NorA and Tet38 efflux pumps enable survival in the cystic fibrosis airway environment, resistance to antibiotics, and coinfection with .

Efflux pumps play multiple roles in bacterial physiology, environmental adaptation, and antibiotic resistance. Early cystic fibrosis (CF) airway infections start with (), often later followed by () infections. In this study, we have evaluated the role of pumps NorA and Tet38 in survival and interaction with in CF patients. Data showed a ≥4-logCFU/mL growth deficit of mutants and in an artificial sputum medium (ASM), suggesting NorA and Tet38 contributed to growth in CF sputum. In ASM, mucin activated but inhibited while extracellular DNA activated but inhibited , demonstrating complementary roles of mucin and DNA in affecting NorA and Tet38 expression. Furthermore, exposure of wild type to -excreted molecules affected pump expression; 3,4-dihydroxy-2-heptylquinoline PQS caused an increase in but a decrease in , 4-hydroxy-2-heptylquinoline HHQ caused a decrease in and , and pyocyanin PYO caused a modest increase in , demonstrating differing additional roles of -secreted molecules influencing NorA and Tet38 expression. Evaluation of 48 randomly selected unique CF-associated showed that 18.8% were NorA-overexpressors and 10.4% were Tet38-overexpressors. NorA-overexpressors showed a fourfold increase in pyocyanin MIC and ≥16-fold in ciprofloxacin MIC. Furthermore, 89% of NorA-overexpressors carried an insertion of CAAT/ACAA/CTAT at the (-10) motif of the promoter, and 62.5% of these were co-isolated with .These data showed that survives killing in CF sputum conditions using sputum key components and -specific signal molecules to regulate NorA and Tet38 expression.