Genetic alterations in methicillin-susceptible Staphylococcus aureus associated with high vancomycin minimum inhibitory concentration

Copyright © 2023 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved..

BACKGROUND: There are many reports on gene mutations observed in methicillin-resistant Staphylococcus aureus (MRSA) showing reduced susceptibility to vancomycin. However, there are limited studies on the genetic alterations that contribute to high vancomycin minimum inhibitory concentrations (MICs) in methicillin-susceptible S. aureus (MSSA). This study aimed to compare MSSA strains with high vancomycin MICs with those with low MICs, and to identify specific genetic alterations associated with increased vancomycin MICs.

METHODS: In total, 124 MSSA strains were analysed, with 62 having vancomycin MICs of 1-2 mg/L (MS-HV) and the remaining 62 having MICs <1 mg/L (MS-LV) as control. Polymerase chain reaction amplification and sequencing were conducted to identify point mutations and amino acid changes in the vraSR, graRS and walRK operons and rpoB gene. The number of single nucleotide polymorphisms (SNPs) and specific mutations in the indicated gene were compared between the two groups.

RESULTS: The MS-HV strains had a significantly higher median number of SNPs in studied genes than the MS-LV strains (5 vs 3; P < 0.0001), with higher frequency of SNPs in the graR and walK genes. The MS-HV strains also displayed a significantly higher prevalence of specific mutations in the graR gene (V135I, I136V and V136I) compared with the MS-LV strains. The odds of having a high vancomycin MIC was 5.54 times higher in strains with a mutation in the graR gene, and 5.32 times higher in strains with a mutation in the walK gene, compared with those without these mutations.

CONCLUSIONS: Mutations in the graR and walK genes may contribute to reduced vancomycin susceptibility in MSSA. This study gives key insights into the mechanisms underlying this phenomenon.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:62

Enthalten in:

International journal of antimicrobial agents - 62(2023), 6 vom: 18. Dez., Seite 106971

Sprache:

Englisch

Beteiligte Personen:

Kang, Yu Ri [VerfasserIn]
Chung, Doo Ryeon [VerfasserIn]
Ko, Jae-Hoon [VerfasserIn]
Huh, Kyungmin [VerfasserIn]
Cho, Sun Young [VerfasserIn]
Kang, Cheol-In [VerfasserIn]
Peck, Kyong Ran [VerfasserIn]

Links:

Volltext

Themen:

6Q205EH1VU
Anti-Bacterial Agents
Antimicrobial resistance
Gene mutations
Journal Article
Methicillin
Methicillin-resistant Staphylococcus aureus
Q91FH1328A
Single nucleotide polymorphism
Vancomycin
Vancomycin resistance

Anmerkungen:

Date Completed 04.12.2023

Date Revised 04.12.2023

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.ijantimicag.2023.106971

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM362136696