Nonmucoid conversion of mucoid Pseudomonas aeruginosa induced by sulfate-stimulated growth

作者：Min Kyung Bae; Lee Kang Mu; Oh Young Taek; Yoon Sang Sun^*

来源：FEMS Microbiology Letters, 2014, 360(2): 157-166.

DOI：10.1111/1574-6968.12600

• Pseudomonas aeruginosa
• mucoid
• sulfate
• nonmucoid reversion
• alginate

Alginate-overproducing mucoid Pseudomonas aeruginosa, responsible for chronic airway infections in cystic fibrosis (CF) patients, is resistant to antibiotic treatments and host immune clearance. In this study, we performed a phenotype microarray screen and identified sulfate ion as a molecule that can suppress alginate production. When a mucoid P.aeruginosa strain CM21 and additional mucoid isolates were grown with 5% sodium sulfate, significantly decreased levels of alginate were produced. Suppression of alginate production was also induced by other sulfate salts. Expression of a reporter gene fused to the algD promoter was considerably decreased when grown with sulfate. Furthermore, bacterial cell shape was abnormally altered in CM21, but not in PAO1, a prototype nonmucoid strain, suggesting that sulfate-stimulated cell shape change is associated with transcriptional suppression of the alginate operon. Finally, a CM21 lpxC mutant defective in lipid A biosynthesis continued to produce alginate and maintained the correct cell shape when grown with sulfate. These results suggest a potential involvement of lipoploysaccharide biosynthesis in the sulfate-induced reversion to nonmucoid phenotype. This study proposes a novel strategy that can be potentially applied to treat persistent infection by recalcitrant mucoid P.aeruginosa.

• 出版日期2014-11