Development of an Amplicon Nanopore Sequencing Strategy for Detection of Mutations Conferring Intermediate Resistance to Vancomycin in Staphylococcus aureus Strains

ABSTRACT Staphylococcus aureus is a major cause of bacteremia and other hospital-acquired infections. The cell-wall active antibiotic vancomycin is commonly used to treat both methicillin-resistant (MRSA) and sensitive (MSSA) infections. Vancomycin intermediate S. aureus (VISA) variants can arise th...

Full description

Bibliographic Details
Main Authors: Abraham G. Moller, Robert A. Petit, Michelle H. Davis, Timothy D. Read
Format: Article
Language:English
Published: American Society for Microbiology 2023-02-01
Series:Microbiology Spectrum
Subjects:
Online Access:https://journals.asm.org/doi/10.1128/spectrum.02728-22
_version_ 1811164351631982592
author Abraham G. Moller
Robert A. Petit
Michelle H. Davis
Timothy D. Read
author_facet Abraham G. Moller
Robert A. Petit
Michelle H. Davis
Timothy D. Read
author_sort Abraham G. Moller
collection DOAJ
description ABSTRACT Staphylococcus aureus is a major cause of bacteremia and other hospital-acquired infections. The cell-wall active antibiotic vancomycin is commonly used to treat both methicillin-resistant (MRSA) and sensitive (MSSA) infections. Vancomycin intermediate S. aureus (VISA) variants can arise through de novo mutations. Here, we performed pilot experiments to develop a combined PCR/long-read sequencing-based method for detection of previously known VISA-causing mutations. Primers were designed to generate 10 amplicons covering 16 genes associated with the VISA phenotype. We sequenced amplicon pools as long reads with Oxford Nanopore adapter ligation on Flongle flow cells. We then detected mutations by mapping reads against a parental consensus or known reference sequence and comparing called variants against a database of known VISA mutations from laboratory selection. Each amplicon in the pool was sequenced to high (>1,000×) coverage, and no relationship was found between amplicon length and coverage. We also were able to detect the causative mutation (walK 646C>G) in a VISA mutant derived from the USA300 strain (N384-3 from parental strain N384). Mixing mutant (N384-3) and parental (N384) DNA at various ratios from 0 to 1 mutant suggested a mutation detection threshold of the average minor allele frequency (6.5%) at 95% confidence (two standard errors above mean mutation frequency). The study lays the groundwork for direct S. aureus antibiotic resistance genotype inference using rapid nanopore sequencing from clinical samples. IMPORTANCE Bacteremia mortality is known to increase rapidly with time after infection, making rapid diagnostics and treatment necessary. Successful treatment depends on correct administration of antibiotics based on knowledge of strain antibiotic susceptibility. Staphylococcus aureus is a major causative agent of bacteremia that is also commonly antibiotic resistant. In this work, we develop a method to accelerate detection of a complex, polygenic antibiotic resistance phenotype in S. aureus, vancomycin-intermediate resistance (VISA), through long-read genomic sequencing of amplicons representing genes most commonly mutated in VISA selection. This method both rapidly identifies VISA genotypes and incorporates the most comprehensive database of VISA genetic determinants known to date.
first_indexed 2024-04-10T15:20:14Z
format Article
id doaj.art-376d62c5359e46f696d2af205e123962
institution Directory Open Access Journal
issn 2165-0497
language English
last_indexed 2024-04-10T15:20:14Z
publishDate 2023-02-01
publisher American Society for Microbiology
record_format Article
series Microbiology Spectrum
spelling doaj.art-376d62c5359e46f696d2af205e1239622023-02-14T14:15:51ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972023-02-0111110.1128/spectrum.02728-22Development of an Amplicon Nanopore Sequencing Strategy for Detection of Mutations Conferring Intermediate Resistance to Vancomycin in Staphylococcus aureus StrainsAbraham G. Moller0Robert A. Petit1Michelle H. Davis2Timothy D. Read3Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, Georgia, USADivision of Infectious Diseases, Department of Medicine, Emory University, Atlanta, Georgia, USADivision of Infectious Diseases, Department of Medicine, Emory University, Atlanta, Georgia, USADivision of Infectious Diseases, Department of Medicine, Emory University, Atlanta, Georgia, USAABSTRACT Staphylococcus aureus is a major cause of bacteremia and other hospital-acquired infections. The cell-wall active antibiotic vancomycin is commonly used to treat both methicillin-resistant (MRSA) and sensitive (MSSA) infections. Vancomycin intermediate S. aureus (VISA) variants can arise through de novo mutations. Here, we performed pilot experiments to develop a combined PCR/long-read sequencing-based method for detection of previously known VISA-causing mutations. Primers were designed to generate 10 amplicons covering 16 genes associated with the VISA phenotype. We sequenced amplicon pools as long reads with Oxford Nanopore adapter ligation on Flongle flow cells. We then detected mutations by mapping reads against a parental consensus or known reference sequence and comparing called variants against a database of known VISA mutations from laboratory selection. Each amplicon in the pool was sequenced to high (>1,000×) coverage, and no relationship was found between amplicon length and coverage. We also were able to detect the causative mutation (walK 646C>G) in a VISA mutant derived from the USA300 strain (N384-3 from parental strain N384). Mixing mutant (N384-3) and parental (N384) DNA at various ratios from 0 to 1 mutant suggested a mutation detection threshold of the average minor allele frequency (6.5%) at 95% confidence (two standard errors above mean mutation frequency). The study lays the groundwork for direct S. aureus antibiotic resistance genotype inference using rapid nanopore sequencing from clinical samples. IMPORTANCE Bacteremia mortality is known to increase rapidly with time after infection, making rapid diagnostics and treatment necessary. Successful treatment depends on correct administration of antibiotics based on knowledge of strain antibiotic susceptibility. Staphylococcus aureus is a major causative agent of bacteremia that is also commonly antibiotic resistant. In this work, we develop a method to accelerate detection of a complex, polygenic antibiotic resistance phenotype in S. aureus, vancomycin-intermediate resistance (VISA), through long-read genomic sequencing of amplicons representing genes most commonly mutated in VISA selection. This method both rapidly identifies VISA genotypes and incorporates the most comprehensive database of VISA genetic determinants known to date.https://journals.asm.org/doi/10.1128/spectrum.02728-22Staphylococcus aureusamplicon sequencingantibiotic resistanceclinical microbiologydiagnosticsgenomics
spellingShingle Abraham G. Moller
Robert A. Petit
Michelle H. Davis
Timothy D. Read
Development of an Amplicon Nanopore Sequencing Strategy for Detection of Mutations Conferring Intermediate Resistance to Vancomycin in Staphylococcus aureus Strains
Microbiology Spectrum
Staphylococcus aureus
amplicon sequencing
antibiotic resistance
clinical microbiology
diagnostics
genomics
title Development of an Amplicon Nanopore Sequencing Strategy for Detection of Mutations Conferring Intermediate Resistance to Vancomycin in Staphylococcus aureus Strains
title_full Development of an Amplicon Nanopore Sequencing Strategy for Detection of Mutations Conferring Intermediate Resistance to Vancomycin in Staphylococcus aureus Strains
title_fullStr Development of an Amplicon Nanopore Sequencing Strategy for Detection of Mutations Conferring Intermediate Resistance to Vancomycin in Staphylococcus aureus Strains
title_full_unstemmed Development of an Amplicon Nanopore Sequencing Strategy for Detection of Mutations Conferring Intermediate Resistance to Vancomycin in Staphylococcus aureus Strains
title_short Development of an Amplicon Nanopore Sequencing Strategy for Detection of Mutations Conferring Intermediate Resistance to Vancomycin in Staphylococcus aureus Strains
title_sort development of an amplicon nanopore sequencing strategy for detection of mutations conferring intermediate resistance to vancomycin in staphylococcus aureus strains
topic Staphylococcus aureus
amplicon sequencing
antibiotic resistance
clinical microbiology
diagnostics
genomics
url https://journals.asm.org/doi/10.1128/spectrum.02728-22
work_keys_str_mv AT abrahamgmoller developmentofanampliconnanoporesequencingstrategyfordetectionofmutationsconferringintermediateresistancetovancomycininstaphylococcusaureusstrains
AT robertapetit developmentofanampliconnanoporesequencingstrategyfordetectionofmutationsconferringintermediateresistancetovancomycininstaphylococcusaureusstrains
AT michellehdavis developmentofanampliconnanoporesequencingstrategyfordetectionofmutationsconferringintermediateresistancetovancomycininstaphylococcusaureusstrains
AT timothydread developmentofanampliconnanoporesequencingstrategyfordetectionofmutationsconferringintermediateresistancetovancomycininstaphylococcusaureusstrains