The following statement(s) is/are true concerning gram-negative bacterial sepsis

c. Predisposing factors include old age, malnutrition, and immunosuppression

e. Polymicrobial sepsis is generally considered a more serious problem than sepsis due to a single organism

Gram-negative bacterial sepsis is a serious disease process that produces substantial morbidity and mortality in both normal and immunocompromised patients (10% to 20% and 30% lethality, respectively), despite therapeutic intervention with antimicrobial agents, aggressive hemodynamic monitoring, fluid resuscitation, and metabolic support. During the past several decades, nosocomial infections due to gram-negative pathogens have increased in frequency with resultant increase in the incidence of gram-negative bacteremia to between 3 and 13 cases per 1000 hospital admissions. Factors that predispose to these infections include: 1) underlying host disease processes such as malignancy, diabetes; 2) old age and disability; 3) malnutrition; 4) previous or concurrent antimicrobial antibiotic therapy; 5) major operations; 6) respiratory or urinary manipulation or intubation; and 7) immunosuppression. Although many different organisms cause this form of sepsis, E. coli predominates in overall frequency. Also common are isolates of Klebsiella, Enterobacter and Serratia; Pseudomonas bacteremia is less common. Some studies, however, have suggested that Pseudomonas sepsis is associated with the highest lethality. In several series, 10% to 20% of patients have had polymicrobial series, and most investigators agree that polymicrobial sepsis is more lethal than infection with a single organism.