Serratia marcescens as a postoperative pathogen

Serratia marcescens is becoming a frequent nosocomial pathogen. Portals of entry include indwelling intravenous or intraperitoneal polyethylene catheters, indwelling bladder catheters or urologic instrumentation, and inhalation therapy equipment. Twenty-four isolates were tested for in vitro susceptibility to nine antibiotics. The majority of the strains were nonpigmented and resistent to most antimicrobial agents except gentamicin, nalidixic acid, and chloramphenicol. Four cases are reported illustrating the severity of the disease, portals of entry, and response to therapy. Empirical therapy for systemic S marcescens infection should start with gentamicin.