NGS Journal Club

Mette Voldby Larsen PhD, associate professor

DTU-SystemsBiology

Paper

A possible MRSA outbreak on a Special Care Baby Unit (SCBU) was analyzed using conventional methods.

Colonized patients from SCBU and MRSA isolates with the same antibiotic resistance profile from patients in other wards or from society were whole-genome sequenced.

What was done:

Antibiogram profiles

Red: ResistantWhite: Susceptible

Epidemiological map of 14 infants from SCBU

Possible outbreak?

Not the same antibiotics resistance profile – not the same outbreak

New case after cleaning?

Then they start sequencing…

A

Phylogenetic tree based on core snps

All ST2371

Antibiogram profiles

Red: Resistant

Green: Initially tested as susceptible, but re-testing shows it is resistant

White: Susceptible

Extended search

• MRSA isolates with similar antibiotic resistance profiles from other wards are sequenced (retro- and prospectively) = 19 isolates• Ten of these are also ST2371

Epidemiological map, incl. 10 cases outside the SCBU

154 employees are screened for MRSA – ONE is found positive for ST2371

Antibiogram profiles for the later cases

Epidemiological map, incl. 11 cases outside the SCBU and one employee.

Conclusion

• WGS performed better for identifying patients and citizens part of the outbreak

• Identification of the outbreak led to the investigation and the identification of a hospital employed carrier