Whole genome sequencing in the investigation of recurrent invasive Group A streptococcus outbreaks in a maternity unit

Dickinson, Harriet, Reacher, Mark, Nazareth, Bernadette, Eagle, Heidi, Fowler, Deirdre, Underwood, Anthony, Chand, Meera, Chalker, Victoria, Coelho, Juliana, Daniel, Roger, Kapatai, Georgia, Al-Shabib, Ali and Puleston, Richard (2018) Whole genome sequencing in the investigation of recurrent invasive Group A streptococcus outbreaks in a maternity unit. Journal of Hospital Infection . ISSN 1532-2939 (In Press)

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Background: The clinical manifestations of Group A streptococcus (GAS) – (Streptococcus pyogenes) are diverse, ranging from asymptomatic colonisation to devastating invasive disease. Maternity related clusters of invasive Group A streptococcus (iGAS) infection are complex to investigate and control, especially if recurrent.

Aim: We report on the investigation into three episodes of emm 75 GAS/iGAS infection in maternity patients at one hospital site over a 4 year period, two with monophyletic ancestry.

Methods: The episodes are described, together with whole genome sequence isolate analyses. Single nucleotide polymorphism differences were compared with contemporaneous emm 75 genomes.

Findings: Seven mothers had GAS/iGAS in over a 4 year period, emm 75, S.pyogenes and one had iGAS (in year 4) emm 3, S.pyogenes (subsequently discounted as linked). Three (clinical/screening samples) of the seven babies of emm 75 positive mothers and 3 screened healthcare workers were positive for GAS emm 75. Whole genome sequence similarity suggests a shared ancestral lineage and suggested a common source transmission but directionality of transmission cannot be inferred. However the findings indicate that persistence of a particular clone in a given setting may be long-term.

Conclusions: Occupational health procedures were enhanced, staff were screened and antibiotic therapy provided to GAS positive staff and patients. The definitive source of infection could not be identified, although staff/patient transmission is the most likely route. The pattern of clonal GAS transmission over 4 years suggests long-term persistence of GAS may have occurred.

Item Type: Article
Keywords: iGAS, Streptococcus, maternity, whole genome sequencing
Schools/Departments: University of Nottingham, UK > Faculty of Medicine and Health Sciences > School of Medicine > Division of Epidemiology and Public Health
Identification Number: https://doi.org/10.1016/j.jhin.2018.03.018
Depositing User: Claringburn, Tara
Date Deposited: 17 Apr 2018 09:52
Last Modified: 22 Mar 2019 04:30
URI: https://eprints.nottingham.ac.uk/id/eprint/51180

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