[Analysis of clinical characteristics of bloodstream infection in patients with immune function inhibition]

To analyze the clinical characteristics of bloodstream infection in patients with immune function inhibition.

A retrospective analysis was conducted. 234 patients with bloodstream infection admitted to intensive care unit (ICU) of the Affiliated Drum Tower Hospital of Nanjing University Medical School from August 1st in 2015 to December 31st in 2017 were enrolled. According to the immune function on the day of bloodstream infection, they were divided into normal immune function group [human leukocyte antigen DR (HLA-DR) > 30%, n = 144] and immunosuppression group (HLA-DR ≤ 30%, n = 90). The gender, age, primary disease, complication, acute physiology and chronic health evaluation II (APACHE II) with 24 hours after ICU admission, sequential organ failure assessment (SOFA) score, etiology, infection parameters on the day of bloodstream infection [peak temperature, white blood count (WBC), neutrophils ratio, procalcitonin (PCT), and C-reactive protein (CRP)] and prognosis parameters (bacterial clearance time, the length of ICU and hospital stay, 28-day mortality) between the two groups were analyzed.

234 patients were enrolled in the final analysis, including 132 males and 102 females, with an average age of (60.5±18.4) years old. Severe pneumonia and abdominal infection were the main causes of primary diseases. There was no significant difference in gender composition, age, APACHE II, SOFA score, other complications and primary morbidity between the two groups except that the proportion of malignant tumors in the immunosuppressive group was higher than that in the normal immune function group [43.3% (39/90) vs. 41.7% (60/144), P < 0.05]. Compared with the normal immune function group, the Gram-positive cocci infection rate in the immunosuppressive group was significantly lowered [40.0% (36/90) vs. 56.2% (81/144)], Gram-negative bacilli infection rate [50.0% (45/90) vs. 39.6% (57/144)] and fungus infection rate [10.0% (9/90) vs. 4.2% (6/144)] were significantly increased (both P < 0.05). The levels of WBC, neutrophils ratio, and PCT on the day of bloodstream infection in the immunosuppressive group were significantly lower than those of normal immune function group [WBC (×10⁹/L): 10.2±2.1 vs. 13.5±3.6, neutrophils ratio: 0.87±0.17 vs. 0.96±0.22, PCT (μg/L): 1.3±1.1 vs. 4.7±2.1, all P < 0.05], but no significant difference in the peak temperature (centigrade: 38.5±1.7 vs. 38.9±1.3) or CRP (mg/L: 134.0±42.6 vs. 164.0±55.8) was found as compared with normal immune function group (both P > 0.05). Compared with the normal immune function group, the bacterial clearance time in the immunosuppressive group was significantly prolonged (days: 16.0±10.1 vs. 12.3±4.7), 28-day mortality was significantly increased [61.1% (55/90) vs. 44.4% (64/144)] with statistical significances (both P < 0.05), but no significance was found in the length of ICU stay (days: 21.0±17.1 vs. 18.7±10.4) or the length of hospital stay (days: 36.0±28.1 vs. 33.8±16.8, both P > 0.05).

Gram-negative bacilli was the main pathogen of bloodstream infection in immunosuppressive patients, and the fungal infection rate was high, inflammation reaction was not obvious, bacterial clearance time was long, and prognosis was poor.