Import of multidrug-resistant bacteria from abroad through interhospital transfers, Finland, 2010–2019

The spread of antimicrobial resistance (AMR) is strongly associated with international travel: 20–80% of visitors to high-risk regions become colonised and carry multidrug-resistant (MDR) bacteria back to their home country. In high-income countries, rising background resistance and, particularly, import of MDR bacteria into hospitals from overseas is a concern.

Compared with infections by bacteria susceptible to antibiotics, infections by resistant bacteria are associated with greater mortality, longer hospitalisation and higher costs. Colonisation by MDR bacteria, such as extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE), carbapenemase-producing Enterobacteriaceae (CPE), meticillin-resistant Staphylococcus aureus (MRSA), MDR Acinetobacter species (MDRACI), MDR Pseudomonas aeruginosa (MDRPA) and vancomycin-resistant Enterococcus (VRE), often remains asymptomatic but increases the risk of developing an infection. Colonised individuals may spread bacteria to contacts and the broader environment. Recently, we showed that approximately half of all ESBL-PE imported by travellers carry either intestinal or extraintestinal/uropathogenic virulence genes.