2. Abstract:
Infectious diseases remain one of the principal causes of
morbidity and mortality in the world .
Efflux pumps are elements that antibiotics are effective in
resistance and are involved in the pathogenesis of bacteria .
efflux pumps are important for processes of detoxification of
intracellular
metabolites, bacterial virulence in both animal an Man hosts, and
etc .
So today we're in a selection pressure for antibiotic use and for
the treatment of bacterial infections are a new development .
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3. Efflux as a mechanism for antibiotic resistance was first
described in 1980 .
Multidrug efflux pumps cause serious problems in cancer
chemotherapy and the treatment of bacterial infections.
In Gram negative bacteria, the pumps belonging to the
resistance-nodulation-division (RND) family are especially
effective in generating resistance.
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4. Antimicrobial resistance has been considered the new challenge
of the 21st century for example : Salmonella enterica ,
Escherichia coli ,
Different studies have demonstrated that MDR pumps are
capable of extruding not only antibiotics but also antiseptics.
4
6. The importance of efflux pumps:
In general it can be said:
Promotes the excretion of drugs and chemicals are.
Metabolites and toxins that repel bacteria
Microorganisms against antibiotics and chemicals, toxins, stress and
protect
The survival of microorganisms in different environments.
The supply of materials for the synthesis of bacterial surface structures
involved
In balancing solutions, ionic homeostasis and balance are important.
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7. Classification:
Efflux pump that was first detected : Efflux pumps was for a
family of tetracycline
Bacterial efflux transporters are classified into five major
superfamilies, based on the amino acid sequence and the
energy source used to export their substrates.
In the prokaryotic kingdom there are five major families of efflux
transporters.
(ATP)-binding cassette (ABC) superfamily
the resistance-nodulation-division (RND)family ,
the small multidrug resistance (SMR) family
the major facilitator superfamily(MFS)
the multidrug and toxic compound extrusion (MATE) family
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8. ABC: membrane proteins that translocate variety of substrates
across extra- and intra-cellular membranes
48 known ABC transporters; divided into 7 subfamilies of
proteins
RND: Fall into 7 phylogenetic families
3 Restricted to Gram – ive Bacteria; other 4 either restricted to
Gram + ive or represented in both
Also in bacteria, archaea and eukarya
SMR The smaller size . is unusual bacteria. Its pumps contain
only 100-120 amino acid
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9. MFS: One of two largest families
17 MFS Families
Present in bacteria, archaea and eukarya
MATE :
14 Phylogenetic Families
Also in bacteria, archaea and eukarya .
It has the same size mfs
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12. Energy used in the efflux pump :
The energy source:
ABC transporters are dependent on ATP hydrolysis;
)The primary active transport(
MFS, RND and SMR are proton-driven efflux pumps.
MATE transporters consist of a Na/H drug antiporter
system.
)Secondary active transport(
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15. The most important mechanisms of drug resistance:
Inactivating
Change the form of the drug
The aim of antibiotic succession and delegation
Increase the amount of target
Reduced affinity:
Recombination
Modification enzymes
• Efflux pumps
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16. Important note :
The resistance who efflux pump caused by antibiotic depends on
the nature of microorganisms and substrate
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17. Structure of drug efflux systems:
In Gram-positive bacteria:
A cytoplasmic membrane transport proteins that recognize
specific substrate. and the resistance.
In Gram-negative bacteria:
3 component in a system:
Two transport proteins within the membrane.
A periplasmic lipoprotein adapter
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19. ABC tranceporters :
In contrast with prokaryotes,the major mechanism of efflux in
eukaryotes is dependent on proteins that derive their transport
energy from the hydrolysis of ATP.
Has a membrane-binding region of the cytoplasmic membrane
is in addition to the Alpha Helix to allow them The energy of ATP
hydrolysis to transport the drug, unlike other gradient used for
this purpose are proton exchange membrane of the
electrochemical gradient.
Is an arsenic/antimony pump that is responsible for resistance to
the antimonial drug Pentostam in leishmania
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20. ABC tranceporters :
ABC 200 amino acid, domains specific areas ABC, which is the
second hydrophobic combination of 6 alfa hlyksmy.
The presence of walkers areas A, B sequence LSGGQ on all
members of the family.
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22. The SMR family :
The unusual bacteria found
Of the 100 amino acids that made the four-helix
For example : EmrE is in E.coli
QacH-2 resistance in Staphylococcus aureus causes a number
of disinfectants.
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23. The MFS family :
In eukaryotes, bacteria and Archaea are available.
MFS are made of 400 amino acids arranged in 12 Helix
membrane and a cytoplasmic loop between helices 6 and 7 are
large.
Mfs transport of drugs in two classes be:
1- Class B: Transport tetracycline in E Coli
2-class k: Transport tetracycline in Staphylococcus aureus
• MFS characterized by multi-drug pumps that to be anti ports
drug / proton acts and the transmission becomes very large
sugar and drugs.
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25. RND transporters :
Typical emerged were larger than 1,000 amino acids. 12-helix
structure. They have a great second or subsequent
intracytoplasmic Periplasmic between helices 1 and 2, 7 and 8.
There are more gram-negative bacteria.
Pump compounds: toxic metal ions, lipophilic drugs such as
tetracycline, quinolones, and beta-lactamase and
chloramphenicol factors chemotherapy.
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27. Structure :
DNA structure is composed of 3 components:
1-AcrA: inner membrane.
2-AcrB: inner membrane.
3-TolC: in the outer membrane.
The third monomer forming the inner membrane creates an area
that extends Periplasmic..
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28. TOLC PROTEIN;
Is a multifunctional protein. Moving in small drugs and toxins
polypeptide involved.for example: hemolysin .
TolC is divided into two domains:
1-domain beta : in the outer membrane.
2-domain alpha : in the periplasmic space.
TolC several actions have to cross the outer membrane
periplasmic substrates.
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30. β-barrel :
Opens the outer membrane.
Beta consists of 12 strings and are arranged in a right-handed
barrel.
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31. Α-helical :
12 left-handed filament is composed of two types of grape that
are
Short
Tall
Alpha Helix Coils-Coiled arranged in the area and the
composition and structure of alpha and beta binding steadily
alpha helix, like a belt around it were shorter.
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36. MATE transporters :
Of 450 amino acids that have been arranged in 12 Helix These
trans Porter Na or protons act as anti ports.
NorM resistance in Vibrio parahaemolyticus color,
aminoglycosides and fluoroquinolones cause.
YdhE in E.Coli is a cationic resistance to antibiotics cause
MepA in the transfer tetracycline Staphylococcus aureus,
detergents and paints as well.
PepM in Pseudomonas aeruginosa substrate fluoroquinolones,
is ethidium bromide and disinfectants.
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41. Salmonella has a specific regulator, RamA, which controls the
expression ofacrABin response to environmental signals. We
suggest that
RamA is a master regulator ofacrABand that the AcrAB induction
pathway inSalmonellais different from that inE. coli. In one
pathway, bile binds to the RamA protein, which is then
converted from a low to a high activity state. In the other
pathway, indole may activateramAtranscription to induceacrAB.
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42. Inhibitors :
Inhibitors of efflux pumps have great potential as
pharmacological agents that restore the drug suseptibility of
multidrug resistant bacterial pathogens
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43. High-potential pharmacological agents that can be multi-drug
resistant pathogens return sensitivity to the drug.
Example:
Phenylalanine, arginine beta - naphthyl amide
Phenyl-Arginyl ß N-naphtylamide
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