Eurosurveillance - Volume 24, Issue 38, 19 September 2019

Two epidemiologically-unrelated clusters of Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae were detected among several healthcare facilities (HCF) in Finland by routine surveillance using whole genome sequencing (WGS).

The objective was to investigate transmission chains to stop further spread of the responsible strain.

In this observational retrospective study, cases were defined as patients with K. pneumoniae KPC-3 sequence type (ST)512 strain detected in Finland from August 2013 to May 2018. Environmental specimens were obtained from surfaces, sinks and toilets in affected wards. WGS was performed on K. pneumoniae cultures using Illumina MiSeq platform and data were analysed using Ridom SeqShere software K. pneumoniae core genome multilocus sequence typing (cgMLST) scheme. Epidemiological information of the cases was provided by HCFs.

We identified 20 cases in six HCFs: cluster 1 included 18 cases in five HCFs and cluster 2 two cases in one HCF. In cluster 1, a link with a foreign country was unclear, 6/18 cases without overlapping stay had occupied the same room in one of the five HCFs within > 3 years. In cluster 2, the index case was transferred from abroad, both cases occupied the same room 8 months apart. A strain identical to that of the two cases in cgMLST was isolated from the toilet of the room, suggesting a clonal origin.

The clusters were mostly related to case transfer between facilities and likely involved environmental transmission. We show that CPE surveillance using WGS and collaboration between hospitals are crucial to identify clusters and trace transmission chains.

In 2015, there was an increase in the number of asylum seekers arriving in Europe. Like in other countries, deciding screening priorities for tuberculosis (TB) and meticillin-resistant Staphylococcus aureus (MRSA) was a challenge. At least five of 428 municipalities chose to screen asylum seekers for MRSA before TB; the Norwegian Institute for Public Health advised against this.

To evaluate the MRSA/TB screening results from 2014 to 2016 and create a generalised framework for screening prioritisation in Norway through simulation modelling.

This is a register-based cohort study of asylum seekers using data from the Norwegian Surveillance System for Communicable Diseases from 2014 to 2016. We used survey data from municipalities that screened all asylum seekers for MRSA and denominator data from the Directorate of Immigration. A comparative risk assessment model was built to investigate the outcomes of prioritising between TB and MRSA in screening regimes.

Of 46,090 asylum seekers, 137 (0.30%) were diagnosed with active TB (notification rate: 300/100,000 person-years). In the municipalities that screened all asylum seekers for MRSA, 13 of 1,768 (0.74%) were found to be infected with MRSA. The model estimated that screening for MRSA would prevent eight MRSA infections while prioritising TB screening would prevent 24 cases of active TB and one death.

Our findings support the decision to advise against screening for MRSA before TB among newly arrived asylum seekers. The model was an effective tool for comparing screening priorities and can be applied to other scenarios in other countries.