Whole-Genome Sequencing Can Identify MRSA Outbreaks
Sequencing allows construction of phylogenetic trees; provides data in clinically relevant time frame
WEDNESDAY, June 13 (HealthDay News) -- High throughput, whole-genome sequencing of methicillin-resistant Staphylococcus aureus (MRSA) isolates can provide important phylogenetic information in a clinically relevant time frame, according to a study published in the June 14 issue of the New England Journal of Medicine.
Claudio U. Köser, from the University of Cambridge in the United Kingdom, and colleagues used rapid, high-throughput sequencing technology to investigate a MRSA outbreak in a neonatal intensive care unit. Seven isolates associated with the outbreak and another seven MRSA isolates associated with carriage of MRSA or bacteremia in the same hospital were retrospectively sequenced with clinically relevant turnaround time.
Through construction of a phylogenetic tree using a reference genome (EMRSA-15 [sequence type 22]), the researchers found that there was a distinct cluster of outbreak isolates and a clear distinction between the cluster and the non-outbreak isolates. Two patients with bacteremia who were not part of the outbreak were identified as a previously missed transmission event. An artificial "resistome" of antibiotic-resistance genes was created and concordance was demonstrated between this resistome and the results of phenotypic susceptibility testing. A "toxome" was created based on toxin genes. One isolate from the outbreak cluster had a higher number of single nucleotide polymorphisms.
"We predict that whole-genome sequencing will become a standard tool for infection control and will provide the capability to monitor the spread and evolution of major pathogens both within and outside of hospitals in real time," the authors write.
Several authors disclosed financial ties to the pharmaceutical and biotechnology industries.