Septicemia due to Aeromonas hydrophila: clinical and immunologic aspects.

Abstract

Over a 32-month period, nine patients treated for neoplastic disease at Memorial Sloan-Kettering Cancer Center developed septicemia caused by Aeromonas hydrophila. Five patients had skin lesions associated with onset of infection; in two patients these lesions were indistinguishable from ecthyma gangrenosum, the skin lesion classically associated with infection due to Pseudomonas aeruginosa. Invitro studies indicate that, like P. aeruginosa, invasive strains of A. hydrophila are resistant to the bactericidal action of normal serum. Recovery from infection was associated with high titers of serum opsonins against A. hydrophila; and fatal infection, with negligible opsonizing activity. A. hydrophila is an increasing cause of nosocomial septicemia in immunologically compromised hosts, and the clinical features of A. hydrophila septicemia resemble those of systemic P. aeruginosa infection. Several recent reports have detailed the bacteriologic, clinical, and epidemiologic evidence for the role of Aeromonas hydrophila in human infections [1-3]. The majority of specimens from which this organism was isolated, however, contained other bacteria, thereby raising questions about the pathogenic significance of A. hydrophila. At Memorial Hospital, the clinical unit of the Memorial Sloan-Kettering Cancer Center, nine cases of septicemia due to A. hydrophila were observed in the 32-month period between October 1969 and May 1972. This number exceeded that of cases of septicemia caused by either Serratia marcescens or Erwinia species for the same period. This report will focus on the clinical and immunologic aspects of these cases. The availability of serum from two cases of fatal infection and one patient convalescing from infection has permitted specific assessment of bactericidins and opsonins in relation to the clinical course of these patients.