Proportion of asylum seekers carrying multi-drug resistant microorganisms is persistently increased after arrival in the Netherlands.

Background: Several studies have shown a high prevalence of multi-drug resistant organisms (MDRO) amongst asylum seekers when compared to the general population. The aim of this study is to assess the duration of MDRO carriage in this population.

Methods: Data were retrospectively collected between January 1st 2014 through December 31st 2016. Study material included screening samples for MDRO carriage and clinical samples from asylum seekers in need of medical care. The study focused on methicillin-resistant Staphylococcus aureus (MRSA) and multi-drug resistant Enterobacteriaceae (MDRE). The rates of MRSA and MDRE detected were calculated every four weeks after arrival in the Netherlands.

Results: Samples from 2091 asylum seekers were included. 1270 (60.7%) were female, median age was 26 years (IQR 20-34) and median number of days in the Netherlands until first sample was 67 (IQR 4-235). In the patients' first obtained samples, the rate of MRSA varied between 4.5 and 13.0% per time interval after arrival. The rate of MDRE fluctuated between 7.4% and 25.0%. No particular decline in positivity rates in first obtained samples was observed after arrival in the Netherlands. In the group of asylum seekers who arrived more than one year ago, MRSA was isolated in a percentage of 5.1% ( n  = 273, median months after arrival 34.1 (IQR 16.5-63.1)) and MDRE in 9.4% ( n  = 276, median months after arrival 35.4 (IQR 17-65)).

Conclusion: To our knowledge, this is the first study demonstrating that carriage rate of MDRO in asylum seekers remains high even after prolonged stay in the Netherlands. Longitudinal data on MDRO carriage after arrival in countries with a low MDRO prevalence are needed to determine optimal screening strategies, infection control measures and empirical antibiotic therapy.