Table 2. Urokinase exposure attack rates, Ralstonia mannitolilytica bloodstream infection outbreak in haemodialysis patients with CVC, four hospitals in north-eastern Italy, January–April 2023 (n = 178).

Hospital	Exposed to urokinasea
	Cases	Total	AR (95% CI)
A	13	33	39% (22.9–57–4)
B	2	7	29% (3.7–71.0)
C	3	8	38% (8.5–75.6)
D	2	11	18% (2.3–51.8)
Overall	20	59	34% (22.1–47.4)

CI: confidence interval; AR: attack rate.

^a Urokinase exposure corresponds to ≥ 1 exposure events to contaminated or non-contaminated urokinase solution.

95% CI were calculated using exact methods.