A Genetic Screen Reveals Novel Targets to Render Pseudomonas aeruginosa Sensitive to Lysozyme and Cell Wall-Targeting Antibiotics

Abstract

Pseudomonas aeruginosa is capable of establishing airway infections. Human airway mucus contains a large amount of lysozyme, which hydrolyzes bacterial cell walls. P. aeruginosa, however, is known to be resistant to lysozyme. Here, we performed a genetic screen using a mutant library of PAO1, a prototype P. aeruginosa strain, and identified two mutants (ΔbamB and ΔfabY) that exhibited decrease in survival after lysozyme treatment. The bamB and fabY genes encode an outer membrane assembly protein and a fatty acid synthesis enzyme, respectively. These two mutants displayed retarded growth in the airway mucus secretion (AMS). In addition, these mutants exhibited reduced virulence and compromised survival fitness in two different in vivo infection models. The mutants also showed susceptibility to several antibiotics. Especially, ΔbamB mutant was very sensitive to vancomycin, ampicillin, and ceftazidime that target cell wall synthesis. The ΔfabY displayed compromised membrane integrity. In conclusion, this study uncovered a common aspect of two different P. aeruginosa mutants with pleiotropic phenotypes, and suggests that BamB and FabY could be novel potential drug targets for the treatment of P. aeruginosa infection.

Deprivation of the Periplasmic Chaperone SurA Reduces Virulence and Restores Antibiotic Susceptibility of Multidrug-Resistant Pseudomonas aeruginosa

“…Like in Kp , several porins as well as the autotransporter invasin were significantly decreased in Ye . Another study addressing the role of BamB in Pa PAO1 already showed that bamB deletion also leads to sensitization against lysozyme, vancomycin and cefotaxime (Lee et al, 2017), which could be confirmed in our study. However, in contrast to Ye or Kp , neither increased sensitivity against human serum nor attenuation of virulence was observed.…”

“…Thus, BamB may contribute to the assembly of porins and autotransporters in Pa , but in contrast to the function of BamB in Kp or Ye , the rather mild phenotypes we found upon deletion of bamB in Pa PA14 do not justify considering it as a promising target for drug development from our point of view. Nonetheless, given the results that have been obtained with e.g., Pa PAO1 and Salmonella (Namdari et al, 2012; Lee et al, 2017), it cannot be ruled out that the importance of BamB for OM composition and consequently the resulting phenotypes might vary significantly between strains and species.…”

“…In Pa , BamA, and the BamE-homolog OmlA have already been recognized to play a role in the stability of the OM and susceptibility to environmental stress (Ochsner et al, 1999; Yorgey et al, 2001; Hoang et al, 2011). For BamB of Pa , an enhanced susceptibility against lysozyme and cell wall targeting antibiotics as well as a decreased growth in vivo have been demonstrated recently (Lee et al, 2017).…”

Non‐invasive, ratiometric determination of intracellular pH in Pseudomonas species using a novel genetically encoded indicator

“…This phenomenon has been reported for P . aeruginosa when exposed to different antibiotics, including treatment with CIP (Day et al ., ; Lee et al ., ).…”

A multi-host approach to identify a transposon mutant of Pseudomonas aeruginosa LESB58 lacking full virulence

“…It was demonstrated that a bamB mutant in reference strain PAO1 is highly sensitive to antibiotics (especially those targeting cell wall synthesis) and lysozymes [ 27 ]. Therefore, we tested the resistance of the STM PALES_11731 mutant to piperacillin (a β-lactam antibiotic), tobramycin (an aminoglycoside antibiotic) and lysozymes.…”