Introduction: Twelve strains of meticillin-resistant Staphylococcus aureus (MRSA) isolated during a suspected outbreak in a paediatric intensive care unit were analysed by whole-genome sequencing (WGS).
Aim: To define the clonality of MRSA strains to a high discriminative power, and to evaluate the presence of genetic determinants responsible for antibiotic resistance and virulence.
Results: Ten out of 12 strains belonged to multi-locus sequence type ST2625, while the other two strains were ST8. Among the ST2625 strains, analysis based on 1126 genes showed that they were clonal, sharing more than 98.3% of allelic identities, and one strain was isolated from a healthcare worker. All ST2625 strains were characterized by the SCC-Mec cassette IVa, and resistoma analysis indicated correspondence between phenotypic and genotypic characteristics. The study of 63 genes associated with virulence was correlated with the pattern of clonality shown.
Conclusion: This analysis confirmed the occurrence of an outbreak. As such, standard infection control measures were strictly enforced, and this led to prompt termination of the outbreak.
Keywords: MRSA; Paediatric nosocomial infections; Resistoma; Staphylococcus aureus; Toxoma; Whole-genome sequencing.
Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.