Gram-Negative Sepsis (3)The distributions of Gram-negative isolates and associated mortality rates summarized by Young2 for 11 studies covering the period 1955 to 1986 are shown in Table 1. Our center was involved in a recent prospective study of the natural history of Gram-negative bacterial sepsis. This investigation was conducted during the period from early 1987 to mid-1988. A total of 266 patients meeting clinical criteria for sepsis received conventional treatment in 35 tertiary care centers. Rapidly fatal, ultimately fatal, and nonfatal conditions were present in 10 percent, 36 percent, and 54 percent of patients, respectively.

Gram-negative bacteria were isolated in 152 (67 percent) patients, all but one of whom received appropriate antibiotics based on minimum inhibitory concentrations (MICs). Cumulative mortalities at day 14 for patients with and without proven Gram-negative sepsis were 26 percent and 23 percent, respectively. The presence of disseminated intravascular coagulation (DIC) and adult respiratory distress syndrome (ARDS) were the variables most predictive of death by day 7. Although the increased incidence of Gram-negative sepsis has coincided with the expanded range and deployment of antimicrobial agents, it has also paralleled the introduction of medical and surgical advances that have produced new risk factors for its emergence.

Table 1—Distribution of Gram-Negative Bacteremic Isolates Excluding Polymicrobial Infections

Period of Observation E coli (%) Klebsiella Enterobacter Serratia P aeruginosa Proteus

species

Total Episodes/ Mortality (%)
1983-1986 63 9 34 129 (12)
1981-1983 38 8 23 83 (17)
1975-1977 76 (35)t 25 (48) 22 (72) 123 (39.8)
1968-1974 127 (38.6) 233 (31.8) 67 (35.8) 37 (32.4) 74 (68.9)* 30 (36.7) 568 (38.9)
1965-1974 189 (19.5) 74 (24.3) 47 (17.0) 11 (18.0) 60 (36.6) 49 (16.3) 430 (22.1)
1972-1973 86 (17.4) 37 (43.2) 4 (0) 30 (60) 14 (35.7) 171 (31.6)
1967-1972 68 (26.4) 72 (26.9) 35 (14.3) 8 (25) 29 (48.3) 11 (27.3) 233 (27.3)
1968-1969 58 (18) 23 (13) 9 (0) 27 (54) 21 (57)* 13 (16) 151 (27.8)
1965-1968 83 (21) 57 (33)* 45 (71) 19 (16) 204 (34.8)
1958-1966 190 (42) 138 (55)* 67 (67)* 63 (33) 458 (50.7)
1955-1967 93 (48) 68 (66)* 39 (77) 42 (67) 242 (61.2)
Usual rank order for frequency 1 2 45 3
Usual rank order for mortality 2 1