Management of a cluster of invasive group A streptococcus infection in elderly patients linked to a district nursing team in the UK

Abstract

BackgroundGiven the associated high mortality rate, effective and prompt management of outbreaks of invasive group A streptococcus is essential. Between October, 2013, and April, 2014, five patients (aged 80–100 years) were admitted to local hospitals with severe cellulitis and laboratory confirmed invasive group A streptococcus infection. One patient died from septicaemia. Patients were living in their own home or care home at the time of disease onset. We describe the ensuing investigation by the local Health Protection Team. MethodsNotification of two cases of invasive group A streptococcus infection from the same area within 3 weeks triggered an investigation. Retrospective review identified a further two cases and a fifth was notified shortly after. As per present UK guidelines, household and health-care contacts (general practitioners and district nurses) were risk assessed and investigations into a possible common source initiated. FindingsFour cases were typed as emm st89.0 suggesting an epidemiological link. Results were not available for the index case. Investigations identified that all cases received care from the same district nursing team in the 7 days before onset of infection. No other common links were found. All members of the nursing team (n=10) were screened for group A streptococcus (throat swabs and any skin lesions) and given chemoprophylaxis. All results were culture negative. A detailed review of nursing contact identified that one nurse had contact with four of the five cases in the 7 days before onset. There were no further cases linked to the district nursing team after screening and chemoprophylaxis. InterpretationAlthough the review of nurse contacts suggests a link to the district nursing team, and one nurse in particular, this conclusion should be interpreted with caution because of a lack of microbiological evidence and the challenges of identifying all members of the team in contact with cases. Positive screening results can assist with targeting control measures, but a negative result cannot rule out an individual as the source of infection given the limitations of screening, particularly the potential for carriage of group A streptococcus from a non-screened site. FundingNone.