Impact of Multiple Single-Nucleotide Polymorphisms Within mprF on Daptomycin Resistance in Staphylococcus aureus.
A number of single nucleotide polymorphisms (SNPs) within the mprF open reading frame (ORF) have been associated with daptomycin-resistance (DAP-R) in Staphylococcus aureus. Such SNPs have been found throughout the mprF ORF, although there are clearly preferred "hot spots" within this gene frequently linked to DAP-R phenotype. These mprF SNPs are often correlated with a gain-in-function phenotype, either in terms of increased production (synthase activity) and/or enhanced translocation (translocase activity) of lysyl-phosphatidylglycerol (L-PG) within its cell membrane. However, it is unclear if multiple hot spot mprF SNPs can accumulate within mprF ORFs and cause additive elevations of DAP minimum inhibitory concentrations (MICs). In this study, we used a previously well-characterized plasmid complementation system in S. aureus Newman ΔmprF mutant to express: (1) single point-mutated forms of mprF ORFs cloned from two DAP-R S. aureus strains (mprFS295L or mprFT345A) and (2) dual point-mutated forms of mprF ORFs simultaneously harboring SNPs in the central bifunctional domain and synthase domain in MprF, respectively (mprFS295L+L826F or mprFT345A+L826F). The current study revealed that, although individual hot spot point mutations within mprF ORF can recapitulate signature DAP-R-associated phenotypes (i.e., increased DAP MICs, enhanced surface positive charge, and increased L-PG synthesis), accumulation of such hot spot point mutations paradoxically caused reduction in these latter three metrics.
['Yang|Soo-Jin|SJ|', 'Mishra|Nagendra N|NN|', 'Kang|Kyoung-Mi|KM|', 'Lee|Gi-Yong|GY|', 'Park|Jong-Hwan|JH|', 'Bayer|Arnold S|AS|']
D019881:Aminoacyltransferases D000900:Anti-Bacterial Agents D001426:Bacterial Proteins D002462:Cell Membrane D017576:Daptomycin D024881:Drug Resistance, Bacterial D005838:Genotype D008826:Microbial Sensitivity Tests D016366:Open Reading Frames D010957:Plasmids D020641:Polymorphism, Single Nucleotide D013203:Staphylococcal Infections D013211:Staphylococcus aureus
mprF daptomycin Staphylococcus aureus antimicrobial peptides