FIG. 1.

Weight monitoring as a surrogate for lung infections in young cystic fibrosis (CF) ferrets. The weights of kits were measured every 6 hr and were compared between paired CF and non-CF kits born to the same jill. (A) Typical patterns of total daily weight gain for CF kits (blue bars) and non-CF kits (red bars). (B) The rolling average 6-hr delta weight gain over a 24-hr period (calculated as the average of five measurements over a 24-hr period) is plotted for a CF (blue bars)/non-CF (red bars) pair. A decline in this rolling average indicated early lung infection (yellow shaded region), and thus a second antibiotic (Baytril) was applied (at arrowhead). (C) A second set of CF and non-CF animals reared on Zosyn from birth, given Baytril on day 12 because of weight loss in the CF animal, and then removed from Baytril on day 15. The CF animal succumbed to lung infection at 19 days. (D and E) Lung histology and bacterial colony-forming units (CFU) in lung lysates from the 19-day-old (D) non-CF control and (E) CF animal shown in (C). (A) and (B) are reproduced with permission from Sun et al.¹⁰⁵