Indwelling arterial catheters as a source of nosocomial bacteremia. An outbreak caused by Flavobacterium Species.

Between mid-May and mid-October, 1973, 49 blood cultures from 14 patients in an intensive care unit were positive for flavobacterium species, Group II-b. We conducted an investigation to determine how patients were being infected with this unusual organism. Comparison of the 14 infected patients with 37 controls associated indwelling arterial catheters with subsequent flavobacterium bacteremia (p = 0.005). Risk of infection was greatest during the period in which blood gas determinations were done most frequently (the first three days of catheterization) and in which infected patients had more blood gas determinations than control patients with arterial catheters (p less than 0.05). Flavobacterium species was cultured from in-use arterial catheters, from stopcocks, and from ice in the intensive-care unit's ice machine; the catheters were probably contaminated by syringes that were cooled in ice before being used to obtain arterial specimens for blood gas determination. This outbreak calls attention to arterial monitoring systems as a potential source of nosocomial infection.