Genes qac as a possible selection factor for multiresistant Staphylococcus aureus

RAGO L; VIELMA VALLENILLA J; HAIM MS; MOLLERACH M; DI GREGORIO S

Cambridge

Conferencia; Applied Bioinformatics & Public Health Microbiology 2023; 2023

Wellcome Connecting Science Conferences

Introduction: S. aureus is a relevant pathogen worldwide causing multiple pathologies relatedto high morbidity and mortality. The presence of antimicrobial resistance genes on mobilegenetic elements spreading across S. aureus is an important public health concern. Antisepticresistance has been related with the presence of plasmidic qac genes, and for this reason theycan be transferred together with antibiotics resistance determinants.Objective: We aimed to evaluate the relationship between carrying qac genes and theantimicrobial resistance in S. aureus strains from South America.Materials and methods: We studied 404 S. aureus strains isolated from blood cultures in 57South American hospitals during 2019. Genomic DNA was extracted and sequenced usingIllumina HiSeq platform. Quality control of reads and the novo assemblies was performed withGHRU pipelines (https://gitlab.com/cgps/ghru/pipelines). Detection of rep genes, AMR andantiseptic resistance determinants was carried out with ARIBA v.2.14.6 using plasmidfinder,NCBI/pointfinder and an in-house database including qac reference sequences (qacA/B,qacC/smr, qacE, qacF, qacG, qacH, qacJ and qacZ).Results: The qac genes were detected in 13.4% (54/404) of genomes: qacC/smr (47/54, 87%),qacJ (5/54, 9.2%), qacA (1/54, 1.9%) and qacG (1/54, 1.9%), and the remaining 350 were qac-.High proportion of strains with qacC harboured rep13 (44/47) but also rep16 (21/47) and rep19(17/47). Most qac+ strains were MRSA (63%, 34/54, Fisher's Exact test, p=0.001,). Moreover,74% (40/54) of qac+ strains carried 4 or more AMR determinants, while only 32% (113/350) ofthe qac- strains carried 4 or more AMR determinants (Fisher's Exact Test, p