What Is Efflux In Biology?


Drug efflux is a key mechanism of resistance in Gram-negative bacteria. These systems pump solutes out of the cell. Efflux pumps allow the microorganisms to regulate their internal environment by removing toxic substances, including antimicrobial agents, metabolites and quorum sensing signal molecules.

What is active drug efflux?

Abstract. Active efflux is a common resistance mechanism in a wide range of bacterial pathogens. It is responsible for the transport of such toxic compounds as drugs, toxins, and detergents.

What are efflux pumps made of?

Efflux pumps generally consist of an outer membrane protein, middle periplasmic protein, inner membrane protein, and transmembrane duct. The transmembrane duct is located in the outer membrane of the cell. The duct is also bound to two other proteins: a periplasmic membrane protein and an integral membrane transporter.

Can bacteria produce efflux pumps?

Efflux pumps are membrane proteins that are involved in the export of noxious substances from within the bacterial cell into the external environment. They are found in all species of bacteria, and efflux pump genes can be found in bacterial chromosomes or mobile genetic elements, such as plasmids.

What are efflux pump inhibitors?

Efflux pump inhibitors (EPIs) are molecules that can inhibit efflux pumps; they have been considered potential therapeutic agents for rejuvenating the activity of antibiotics that have already lost their activity against bacteria.

What is the purpose of efflux pump?

Efflux pumps are required for colonization and dissemination during host infection by many pathogenic bacteria and can help bacteria extrude innate host defences. This is particularly clear in Neisseria, which uses RND efflux pumps to extrude host antimicrobial fatty acids and antimicrobial peptides.

What is efflux rate?

Efflux rate of tritiated cholesterol is expressed as the percentage of total radioactive counts removed from the cells during the efflux period.

What are the 6 modes by which bacteria become resistant to antimicrobial agents?

Common modes of antimicrobial drug resistance include drug modification or inactivation, prevention of cellular uptake or efflux, target modification, target overproduction or enzymatic bypass, and target mimicry.

What are efflux genes?

Efflux pumps are transport proteins involved in the extrusion of toxic substrates (including virtually all classes of clinically relevant antibiotics) from within cells into the external environment. These proteins are found in both Gram-positive and -negative bacteria as well as in eukaryotic organisms.

What is the significance of antibiotic resistance?

Antibiotic resistance happens when germs like bacteria and fungi develop the ability to defeat the drugs designed to kill them. That means the germs are not killed and continue to grow. Infections caused by antibiotic-resistant germs are difficult, and sometimes impossible, to treat.

What is a multidrug efflux pump?

Multidrug efflux pumps are ancient elements encoded in the chromosomes of microorganisms. They can confer resistance to antibiotics at different levels: intrinsic resistance, acquired resistance, and transient induced phenotypic resistance.

What is influx and efflux?

“Influx & efflux”—a phrase borrowed from Whitman’s “Song of Myself”—refers to everyday movements whereby outside influences enter bodies, infuse and confuse their organization, and then exit, themselves having been transformed into something new.


How do RND efflux pumps work?

RND-type drug efflux pumps from Gram-negative bacteria: molecular mechanism and inhibition. Drug efflux protein complexes confer multidrug resistance on bacteria by transporting a wide spectrum of structurally diverse antibiotics. Moreover, organisms can only acquire resistance in the presence of an active efflux pump.

What is AcrAB TolC?

AcrAB-TolC is a RND-based tripartite efflux pump, comprised of the outer membrane protein TolC, the periplasmic membrane fusion protein AcrA, and the inner membrane transporter AcrB, which cycles through three different conformational states during the drug transport process: access (L), binding (T) and extrusion (O) ( …

How is efflux drug measured?

The cells are then reenergized, e.g., by the addition of glucose, allowing efflux to restart and the dye is effluxed out of the cells. Efflux is directly measured by recording the change in fluorescence over time as the dye is pumped out of the cells.

What is efflux Class 11?

Efflux is something going out. When there is an opening in a container with liquid, it is ejected through the opening with a speed which is called the speed of efflux. Previous videos – ? Introduction to ‘Mechanical Properties of Fluids’ for Class 11.

Which is the efflux transporter?

The cellular bouncers are efflux transporter proteins belonging to the adenosine triphosphate (ATP)-binding cassette (ABC) superfamily, one of the largest families encoded in the human genome (1).

Do efflux pumps use ATP?

Extrusion of compounds by efflux pumps is energy dependent. ABC transporters use ATP hydrolysis for efflux. The rest of the characterized pumps use proton motive force. … In bacteria, overexpression of some efflux pumps can result in decreased susceptibility to multiple antibiotics.

What role do efflux pumps serve for bacterial cells in addition to pumping out antibiotics?

Bacterial efflux pumps (EPs) are proteins that are localized and imbedded in the plasma membrane of the bacterium and whose function is to recognize noxious agents that have penetrated the protective cell wall of the organism and reached the periplasm or cytoplasm, and extrude them before they reach their intended

Do Gram positive bacteria have efflux pumps?

In Gram-positive bacteria, the clinically significant efflux pumps are members of the MFS family, for example NorA in Staphylococcus aureus and PmrA in Streptococcus pneumoniae .

What is NorA efflux pump?

aureus protein NorA, an efflux pump belonging to the major facilitator superfamily (MFS), contributes to resistance to fluoroquinolones (e.g., ciprofloxacin), biocides, dyes, quaternary ammonium compounds, and antiseptics. … In the present study, we screened approved drugs for possible efflux pump inhibition.

Which of the following are side effects associated with antimicrobial drugs?

Common side effects of antibiotics

  • nausea.
  • indigestion.
  • vomiting.
  • diarrhea.
  • bloating.
  • feeling of fullness.
  • loss of appetite.
  • stomach cramping or pain.

What is PGP substrate?

Efflux transporters such as P-glycoprotein play an important role in drug transport in many organs. … Important substrates of P-glycoprotein include calcium channel blockers, cyclosporin, dabigatran etexilate, digoxin, erythromycin, loperamide, protease inhibitors and tacrolimus.