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

Abstract

Pseudomonas aeruginosa is one of the main causative agents of nosocomial infections and the spread of multidrug-resistant strains is rising. Therefore, novel strategies for therapy are urgently required. The outer membrane composition of Gram-negative pathogens and especially of Pa restricts the efficacy of antibiotic entry into the cell and determines virulence. For efficient outer membrane protein biogenesis, the β-barrel assembly machinery (BAM) complex in the outer membrane and periplasmic chaperones like Skp and SurA are crucial. Previous studies indicated that the importance of individual proteins involved in outer membrane protein biogenesis may vary between different Gram-negative species. In addition, since multidrug-resistant Pa strains pose a serious global threat, the interference with both virulence and antibiotic resistance by disturbing outer membrane protein biogenesis might be a new strategy to cope with this challenge. Therefore, deletion mutants of the non-essential BAM complex components bamB and bamC , of the skp homolog hlpA as well as a conditional mutant of surA were investigated. The most profound effects for both traits were associated with reduced levels of SurA, characterized by increased membrane permeability, enhanced sensitivity to antibiotic treatment and attenuation of virulence in a Galleria mellonella infection model. Strikingly, the depletion of SurA in a multidrug-resistant clinical bloodstream isolate re-sensitized the strain to antibiotic treatment. From our data we conclude that SurA of Pa serves as a promising target for developing a drug that shows antiinfective activity and re-sensitizes multidrug-resistant strains to antibiotics.

Identification of Drug Resistance Determinants in a Clinical Isolate of Pseudomonas aeruginosa by High-Density Transposon Mutagenesis

“…RNA isolation and qRT-PCR. RNA isolation and quantitative reverse transcription-PCR (qRT-PCR) were performed as previously described (68).…”

Maintaining Integrity Under Stress: Envelope Stress Response Regulation of Pathogenesis in Gram-Negative Bacteria

“…Several of the chaperones and proteases involved in maintenance of OM and periplasmic homeostasis in E. coli and Salmonella are conserved in Pseudomonas sp. A recent paper described a surA deletion re-sensitizes a MDR strain to antibiotics, suggesting that SurA could be a promising therapeutic target (Klein et al, 2019). Moreover, in support of this conclusion, deletion of surA also increased sensitivity to normal human serum.…”

Comparison of type 5d autotransporter phospholipases demonstrates a correlation between high activity and intracellular pathogenic lifestyle

“…The Pseudomonas aeruginosa type 5d secretion system (T5dSS), called patatin-like protein D (PlpD), belongs to the family of patatin-like lipolytic enzymes (11). In accordance with the T5SS in general, PlpD possesses an N-terminal signal sequence for Sec-dependent translocation across the inner membrane and is dependent on the periplasmic chaperone SurA (12,13) and presumably the BAM complex for integration of the C-terminal 16-stranded β-barrel domain into the outer membrane (9,(13)(14)(15). The β-barrel is connected by a single periplasmic polypeptide transport associated (POTRA) domain and a short linker to the N-terminal effector domain or passenger, which confers the lipolytic activity of PlpD.…”