Objectives – We investigated for change in blood stream infections (BSI) with Enterobacterales, coagulase negative staphylococci (CoNS), Streptococcus pneumoniae, and Staphylococcus aureus during the first UK wave of SARS-CoV-2 across six London hospitals.

Methods – A retrospective multicentre ecological analysis was undertaken evaluating all blood cultures taken from adults from 01 April 2017 to 30 April 2020 across six acute hospitals in London. Linear trend analysis and ARIMA models allowing for seasonality were used to look for significant variation.

Results –119,584 blood cultures were included. At the height of the UK SARS-CoV-2 first wave in April 2020, Enterobacterales bacteraemias were at an historic low across two London trusts (63/3814, 1.65%), whilst CoNS were at an historic high (173/3814, 4.25%). This differed significantly for both Enterobacterales (p=0.013) and CoNS (p<0.01), when compared with prior periods, even allowing for seasonal variation. S. pneumoniae (p=0.631) and S. aureus (p=0.617) BSI did not vary significant throughout the study period.

Conclusions – Significantly fewer than expected Enterobacteriales BSI occurred during the UK peak of the COVID-19 pandemic; identifying potential causes, including potential unintended consequences of national self-isolation public health messaging, is essential. High rates of CoNS BSI, presumably representing contamination associated with increased use of personal protective equipment, may result in inappropriate antimicrobial use and indicates a clear area for intervention during further waves.