Interference with lipoprotein maturation sensitizes methicillin-resistantStaphylococcus aureusto human group IIA secreted phospholipase A₂and daptomycin

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) has been classified as a high priority pathogen by the World Health Organization underlining the high demand for new therapeutics to treat infections. Human group IIA secreted phospholipase A2 (hGIIA) is among the most potent bactericidal proteins against Gram-positive bacteria, including S. aureus. To determine hGIIA-resistance mechanisms of MRSA we screened the Nebraska Transposon Mutant Library using a sublethal concentration of recombinant hGIIA. We identified and confirmed the role of lspA, encoding the lipoprotein signal peptidase LspA, as a new hGIIA resistance gene in both in vitro assays and an infection model in hGIIA-transgenic mice. Increased susceptibility of the lspA mutant was associated with faster and increased cell wall penetration of hGIIA. Moreover, lspA deletion also increased susceptibility to daptomycin, a last-resort antibiotic to treat MRSA infections. Exposure of MRSA wild-type to the LspA-specific inhibitors globomycin and myxovirescin A1 induced a lspA mutant phenotype with regard to hGIIA and daptomycin killing. Analysis of >26,000 S. aureus genomes showed that LspA is highly sequence-conserved, suggesting that LspA inhibition could be applied universally. The role of LspA in hGIIA resistance was not restricted to MRSA since Streptococcus mutans and Enterococcus faecalis were also more hGIIA-susceptible after lspA deletion or LspA inhibition, respectively. Overall, our data suggest that pharmacological blocking of LspA may disarm Gram-positive pathogens, including MRSA, to enhance clearance by innate host defense molecules and clinically-applied antibiotics.

In Vitro, In Vivo, and In Silico Activities of Ginkgolic Acid C15:1 against Streptococcus agalactiae Clinical Isolates

“…Likewise, lspA deletion S. aureus was more susceptible to daptomycin, a last-resort antibiotic target membrane. 46 According to Kuijk et al, blocking lspA has a concentration-dependent influence on membrane permeability and depolarization. 46 Lipoproteins are also crucial for the biosynthesis of cell membranes.…”

“…46 According to Kuijk et al, blocking lspA has a concentration-dependent influence on membrane permeability and depolarization. 46 Lipoproteins are also crucial for the biosynthesis of cell membranes. Therefore, we suspect that the destruction of cell membranes caused by GA (15:1) treatment is likely attributable to both functional inhibition of lspA by GA and indirect targeting of GA l'Etoile, France) was used to identify all isolates before they were inoculated onto plate media for MALDI-TOF MS (IVD MALDI Biotyper, Germany) identification.…”

Interference with Lipoprotein Maturation Sensitizes Methicillin-Resistant <b><i>Staphylococcus aureus</i></b> to Human Group IIA-Secreted Phospholipase A₂ and Daptomycin

“…Data and other resources are available upon request from the corresponding author. A preprint version of this article is available on bioRxiv [80].…”