Identification of Single Nucleotide Polymorphisms Associated with Hyperproduction of Alpha-Toxin in Staphylococcus aureus

ABSTRACTSingle nucleotide polymorphisms (SNPs) within themprFopen reading frame (ORF) have been commonly observed in daptomycin-resistant (DAPr)Staphylococcus aureusstrains. Such SNPs are usually associated with a gain-in-function phenotype, in terms of either increased synthesis or enhanced translocation (flipping) of lysyl-phosphatidylglycerol (L-PG). However, it is unclear if suchmprFSNPs are causal in DAPrstrains or are merely a biomarker for this phenotype. In this study, we used an isogenic set ofS. aureusstrains: (i) Newman, (ii) its isogenic ΔmprFmutant, and (iii) several intransplasmid complementation constructs, expressing either a wild-type or point-mutated form of themprFORF cloned from two isogenic DAP-susceptible (DAPs)-DAPrstrain pairs (616-701 and MRSA11/11-REF2145). Complementation of the ΔmprFstrain with singly point-mutatedmprFgenes (mprFS295LormprFT345A) revealed that (i) individual and distinct point mutations within themprFORF can recapitulate phenotypes observed in donor strains (i.e., changes in DAP MICs, positive surface charge, and cell membrane phospholipid profiles) and (ii) these gain-in-function SNPs (i.e., enhanced L-PG synthesis) likely promote reduced DAP binding toS. aureusby a charge repulsion mechanism. Thus, for these two DAPrstrains, the definedmprFSNPs appear to be causally related to this phenotype.

Download Full-text

Single-nucleotide polymorphisms in a vancomycin-resistant Staphylococcus aureus strain based on whole-genome sequencing

Archives of Microbiology ◽

10.1007/s00203-020-01906-y ◽

2020 ◽

Vol 202 (8) ◽

pp. 2255-2261

Author(s):

Jung Wook Kim ◽

Kwang Jun Lee

Keyword(s):

Staphylococcus Aureus ◽

Single Nucleotide Polymorphisms ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Aureus Strain ◽

Whole Genome ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Vancomycin Resistant

Download Full-text

Evolution and Single-Nucleotide Polymorphisms in Methicillin-Resistant Staphylococcus aureus Strains with Reduced Susceptibility to Vancomycin and Daptomycin, Based on Determination of the Complete Genome

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05159-14 ◽

2015 ◽

Vol 59 (6) ◽

pp. 3585-3587 ◽

Cited By ~ 10

Author(s):

Tetsuo Yamaguchi ◽

Shingo Suzuki ◽

Sakiko Okamura ◽

Yuri Miura ◽

Ayaka Tsukimori ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Single Nucleotide Polymorphisms ◽

Complete Genome ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Methicillin Resistant ◽

Content Type ◽

Rifampin Resistance ◽

Generation Sequencing

ABSTRACTWe obtained a series of methicillin-resistantStaphylococcus aureusisolates, including both daptomycin-susceptible strain TD1 and daptomycin-resistant strain TD4, from a patient. We determined the complete genome sequences of TD1 and TD4 using next-generation sequencing, and only four single-nucleotide polymorphisms (SNPs) were identified, one each incapB(E58K),rpoB(H481Y),lytN(I16V), andmprF(V351E). We determined that these four SNPs were sufficient to cause the strains to develop daptomycin, vancomycin, and rifampin resistance.

Download Full-text

Frequency and Distribution of Single-Nucleotide Polymorphisms withinmprFin Methicillin-Resistant Staphylococcus aureus Clinical Isolates and Their Role in Cross-Resistance to Daptomycin and Host Defense Antimicrobial Peptides

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00970-15 ◽

2015 ◽

Vol 59 (8) ◽

pp. 4930-4937 ◽

Cited By ~ 46

Author(s):

Arnold S. Bayer ◽

Nagendra N. Mishra ◽

Liang Chen ◽

Barry N. Kreiswirth ◽

Aileen Rubio ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Single Nucleotide Polymorphisms ◽

Surface Charge ◽

Host Defense ◽

Cross Resistance ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Methicillin Resistant ◽

Content Type ◽

Positive Surface Charge

ABSTRACTMprF is responsible for the lysinylation of phosphatidylglycerol (PG) to synthesize the positively charged phospholipid (PL) species, lysyl-PG (L-PG). It has been proposed that the single-nucleotide polymorphisms (SNPs) within themprFopen reading frame (ORF) are associated with a gain-in-function phenotype in terms of daptomycin resistance inStaphylococcus aureus. (Note that although the official term is daptomycin nonsusceptibility, we use the term daptomycin resistance in this paper for ease of presentation.) Using 22 daptomycin-susceptible (DAPs)/daptomycin-resistant (DAPr) clinical methicillin-resistantS. aureus(MRSA) strain pairs, we assessed (i) the frequencies and distribution of putativemprFgain-in-function SNPs, (ii) the relationships of the SNPs to both daptomycin resistance and cross-resistance to the prototypical endovascular host defense peptide (HDP) thrombin-induced platelet microbicidal protein (tPMP), and (iii) the impact ofmprFSNPs on positive surface charge phenotype and modifications of membrane PL profiles. Most of themprFSNPs identified in our DAPrstrains were clustered within the two MprF loci, (i) the central bifunctional domain and (ii) the C-terminal synthase domain. Moreover, we were able to correlate the presence and location ofmprFSNPs in DAPrstrains with HDP cross-resistance, positive surface charge, and L-PG profiles. Although DAPrstrains withmprFSNPs in the bifunctional domain showed higher resistance to tPMPs than DAPrstrains with SNPs in the synthase domain, this relationship was not observed in positive surface charge assays. These results demonstrated that both charge-mediated and -unrelated mechanisms are involved in DAP resistance and HDP cross-resistance inS. aureus.

Download Full-text

Detection of single nucleotide polymorphisms based on the multilocus sequence typing database of Staphylococcus aureus using locked nucleic acid oligonucleotides

Journal of Medical Microbiology ◽

10.1099/jmm.0.007534-0 ◽

2009 ◽

Vol 58 (5) ◽

pp. 693-695 ◽

Cited By ~ 1

Author(s):

M. Stone ◽

K. Bamford ◽

J. Wain

Keyword(s):

Staphylococcus Aureus ◽

Nucleic Acid ◽

Single Nucleotide Polymorphisms ◽

Multilocus Sequence Typing ◽

Locked Nucleic Acid ◽

Nucleotide Polymorphisms ◽

Single Nucleotide

Download Full-text

Association between Type AblaZGene Polymorphism and Cefazolin Inoculum Effect in Methicillin-Susceptible Staphylococcus aureus

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01517-16 ◽

2016 ◽

Vol 60 (11) ◽

pp. 6928-6932 ◽

Cited By ~ 7

Author(s):

Sun Hee Lee ◽

Wan Beom Park ◽

Shinwon Lee ◽

Sohee Park ◽

Shin Woo Kim ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Amino Acid ◽

Single Nucleotide Polymorphisms ◽

Amino Acid Sequence ◽

Type A ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Inoculum Concentration ◽

Content Type ◽

Inoculum Effect

ABSTRACTSome proportion of type AblaZgene-positive methicillin-susceptibleStaphylococcus aureusstrains exhibit the cefazolin inoculum effect (CIE). The type AblaZgene was divided into two groups by single nucleotide polymorphisms (SNPs) at Ser226Pro and Cys229Tyr. The median cefazolin MICs at a high inoculum concentration were 5.69 μg/ml for the Ser-Cys group and 40.32 μg/ml for the Pro-Tyr group (P= 0.01). The SNPs at codons 226 and 229 in the amino acid sequence encoded by theblaZgene were closely associated with the CIE.

Download Full-text