P1775 Low frequency of intestinal colonisation with multidrug-resistant Enterobacteriaceae in Swiss military deployed to Kosovo Esther Kuenzli*1,2, Thomas Büdel3, Mathieu Clement3,4, Odette J Bernasconi3,4, Patricia Schlagenhauf1, Peter Florek5, Nejla Gueltekin6, Markus Hilty3, Christoph Hatz1,2, andrea Endimiani3

1 Epidemiology, Biostatistics and Prevention Institute, University of Zürich, Zürich, , 2 Swiss Tropical and Public Health Institute, Basel, Switzerland, 3 Institute for Infectious Diseases, University of Bern, Bern, Switzerland, 4 Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland, 5 Armed Forces International Command SWISSINT, -Oberdorf, Switzerland, 6 Centre of Competence for Military and Disaster Medicine, Federal Department of Defence, Civil Protection and Sport DDPS, , Ittigen, Switzerland Background: Travelers visiting certain areas abroad can remain colonized at gut level with extended-spectrum cephalosporin- (ESC-R) and/or colistin-resistant (COL-R) Enterobacteriaceae (Ent). This can contribute to the importation of these pathogens to countries with a low prevalence of multidrug-resistant (MDR) bacteria. Military personnel deployed to high-risk geographic areas may present the same colonization phenomenon as travelers. However, data regarding this specific population are scarce. Materials/methods: Swiss military personnel deployed to Kosovo provided stool samples before and after their 6-month period of service (November - April, 2018) and completed epidemiological questionnaires at the same times. After overnight enrichment of stools in LB broth, aliquots were plated on ChromID ESBL/Carba or CHROMagar Orientation plus COL and incubated overnight. Identification of resistant colonies was achieved using the MALDI-TOF MS. MICs were obtained implementing the Sensititre GNX2F plates and interpreted using the EUCAST-2018. Microarray CT103XL and whole genome sequencing (Illumina/MinION) were used to characterize strains. Results: We enrolled 35 Swiss military personnel. Before leaving Switzerland, only one subject (#1) was colonized at intestinal level with two ESC-R E. coli strains (a new ST CTX-M-15 producer and an ST636 CTX-M-14 producer). Moreover, one person (#25) was colonized with a COL-R E. coli (fully susceptible to ESCs) of ST69 and carrying a mcr-1.2-IncX4 plasmid. Another subject (#26) carried a non-ESC-R but COL-R E. coli with amino acid substitutions in PmrA/B. We have screened the post-service stools of 21 deployed personnel (not including #1, #25, and #26). Three of them (14.3%) returned colonized with fluoroquinolone-susceptible CTX-M-15-producing E. coli strains of which two co-carried the qnrS1 gene; no carriers of COL-R-Ent were identified. Conclusions: This is the first study investigating the intestinal prevalence of ESC-/COL-R-Ent in Swiss military deployed to Kosovo. Our data seem to indicate that the frequency of returning military personnel colonized with MDR bacteria is low and does not reflect observations in travelers returning from other regions. This is most probably due to the fact that military personnel deployed to a foreign country stay more segregated, not least in their eating conditions, from the local population than travelers.

29TH ECCMID 13-16 APRIL 2019 AMSTERDAM, NETHERLANDS POWERED BY M-ANAGE.COM