So excited to finally see this out!Tyler’s tour de force from his PhD. Using an evolve and resequence approach, we tracked how Listeria monocytogenes adapts to sublethal exposure to the sanitizer benzalkonium chloride. Genomics, phenotyping, and a whole lot more. journals.asm.org/doi/10.1128/...
Experimental evolution reveals genetic and transcriptomic mechanisms underlying benzalkonium chloride tolerance and fluoroquinolone cross-resistance in Listeria monocytogenes | mSystems
Listeria monocytogenes persistence in food facilities poses major public health and economic burdens. We modeled long-term exposure to sublethal benzalkonium chloride (BAC) to approximate conditions similar to those in food processing facility drains and uncovered two complementary routes to sanitizer tolerance: (i) repeated inactivation of the fepR regulator with accompanying alterations in the fepA efflux pump, driving BAC tolerance and fluoroquinolone cross-resistance, and (ii) convergence on mutations in ptsH (HPr) within the phosphotransferase system, supported by RNA-seq upregulation of phosphotransferase system (PTS) pathways and biophysical evidence of destabilized HPr variants. Efflux inhibition reduced BAC tolerance where fepR/fepA was mutated but had limited impact in a bcrABC-positive background (where bcrABC encodes a plasmid-borne BAC resistance efflux cassette), highlighting the role of genetic context. These findings connect sanitizer adaptation to antibiotic resistance and identify PTS signaling as a systems-level contributor, informing surveillance and sanitation strategies in food production.
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