FIGURE 1.

Schematic diagrams of some of the patient ties (connections) analyzed. Room numbers correspond to physical locations of rooms relative to one another (that is, room 1 is immediately next to room 2, whereas there are 3 rooms between rooms 1 and 5). Details of tie definitions are presented in the text. Pt indicates patient; RN, nurse. A, Black lines represent ties between patient 1 and 4 other patients who were in the NICU with patient 1. From the perspective of patient 1, patient 4 is a roommate, patient 2 is 1 room away, patient 5 is 2 rooms away, and patient 3 is >2 rooms away. B, Patients 2 and 3 are connected through a direct nursing connection (red circle). As a result, indirect nursing connections (dotted lines) exist between patient 3 and patients 1, 4, and 5, because they are all within 1 room of patient 2. C, The normalized group degree centrality in this diagram is 0.33, because only 1 of 3 possible direct nursing connections exists between MRSA-negative infants (yellow text) and ≥1 MRSA-positive infant (red text).