Annette Westgeest

88 Chapter 5 Table 1 Baseline and treatment characteristics Characteristic Treatment failure Successful decolonization P n = 12 n = 44 Sex, male (n (%)) 6 (50.0) 25 (56.8) 0.75 Age (median (IQR)) 23.5 (23) 35.5 (41) 0.11 Complicated carriage 11 (91.7) 33 (75.0) 1.00 Uncomplicated carriage 1 (8.3) 3 (6.8) 1.00 MRSA infection, no subsequent carriage 0 8 (18.2) n.a MRSA infection (n (%)) 3 (25.0) 18 (41.9) 0.34 Treatment regimen (n (%))* 0.24 Rifampicin + doxycycline 3/11 (27.3) 9/23 (39.1) Rifampicin + cotrimoxazole 4/11 (36.4) 7/23 (30.4) Rifampicin + trimethoprim 4/11 (36.4) 3/23 (13.0) Rifampicin + clindamycin 0 3/23 (13.0) Vancomycin + clindamycin 0 1/23 (4.3) Treatment duration (n (%))* 7-day treatment 10/11 (90.9) 19/23 (82.6) 1.00 14-day treatment 1/11 (9.1) 4/23 (17.4) 1.00 *This percentage represents the percentage of the patients who were treated with systemic antibiotics. Patients with uncomplicated carriage, MRSA infection without subsequent carriage, or spontaneous decolonization were not treated with systemic antibiotics n.a. not applicable Lineages Among the 56 MRSA isolates, 24 different MLST types were represented. The most predominant MLST types were ST5 (8/56) and ST22 (8/56), followed by ST8 (5/56) and ST398 (5/56) (Figure 2 and Table S1). The complex types were mostly unique, only seven complex types were represented twice (2615, 4940, 6749, 9359, 10,282, 17,413, 24,737). All isolates (n =7) with livestock-associated Spa-types belonged to clonal complex 398. The non-livestock-associated MLST types ST1 (2/3), ST97 t2770 (2/2), ST6627 (1/1), and ST7119 (1/1) were more frequently or exclusively found in the failure group. In contrast, isolates of patients with successful decolonization predominantly belonged to community-associated lineages ST6-t304 (4/4), ST8-t008 (5/5), and the livestock-associated clonal cluster 398 (7/7) (Figure 2). Figure 2 (next page). Phylogenetic tree of MRSA isolates. Neighbor-joining tree from SeqSphere software based on curated schema where comparison of 1861 core genes of S. aureus was used. The study isolates from patients who failed on eradication treatment are presented in blue, and from patients with successful decolonization in pink. The corresponding isolate antibiotic susceptibility profiles are shown in supplementary table S1

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