Serratia bacteremia.

During a 6-yr period, 146 patients at our institution had Serratia bacteremia (3.8% of the total number of episodes of bacteremia), with an incidence of 1.24/1000 admitted patients. We chose a random group of 50 cases for clinical analysis in the present study. The disease was community-acquired in 8% of the cases and nosocomially-acquired in the remaining 92%. The bacteremia was unimicrobial in 84% and part of a polymicrobial bacteremia in 16% of the episodes. The most frequently isolated species of the Serratia genus was S. marcescens. Portals of entry, in decreasing order of frequency, were: urinary, unknown, respiratory, and surgical wound infections. Clinically, the most frequent finding was fever (100%). Shock occurred in 28% of the patients, and none of our cases showed evidence of disseminated intravascular coagulation. We found 62% of Serratia isolates resistant to gentamicin. Overall mortality was 38% and factors associated with a poor prognosis were: severity of the underlying disease, critical clinical situation at onset of bacteremia, presence in the intensive care unit (I.C.U.), occurrence of shock or polymicrobial bacteremia, portal of entry in the respiratory tract, and inadequate treatment.