 214 million new cases reported for malaria worldwide(African region-88%, South East Asian region-10% and East Mediterranean region-2% ).
• About 438,000 deaths worldwide.• 3.2 billion people (about half of the population of world)
live in high risk zone of malaria.• About 12 billon USD per year expenses on malaria
(illness, treatment and diagnosis) globally.• In 2014 itself 535 death in India. • Drug resistance increases the burden of disease,
mortality and financial expenses.
INTRODUCTION• Malaria is caused by mosquito vector.• Parasites involved are - P. falciparum, P. malariae, P. vivax and
P. ovale.• Different drugs are known for different mechanism of action.• Ability of a parasite strain to survive and/or to multiply despite
the administration and absorption of a drug given in doses equal or higher than those usually recommended, but within the limits of tolerance of the patients is known as drug resistance.
• Resistance from drug of choice is because of different mechanisms associated with respective drugs.
• First anti malarial drug resistance started in 1957 in South East Asia region against chloroquinine.
DISEASE BURDEN….
DISTRIBUTION OF DRUG RESISTANT MALARIA
Drug Introduction “First” year resistance reported
Difference (years)
Quinine 1632 1910 278
Chloroquine 1945 1957 12
Proguanil 1948 1949 1
Sulfadoxine-pyrimethamine
1967 1967 <1
Mefloquine 1977 1982 5
Atovaquone 1996 1996 <1
Artemisinins 1971 1998 35
Development of drug resistance
REASONS FOR DEVELOPING RESISTANCE..??
Unregulated or poorly administered antimalarial drug use.
Combination drug therapy use without a complementary drug.
The malaria parasite increases its capacity to repair the damage
caused by anti malarial drug gives it a higher chance of survival.
Because the drug is more effective against the parasite at its later
stage of development, the parasite slowed down its growth so it
could survive longer in the younger stages.
Long residual effect of antimalarial drugs.
DRUGS OF CHOICE…..Combination therapy:
•Mefloquine+Artesunate•Sulfadoxine/Pyrimethamine+Artesunate•Lumefantrine+Artemether
Single-Agent Therapy:
•Chloroquine•Amodiaquine•Slfadoxine/Pyrimethamine•Mefloquine•Halofantrine•Quinine•Tetrayclin/Doxycyclin•Atovaquone•Primaquine•Artemisine compounds
MECHANISM OF DRUG ACTION&
RESISTANCE DEVELOPMENT
Chloroquine, Amodiaquine, Quinine, Quinidine, Mefloquine,
Primaquine Lumefantrine and
Halofantrine.
•Theses drugs kills the erythrocytic stage of
parasite.•Primaquine also kills the intrahepatic forms
and gametocytic stages.
QUINOLINE DERIVATIVE
Choloroquine :Mode of action- Accumulating in plasmodium food vacuole leading to inhibition of utilization of heme and producing complexes which are toxic to plasmodium.Resistance-Among Chloroquine resistant parasites, there is a decrease in accumulation of drug within the food vacuole.Molecular basis-•Mutation in the gene encoding the “Chloroquine Resistance Transporter(Pf CRT)” in chromosome 7 (alteration K76T). •In SEA S163R mutation(fourth transmembrane domain) was found along with K76T.
Amodiaquine :It is similar to chloroquin and available in coformulation with artesunate and treated in chloroquine resistance cases.Side effects agranulocytosis and hepatotoxicity.Molecular basis for resistance-Pfcrt and Pfmdr1
Quinine and QuinidineMode of action-
Depresses oxygen uptake and
carbohydrate metabolism; disrupting
Na/K channel, intercalates into DNA, disrupting parasites
replication and transcription.
Resistance –Gene associated pfcrt1,
pfmdr1 and pfnhe1
4-methanolquinolines
Quinoline - methanol compound
Affective against all asexual stages of different malarial
parasites.Mode of action similar to
CQ
Resistance-Gene associated pfmdr1
Mefloquine
Similar to 4-methanolquinolines in structure. Used against
chloroquine & Mefloquine resistant infections.
Mode of action same as CQ.
Resistance –Gene associated pfcrt1 &
pfmdr1
Lumefantrine & halofantrine
Mode of action- It is a competitive inhibitor
of ubiquinol, specially inhibiting the mitochondrial
ETS at the bc1 complex. Inhbition of bc1 activity
results in a loss of mitochondrial function.
Resistance-Single nucleotide
polymorphism in the cytochrome b gene
Atovaquone
Drugs include: Pyrimethamine,
Sulphonamides, Proguanil and Dapsone.
Mode of action –Drug synergistically target enzymes involved in Folate
synthesis (DHFRase).Resistance –
Due to mutational changes in the plasmodium DHFRase enzyme.
Resistance can be delayed by using in combination
with Sulphonamide
Antifolates
Mode of action – Sulfadoxine interferes with
bacterial folic acid synthesis and growth via competitive inhibition of para-aminiobenzoic acid; pyrimethamine inhibits microbial dihydrofolate reductase, resulting in
inhibition of tetrahydrofolic acid synthesis
Resistance-
Sulfadoxine – Pyrimethamine
Point mutations in pfdhfr and pfdhps associated genes.
Mode of action –It act by binding iron, breaking down peroxide bridges leading
to the generation of free radicals that damage parasite
proteins.They act rapidly by clearly all blood stages and gametocytes
of plasmodium species.
Resistance :
Pf kelch protein gene on chromosome 13 (kelch13)
Artemisinin
Drug Mutations Chloroquine pfcrt (K76T) codons:72-76; pfmdr1 (P. falciparum multidrug
resistance transporter 1) codon: 86Y/Y184/1246Y Quinine pfcrt, pfmdr1, and pfnhe1 (P. falciparum sodium/proton
exchanger 1)Amodiaquine pfcrt, pfmdr1
Mefloquine Increased copy number of pfmdr1
Piperaquine Pfcrt :76T; pfmdr 1 codon: 86Y/Y184/1246Y
Lumefantrine Pfcrt codon: 72-76; pfmdr1 N86/184F/D1246 or increased copy number
Atovaquone Single nucleotide polymorphisms in the cytochrome b gene
SP Point mutations in pfdhfr and pfdhpsArtemisinin Pf kelch protein gene on chromosome 13 (kelch13)
Sulfadoxine pfdhps: 437G/540E
Pyrimethamine pfdhfr : 51I/59R/108N- triplet mutation
P. vivax PvMDR1, pvdhfr and pvdhps
Genes involved in drug resistance
Response to therapy
EVALUATION OF DRUG RESISTANCEENDEMIC REGION:
EPIDEMIC REGION:PCR
REFERENCES
Articles:
•Ingrid B Müller and John E Hyde ., Antimalarial Drugs: Modes of Action and Mechanisms of Parasite Resistance; Future Microbiol. 2010;5(12)•Carol Hopkins Sibley., Understanding drug resistance in malaria parasites: Basic science for public health; Molecular & Biochemical Parasitology 195 (2014) 107–114 •Hiasindh Ashmi Antony and Subhash Chandra Parija., Antimalarial drug resistance: An overview; Trop Parasitol. 2016 JanJun; 6(1): 30–41•Liwang Cui aand et al., Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network; Am. J. Trop. Med. Hyg., 93(Suppl 3), 2015, pp. 57–68
WWW :
•www.malariasite.com/drug-resistance/
THANKSTHANKS