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How Bacteria Communicate?

Know about Bacterial Quorum Sensing

By Jay Prakash Yadav*, Pankaj Dhaka** and Deepthi Vijay**

WHAT IS QUORUM SENSING? cell medium. Initially, they ascribed public health risk and ultimately
Quorum sensing (QS) is cell-to- this conditioning of medium is due bacterial drug resistance. The biofi lm
cell communication system in to the growing population of cells acts as an effective drug barrier and
bacteria. It occurs due to the and termed this phenomenon as reduces antibiotic permeability.
production, secretion and sensing of “autoinduction”. In microenvironment of biofi lm,
extracellular molecules or signals, bacteria produce heterogeneity
called as autoinducers (AIs). The AIs WHEN DO BACTERIA USE QUORUM (difference in nutrient concentration
take parts in many physiological SENSING? and bacterial secretion) and regulate
metabolic processes of cells, such as From public health perspective, the drug resistance. The extreme
bioluminescence, biofi lm formation, the bacterial QS signaling environmental changes outside

bacterial virulence, antibiotic play important roles in biofi lm the biofilm, such as changes in
production, motility, sporulation etc. formation, antimicrobial resistance temperature, pH and concentration
The process of QS starts whenever and bacterial virulence. These of certain chemicals regulate the
bacterial cell number increases phenomena occur due to production, physiological and biochemical
beyond a particular point, known as release and detection of extracellular functions of bacteria by reducing its

threshold concentration. The signal signal molecules (autoinducers). growth efficiency and forms a state
molecules (AIs) interact with the These molecules allow cells to of resistance to antibiotics (Zhao et
bacterial receptors in the process of coordinate gene expression based al., 2020).
cell-to-cell communication (Figure 1). on bacterial cell density in the outer
cell environment. Antibiotic resistance: The large-
HOW WAS QUORUM SENSING scale use of antibiotics in clinical
DISCOVERED? Biofi lm formation: Biofi lm formation treatment and animal production
Quorum sensing was fi rst described occurs in the bacteria through leads to the emergence of multi
in1970, by Kenneth Nealson, Terry the production of extracellular drug resistant (MDR) pathogens.
Platt, and J. Woodland Hastings mucopolysaccharides and adhesion Increased antibiotic resistance
in the bioluminescent marine matrix. The biofilm formation on against common and available

bacterium- Vibrio fi scheri through the hospital devices, pasteurization antibiotics for human and animal
the identification of “autoinducing” plants, teeth surfaces and other medicine may pose another

activity in the high density bacterial pathological tissues may pose major pandemic in near future. Bacteria
hides the harmful effect of antibiotics
and survives in living organisms
by following the mechanisms of
chemical alteration of antibiotics
by secretion of modifi ed enzymes
in cell environment, effl ux pump
derived elimination of antibiotics

and modification of drug target sites
(Zhao et al., 2020).

Bacterial virulence: Bacteria evade
the host’s immune response through
the production of several virulence
factors, which is essential for the
pathological damage and course
Figure 1: An overview of population dependent quorum sensing among bacteria

Food Marketing & Technology 24 April 2021