[Clinical study on bacterial translocation in severe multiple trauma patients]

Abstract

Objective: To investigate bacterial translocation in severe multiple trauma patients using polymerase chain reaction (PCR) to detect the presence of bacteria in the blood.

Methods: Sixteen severe multiple trauma patients [injury severity score (ISS)>20] in surgery intensive care unit (SICU) were selected. Blood samples were collected 2, 24 and 48 hours after trauma for bacterial culture and microbial DNA detection. Meanwhile, plasma levels of D-lactate and lipopolysaccharide (LPS) in systemic circulation were determined. PCR was performed after DNA extraction, with target beta-lactosidase gene of E. coli and 16SrRNA gene of most pathogenic bacteria. All patients were observed within 30 days for infectious complications. D-lactate and LPS levels were determined in 63 patients before selective operation.

Results: Microbial DNA could be detected in blood as early as 2 hours following severe trauma, and altogether positive results were found in 10 patients (62.50%). All PCR-positive patients manifested sepsis, but none of the PCR-negative patients did (P<0.01). Bacterial DNA was discovered in 100.00% of sepsis patients and none in non-sepsis patients (P<0.01). Seventy percent of PCR-positive patients developed infectious complications, while none of PCR-negative patients did (P<0.01). The blood culture was positive only in 3 patients (18.75%), all of them were PCR-positive. E.coli DNA was found in 70.00% of all the PCR positive blood specimens. Systemic plasma concentration of D-lactate and LPS of all patients was significantly higher than that in control group, which consisted of 63 inpatients waiting for elective operations. Systemic plasma level of D-lactate showed a positive correlation with that of LPS (r=0.94, P<0.01).

Conclusion: Intestinal bacterial translocation (most commonly E. coli) might occur early (2 hours) after severe trauma. Infection and sepsis have a close relationship with bacterial translocation. Detection of blood microbial DNA using PCR could reflect bacteria translocation and forecast imminent infection and sepsis.