Hospital transmission of borderline oxacillin-resistant Staphylococcus aureus evaluated by whole-genome sequencing

Abstract

Introduction. Staphylococcus aureus is a major cause of hospital infections worldwide. Awareness towards methicillin-resistant S. aureus (MRSA) infections is high but attention towards borderline oxacillin-resistant S. aureus (BORSA) is limited, possibly due to an underestimated clinical relevance, presumption of low incidence and diagnostic limitations. Gap statement. BORSA surveillance has not been routinely implemented, and thus consensus with regard to a definition and infection control measures is lacking. Aim. Our goals were to investigate the occurrence, molecular characteristics and clinical manifestations of BORSA infections in the hospital setting. Methodology. Following an increased incidence in 2016, BORSA cases in 2014/2016 (in our institution) were more specifically evaluated. Medical records were reviewed to investigate epidemiological links, clinical characteristics and outcomes. Resistance and virulence markers were assessed by whole genome sequencing (WGS). Conventional methods: amplified fragment length polymorphism (AFLP) ; multilocus sequence typing (MLST) and multiple locus variable-number tandem repeat analysis (MLVA) were compared with core genome MLST (cgMLST) and whole-genome single nucleotide polymorphism (wgSNP) analysis to confirm genetic clusters. Results. From 2009 to 2013, BORSA comprised 0.1 % of all clinical S. aureus strains. In 2016, the incidence was six-fold higher in comparison to the baseline. Whole-genome SNP and cgMLST confirmed two BORSA clusters among patients with dermatological conditions. Patients with BORSA presented with skin infections, and one case developed a severe invasive infection with a fatal outcome. Infection control measures successfully prevented further transmission in both clusters. WGS findings showed that BORSA strains carried multiple resistance and virulence genes with increased pathogenic potential. Conclusion. WGS and cgMLST effectively characterized and confirmed BORSA clusters among at-risk patients with clinical manifestations ranging from mild skin infections to life-threatening bacteraemia. Clinical awareness and active monitoring are therefore warranted for the timely implementation of infection control measures to prevent BORSA transmission in high-risk patients.

Progress in the Prevalence, Classification and Drug Resistance Mechanisms of Methicillin-Resistant Staphylococcus aureus

“…However, there is a lack of surveillance for BORSA, and the prevalence, epidemic typing and infection control measures of BORSA are unknown ( Table 2 ). 53 …”

From Hospital to Community: Exploring Antibiotic Resistance and Genes Associated with Virulence Factor Diversity of Coagulase-Positive Staphylococci

“…The lower overall selective pressure from antibiotic use in the community may result in a lower prevalence of resistant strains. While specific data on oxacillin consumption in hospitals and the community were not directly assessed in this study, it is plausible that the higher resistance to oxacillin in hospitals is associated with higher antibiotic consumption in those settings [32,37]. However, further studies specifically investigating the antibiotic consumption patterns and their impact on resistance development are needed to establish a direct relationship.…”

Characteristics of Virulent ST5-SCCmec II Methicillin-Resistant Staphylococcus aureus Prevalent in a Surgery Ward

“…aureus is a key pathogen of nosocomial infection, especially MRSA, which poses a great challenge to health due to its multidrug resistance, prevalence and refractoriness. [17][18][19][20][21][22][23] Staphylococcus aureus is the most common pathogen causing surgical site infections (SSIs). 24 MRSA can survive for a long time in nature, increasing the risk of nosocomial infection of patients undergoing complex surgical procedures.…”