Retrospective cohort study of Gram-negative bacteraemia shows transmission of hypervirulent Klebsiella pneumoniae in a UK Intensive Care Unit during the Covid-19 pandemic.

BACKGROUND

The National incidence of bloodstream infection (BSI) caused by Klebsiella Pneumoniae increased during the Covid-19 pandemic in the United Kingdom, whilst we observed an increase in BSI caused by Gram-negative bacteria in our adult Intensive Care Unit (ICU).

METHODS

We audited all Gram-negative bacterial BSIs between 13th April 2020 and 25th December 2021 in our ICU. In total, 41 organisms underwent antimicrobial susceptibility testing and genome sequencing. Notable organisms isolated included 16 Klebsiella spp., 4 E. coli, and 4 Pseudomonas spp.

RESULTS

Overall, we observed a low prevalence of multi-drug resistant (MDR) organisms causing BSI on our unit. A fifth (4/20) of E. coli and Klebsiella spp. isolates carried ESBL or AmpC genes and a single P. monteilli carried the IMP-1 gene. At least 3/16 (19%) BSI with Klebsiella spp. were likely associated with transmission between patients in nearby beds. These transmission events were associated with two hypervirulent K. pneumoniae (ST412 and ST86) and a K. aerogenes ∗002b. Half of all K. pneumoniae associated with BSI were hypervirulent, having K2 or K57 capsule type and the presence of iuc, iro, Rmp genes.

DISCUSSION: Hypervirulent K. pneumoniae is an emerging problem, capable of causing a severe, disseminated infection. We suggest risk factors for transmission may include shared equipment, environmental and PPE contamination, and failure of effective hand hygiene. With COVID-19 infection endemic, if SARS-CoV-2 patients require cohort nursing in bays with sessional use gowns, we recommend these are short-sleeved, to facilitate effective hand hygiene. We argue strict Infection Control policy, including enhanced cleaning, is critical to reduce transmission of hypervirulent K. pneumoniae and advocate for enhanced national surveillance systems.