Genome Sequence Comparison of Staphylococcus aureus TX0117 and a Beta-Lactamase-Cured Derivative Shows Increased Cationic Peptide Resistance Accompanying Mutations in relA and mnaA.

Irene L G Newton,Mia Jade Sales,Bernhard Palsson,Kavindra V Singh,Cesar Arias,Jonathan M Monk,Barbara E Murray,George Sakoulas,Richard Szubin

doi:10.1128/mra.01515-19

Abstract

Staphylococcus aureus strain TX0117 is a methicillin-susceptible bacterium with type A beta-lactamase exhibiting a high cefazolin inoculum effect. TX0117 was cured of blaZ, yielding TX0117c with increased antimicrobial peptide resistance. The sequencing and genome assembly of TX0117 elucidate six mutations between TX0117 and TX0117c, including relA truncation and mnA_1 substitution.

Highlights

Staphylococcus aureus strain TX0117 is a methicillin-susceptible bacterium with type A beta-lactamase exhibiting a high cefazolin inoculum effect
Our evaluation of TX0117 and TX0117c showed subtle but consistent increased resistance to cationic antimicrobial peptides in strain TX0117c compared to that in the TX0117 parent strain (Fig. 1), leading us to hypothesize that in addition to curing the Volume 9 Issue 18 e01515-19
The resulting short reads were checked for quality control using FastQC, which showed that 698,669 paired-end reads were produced in the TX0117c sequencing run with 32% GC content, and approximately 710,028 paired-end reads were produced in the TX0117 run with 33% GC content

Summary

Introduction

Staphylococcus aureus strain TX0117 is a methicillin-susceptible bacterium with type A beta-lactamase exhibiting a high cefazolin inoculum effect. Strain of beta-lactamase, novobiocin and heat treatment may have coselected previously uncharacterized mutations in TX0117c. We mapped short reads from the TX0117c genome to our newly sequenced and assembled TX0117 genome using breseq version 0.31.0 (option breseq -r TX0117_reference.gbk TX0117c_R1.fastq TX0117c_R2.fasta) [21].

Results

Conclusion