Active surveillance cultures in critically ill patients: pathogens, patterns, and correlation with eventual bloodstream infections.

BACKGROUND

The role of routine active surveillance cultures (ASCs) in predicting consequent bloodstream infections is unclear.

OBJECTIVES

To determine prospectively whether routine screening ASCs obtained on admission to the intensive care unit (ICU) can predict the causative agent of subsequent bloodstream infections.

METHODS

We prospectively studied a cohort of 100 mechanically ventilated patients admitted consecutively to a 16-bed ICU. On admission, ASCs were obtained from four sites: skin cultures (swabs) from the axillary region, rectal swabs, nasal swabs, and deep tracheal aspirates. Thereafter, cultures were obtained from all four sites daily for the next 5 days of the ICU stay.

RESULTS

Of the 100 recruited patients 31 (31%) had culture-proven bacteremia; the median time to development of bacteremia was 5 days (range 1-18). Patients with bacteremia had a longer median ICU stay than patients without bacteremia: 14 days (range 2-45) vs. 5 days (1-41) (P < 0.001). ICU and 28 day mortality were similar in patients with and without bacteremia. Most ASCs grew multiple organisms. However, there was no association between pathogens growing on ASCs and eventual development of bacteremia.

CONCLUSIONS

ASCs obtained on ICU admission did not identify the causative agents of most subsequent bacteremia events. Therefore, bloodstream infections could not be related to ASCs.