Fig. 4: Schematic illustration of mexZ* colonization behaviour. | Nature Communications

Fig. 4: Schematic illustration of mexZ* colonization behaviour.

From: Mutations in the efflux pump regulator MexZ shift tissue colonization by Pseudomonas aeruginosa to a state of antibiotic tolerance

Fig. 4

Bacteria with a loss-of-function mutation in mexZ are more prone to accumulate inside the epithelial barrier, a compartment in which many antibiotics (represented by pills) barely reach. The mutation in mexZ leads to an overproduction of MexXY-OprM efflux pump, reducing the amount of available OprM porin for the formation of MexAB-OprM efflux pump. The latter causes an alteration of the intracellular amount of Quorum Sensing (QS) signals normally extruded by MexAB-OprM. The disruption of the level of QS signals causes an overexpression of lecA, which encodes a lectin involved in Pseudomonas aeruginosa invasiveness and attachment to epithelial cells. The result is an increased protection from antibiotics during infection of lung epithelia.

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